HFGH Polycarb Panels failing!

laserfan(Zone 8b)April 30, 2008

OK mudhouse (Sheri) and I have been discussing problems with the twinwall polycarb panels and it's time to make a new thread about it.

This spring I noticed several small holes in the roof panels, smaller than dime-size, in my just-one-year-old-10x12HFGH.

To which mudhouse replied:

I'm really disheartened by this...I'm worrying about the panels being manufactured in a defective manner...I have had a lurking concern that IF there is a panel deterioration problem, it may be heat related...I note that the three mentions of this problem so far (the Tucson person, yours, and Jamesy40's) have all happened in southern states.

Then I said:

Sheri we are in sunny So. Central Texas--yes it gets hot here, but frankly I suspect UV as the culprit. If you have looked at all at other types of plastic panels (that you get at Home Depot or Lowes) these typically have a side that is "UV protected" somehow, and they even state that if the panel is used in such a manner that the underside is exposed to light, that these can fail as well. Couple thoughts:

1. We should start a new thread!? OK I HAVE!

2. The holes are small and on one side only (so far) and limited to a single "channel" of the polycarb. Time to do something!

3. Given we are in the Sunny South and our GHs are overexposed to sun as it is, we should consider painting the roof.

4. There's a product out for GHs that apparently changes color; white-to-clear-and-back or some such magic. Prolly way expensive.

Gotta start researching what kind of paint(s) might adhere to the polycarb. Then my thought is to flip my damaged panels over and paint the good sides. Heck, even in the dead of winter the sun drives inside temps to >100 around here--we could use the extra shade that paint might provide (roof only I'm thinking, for now).

Need some feedback from anyone who's tried to paint their polycarb!!!

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Thanks for starting this, Laserfan! If this is going to be a problem that begins to surface for some of us, I'm glad to have a discussion of it all in one place.

Just to put all the info here...Laserfan's recent post in another thread made me remember these recent threads by Jamesy40 (in Arkansas) who also reported the development of small holes in his HFGH panels (in the second year.)
holes developing on south side HFGH panels
HFGH panels are deteriorating
HFGH panels destroyed by hail

Also, I referenced a post I read in another forum last year, from a C&S collector in Tucson, AZ who used the poly panels from two 6x8 HFGH kits to complete his wood framed greenhouse. After the second year he briefly mentioned that the roof panels had become so brittle they were breaking. I don't believe this collector uses his GH in the summer, so I figured his roof panels must have been subjected to extreme temps (110° outside, so imagine the temps in an uncooled GH in Tucson, especially at roof height...) Until Jamesy40 and Laserfan's posts, this was the only reference I'd seen anywhere about HFGH panel problems.

I wonder if Harbor Freight has any record of similar complaints? In my experience companies usually need to receive a huge number of similar complaints before they acknowledge it as a "known problem", and I suspect it's too early for that.

I've read enough comments here to know that some kits vary from others (some have missing parts, some have roof panels not quite long enough to extend over the gutters, etc.) I'm also wondering if this is consistent throughout all HFGH poly panels...or if some folks are just drawing "lucky" straws.

Laserfan, that's a really interesting thought about the paint...will go do some research to see what I can find. I've been thinking about ordering 60 or 70% shadecloth for my roof (I think I really muffed it when I ordered 40%) so you're right, a little less light through my roof would not bother me a bit.

I gave my roof a visual inspection yesterday, and I can't see any trouble yet, but if it is heat or UV related, my problems will surely surface before much more time goes by. I'd rather be ready than caught off guard, and I appreciate your posts!

    Bookmark   April 30, 2008 at 12:08PM
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Does not go into detail as to what types of coverings it can be used on.

Here is a link that might be useful: shade paint

    Bookmark   April 30, 2008 at 12:31PM
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laserfan(Zone 8b)

Thanks for the link cactusfreak--that's what I was afraid of though; $100 and up, and it's guaranteed to wash off!!!???!!! I think I'll pass. This polycarb is so "shiny" and smooth though I do wonder if any paint, even that Krylon that's meant for plastics, will work on it.

I had another (probably useless) thought today: the polycarb sheets arrived with a thin film of protective plastic IIRC. I wonder if that film was meant to ID a UV-protected side. Probably not... and if this were true we'd probably notice a visual difference on some of our panels (50% maybe! I sure didn't pay attention to "this side up" nor do the instructions say anything about this).

I took one panel off the roof the other day and power-washed it. It was plenty dirty but even after washing there's a noticeable yellowing that's occurred.

BTW as a data point--we had an exceptionally rainy (thus more clouds than usual) summer last year. This year is severe drought again (

    Bookmark   April 30, 2008 at 5:55PM
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When the polycarb panels for my Cross Country arrived, they also had a protective film on one side and per instructions, they were most definately the UV coated side.

If the panels for the HFGH's are also protected in that manner, logic would seem to dictate the same would apply to them, so could some of the damage problems being reported be a result of the panels being installed with the unprotected side exposed to the elements?

    Bookmark   April 30, 2008 at 6:17PM
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birdwidow is completely correct. The protective film identifies the UV protected side of the panel. If installed reversed, the premature U.V. caused breakdown would be noticible in a relatively short time.

    Bookmark   April 30, 2008 at 7:25PM
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I find it strange that the poly carb pinholes. If uv protection breaking down was the cause i would guess the result would be fairly widespread damage across the panel rather than just small holes.

Chemicals have been mentioned as possible causes and seems more in line with the holes. Plain old water droplets can act as magnifying lenses to direct sunlight and although its highly improbable they would survive long enough in fierce sunshine to cause damage..it would account for the small holes.

Figuring out the cause is the hard part :)

    Bookmark   April 30, 2008 at 8:20PM
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Laserfan, are you sure your poly panels only came with plastic on one side? Our HFGH poly panels all had plastic on both sides, and I remember posts here saying that Harbor Freight (when asked) says that both sides of the poly panels are UV protected, and there is no "right" or "wrong" way to install them. (Don't have that link, will go see if I can find it.)

The yellowing doesn't sound good like a good sign. I sure wish we knew what was going on here.

    Bookmark   April 30, 2008 at 8:55PM
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OK, here's a thread including a post from Gardenerwantabe stating that the HFGH poly panels have UV coating on both sides:
Which side of panel has UV coating?

And in this (long 2005) thread, tdev riverbend says: "Oranjelo: This forum researched a year or so ago which side was UV coated and Harbor Freight said both sides are, so it doesn't matter how you install the panels."
Harbor Freight Club

As Laserfan says, the manual doesn't mention the issue at all, although it does say to "remove the protective film from both sides of the panels"...so I'm thinking that's not the cause here.

    Bookmark   April 30, 2008 at 9:12PM
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C Schaffner

It looks like these have been out since at least 2004. Maybe someone who has had one since then will chime in here. It looks like most of the origional Harbor Freight Club posters don't post any longer.

    Bookmark   May 1, 2008 at 9:52AM
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laserfan(Zone 8b)

OK y'all have reminded me that my panels indeed did have protective film on both sides (an awful lot of film was thrown away!) so the question remains "what's causing the little holes" and until someone gives a better answer UV is what I'm going with as the likely cause. Heck, I've seen so many things "yellow" hopelessly over the years I know how destructive it can be, and who knows maybe we have just a huge hole in the ozone layer over our ranch!!! ;-)

Now, maybe it's too early to panic, since I only have 3 or 4 of these 1/4"-size holes (that I have spotted, I haven't done a full inspection yet, too sunny here--I'd be blinded!) but it occurred to me yesterday that we used a material on a flat roof some years ago called Snow Roof, so I am trying some of this leftover material on a scrap of polycarb. It's pure white, the effect (so far that I can see) is of converting the panels to translucent white like you find in those corrugated "polysun" panels at Home Depot. But the application results in a coating that is not uniformly, purely white. Brush strokes of course.

But I have done a piece with one coat, and part with two coats, and tomorrow or Saturday (when I think it's "cured") I will put a garden hose to it. If it doesn't come-off, I will put my pressure washer to it. If THAT doesn't come off, then "the Boss" (my wife) will have to decide whether to Snow Roof at least the roof and possibly the South wall of our 10x12 HFGH. The flat (house) roof we did, and the inside of a gutter associated with it, remain perfectly white after 3 or 4 summers so I know the material stands-up well. But will it adhere. It's less than $20/gallon and I'm certain would cover the whole bloody GH twice-over if need be...

The HFGH has been a wonderfully inexpensive way to get into GH'ing, but at the same time if it self-destructs in less than 5 years that would not make me/us very happy...

    Bookmark   May 1, 2008 at 4:01PM
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laserfan(Zone 8b)

Oops, I was wrong--time to panic. One half of the roof has a couple holes per panel/vent! Maybe a dozen total! What's curious is, the other side has only 2 or 3 holes that I can see, and that side gets more sun I believe (morning & early afternoon sun). Maybe because of our elevation, there are usually clouds in the a.m. (we're in 'em) and dew on the roof and so it cools this "a.m. side roof" for the early part of the day. Note: I did not find any holes in the (vertical) walls.
But the "p.m. roof" is definitely in bad shape. I hope the Snow Roof stuff adheres, that would be a cheap & reasonably attractive solution I think.

