How Much Air Sealing Do I Need?
Trying to figure out how much air sealing is needed.
We are building a single story house in central Missouri (Jefferson City are so zone 4c, I think- mixed/humid). It has 2×4 walls and we have spray foamed the exterior walls with open cell spray foam. They also caulked along all the of all exterior walls to the subfloor. Going outwards, it then has house wrap and then HardieBoard siding. It is on a crawl space that has been encapsulated with about 2” closed cell spray foam or more on the inside walls and spray foam is sprayed over the floor joists and sill plate as well. It has a flat ceiling and we will be doing loose fill cellulose up in the attic, and the attic access is from the outside above the insulation level, so no air leakage from inside the house. The insulation isn’t in yet, so I went up to the attic and did “great stuff” spray foam into any holes for wires and also where the interior walls intersect the ceiling, so I tried to seal between the wood and the drywall ceiling from above. I also did a “cap” of great stuff foam over light housings and ceiling fans and tried to seal the bathroom fans similarly as well. All vents go to the soffit or outside. We are using ductless multi-head mini split to heat and cool, so no duct leakages.
—So, my question is:
I was telling my spouse that we should caulk everywhere the drywall meets the floor, the outlets, and the light housings before we put in the plugs, lights, etc to stop any air Leakage going there and up behind the drywall. He says since I did the spray foam up above that this is an unnecessary waste of time and money. I know you can’t have too many air barriers, but he is reluctant to spend time on this unless it really makes a difference. If it is overkill it is not worth the strife. So I am asking for advice. Should we caulk anything now? If so, what. I also wonder if vibration of ceiling fans and bath fans could cause cracks in the great stuff foam that we won’t be able to find under the insulation later.
Thank you all in advance.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part