Attic Insulation Vermiculite safe?

jcoenenMarch 30, 2008

I am starting my SFG this year and just picked up some 3.5 cu ft bags of vermiculite from Menards for $8.99 a bag. The bag says Micaflakes loose fill attic insulation and Menards had it labeled as vermiculite. On the bag it says it is made by Sun Gro Horticulture out of Seneca, IL. I'm assuming it's the same stuff, but just want to double check.

I stopped by Steins across the road and they had 4 cu ft vermiculite that was labeled as Horticulture Vermiculite and that was $21.99 so quite a bit more and it was also made by Sun Gro Horticulture. Does anyone know if the stuff I bought from Menards is the same stuff and would be safe to use?

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Here is a pic of the bag.

    Bookmark   March 30, 2008 at 4:17PM
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Ray_Scheel(z8b/SS31 E. TX)

Should be, it is sold in various grades but for just mixing into "dirt" any variety will do.

    Bookmark   March 31, 2008 at 10:19AM
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moabgail(CO Z3)

Is the mica expanded so it looks like vermiculite or is it the thin brown to grey flakes that sort of shine?

In a previous home I had the thin brown to grey flakes used as attic insulation which was common in the past. Much of this stuff was later found to contain asbestos and had to be removed because it was a serious health hazard.

All of that aside, if the mica isn't expanded, I don't see how it would have the water holding benefits of vermiculite.


    Bookmark   April 1, 2008 at 1:42PM
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Ray_Scheel(z8b/SS31 E. TX)

I did some more poking to be sure, and the "Sunshine Mica Flakes" product *is* vermiculite, and uses the same Material Safety Data Sheet as the SunGrow Horticulture Vermiculite (in other words, it is composed of exactly the same stuff, possibly different only in particle size or uniformity).

Here is a link that might be useful: MSDS for Sunshine Mica Flakes and Horticulture Vermiculite

    Bookmark   April 3, 2008 at 12:00PM
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Reading the MSDS, it says to keep this product away from children and pets. Is there a danger to using Vermiculite? I know there have been some questions in the past about the possibility of it containing asbestos, but those seem to have been dismissed.

Is vermiculite 100% safe?

Thanks for the link to the MSDS. Because if going with Vermiculite this is possibly a more economical source.

coenen - how would you classify the grade? Coarse? Medium?

    Bookmark   April 3, 2008 at 12:43PM
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As the safety guidelines say, breathing the dust can be irritating, which is probably reason one for the "children and pets" warning, as vermiculite, fresh from the bag is dusty (I believe that Mel recommends making your Mel's mix outdoors and using a respirator/dust mask) and if you play in it it is REALLY dusty. Once moistened and incorporated into the Mel's mix the dust issue goes away.

Reason two is that they (the kids and pets, little kids particularly) may try to eat it. I can imagine it being unfortunately easy to choke on a big mouthful of vermiculite.

Overall the most dangerous part of the bag of vermiculite for your children and pets is most likely the plastic bag itself.

    Bookmark   April 3, 2008 at 2:50PM
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ray_scheel - thanks so much for doing the additional research - makes me feel a lot more confident about using it and at roughly $2.50 a square foot it is significantly cheaper than all of the other places I have found it.

bugster74 - Seeing as how it is the only vermiculite I have ever seen I am not sure how to classify the grade. I will try to take some pictures this weekend and post them.

    Bookmark   April 3, 2008 at 9:37PM
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Ray_Scheel(z8b/SS31 E. TX)

Cheap is good. For this application, grade / coarseness doesn't matter, or rather, IMO the cheaper grades are actually better suited to this particular application than the "horticultural" vermiculite aimed at starting seedlings.

There is some coverage of this in the FAQ too...

    Bookmark   April 6, 2008 at 9:57PM
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Thank you for the tip! Just to be sure, I called Sun Gro Horticulture and spoke with a saleswoman. The attic insulation is the exact same product as what is sold in the gardening department.

She also mentioned that Menards is the only place that she is aware of in our area that sells it that way.

Thanks again for the tip!


    Bookmark   April 25, 2008 at 9:37AM
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about the asbestos thing, I hate it. The rumors of it perpetuate like wildfire. If you're vermiculite (mica) was mined within the last 20 years then it's guaranteed not to have asbestos in it. The veins of the mica in the mines are tested serveral times a year to ensure there is no asbestos contained within the vein. Yet at least three or four times a year I hear why such & such place wont carry it because it contains asbestos.

I'm sure if your attic insulation was 20+ years old when you were told that it had asbestos in it, it was possible - probably not likely, but possible - anything after that it's more likely that someone was just fear-mongering rumors they heard second hand.

US EPA on Vermiculite & Asbestos
Vermiculite and Its Uses
Vermiculite is the mineralogical name given to hydrated laminar magnesium-aluminum-iron silicate which resembles mica in appearance. All vermiculite ores contain a range of other minerals that were formed along with the vermiculite in the rock. Vermiculite ores from some sources have been found to contain asbestos minerals but asbestos is not intrinsic to vermiculite and only a few ore bodies have been found to contain more than tiny trace amounts.

Technically, although they don't name it, it was one mine in Libby, MO that was closed down around twenty years ago...

Here is a link that might be useful: Confusion about vermiculite in general

    Bookmark   April 25, 2008 at 10:26AM
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Ray_Scheel(z8b/SS31 E. TX)

To drive in the last nail on the rumor, even if a source of vermiculite *did* contain asbestos (including recycling old attic insulation originating from the Libby, MO mine), it would be rendered harmless when mixed into the "dirt", provided you followed the safety recommendations for working with dry vermiculite in general: wear a good dust mask and wet it down immediately to eliminate flying dust.

