spray foam quesion - Contractor Talk - Professional Construction and Remodeling Forum

mikeybobo · 06-15-2009, 08:22 PM

I cant get a straight answer about spray foam. everyones got a different, theory......
we've only had 2 jobs that we have done spray foamed, one just being the ceiling of an old farm house. now I'm getting ready for the insulation of my own home that I'm renovating (2x4 walls, 3x6 ceiling joists upstairs, new 2x10 rafters). Now the company we have used at work the two times says to do a closed cell in the walls and ceiling. Now my neighbor who is some sort of energy star rep says that it will make the house too tight, and he thinks that doing open cell in the walls and ceiling will help with the house breathing, and even though its about r-14 for the walls (4"@r3.5) and r21 in the upstairs ceiling, that the open cell foam is a true r-rating, meaning when they say r13 for example for 2x4 batt insulation, on average it gets a much lower actual r rating, so the true r14 is much better than the fiberglass and a fraction of the cost for the open cell compared to the closed and lets the house breath better. Now my HVAC friend tells me I should do a closed cell in the walls, and an open cell in the rafters and the ceiling joists, or just the rafters alone. I know making the attic part of the insulated space can be good if you have air handlers, ect in the attic, but all I have up there is a 4' length of 14" flex going to a ceiling return grill, all other ducts and handlers are in conditioned space.
So I figured I'd throw this out there and see how many different responses I get and go with the majority vote

SLSTech · 06-16-2009, 08:40 AM

Closed Cell is the only Code Tested & approved system still to my knowledge (Demilic is best IMHO)

Icenyne is good with their marketing & are pushing their product through all sorts of groups, but they only sell open cell foam which still is not approved

Fine Home Building just had a good article on this, there are quite a few posts by me & others on here (pull a search for posts by me with the words Demilic or close cell foam in them) & last but not least - building science website is another resource

Yes, if you seal up a building properly, you need to introduce fresh air - thus an ERV or HRV is needed & truthfully not that hard to install. I generally recommend staying away from one tied to the AC / Heater & go with a simple standalone one - as you won't be running the AC / Heater as much & it may not draw in enough air to help get the containments out

You really need to find someone local that understands all the systems & how they tie together. The biggest issue with the LEED, Energy Star, NAHB, etc... systems - is they generally go by points & look at getting to X standard, not how everything ties together.