BTW we are at 30 degrees north latitude here. I don't think you (sad, unfortunate) Northerners need worry quite as much... :D

    Bookmark   May 1, 2008 at 4:29PM
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slaphead(z8 WA)

We've had our HFG for 4 years now and the panels have not yellowed or pin holed. The Seattle area certainly isn't the sunniest location but we do have generally sunny weather from Late June through September. Considering the time span of HFG production it is entirely possible several different manufacturers of the polycarbonate panels have been used over the years with some variation in quality. It might be worth starting a survey to determine what percentage of the HFGs out there for longer than a couple of years have developed this problem and when they were purchased.

Just my 2 cents worth,


    Bookmark   May 3, 2008 at 5:39PM
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""Our HFGH poly panels all had plastic on both sides, and I remember posts here saying that Harbor Freight (when asked) says that both sides of the poly panels are UV protected, and there is no "right" or "wrong" way to install them"".

Both sides of some polycarbonate panels are covered with protective plastic (polyethylene)film,which should be peeled away.The side with the blue or labeled film is the UV-resistant side, and the panel has to be installed so that this side faces outside. Other than a reported call to a HFGH rep. , there is no evidence HFGH panels are treated on both sides. Neither the HFGH web site nor the manual for the gh makes any claim that both sides are treated. The manual only says "remove the protective film from both sides". In looking at many manufacturer sites, none state that standard polycarbonate panels are UV treated on both sides.

Also, " Avoid the use of chlorine, copper or sulfur based products around plastic, as these chemicals can lead to premature degradation ." This warning is in addtion to the chemicals mentioned in the link.

In addition to installing the UV protected side backwards, if any of the un-recommended chemicals have been used in or near polycarbonate panels, premature breakdown could be expected.

Here is a link that might be useful: polycarbonate cleaning materials

    Bookmark   May 4, 2008 at 12:38AM
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domeman(NSW Aust)

I suspect that all polycarb panels are coated on one side only. The industry standard seems to be to put clear protection on the uncoated side and blue text protection film on the coated side. I find it unlikely that the HFGH would be different as there is no need to coat both sides.

I am still trying to find the way to identify which side is which when the protective film is no longer in place.

    Bookmark   May 4, 2008 at 1:33AM
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milwdave(Zone5 Milwaukee)

I've had my HFGH since about 2005 (6x8) and I had film on both sides of the panels. Both sides had to be removed. I have not noticed any deterioration in the panels to date.


    Bookmark   May 4, 2008 at 6:39AM
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laserfan(Zone 8b)

Hey Dave, is the ice off Lake Michigan yet? ;-)

I wouldn't expect Beertown (or Seattle) to have any UV problems, at least not yet. Growing-up in WI myself, I can tell you the sun here in So. Texas is awesomely, *radically* different from Up North. For example, our GH will get to >100F in late December & January! Yesterday w/high winds & roof panels off it still got to >125F in there.

Still, I don't think the panels are "melting" from the heat, I think it's UV. And either the HFGH panels have no protective coating against UV, or it's inadequate. I'd just say to anyone like me who's developing holes after only a year, y'all might want to consider whether you care, and do something about it.

Today seems calm enough that I'm gonna Snow Roof at least half of my 10x12 HFGH. I'll post pics after I'm done.

Here is a link that might be useful: Snow Roof elastomeric liquid roof coating

    Bookmark   May 4, 2008 at 9:53AM
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When I built mine it was in Jan. 06 it sit in the summer sun all summer but in the fall I put a pool cover on it and it is permanently installed with no way of blowing off.

The cover has been on since the fall of 06 and my panels look OK so could this be acid rain.

Modern cars are painted with a poly finish what we call clear coat and it can be damaged by acid rain.
That could explain why mine still looks like new it has not only been protected from acid rain but the heavy cover has to reduce the UV rays.
Just something to think about.
This is our third season of growing plants from seed and our GH is nearly empty now almost all of them are in the ground in our different gardens.
Soon I will just shut off the exhaust fan and open the doors and let it sit till next Jan. and it will exceed
120-F inside in the summer.

    Bookmark   May 4, 2008 at 10:43AM
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Cuestaroble posted:
"Other than a reported call to a HFGH rep., there is no evidence HFGH panels are treated on both sides. Neither the HFGH web site nor the manual for the gh makes any claim that both sides are treated. The manual only says "remove the protective film from both sides". In looking at many manufacturer sites, none state that standard polycarbonate panels are UV treated on both sides."

Domeman posted:
"I find it unlikely that the HFGH would be different as there is no need to coat both sides."

Both are good observations. Earlier this year I received several prompt and very courteous email replies from a Harbor Freight customer support person, and I've just emailed for clarification on this point (no UV protection, UV protection on one side only, or UV protection on both sides?)

I also asked if they'd had reports of problems with panel deterioration after only one or two years.

I'm stubbornly optimistic I'll get a reply, because my previous experience was so positive. If I learn anything helpful to this conversation, I'll let you folks know. If I don't receive any response to these worrisome (and important) questions...I guess that will be an answer in itself. ;-)

Hopefully we can get some clarification from the folks who sell the greenhouses.

    Bookmark   May 4, 2008 at 12:46PM
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domeman(NSW Aust)

Just in case there is any confusion...The peel off film is NOT the UV coating. The UV coating is impossible to see and does not peel off. The peel off film is a protective film which should be removed when the panels are installed.

    Bookmark   May 5, 2008 at 7:11AM
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laserfan(Zone 8b)

I Snow-Roofed half of our roof yesterday and while it worked OK, it ain't pretty--it's simply not possible to spread the liquid coating smoothly & evenly i.e. although from the outside it's perfectly white, from the inside it looks streaky & brownish in color. Not sure pics are going to show this properly. But the worst panels are repaired now and should last "forever" given the Snow Roof stuff is like magic. BUT the Snow Roof if perfectly applied is 90% reflective so... well who knows if this is good or bad for plants. We'll just have to wait & see.

For grins this a.m. I looked at polycarb from GH megastore and replacing our roof panels with 8mm Opal (white) 44% transmissivity, UV-stabilized, 10-year warranteed material would cost from $400-500 shipped (4 or 6 48"x6' panels, I'm not sure if the 8mm material would fit the vents?). Anyway that's our fallback plan if She Who Must Be Obeyed can't live with my repairs long term.

I personally will doubt any response from HFGH that their panels are UV protected at all...to coat both sides would suggest a "premium product" and this kit is certainly not THAT! ;-)

    Bookmark   May 5, 2008 at 9:13AM
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I received a prompt reply from Harbor Freight this morning. I'm pressed for time right now, but felt I should post their exact reply to the group as soon as possible; it obviously has implications for many of us.

My question 1: Do the Harbor Freight polycarbonate panels have UV protection on both sides, or on one side only, or no UV protection at all? There is no mention of any "right" or "wrong" way to install the panels in the manual...and no way to tell the two sides apart.

Harbor Freight's reply to question 1: "The greenhouse only has a small amount of UV filtering through the panels. To have the manufacture increase the UV protection would increase the cost of the greenhouse to us and our customers."

My question 2: Have you folks received complaints about the apparent deterioration of Harbor Freight polycarbonate panels after only one or two years in service, including yellowing and specifically the appearance of small holes?

Harbor Freight's reply to question 2: "Our panels are constructed to resist the higher ambient temperatures but that may differ depending on what state the customers are in. Places like Arizona, Las Vegas, and Texas may cause them to deteriorate faster. Unfortunately our warranty on the parts for this item is only 90 days and we take case by case in determining how we replace the panels for each customer. We know that the panels last longer than that but from a company stand point that is the warranty."

    Bookmark   May 5, 2008 at 2:32PM
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C Schaffner
    Bookmark   May 5, 2008 at 3:47PM
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I use aerospace 303 on the tonneau cover of my pickup truck.
Problem with it is that it cost 60 bucks a gallon and it will only last a few weeks or less if it is raining.

About $200.00 per month should keep your GH coated with 303.

    Bookmark   May 5, 2008 at 4:49PM
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Thanks very much for doing the research and posting the reply from HFGH. It is interesting that they say "only a small amount of uv filtering". I would take that to mean that there is no uv protection on either side of the panels. All polycarbonate absorbs almost all UV, but the coating is to keep it from damaging the panel before it is absorbed.

    Bookmark   May 5, 2008 at 6:13PM
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laserfan(Zone 8b)

Thanks mudhouse; as we suspected, no UV coating at all.

gardenerwantabe: "About $200.00 per month should keep your GH coated with 303."


