TOH has advocated spray insulation on many projects. I like the R factor, but I really like the airtight environment it provides. I have lived in ‘pink-batt’ insulated houses and no matter how hard one tries to create an airtight seal, over time they seem to leak.

I am gutting a 1929 2-story house and want to use a spray foam product. Open cell or closed cell is still a consideration (except for Bay Harbor Insulation water comments). I am inclined to use spray foam in the exterior walls. I’ll use the pink stuff in the 1st floor joists, 2nd floor joists and interior walls (primarily for sound insulation).

I haven’t finalized the roofing material. The two considerations are either a standing seam metal roof or dimensional asphalt roof. I live in Southern California and it gets pretty hot. If a metal roof is used, there seems to be no issue spraying foam between the roof rafters. In this application there is no attic ventilation and the gable ends would have to be sprayed. If an asphalt roof is used and the same roof rafter spraying technique is used, the asphalt roof will get ‘cooked’, greatly reducing its life expectancy. This has been told to me by multiple roofing contractors. If asphalt is the product I would think my only option is to spray the ceiling joists, vent the attic and leave the roof rafters open as in a traditional manner. It would also seem this we would be less expensive since the square footage is reduced as well.

Any thoughts or comments? All is welcomed. Thank you in advance.