I am an architect working on a 2 BR/2BA high end addition above an existing garage in the mountains of Colorado. The exterior walls are 2x6 walls, roof has 2x12 rafters, floor is 11-7/8" TJI's with 1 1/2" of gypcrete for radiant heating and tile floor. Garage below is heated and insulated. The contractor just insulated the new space and did it differently than spec'd. We caught it before drywall and he is going to go back and make changes to bring things to what was spec'd. We are having extremely cold temperatures right now (-15) and I'm concerned about installing foam on very cold sheathing. Here is what was spec'd and what was installed:
2x6 Wall spec: 2" min. spray foam with blown-in cellulose insulation to fill the cavity, no vapor barrier. Installed: 5 1/2" of blown fiberglass with vapor barrier.
2x12 Roof spec: 4" min. spray foam with blown-in cellulose insulation, no vapor barrier.
Installed: roughly 2 1/2" to 9" spray foam and R-30C kraft faced batts. Doing a partial inspection I found one area about 12"x24" where there was no foam against the roof sheathing.
2x Interior Wall spec: blown-in cellulose.
Installed: kraft faced batts and open faced batts.
11-7/8 TJI Garage Ceiling spec: blown-in cellulose for sound and insulation.
Installed: kraft faced batts. There are plumbing lines in the garage ceiling and contractor felt that batts would be better if there were ever a water leak.
We also called out to spray foam all penetrations and rim joists. All penetrations in studs, plates, rafters, and sheathing were also to be filled. Wood to wood connections and gaps were to be caulked and sealed. The rim was not foamed and some penetrations were filled but many were not. I don't know if penetrations at the exterior fiberglass filled wall were foamed.
I had a very helpful conversation with an insulation expert from Wisconsin yesterday who has cold climate concerns about the "flash and batt" system and also expressed concerns about trying to apply foam to extremely cold sheathing, should we stay with the spec.
I'm curious to get forum input about our best options at this stage. Does the extreme cold we are having make our spec'd wall system much more difficult to install properly right now? Would heating the interior make it less likely to have foam adhesion issues?
I'd also be curious to get thoughts about the existing blown in fiberglass insulation vs. our spec'd system. The owner wants a very good thermal envelope. And finally, thoughts about the garage ceiling as installed vs. spec'd would be great.
In addition: blower door test? foam manufacturer inspection?
Thank you for your time and consideration of our situation.
Posted Fri, 12/06/2013 - 12:06
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