I believe that *every* HFGH owner should expect yellowing sooner or later. Whether everyone gets holes in theirs is questionable, unless you're lucky enough to live in the sun belt! And the "good news" I suppose is that the walls are gonna last a lot longer than the roof, i.e. it won't be necessary to replace all the panels at one time.

P.S. Re: HF's "Las Vegas"!!!!!???!! Damn, those folks are gettin' hit night AND day!

    Bookmark   May 5, 2008 at 7:50PM
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C Schaffner

"About $200.00 per month should keep your GH coated with 303."

Ahhhh. I thought it would take a can or two. I'm glad someone is familiar with it. Back to the drawing board.

    Bookmark   May 5, 2008 at 8:19PM
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I agree, no UV coating at all. That could explain the common misconception among forum members here. Harbor Freight may merely have replied to previous inquiries that the panels were equally protected on either side...which is true; in fact, the panels have no UV coating on either side, so both sides are equal.

I can't decide if I should modify my HFGH 10x12 blog to include this revelation, or take the blog down entirely. I don't feel like I'm being very helpful if I'm sharing tips on erecting a greenhouse with polycarbonate panels that may only have a lifespan of one to two years (in some climates.)

On the other hand, if I leave the blog up, and make this new information available, it might prevent folks in warm climates from making a purchase that doesn't last. Any thoughts?

    Bookmark   May 5, 2008 at 8:24PM
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C Schaffner

Okay, here's another wandering thought. What about the uv plastic rolls you put on windows. I'm not sure if that would be a fortune. I have my shade cloth up year around. The sun here is bright even in the winter. I'm hoping that will help.

    Bookmark   May 5, 2008 at 9:43PM
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This info is very useful for everyone. And you have the HFGH answers down well - "equally coated" = none. The more this info is shared, the more it will help others. Sorry for the revelation, but it is important for any current or prospective owners to know. The least expensive is not necessarily (or usually) the most cost effective investment.

    Bookmark   May 5, 2008 at 9:48PM
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Well, I've been beating myself up all day for having the wrong impression that the polycarbonate panels on my Harbor Freight greenhouse were advertised as having a protective UV coating.

Just before turning in, I checked the Harbor Freight website for the 10x12 greenhouse. Look for yourself, and see what their website copy says:
Harbor Freight 10x12 greenhouse website page

Just in case Harbor Freight decides to change the copy on the website (which I've screen printed) here is what it says. Note the second item, please.

- Four vents ensure proper conditions for your plants
- UV coated polycarbonate panels are nearly
- Two sliding doors give easy access
- Durable extruded aluminum frame
- Metal foundation base for extra stability


    Bookmark   May 6, 2008 at 2:10AM
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domeman(NSW Aust)

I asked HF "SPECIFICALLY" about the UV protection. I am still waiting for an answer.....

    Bookmark   May 6, 2008 at 3:42AM
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I was concerned about this a long time ago
When I talked to them three years ago I was told that the panels were UV coated on both sides.
It seems like it depends on who you talk to what kind of answer you get.
I doubt that anyone who you talk to on the phone or the internet really knows.
They just go by what they were told or what info HF has provided for them.
I checked mine yesterday and after three seasons it looks like new so I'm not going to worry about it regardless of what someone at HF tech tells people.

when I called tech support I got someone in India and I could barely understand what he was saying.
I would not put much faith into anything you got by E-Mail
If their is no coating why do they go to the trouble of putting a plastic protector on both sides.
Why does the building instructions say be careful not to scratch because of UV coating
Why do they clearly state in their ad that it has UV if it don't opening themselves to legal liability.
Makes no sense.

    Bookmark   May 6, 2008 at 8:48AM
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laserfan(Zone 8b)

>Why do they clearly state in their ad that it has UV if it don't opening themselves to legal liability.

Nope, no legal worries for them; "caveat emptor". The fact is that they have only a 90-day warranty, so the only recourse you have is if they fail w/in 90 days, and even then it would surely be a real PIA to get them replaced.

Another fact is that "UV coating" or "protection" is still never 100%. Even those companies advertising a 10yr warranty (which BTW doesn't mean full replacement, it means pro rata exchange after X years i.e. $$) are counting on people not taking advantage of it. History/research/reality shows that folks just don't take advantage of warranties, much like many forget to send-in rebate forms.

I like pelicanhead's thought about UV plastic rolls; I saw those in my surfing and they'd probably be relatively cheap and easy to apply. Fold them over the panels and snap them down again--it oughta work.

But in the end remember it's probably only the roof panels at greatest susceptibility, and in the case of those of us who live in the Sun Belt and are at greatest risk, we ALSO need to SHIELD our roofs ANYWAY from the sun (i.e. the HFGH roof panels alone don't cut it), because it gets too hot inside if we don't, even in the dead of winter. So we gotta do something anyway.

    Bookmark   May 6, 2008 at 10:19AM
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In contacting several manufacturers of coating materials for polycarbonate panels, I received a reply from one today. They say that the UV formula of clear Plasti Dip can be used on polycarbonate. It comes as a liquid and spray paint type. Might be worth a try to seal the small holes and add some UV protection. The 11 oz. spray can is about $7

Here is a link that might be useful: panel coating

    Bookmark   May 6, 2008 at 11:40AM
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laserfan(Zone 8b)

Very nice catch cuestaroble! That stuff looks like the Snow Roof I bought, except that you can get it in Clear which would certainly be more aesthetically appealing. Hope someone here tries it--get a gallon and cover the entire GH. Not sure though where you can buy it by the gallon, or if it can be shipped i.e. UPS or FedEx?

I bought the Snow Roof cuz I was familiar with it, and I could get it at the local hardware store.

    Bookmark   May 6, 2008 at 2:50PM
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I agree with Gardenerwantabe, there's no way of knowing if info received from calls or emails to Harbor Freight is accurate. The lack of clarity is frustrating. Having a website that still proclaims the panels are "nearly indestructible" while simultaneously emailing me that "Places like Arizona, Las Vegas, and Texas may cause them to deteriorate faster" is hardly encouraging.

If I had three years under my belt with no troubles, and lived in a cooler climate, I most likely wouldn't worry either. It's the mention of panel deterioration from states all around me that has my full attention! ;-)

My HFGH blog makes it a bit trickier for me, because some folks find that through internet search engines now, and not through GW. I will update it ASAP, to at least direct potential buyers to this thread, so they can form their own conclusions. Sure would be easier to do an accurate description of the extent of the problem if I could get better info from Harbor Freight, but I don't seem to be getting any more email replies from them.

Laserfan, I hope you're right about the roof being the main problem. Jamesy40's first thread mentions the problem occurring on his south wall, and the second thread mentions the west wall, and he never mentions the roof at all. (Jamesy40, are you out there?) But, it sure seems like the roof would at least be the first to go...?

I really appreciate the ideas here for solutions (thanks Laserfan, pelicanhead, and cuestaroble.) I'll do some checking on availability of the UV formula of clear Plasti-Dip...great to know that can be applied to polycarbonate!

    Bookmark   May 6, 2008 at 4:50PM
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I wonder how the plastic film that you can buy in rolls for tinting windows would work.
Unless you use a light tint it may cut out too much light but that stuff is not very expensive.
Last summer we had one of the hottest summers on record and mine is fine but it has a pool cover on it and that may be the difference.
I would not rule out acid rain the clear coat on a car is much harder and more durable that polycarbonate and acid rain will etch the clear coat on a car so how can you dismiss it as a possible cause of damage to the GH

    Bookmark   May 6, 2008 at 8:45PM
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laserfan(Zone 8b)

Acid rain? I don't know much about this, except we live in the "extreme country" i.e. no heavy industry of any kind for literally hundreds of miles. I know acid rain is everywhere, but I very seriously doubt that's had anything to do with our problem.

Now that HF has effectively come-clean that there's no UV coating I'm sure that's the cause of *our* problems, anyway. Heck we even have white plastic things inside the house (behind UV coated windows) that are yellowing. The sun here is a very destructive force...

I had taken-down my panels to paint them, and when putting them back-up I cleverly installed spring clips to only the bottom edge this time (along with the screws at the lateral support beams) and last night one of my panels ripped-off from the wind and broke in half. That it ripped-off is a stupid mistake on my part, but the breakage attests to the degradation-to-brittleness of the polycarb. I'll probably try to tape it or something but I think we're going to have to find some replacement panels for the roof. Will probably go with Opal/White, UV treated, and perhaps 8mm thickness next time. :-(

    Bookmark   May 7, 2008 at 10:01AM
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laserfan(Zone 8b)

I found 2'x6'x8mm Heat Control sheets on sale at Charley's for $25 and thought I was golden. Perfect size, great price, Heat Control to boot. Figuring 8mm would not fit the vents, I double-checked and not only do the VENTS demand 4mm, even the ROOF PANELS can't be >4mm in thickness! Damn!!! Although at first glance the upper channel of the roof ridge looks like it will handle a thicker material, the bolts and the side ridges indicate that's not the case. Even 6mm twinwall would be too thick!

