Ontario building code and greenhouses

paul_ontario_2009October 25, 2009

I am trying to build a greenhouse in Ontario Canada. When I contacted the building inspector, he said that the code required any windows in a heated structure to meet strict heat loss requirements. This would include the glazing in a greenhouse.

From what I could tell reading the code itself, even regular double pane glass would not qualify. It would have to have some additional treatment as well. (not that I could afford double pane glass anyway)

I could meet the requirements (come to the right heat value) with double wall polycarbonate and one or two layers of plastic, but I am not sure if I can do this. I do have lots of old windows, but I can't just triple pane them myself because each window does not have a rating.

I can't ignore the building inspector. Not only am I visible on his way home from work, I am building on the site of a building that he forced the former owner to take down when it was almost completed (he had no permit).

Does anyone have a way around this ?

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I don't know squat about Canadian laws in OH, we can seek a variance on building codes.


    Bookmark   October 25, 2009 at 6:20PM
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kudzu9(Zone 8a - PNW)

I also don't know Canadian code, but I think this guy is slightly over the line. There are also requirements about window efficiency in my building code, and limitations of glazing area to 25% of the area of the external walls. But these requirements do not apply to structures smaller than 200 square feet (mine is 150 square feet). And if they applied to greenhouses larger than 200 square feet, then what kind of greenhouse could you build? What you're building is not a dwelling, and, although the worthy goal of conservation codes is reducing use of fossil fuels, I'm just not sure he's requiring something that he has the authority to do. Do your codes apply to "accessory structures"? Do they apply to structures that do not have a permanent heating device installed? I've run into more than one building inspector who tried for an "expansive" view of what the code required, and sometimes have had to engage in appeals, either formally or informally to get a reasonable conclusion. I think you need to do a little research. For example, check with other residential and commercial greenhouse owners to see what was required of them. Read the building code for loopholes that might indicate the code simply doesn't cover your planned structure. And consider getting someone else in the building department involved. This guy has a boss, and, if you are polite but persistent, you may get a different answer. It's entirely possible that this guy is selectively quoting code to you and counting on your unfamiliarity with it to not know there are exceptions. Good luck, and please update us on your progress.

    Bookmark   October 26, 2009 at 1:45PM
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Commercial Greenhouses are covered by a different code in Ontario (the farm building code). I don't fall under that because I am in a residential area.

I haven't been able to find someone who has built a heated greenhouse with a permit since the new rules came into effect (year or two ago). Thats why I was posting here.

Small town, so this guys boss is the mayor :( I have read the code, but there does not seem to be special rules for accessory structures when it comes to this. For energy ratings there is heated and unheated.

The applicable section of code reads like this
" (1) Except as permitted in Sentence (2), all windows that separate heated space from unheated space shall have,
(a) an overall coefficient of heat transfer of not more than 2.0 W/ m²â°C, or
(b) an energy rating of not less than,
(i) 17 for operable windows, and
(ii) 27 for fixed windows.
" Sentence 2 has no bearing on this.

    Bookmark   October 26, 2009 at 4:51PM
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kudzu9(Zone 8a - PNW)

Yes, I assumed your greenhouse would not be commercial, but what standard would a commercial greenhouse need to meet? I suspect that it's probably not as stringent as what they are trying to hold you to. And I would argue that it is discriminatory for them to have a less restrictive standard for a business than a homeowner who just wants a hobby greenhouse. When they put this standard in place, I doubt that any of them gave any thought to small greenhouses. Now they are just trying to cover for themselves by saying it applies to your situation. Are they also saying that if you build a garage and have an electric space heater plugged in that it requires you to have super efficient windows?

A few years ago I, too, lived in a small town (1500 people) and the chief building inspector was a jerk. I finally had to go to the mayor to get a dialogue going and resolve a ridiculous ruling by the inspector. I won, but not without some time, effort, and persistence. You may have to think outside the box and be willing to make yourself heard by someone other than just the inspector. You also may have to apply for a variance. Otherwise, I think you are stuck.

    Bookmark   October 26, 2009 at 6:24PM
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garyfla_gw(10 Florida)

You need to talk to someone within the area that you're building and familiar with local codes.
Not sure I would argue about appropriate building materials for your area. After all operating a GH can be more expensive than building one for sure. Could see where that type of covering would save a fortune in heating costs.??
I guarantee you DON"T want to build something out of code. The real surpise comes when you go to sell even if you get by with it. If nothing else would cause serious evaluation problems maybe even impossible to sell
First step is to talk to "Code enforcement" Don't like the answer talk to a lawyer.
Heard the old saying"You can't fight with city hall"??
Sure you can but be prepared to drain your bank account!!! lol gary

    Bookmark   October 28, 2009 at 6:07AM
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kudzu9(Zone 8a - PNW)

I'd be interested to know if you've had any luck making progress with this issue...

    Bookmark   November 2, 2009 at 1:10PM
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I know this is probably kind of old, but this is the solution I have come to. I am building a heated shed (with energy effectient windows) behind the unheated greenhouse. There were be a window and door between the unheated greenhouse and the heated shed.

There is nothing in the building code about forgetting to close a window or door :-)

    Bookmark   August 9, 2010 at 11:24AM
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