If I use spray foam inside my garage do I have to install a vapour barrier over it like ordinary insulation ? I'm in Canada, so I have no clue if the Ontario Building code says that you have to install a vapour barrier.
Thank you.
Sir:
The reason for installing a vapor barrier is not related to code. If you want your insulation to stay free of moisture and remain an insulation a vapor barrier should be placed on the warm side of the insulation. If you are going to use air conditioning the requirement would be to place a vapor barrier on the walls and ceiling prior to placing the insulation. If you are planning to heat the area a vapor barrier and a flame barrier should be placed on the exposed insulation.
"Section 31" wrote in news:1156044487.873034.102800 @i3g2000cwc.googlegroups.com:
It depends on the type of foam used. Low density (open cell) foam requires a vapour barrier. High density, closed cell foam is completely air tight and waterproof, so it requires no other vapour barrier.
I am in Calgary, so I can't help you with Ontario code requirements. The companies that do foam insulation will know the local code requirements.
Hey Murray:
Art,
I'm not saying you're wrong about sprayed in foam needing a vapor barrier, but can you provide some verification? The info I've come across tends to lead me to believe no vapor barrier is required (even building codes). Or, are you referring to specifically cold storage design?
"Art Yokell" wrote in news:r7ZFg.10864$ snipped-for-privacy@newsread4.news.pas.earthlink.net:
Strange -- the manufacturers of the foam products are asserting otherwise (including the ones that insulated the walls of my house). For example:
The on-line vendor of
Murray Peters> "Art Yokell" wrote in
Well, sales literature like this has been around for years. Please note that none of the testing indicates no vapor barrier only the claims of the manufacturer. None of the companies mentioned are amongst the major spray foam suppliers of the world.
"Art Yokell" wrote in news:jH3Gg.10145$ snipped-for-privacy@newsread1.news.pas.earthlink.net:
I think it's a bit more than just sales literature. My house walls are insulated with 2-lb SPF, and have no vapour barrier. Both the foam contractor and the building inspector believed that this fully met all Canadian (residential) building code requrements. I can't speak for refrigeration facilities -- that's a different kettle of fish entirely.
Murray: I started out in my initial post saying the the vapor barrier has nothing to do with buidling codes. The fact that your house has no vapor barrier has no impact on the discussion. It will in my opinion take some time in a home for this to become noticable. However, you will slowly but surely be paying for the lack of a vapor barrier in higher heating or cooling bills.
Hate to break it to you but there is obviously a huge difference between cold storage and residential construction because that is flat out wrong.
Vapor barrier in a house goes on the warm side. The only place the vapor barrier goes up before the insulation is in the very far Southern US. In Canada it is ALWAYS on the inside under the drywall regardless of air conditioning.
Closed cell foams, such as Corbond, do not require a vapor barrier. Open cell, such as Icynene, do.
Steve.
I don't know what's in the Canadian Building Codes, but it is certainly required here in the US (by building codes). And my guess is that they are also required by the CBC as well.
In the 2003 IRC, "Moisture Vapor Retarders" are required by Section 318 except for certain counties in the extreme southern states or where wall cavities have beed designed to allow for ventialtion of the moisture.
"PPS" wrote in news:%okGg.4014$hP6.366@trnddc04:
Here is the "final word" as given by the Canadian National Research Council (NRC):
Interesting read, thanks for posting. Have they adopted this into the NBC?
Anyone have a rough guess as to what the installed price of closed (such as Corbond) or open (Icynene) cell foam is going for (per sq. ft.)
Murray, you were absolutely correct. Not only does the closed cell not require a vapor retarder, it should not be used at all, especially on the exerior side.
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