So far I've found only one supplier for 4mm (growerssupply.com) and it's Clear and it's 4'x8' and shipping is wildly expensive.

Back to the drawing board... not happy here! :-(

    Bookmark   May 7, 2008 at 11:38AM
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Ok, I've modified the first page of my blog to direct folks here for further reading. As I have time, I'll have to add links on each blog section, so folks don't miss my update on the first page.
mudhouse's blog

BTW, found this website saying "When purchasing polycarbonate panels make sure they are UV coated to guard against premature yellowing" so the yellowing description fits. hobby-greenhouse.com

Laserfan, shoot, sorry to hear about the torn panel. Regarding making a thicker panel replacement panel work, I just got on a ladder to look at my roof. I can see that the vent windows will be a challenge, and I see the channel at the top in the roof crown (parts 10 and 11) where the poly panel has to slide in, but I can't place your comments about "the bolts and the side ridges." Can you help me understand what you're seeing? I'm missing something.

Regarding the challenge of the top crown channel and the roof vent windows, I think we may be able to slightly crimp the poly panel on the very edge to decrease the thickness so it will slide into the groove. I discovered this technique by accident...I stupidly put aluminum tape over the top and bottom edges of each of the eight door poly panels, and then found it made them far too thick to slide into the grooves in the door parts. The tape stuck like heck and could not be removed without hours of work. I finally took a pair of wide, flat-jaw pliers, and worked along the edge of the poly panel, applying a very small amount of pressure as I went. The poly panel collapsed immediately to whatever thickness I needed with just a little pressure in the jaws of the pliers. Not saying it will be fun, but I hope I'll be able to use that technique to make it work, if I need to. I suppose it would be harder to collapse the sides of the panels (parallel to the channels) but the top and bottom of the 4mm panels were very easy to compress.

Personally, if I have to replace my roof panels, I'm sure interested in going with at least 6mm anyway, since most of the heat is lost through the roof. It's going to be very annoying if we can't use anything other than 4mm.

    Bookmark   May 7, 2008 at 12:54PM
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laserfan(Zone 8b)

> I can't place your comments about "the bolts and the side ridges." Can you help me understand what you're seeing? I'm missing something.

This is something that isn't (at all) obvious when the panels are in place, but since one of mine blew-out I can see clearly: although the "roof crown" appears to have plenty of room, the diagonal pieces have ridges on them, and the end diags have exposed bolts (to hold them to the roof crown) and a ridge along its length to support the polycarb. Net effect is that while it may be possible to fit something as thin as 5mm (twinwall doesn't exist) not even a 6mm panel will work, much less an 8.

I've looked at it a couple of times now and can't see a way to remodel the bloody thing--the roof will accommodate 4mm, period. The walls are not as critical i.e. they don't have to fit into a slot as the roof panels do (at the top).

I'll try to take some pics for you.

    Bookmark   May 7, 2008 at 2:48PM
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laserfan(Zone 8b)

Ok, the first two pics on my Details page should reveal most-if-not-all, although the "ridge" on the end piece is hard to see given my pic is taken straight-on.

Here is a link that might be useful: First two pics show gap available for 4mm twinwall

    Bookmark   May 7, 2008 at 3:34PM
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Laserfan, thanks for the good pics. I'll show them to my Chief Structural Engineer (He Who Must Lift Heavy Objects.) ;-)

    Bookmark   May 7, 2008 at 5:19PM
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laserfan(Zone 8b)

My only idea at this point is to buy the 8mm panels and take a box-cutter and slit the end of the panel about 1/2 inch deep right across the middle, then jam it into the upper lip of the roof crown. To keep water out of the exposed half of the panel, since I know/believe tape will NOT work, I'm trying to figure-out how to add a new crown to the ridge.

Maybe your CSE has some ideas about this--I would surely welcome anything at this point! In the meantime I've set-about to repairing my broken roof panel. Not a pretty sight...

    Bookmark   May 7, 2008 at 7:27PM
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I see what you mean now. We agree, no point in trying to modify the frame to accomodate the thicker panels, seems like the polycarbonate is the thing to adapt. My CSE said the same thing you did - box cutter - except we wondered if the bottom 4mm of the 8mm panel thickness could be completely cut away, only from the areas that create problems. The top (uncut) surface could face up, so hopefully would still shed rain, and slip into the crown channel at the top. The bottom 4mm would need to be carved away in the areas that would hit a bolt head, or the frame itself at the crown, and along the sides of the panels. (Would that work?)

Like, when you're installing a piece of wooden trim over the top of bolt heads, and you have to route out some wood on the back of the trim to allow space for the bolt heads beneath?

Sounds like a lot of panel carving (especially on the sides) but maybe the first one would be the worst, since fiddling would be required to get the fit right.

I noticed the aluminum tape I applied to the bottom edge of my roof panels (to direct rainwater into the gutters) has started to peel up after 7 months. I don't mind reapplying new tape to the panel edges over the gutters, but I think you're right, trying to keep tape in place at the crown would be a problem (for me, anyway.)

    Bookmark   May 8, 2008 at 1:13AM
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This is a tragedy!

If what is unfolding is true then the biggest single event that brought the pleasure of greenhousing to many who would not have considered it because of the cost seems so unfair.

I don't think that anyone can deny that the HFGH has allowed many more people to enjoy our hobby.

I am on record here in this forum encouraging greenhousers to buy a HFGH even though I do not own one. "the cost of the polycarbonate covering alone is worth it"

    Bookmark   May 8, 2008 at 5:14AM
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laserfan(Zone 8b)

>we wondered if the bottom 4mm of the 8mm panel thickness could be completely cut away, only from the areas that create problems.

Well, what we need is not only to support the panel w/in the groove in the Roof Ridge on-top, but also along the sides the full length of the panel, and this is wherein the problem lies i.e. the ridges left & right. I suppose one could cut-out a notch for the bolt, and then you'd at least have lengthwise support for the two end panels (one side only) but you'd give-up the support of the inside diagonal pieces, resulting in support at only the top edge, midway point, and bottom edge (and a big caulk job). If you slice the panel away lengthwise, then you give-up the honeycomb that gives its structural rigidity.

I had no luck at all with the metallic tape--apparently the flexing of the panels due to wind (a constant almost here) caused a lot of it to break at the seam rendering it useless. A mess. I suppose if I do decide to slit the end like I'd mentioned, instead of tape across the top I'd try to silicone caulk. It'd be an awful job, but the couple places I siliconed elsewhere have held up.

A tragedy? No. Myanmar's a tragedy. Katrina was a tragedy. Even anyone here whose kids are walking barefoot to school because they spent their last $599 on a HFGH aren't experiencing tragedy--their GH just needs some repairs.

I want to do the repairs Nice, i.e. a year and 1/2 ago I almost bought a $3500 greenhouse. I've seen those greenhouses since my dec'n to get the HFGH and they sure aren't worth the extra $$. Yeah you can make a lot classier structure (though mudhouse's is very nice!!! ;-)) but you're gonna spend $5-10,000.

Oh, BTW the vents too only accept 4mm!!!

    Bookmark   May 8, 2008 at 10:29AM
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If you want more insulation from thicker panels why not just buy 4 or 6mm panels and lay them on top of the existing panels.

Lay the panel on top and put self tapping screws into the lip down both sides and top and bottom of each panel.
Any water that may get under the top panel will not run up hill so it will run down to the bottom eliminating the need to seal the top panel.

If the top panel had a good UV coating not only would it last but it would protect the one under it.
Why throw away the original panel it would provide addition insulation.

When I built mine in addition to the clips I used screws down the side of the roof panels to make sure the wind did not blow them off so I know the screw idea will work I have already done it.

Instead of removing the original panel and modifying the new one just silicone it and then screw it down on top of what you have now.
When my pool cover goes bad I may do this because it is very cold here in the winter time and energy cost is skyrocketing so a 8mm piece over my exsisting 4mm would be good.

    Bookmark   May 8, 2008 at 10:30AM
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Hmmm, this is what I like about this group, lots of good ideas and approaches to kick around. Before Laserfan found out that the panel thickness was a problem, my plan was to move the south panels to the north side (double them up) and coat them with a protective substance, and only buy new roof panels for the south side. Maybe I could still do that with Gardenerwantabe's idea.

"If you slice the panel away lengthwise, then you give-up the honeycomb that gives its structural rigidity." Good point. I wish I had a scrap of this stuff to experiment with. (Wonder if Charley's sells small samples?)

Here's what I meant about the crimping idea. (I used the scrap of poly we removed for the exhaust fan to take the photo.) To the left of the plier jaws is the normal, uncrimped 4mm width. To the right of the plier jaws is the compressed. It took almost no pressure to collapse it to about 1/2 (or less) of the previous thickness.