    Bookmark   April 25, 2008 at 12:33PM
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I'm a little oversensitive to the topic because on organic mushroom forums there's at least one post a week about "OMFG, Vermiculite Contains ASBESTOS!!!!!!!!!" floating through them.

    Bookmark   April 25, 2008 at 1:18PM
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Ray_Scheel(z8b/SS31 E. TX)

I can see how that would drive someone to the brink after a while. It only shows up 1-2 times a year here, and even at that infrequent appearance feels done to death to me (since I've lost track of how long I've been hanging out here, ~7-8 years, I think).

    Bookmark   April 25, 2008 at 3:53PM
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when i looked up what exactly vermiculite was on the web in wikepedia, it is also used as insulation. so that's prob why they have it like that. sometimes i wish thye'd put it "also for...... " LOL make it so much easier for us!!! LOL
i was looking for a cheaper way to make the beds, cuz the hubby was really after me about the price of the stuff plus well all of it. its so costly so i tried to tell him, well honey, its not like we'll have to replace it every year. hmmm that didn't go over good. and some people have been talking about shale. i don't think it'd bother him to much but if we have to move that's alot of money out the window!!
you all are very informative!! thank you!! :'))

    Bookmark   April 27, 2008 at 7:29PM
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Can't say it enough, your local farmer's co-op should have it for less than $18 USD per 4cu. ft. bags if you call them...

I used to use the stuff when growing criminis (baby portabellas) and would pay about $20 for a cubic foot's worth online through ebay. Then I start SFGardening and found a source (local farmer's co-op) of it for x4 as much for $5 cheaper. Go figure...

    Bookmark   April 27, 2008 at 11:23PM
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Arjo... OMFG I think that's the first time I've ever seen "OMFG" used on GW! Even if you were being facetious.

I think I'm gonna like it here. :-)

And, to post an atual related question... I've heard that vermiculite really compacts in container soils. Does perlite do the same thing as vermiculite in Mel's Mix. (I realize he says to follow his mix EXACTLY, but I imagine there are plenty of people who have tinkered a little with it.

Thanks folks,

    Bookmark   April 28, 2008 at 3:36AM
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Arjo and I both talked about this in another thread as well, I've put in the link below. The short(ish) answer is that perlite isn't a good substitute for vermiculite, as it has no water holding capacity of its own. It also has a nasty texture and floats to the top of your soil mix, where it does nothing for its texture/consistency, although I suppose raising its albedo (reflectivity) by making your soil surface bright white could have both good and bad effects.

I found that even tilled or spaded into my native soil (in the days of the first SFG book) it (vermiculite) made more and better difference in my soil quality than anything other than compost, and it was a longer lasting effect.

Also the SFG is a different situation, the soil mix isn't "stuffed" into a container, but stays in a light, fluffy, state in a broad, and fairly shallow (six inches or less by Mel's directions, I built my beds from lumber labeled 2x8, so they should be at least 7" high as modern dimensional lumber is up to a half inch "skinny"). Also, your SFG soil will be regularly "fluffed" as you harvest crops and/or pull up old plants and mix in new compost. I add a little fresh vermiculite to my bed every spring (as well as enough fresh compost to "top up" the box), as I feel that it is more than worth it, and I can't get the really coarse kind that would break down more slowly.

Here is a link that might be useful: The other thread where we talked about this.

    Bookmark   April 28, 2008 at 10:40AM
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asbestos was only found in one type of vermiculite mined in Libby, Montana and sold under the name Zonolite. It has been out of production for quite some time, so as was said anything produced in the last 25-30 years will not contain asbestos.

    Bookmark   September 11, 2008 at 1:52PM
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I realize this thread has been dormant for 3+ years, but in the event that others run across it in their search about vermiculite, I thought I would add a note.

I went to Menards today to buy the "Micaflakes loose fill attic insulation" that was mentioned in the initial post. While they do still have the product, and it is at a reasonable price, I passed on it because the grade seemed too fine. I would say that the size of the flakes was similar to coarsely ground black pepper....about a few millimeters in diameter. From what I could tell, the coarser grades are better for Mel's Mix.

I had a source for the coarse grade here in the Chicago area, and they're getting their shipment in a few weeks. I wanted to get a jump on assembling the new raised beds, so sought the supply from Menards, but I will just wait for the other option. If you haven't other reasonable options, I'm guessing this could work. I was just concerned (perhaps needlessly so) that the smaller particles would be less effective at aerating the soil.

I hope this helps others in the same way I have found so many others' posts.

    Bookmark   March 12, 2012 at 11:02PM
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When OMFG makes its way onto a gardening website, Arjo and Kristimama, you may like it here but is it ok for the rest of you to pass on that term while discussing VERMICULITE of all things? Do the rest of you know what OMFG stands for. It doesn't bother you? Well, enjoy your gardens. Yech.

    Bookmark   March 13, 2012 at 7:42PM
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AJK23, would you mind sharing your source for Vermiculite in the Chicago area?


    Bookmark   March 14, 2012 at 9:31PM
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We are in Texas and do not have the Mernards chain in the area. Local box stores carry an insulation for attics called cellulose insulation made by green fiber insulation. They also sell the owens corning fiberglass blown insulation which is more of a loose fill insulation. We like the blown insulation since it does not settle. Have heard of the vermiculite, just do not have much experience with it. maybe good, maybe bad, who knows

Here is a link that might be useful: Blown Insulation

    Bookmark   December 9, 2014 at 11:10AM
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