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Discussion Starter · #1 ·
Hi all I am in the process of building an extension, 16x24 to an existing
structure in coastal northern CA ( temperate but humid). It rarely gets below freezing in the winter but still seems cold as it is a wet climate then. The walls are 2x6 framing, 12ft high ceilings ( art studio)
I am curious about diy sprayfoam ( tiger/foam it green etc..) but have never seen it done, don't know anyone who's done it and their respective websites are a bit confusing.
Can anyone clarify a few things:
-what is the difference between closed and open cell?
-are these foams applied in one or several layers?
-how accurate are coverage estimates? how much additional surplus do you factor in?

Thanks in advance for your answers.
Cheers!
 

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I'm not an expert on the foam material itself, but every time the option is presented the results seem to be, it's less expensive to just have someone do the job with the bigger machines. The DIY foam kits seem to be best suited for jobs that require foam but are not large enough to attract one of the big companies with a reasonable price.

The question really comes down to what you need for insulation. Is this for the walls or were you looking to foam the rafters, bottom of the roof deck?

Bud
 

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Discussion Starter · #3 ·
Thanks Bud. the problem is that where I live, rural and scarcely populated area, no one does the job..so if that is the route I will take I'll have to do it myself. The attich will be blown in insulation. Here I am just doing the walls.
Floor joist will be fiberglass
 

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My business is energy efficiency consulting so along with some great volunteers here we can offer you some good advice. Using rigid foam is less expensive and far more DIY friendly. Cut to fit with a small gap and foam in place with the can foam.

Are you targeting code minimums? If so, what number?

One step that is required and more beneficial than some extra r-value is air sealing. Of course the spray foam will catch much of that, but the rest of the house could use the same TLC.

Of the people I know who have used the home DIY packs they have basically been satisfied. From what I know it is installed in 1" to 2" lifts so would take several applications. It is best in warm weather, but MUST be installed exactly as instructed. There have been issues with professionally installed foam dealing with off-gassing and even fires due to curing temperatures. I can dig out the name of one particular person who has posted many articles related to his dislike of foam. The emphasis from the mfgs in their defense seems to be, follow the instructions and be sure the installers are properly trained. How much concern carries over to the DIY packs I cannot say.

I did some searching and the gentleman who has done a lot of digging into the issues of spray foam is Richard Beyer. His name comes up often in searches.

Here is a related link on spray foam that should be helpful.
http://www.greenbuildingadvisor.com/green-basics/spray-foam-insulation-open-and-closed-cell

Bud
 

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I think the others have answered most of your questions except for the question about the difference between closed cell and open cell foam. Close cell phone has a slightly higher R-value per " of thickness and forms a complete vapor barrier. The downside is it's slightly more expensive. Open cell foam has a lower R-value and requires the installation of a secondary vapor barrier. I've always used closed cell foam in projects that I've done, mainly because of the higher R-value.
 
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