Click to enlarge

If the 8mm stuff is too sturdy to collapse this easily, you could also make the same 1/2" cut across the center of the cell walls on the panel end...then crimp...and surely it would collapse to a thickness of 4mm or so, to be stuffed inside the crown channel? CSE says he thinks this would work. Whatcha think? We may just have to haul up there and remove a roof panel to see what you do, it's hard to troubleshoot this with the panels still in place.

Chris, if not a real tragedy, it's certainly a major bummer in my book! I agree, this GH has been a great way to "test the waters" without sinking thousands. Frankly, I doubt I'd have a greenhouse if HF did not exist...I would not have had the courage to do it otherwise. If Harbor Freight has decided to keep the cost low by providing panels that deteriorate in hot/sunny climates, they've missed a huge opportunity to develop a product with legs for the future. What a waste!

Also, I really love my ability to pop my wall panels out and pop the screens in, in mere minutes...one feature that the HF design makes possible. I don't think it would be possible with other greenhouses like the Rion.

Thanks for the compliment Laserfan...I just added a paver/steps entrance to the front and a small landscaped area in the back...all of which will be a great nuisance when we have to drag ladders around the perimeter if/when we have to redo the roof. LOL!

    Bookmark   May 8, 2008 at 12:22PM
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I think the idea of adding additonal panels is the best one yet, and it will indeed add to the insulating, but if crimping might cause them to crack, I don't know that leaving them open is a good idea, because eventually, crud and myriads of creepy crawlies will set up housekeeping inside of them.

So- why not just cut a very small opening in a tube of clear silicone, then fill a bit of the ends of each channel while they are new and still clean and perfectly clear?

We lined the entire interior of my GH with very heavy bubble and while it's certainly made a big difference, I've thought about just doubling the polycarb in mine too, but from the inside and when it's time to replace the bubble wrap, I believe it won't be bubbles, but additional polycarb panels- sort of interior storm windows.

    Bookmark   May 8, 2008 at 12:58PM
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laserfan(Zone 8b)

>If you want more insulation from thicker panels why not just buy 4 or 6mm panels and lay them on top of the existing panels.

I don't want more insulation; my panels are "brittling", yellowing, & developing holes. I suppose I could double-up on panels, but I can't find 4mm "heat control" i.e. I only find Clear, and anything thicker is gonna be a challenge to secure i.e. I don't think the spring clips will fit anymore. Also, I still have the challenge of waterproofing up-top such that water doesn't get under up there.

Leaning toward slitting the 8mm as originally thought, then silicone-caulking on top. Crimping-to-fit suggests longterm failure to me in the material, and offends my aesthetic risibilities. ;-)

Will get a final go-ahead from the Demander-in-Chief, let you know how well this turns-out for me.

In the meantime we need a source for Plasti Dip. I think coating the walls with that stuff might just be the ticket, though I do worry again about aesthetics...

    Bookmark   May 8, 2008 at 5:10PM
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Try Farmtek, they carry real 4mm polycarbonate sheets. $41.95

The shipping costs on a 8ft by 4ft panel to me (a few hundred miles) is $77.40 plus a $7 per foot crating charge
($7 x 8ft) $56

So, a single 8ft by 4ft panel will cost me $175.35 !!!

However, Farmtek are not your usual "we just sell and ship what we sell" type of company.

I suggest one of you call them, explain what you need, give sizes of the panels you require a sheet to be chopped up into and I am sure they will at least consider it.

The shipping charges will dramatically decrease and the "crating charge" may vanish.

Another alternative is to swap around your panels and replace the ones on the north side with Coroplast (UV stabilized of course) that may be available from a local print shop or sign maker.


Vents, well they would look great glazed in clear Lexan. Yep I realize the R value is not as great.

Also think about covering the panels in Vinyl, available in 25ft rolls used as window insulation. I used it as a greenhouse covering and it lasted 2 years.

Finally think real glass, again not the same R value, and heavy. But you could replace the walls with old window glass. (glass just a few years old is not that hard to cut) Start at the bottom and use the replaced polycarbonate for the roof.

    Bookmark   May 8, 2008 at 10:58PM
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troykd(7b SE VA)

Ok, here's a question. Those that have panels failing or getting holes/deterioration, do you use a shade cloth?

Mines under shade cloth most of the year and I've not seen any deterioration. Just switched to aluminet vs my old black shade cloth. My HFGH is about a 15 months old.

    Bookmark   May 12, 2008 at 3:13PM
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laserfan(Zone 8b)

No shade cloth for me. I have a new aluminet I'll install after I get the new panels.

    Bookmark   May 12, 2008 at 9:42PM
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Is there anyone who can post the sizes of the panels for the 10x12 HFGH?

I will call farmtek and ask them about cutting up their 4mm polycarbonate.

    Bookmark   May 12, 2008 at 9:54PM
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It may be a long shot but if you can find out who the actual manufacturer is of the poly panels that would allow you to trace exactly what the properties are.

As far as FarmTek, they occasionally have Free Shipping offers. I just received a 600lb+ order from them via freight and got free shipping. The code I used was FS8006 which had expired when I ordered but the salesperson allowed me to use it still. The shipping cost I avoided was close to $200.

    Bookmark   May 12, 2008 at 10:08PM
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Bluepine, thanks for the info on occasional free shipping offers from FarmTek (I'll sure keep that in mind if/when my HF panels deteriorate.) Good to know. The shipping fee (plus a separate crating fee) seems to be the real killer on ordering polycarbonate panels from the little checking I've done.

I'd guess the panels are manufactured in China with the rest of the kit, so probably little hope of helpful info. The manual says "One Stop Gardens" but I believe that's simply a house brand that Harbor Freight uses for their garden-related items. I've read that HF uses house brand names that sound American (Chicago Electric, Drill Master, Central Machinery, Central Pneumatic, U.S. General, Pittsburgh Tools) although though most of their merchandise is made in China.

Chris, lots of good suggestions, thanks. My panels are only 7 months old and don't show problems yet, but I seem to be in "trouble alley" according to HF, so I'd rather be ready.

The parts list shows the roof panels for the HF 10x12 are as follows:
quantity 8 - 1'11" x 5'9"
quantity 4 - 1'11" x 3'4"
quantity 4 - 1'11" x 2'6"

An easier way to state it might be:
quantity 12 panels - 1'11" x 5'10"

...a few passes with a box knife could render all the roof panels from those 12.

The wall/door panels (heaven forbid, if some folks have to replace those as well) are more complicated, as they vary. I'm going to work out the requirements for those too for the heck of it. If Farmtek will quote on the pre-cut roof panels, I can also contact them for pricing on the rest too (just to see how much it would cost to replace all the panels, to scare myself to death.) :-)

    Bookmark   May 13, 2008 at 12:05AM
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Just to add...if we find that shadecloth on the outside of the roof helps extend the life of the panels in sunny climates, I haven't helped myself, because I currently have my Aluminet installed inside my roof (avoiding our winds.)

    Bookmark   May 13, 2008 at 12:37AM
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laserfan(Zone 8b)

I bought qty 8 2x6' 8mm Heat Control twinwall polycarbs from Charley's for "only" $264 ($25/panel, $40 crating charge, and *only* $24 shipping). These 8 will fix my roof, less the 4 parts where the vents are located (and 8mm won't work anyway).

BTW Sheri don't count on the parts list for accurate measurements. At least the roof panels need your closest attention and they are 23 1/4" wide (and make sure you get long enough this time)!

    Bookmark   May 13, 2008 at 8:57AM
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"...don't count on the parts list for accurate measurements...the roof panels...are 23 1/4" wide"
Well, that figures. I will definately measure everything three times before ordering anything, thanks. ;-)

That crating/shipping fee from Charley's is quite reasonable. I'll be interested to see how hard the installation of the 8mm is...would be nice to have the extra insulation up there. (Sorry you get to be the first in our group to experiment though.)

If I have to replace my roof, I may consider doing away with my roof vents entirely, and just replace them with entire panels. I have them wired shut now. I never found them very effective in our extreme heat, and mine would blow open an inch or so even when "closed" in the tightest position. In big winds, they'd bang bang bang, and sometimes fall closed in a slightly open position. I finally decided the small benefit in cooling was not worth the risk for damage in our winds (gusts to 47 mph yesterday, normal spring stuff here.) I haven't seen many others complain about this issue though, so maybe it's just an odd result of my GH orientation, prevailing winds? Having a south wall of screens gives me some wiggle room too. On we go, weighing options, and watching the panels.

    Bookmark   May 13, 2008 at 11:49AM
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laserfan(Zone 8b)

>I'll be interested to see how hard the installation of the 8mm is...

You'd suggested maybe crimping the upper end to fit--it occurred to me that if you slit the panel across w/a box knife, then that part of the end should easily squeeze together w/out crunching. But I will probably still "slit and split" as I originally described.

>I may consider doing away with my roof vents entirely

Yeah one day one (or more) is gonna rip-off and self-destruct for sure. So... eliminating them makes a lot of sense, BUT I do have to say: just the other day (again) I found one of our recently-fledged baby Phoebes in the ceiling of our open-door GH. He-or-she was pretty frantically flying back & forth--the dummies don't even know how to dip-down and fly-out an open door! I had to open 3 of 4 vents until the little doofus found its way out. I think he was close to total exhaustion and possible death-by-fright.

We love our birdies down here, and if you leave the door open this sort of thing happens a lot (hummers are the other little guys that get trapped). Among the many things to contend with and consider... :-(

    Bookmark   May 13, 2008 at 6:56PM
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Glad you got the little guy out! I keep my open doorway covered with a flap of Aluminet (clipped to the doors at the sides so the wind doesn't flip it up.) It's not the hummers; it's the long-beaked Thrashers that tear holes in my succulents (looking for moisture, I guess) or flip little pots over (looking for bugs.) I love birds AND my plants, so No Birds Allowed; they can hunt outside!

Now I have a pair of Thrashers nesting in a tall yucca about ten feet from my GH, and I can enjoy their lovely song (instead of swearing at them.)

The raw flap is just attached above the doors for now with C clamps, but I like it so well I might hang it from a cable using clips or rings, so I can slide it aside like a drape. So far no birds have ventured past, but Our German Shepherd has gotten quite skilled at flipping the drape aside with his nose when he wants to come stomping in!

    Bookmark   May 13, 2008 at 11:22PM
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vegomatic(z5 BHSD)

I wouldn't remove the inner layer of the 8mm twinwall to make it fit a 4mm channel. I'd be afraid that just one layer would flex too easily, allowing the panel to blow out in the wind or sag under a snow load.

Compress or slit and bend inwards, either way, just retain both outer surfaces for their combined strength.

Can the frames that the panels fit into be bent outwards to enlarge them a bit? Or perhaps an adapter can be made that has a 4mm tongue and 8mm groove?

Or just attach slightly larger panels to the outside of the frame, using "Z" channel to secure it.

The rubberized tape made to seal new windows to your home's vapor barrier is incredible stuff. I'd bet it would grip to both panels and frames in a gh application.

I have a homebrew woodframe gh covered with polyethylene panels. It's a completely different arrangement for me, so I'm kinda guessing at what might work on the HFGH.


    Bookmark   May 13, 2008 at 11:59PM
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laserfan(Zone 8b)

>I wouldn't remove the inner layer of the 8mm twinwall to make it fit a 4mm channel...
>Can the frames that the panels fit into be bent...
>The rubberized tape made to seal new windows to your home's vapor barrier is incredible stuff...
>I'm kinda guessing at what might work on the HFGH.

Thanks Ed for your comments. No, I wouldn't be "removing the inner layer"--I'll take pics when I'm done then all will be clear. The roof ridge opening that the roof panels slide-into can NOT be bent--I thought of that, but it's very stiff aluminum (which doesn't bend anyway--it would only fatigue & break). I know about that rubberized tape. It would be perfect to hold the long sides of the panels to the metal below, but like Sheri has mentioned I like the idea of being able to easily take the panels out for whatever reason. Ya never know...

Sheri, aluminet over your door is a brilliant idea to scare birds off!!! You are a wiz with that stuff--I love the "screens" that you made too! We just got a 12x10 (finished) piece for the roof. After I've replaced my panels I'm going to make PVC "stand-offs" for over the vent ends, then I'll place the Aluminet over the top w/weighted pvc (water-filled) pipe holding-down the sides and ends (to protect from wind damage). Hoping the Aluminet will stretch over my vent standoffs (so we can open/close vents w/o risking the corners poking-thru the aluminet).

    Bookmark   May 14, 2008 at 10:40AM
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I appreciate the ideas too Ed. They're good, without your even seeing the details of these HFGHs!

I didn't know about that rubberized tape. Did some research and it sounds like great stuff...even has UV protection. I went to Lowes recently to find tape to correct one occasional HFGH problem...roof panels just a TAD too short to overlap the rain gutters...and found no good solutions. Now I have a better option, thanks to your post. So far I've only found it available in black or blue, but I could live with that if necessary.

As Laserfan says, you never know what will pop up next. I have a suspicion that construction tape will be good to have "in the tool box" for future HFGH needs.

Aluminet is so easy to work with, and light as a feather. I'd consider it for living room drapes if it worked better with our decor. ;-)

    Bookmark   May 14, 2008 at 12:33PM
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jbest123(Zone 5 PA)

It would be helpful if members would post photos of there polycarb panels stating the age and zone there in so we could judge when we could expect when to replace ours.

The HFGH I had in this photo is about 3 years old. This is in SW Pa and you can see some yellowing occurring. After reading the post I checked the HFGH which is at my daughters now and about 5 years old and the yellowing has progressed and there are several small holes.

I have included a photo of my Rion GH which is about 7 mo old just for reference of appearance of the polycarb with no other insinuations intended.


    Bookmark   May 18, 2008 at 8:27AM
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That's really helpful info John. So, yellowing after 3 years, in SW PA, with progressive yellowing and small holes after 5 years.

Laserfan has brittleness, yellowing and small holes, in Texas, after 1 year.

Jamesy40 reported holes and cracks, in Arkansas, after 2 years.

There was a post this morning on another gardening forum regarding yellowing and brittleness in HF panels, in Utah, after 1-2 years.

Laserfan, any chance you could post a picture of what the holes look like...so I'd know what to watch for? I'm seeing what look like tiny bubbles in my panels, but I think they were there from the start. It might be good to have a pic of the holes in this thread, if you have the time to snap one...?

    Bookmark   May 18, 2008 at 1:53PM
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My contribution to photos...I have an 18" square scrap that we removed to install our exhaust fan. This piece was exposed to east sun for one month before we removed it, and since then it's been stored inside the house.

I sprayed the roof with distilled water to wash off the dust. Don't know if you can see it in the photo as well as I can in person, but when I hold the scrap up to the roof, there's clearly a change already. The scrap retains the blue-white color shown so well in John's Rion photo above, and the panels on the greenhouse are starting to develop more of a yellow tone. This is after 7 1/2 months of exposure to the sun, in southern New Mexico (intense sun most of the year, occasional summer temps over 100°.) I'll take more photos periodically to monitor any progression.

    Bookmark   May 19, 2008 at 1:36PM
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jbest123(Zone 5 PA)

mudhouse do a google search on window film+UV. Lowes has some but it is probably available 24" wide some where.


    Bookmark   May 19, 2008 at 3:40PM
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laserfan(Zone 8b)

Am I the only one for which it's taking forever to open this thread???!!??? Not sure what's causing that.

Anyway pics of a couple holes are on my Details page. I don't think you can see the yellowing very well in snapshots, and in our case our panels are very dirty as it hasn't rained here in months... :(

Here is a link that might be useful: Holes in the roof panels

    Bookmark   May 19, 2008 at 6:28PM
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Laserfan, thanks for the helpful pics of the holes. Nothing like that showing up here, yet.

I think this thread is loading slowly because it's getting so long. Hope nobody minds...I started a new thread: HFGH Polycarb Panels Failing, Part 2. Click here to go to the new thread.

    Bookmark   May 21, 2008 at 2:49AM
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laserfan(Zone 8b)

Absolutely, please let's not post in this thread anymore!

I wonder if the embedded pics have anything to do with the slowness i.e. the page has to check all the links before it completes or something? It seems the thread slowed down when the pics appeared...

Regardless, again please let's try to leave this thread alone in favor of Sheri's Part 2 thread.

    Bookmark   May 21, 2008 at 9:02AM
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I am experiencing same failure on the panel. majority on the west side of the roof. A few holes are on the east side, HF quoted an average price of $9.00 per panel. I have check several over location on the net and they have a min ordering cost of several hundred dollars.

What source is everyone using to purchase repllcement panels? I hate to purchase the same problem from HF, Any suggetion would help. Anyone know the price of such etc

    Bookmark   December 26, 2008 at 4:38PM
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Hello mud1, I'm still watching my panels yellow and haven't replaced any yet. No obvious holes yet, but I now have 60% Aluminet covering the roof and west wall, and will do a better inspection after we get through our coldest months.

When I do replace panels, I definately won't use Harbor Freight polycarbonate. They might be acceptable for folks in kinder climates, because of the low cost, but I know the HF panels would only be a very short term solution in my climate. I'd just be tossing money down the drain here.

When the time comes I'll probably price shop with FarmTek and Charleys Greenhouse Supply. As you've found, the shipping costs can be very high, so be sure to ask about shipping AND crating fees when pricing. (Note Bluepine's post above, citing occasional free shipping offers from Farmtek.) I have not found an inexpensive source for twinwall polycarbonate (except to buy from Harbor Freight, which I've ruled out.)

Earlier in this long thread, you probably saw Laserfan's comments about how the HF roof frame will only accomodate 4mm thick twinwall polycarbonate (without some creative re-engineering, anyway.) 4mm twinwall polycarbonate does not seem to be widely available; many sites start with 6mm and go up. Charley's Greenhouse Supply told me they'd probably be able to special order 4mm, so you could contact them for more info.

One heads up...if you decide to go with HF poly panels for a shorter term solution, remember that they're notorious for not being honest about how long the delivery time will be. :-(

This thread is SO long it's hard for folks on dial-up, so you might get more replies by starting a new thread, too. :-)

    Bookmark   December 26, 2008 at 9:38PM
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Well mudhouse I did contact HF about repalcement panel and did order 9 panel to get me going this for this spring. I was very surprise to reC . them with in 3 weeks . Prsently I have contacted Alro plastic , they claim to have poloycarbon sheet in 4 MM thickness , I awiating a reply from them . Thus far the best price I have found is from Charlies . Ihope to locate a good supplier so I can repalceall of them by late summer . I will get by with this 9 new panel until i find a better source, I let you know what I find . Wha treally stinks is I livE ABOUT 50 MILES FROM THE GE PLANT THAT MAKES THESE PANELS AND THEY WILL NOT SELL THEM TO THE PUBLIC !

    Bookmark   January 23, 2009 at 9:26PM
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gjfarm(z3/4 MT)

mud1--did you call their standard phone number? When I do that, don't get much of an answer. Their website does not show any panels. How was the shipping cost? WE had a major hailstorm last fall and did a number on some of the panels

    Bookmark   January 27, 2009 at 3:43PM
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mud1, thanks so much for posting back about the good delivery time on the panels! I hope that means they're including panels in the category of items they try to stock for faster shipping. I know any info you can post to the forum about your research on panels will be appreciated by HFGH owners.

LOL about your local manufacturer refusing to sell to the public...that figures, eh? :-)

gjfarm, I've used the replacement parts phone number listed on the HFGH manual with success in the past, 1-800-444-3353, although I don't know if mud1 used that number.

    Bookmark   January 27, 2009 at 6:54PM
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Just giving my 2009 report on 6 x 8 HFGH. I live in Phoenix and so far no holes. This is my third summer. I do not use the greenhouse in the summer and it does get VERY hot in there. I have not used a summer shade protection of any kind so I am worried about the holes. Do we have any further 2009 updates on quality of panels from different parts of the country.
Mudhouse. I also used your directions in assembly. They were great. Thanks also for the updates on your shade panels and venting. You have saved us all from making a lot of mistakes. Thanks for taking the time to do so.
I thought, if I do get a lot of holes I might just buy another greenhouse kit, when on sale with a coupon, and use those panels for replacement. It almost sounds cheaper than buying panels alone. There is enought polycarbonate in a kit to replace the roof a number of times. What do you all think.

    Bookmark   March 27, 2009 at 1:54PM
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Hi baileybear, good to hear no holes going into your third year, with Phoenix sun and no shade protection. Do you see signs of obvious yellowing? I suppose some of us could be dealing with variability in manufacturing...I don't know why some folks have problems sooner than others.

I looked at the 6x8 manual and I think you're right, looks like you'd get three roof changes out of one kit. If you can get three years out of your roof panels, that would be a good deal, especially since you have an empty greenhouse for part of the year, and changing the panels isn't too disruptive.

My GH remains stuffed year round, so when I replace my panels I'll need to remove 300 or so prickly plants to another sheltered area (out of direct sun.) Otherwise I can't get a ladder inside to have access to screw down the panels of the tall 8x10. The size of your 6x8 probably makes panel swapping a bit easier too, so I personally don't think it's a bad idea for you to consider just buying another kit on sale and robbing the panels...if you don't mind the work of swapping them out periodically.

I think I'll at least buy good UV protected panels elsewhere for the roof...since that's the biggest hassle for me to change. But I can sure see your point!

My roof is not the only part that is plainly yellowed and more brittle; my south and west panels are also. If you eventually have to change out other panels as well, that affects the cost calculation.

I'm more spooked by the risk of brittleness than holes. I worry that brittle panels will break at the points where I've screwed them down, eventually, in ferocious winds.

    Bookmark   March 27, 2009 at 4:03PM
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So far no yellowing either. I have it at the southeast corner of the house. The south is blocked by a tree. The sun is overhead in the summer until about 1-2:00 so even though it is on the east it still gets that darn summer sun a long time. I was planning on using some sun screen this year. I was going to drape it over the gh and then grommet and stake it on either side. I read on one thread that if there is much movement of the sunscreen it will damage the finish on the greenhouse. I was wondering if others have experienced this. Where it is located I don't have a lot of wind but there is some. Your wind sounds bad. We just had a wind storm last night and it lifted one of the vent. Even with our dust storms that is the only damage I have had but I did make all the improvements.
My major goal now is trying to cool the darn thing, both summer and a lot of the winter. I have been reading threads and have been getting some good ideas but any more will sure help. Happy Gardening everyone.

    Bookmark   March 27, 2009 at 5:27PM
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I'm thinking about getting one of these. The price is just so hard to ignore. Has anyone contacted the company with their complaints? What have they said? I wouldn't stand for paying for a defective product.

    Bookmark   April 10, 2009 at 8:15AM
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Harbor Freight is not known for exemplary customer service in many matters. ;-) If you put your cursor about 1/3 of the way down this long thread, and look for the post with the bold type, you'll find the exact response I got from Harbor Freight about this question. I frankly think it just goes with the price of the kit; if we want top notch responsiveness to any concern, we need to buy more expensive greenhouses.

Whether or not the panels can be considered "defective" is open for discussion. As you mention, the price of this kit is so much lower than others, even if I have to replace some of my panels with more expensive (quality) twinwall polycarbonate down the road...I'll still be money ahead, although the labor and hassle will be annoying.

The panels are what they are, and that's one way Harbor Freight keeps their prices low. This problem seems to mainly affect folks in very sunny southern states...and, as Baileybear's encouraging post above shows, perhaps not even everyone! As you've read here, some folks do have seriuous problems, and others don't.

Shadecloth on top of the panels most affected by direct sun does seem to help. It's just something to take into consideration if you live in certain climates.

    Bookmark   April 10, 2009 at 11:40AM
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My climate is really odd. It's very cold during winter and very hot and sunny during summer. I'm not sure what to expect but when I have the money to get it (if that ever happens!) I'll keep all the suggestions from these HFGH threads in mind. It's just too bad that you guys have to go through this.

    Bookmark   April 11, 2009 at 12:13AM
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When I reported the holes in the panels, they were on the roof of the south side. They were small holes that seemed to increase as the greenhouse aged. Then the greenhouse was destroyed in a hail storm. I am currently thinking of buyin another one. If I do, I will cover with shade cloth to prevent this from happening again.

    Bookmark   July 4, 2009 at 12:35AM
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I just went out and looked at the remaining greenhouse structure still standing after the hail storm. I have side panesl on the north and south side still there. I noticed that there were many pin holes on the north side of the house. This is the side that gets the hot July and August sun. In my estimation, the greenhouse panels are good here for about 2 years.


    Bookmark   July 4, 2009 at 12:13PM
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They must be defective panels. Mine are still like knew after several years. No discoloring, pitting - nothing! I do cover my HFGH for the summer with a queen size white sheet. It will come off for the winter if I have an overflow of plants from the larger Rion, also covered for the summer. Both GHs get washed with Palmolive every spring when the plants go outside.

The climate here can go from 103F in the summer to 2 or 3 below in winter. The summer sun is grueling.

    Bookmark   July 5, 2009 at 12:01AM
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No posts since July, 2009. I am thinking about buying a HF greenhouse and would like an up date on the panels before buying. Any info would be appreciated.

I am in hot, sunny and humid Mobile, AL.

    Bookmark   March 18, 2010 at 7:41PM
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I put my HFGH up in the Spring of 2007. In 2009 I noticed that there were small holes in the roof panels. Notice that I said roof panels. All of the roof panels have many holes in them and they are very brittle. Several have cracked.
What's odd to me is that all of the wall panels show no sign of problems. They are still clear, no holes and are not cracking.

To me, it's apparent that the ceiling batch were cut from a different batch that the walls were cut from. The ceiling batch is obviously defective.

I've never complained to HF, but I really think that certain supplies of polycarbonate panels really are defective.

Now, I'm debating whether to find some other material to replace them with or order another HFGH just for the panels.


Here is a link that might be useful: My HFGH

    Bookmark   March 19, 2010 at 10:07AM
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We put ours up in the summer of 2007. To date, the panels receiving the most sun (either from orientation, or from lack of any shadecloth protection) are noticeably yellowed, and probably more brittle (I try not to mess with the yellowed panels, for fear of damage.) The panels on my north side, blocked from almost any sun at all, still look pretty much like new.

However, I still don't see any holes developing, or cracks, as Joe, Laserfan, and others have reported...even in my most yellowed panels. I'm thinking that Joe's suggestion of variation of manufacturing quality (and defects) may be the best explanation. It could also explain why some folks don't report any dissatisfaction with their panels, and others have some pretty impressive failures.

Joe, since you seem to have such a clear indication of varying quality in one structure, I wonder if it would be worth contacting HF to see if they will send you replacement panels for the roof. When I contacted them about this issue some time ago, they said they were replacing some panels on a case-by-case basis. I have no idea what they're doing now, but it might be worth a phone call (and/or, some emailed photos?) before you shell out hard-earned money...?

My greenhouse is still functioning fine, although not quite as pretty as it was when the panels had that nice new blue-white color. But, until cracks or holes develop, I'll live with these panels.

    Bookmark   March 20, 2010 at 11:34PM
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After following these posts for a couple of years now with rising anxiety as I have seen my HFGH roof panels rapidly deteriorating.........it seems the only logical solution (imho)is new panels from farmtek.
However with shipping costs to my area at $107.07 and an added handling charge of I believe around $60 coupled with a reasonable panel cost of $44.95....thats $212,75% of what I paid for my greenhouse.

Possible solution........ Shipping costs from Farmtek are the same whether you purchase one 4x8 panel or 25, I assume handling would be the same.
Has anyone considered a regional purchase that could spread the shipping and handling costs out.
For instance, cost per panel at a purchase of even 10 panels would be $61 instead of $212......
I'd be willing to do a southern new england group.

    Bookmark   March 28, 2010 at 9:53AM
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WOW this is a long thread.
I have not been on this forum in awhile but I see that the panel problem still has not been solved.

I'm in my 6th growing season with my 10x12 HFGH and have no yellowing no pin holes no problems of any kind.

Where I live we don't have the heat of the south west but when mine was first built I put a pool cover on the roof and put alluvium angle pieces at each end of the gable to secure it.
I leave it on year round plus a 50 percent shade cloth in the summer.

The pool cover deflects the sun light so it is not as hot on the panels and I believe it helps the plants as well.

If I lived in Arizona I would have the same set up as I use in Indiana not sure it would totally cure the problem but it sure would be better than what you people are using.

One thing that you should think about is that just because you live in a hot climate you don't need insulation because it will insulate against heat as well as cold.

If you buy 8mm panels don't worry about getting them in the grove just lay them on top of the frame and use screws to hold them down.
Put pool cover over it like mine and NO RAIN can get to the roof panels to leak at the top and the pool cover will protect you panels.

Here is a link that might be useful:

    Bookmark   March 28, 2010 at 4:20PM
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My greenhouse in located in Tucson and is couple year old. I have observed a few 3/16" diameter holes in the outer skin in a few of the panels. I'm sure with time there will be more and eventually I'll have to replace the panels. BUT, in the mean time, I'm thinking about placing a clear plastic patch over the holes. The patch might be 1/2" diameter. Has anyone tried this? If so, has it worked? If so, what did you use for the patching material and the adhesive?

    Bookmark   April 1, 2010 at 6:26PM
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Patch holes with 100% clear silcone caulk - squeeze it into the panel and smooth it off with a wet finger. For shade coating the house, purchase the cheapest white latex paint you can buy. Thin it down to 1 part paint to 6 parts H2O and apply it with an ordinary 2 or 3 gallon hand pesticide sprayer. Apply as many coats as you need to get the desired shading level.(latex paint doesn't adhere well to poly - rain, snow and frost remove it or you can brush it off.

    Bookmark   April 1, 2010 at 7:54PM
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gartenmiester, Thanks for the suggestion. The clear silicone caulk sounds like a relatively easy repair.

I hadn't thought of applying paint for shading, but it's worth considering. I now have shade cloth on the inside, but it obviously provides no protection for the polycarbonate panels.

    Bookmark   April 6, 2010 at 7:55PM
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Pool cover would be a problem over the two vent windows I have.
Silicone would be a temporary fix at the onset of holes starting.
My panels have dozens of holes,cracks,yellowing.......they are disintergratng!Silicone would be a band-aid at best.

    Bookmark   May 10, 2010 at 11:24PM
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laserfan(Zone 8b)

Why are you worried about the vent windows if your panels are disintegrating!!!????!!! My panels are almost completely shot as well--I even have a garbage bag clamped-over a vent that blew-out so our GH is looking sorta sad these days! I think I mentioned earlier in this thread that I "snow-roofed" one side of our GH but that ultimately did not slow the deterioration.

I'm with gardenerwantabe on a flexible cover solution. I've been thinking "clear reinforced tarp" but haven't found one in a suitable size. I'm thinking PVC pipe to protect a tarp from the sharp edges of the GH.

I notice that HF is advertising "UV protected" for their GH these days--I suppose if you trusted them that they've improved their panels you could buy another GH and get fresh panels! But I don't believe them myself...

If I find a nice cover I will take some pics and post-back here.

    Bookmark   May 12, 2010 at 10:26AM
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Time to bite the bullet and replace my roof panels. After a couple of years they were brittle and full of holes. I'm tired of patching them. Sides are just fine.

I've been looking at Charlies selection of polycarbonate panels. Has anyone replaced their panels from Charlies? Did you upgrade to 8mm or even the 8mm Heat Saver ones or go with the normal 6mm twin wall? Any advice would be appreciated.

Thanks in advance,

Finger Lake Region of NYS

Here is a link that might be useful: My HFGH

    Bookmark   December 6, 2010 at 2:22PM
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Hi Joe,
Just making sure you found this thread (also ongoing fairly recently) about the HFGH panel problem:
HFGH Panel Fixes and Failures, Updates?
Laserfan posted in that threat that he hasn't installed his roof panels yet, so you might want to watch that thread as well, to see how he deals with the roof panel thickness problem (roof channel of the HFGH frame isn't designed to accept thicker than 4mm poly panels, as noted earlier in this very long thread.)

My (3 year old) roof panels don't have holes yet, but most of my side panels do. Currently they are patched with clear duct tape to get through the winter. I am considering Solexx instead of clear polycarbonate for replacing mine, but won't decide for sure until spring. I posted some info about Solexx in the other thread, if it helps.

Merry Christmas,

    Bookmark   December 13, 2010 at 2:42PM
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I bit the bullet. After looking at Charlies and the material cost and shipping, I was almost as close to the cost of another HFGH. I called HF customer support and was able to order the replacement panels to cover all of the roof.

***Order Summary***
4 13361-0ZZA 93358 ROOF WINDOW PANEL 1'11 X @ $9.72
8 13366-0ZZA 93358 ROOF PANEL 1'11 X5'9 @ $9.41
Subtotal: 114.16
Tax Rate: 0.08
Tax Total: 10.17
Shipping: 12.99
Handling: 0.00
TOTAL: $137.32

Received them the other day and now all I have to do is wait for a warm day to install them. We have had a real cold spell here with the temp staying in the 20's.

These might not be the same quality as Charlies, but the same qty. would have been about $251 plus shipping. I'll take my chances.


    Bookmark   January 19, 2011 at 1:01PM
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I just bought a HFGH, and was wondering if anyone had tried putting on the clear adhesive UV film as was suggested earlier in this post before assembling the panels? I was thinking this might be a good preventative measure.. Also, thank you to all the contributing members for the informative posts on how to improve the stability of the HFGH, I am so excited to get started!

    Bookmark   November 9, 2012 at 2:58PM
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After reading this post three years ago while building the hf10'x12' gh I decided to order the "Top Secret Coating" and 1qt of suggested thinner, mentioned previously on this post. I'm at about 6000' near Denver. with the suggested 1 quart of thinner I was able to apply 3 coats to the outside of the panels with a paint roller, this may be overdoing it but I had no other use for it at the time. The results have been great no yellowing or holes of any type, we have high uv and summer temps up to 105f here. I think it all ran about $80, well worth it.

    Bookmark   December 11, 2013 at 6:05PM
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Hello rtyu, and thanks so much for posting here. That's really encouraging!

I also applied a Top Secret clear coating to my new roof panels, a little over two years ago. The product I ordered was TS-100 One Part Epoxy Marine Coating, with the suggested thinner. So far I don't have any deterioration, but the roof panels are also under 60% Aluminet shadecloth year round...so they do have some protection from our brutal sun. I figured I'd need to give it another year or so before I knew if the coating was really working. So, I'm happy you started your test of the product a year before I did, that's great feedback!

I only applied two coats with a fine nap roller. Should have applied three...as you did...because I have quite a bit left over. Next spring I need to replace the wall panels, and before I install them, I will be using more of the same product.

I think my cost was around $100 or so for the gallon of coating, the quart of thinner, and shipping, several years ago.

Thanks so much for posting and sharing your results. I will also post to the other (Part Two) of this thread, in case folks pull these threads up in the future.

    Bookmark   December 11, 2013 at 7:51PM
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