Building science case studies have shown Maine home builders the importance of sealing wall systems to prevent air infiltration into the building envelope.
Reducing air infiltration is as important as adding additional insulation as a strategy for improving energy performance.
Additionally, leaky wall assemblies can be prone to condensation and water damage (mildew, mold, dry rot) as the air exchange creates cold spots for moisture laden air from within the building to condensate.
We have previously discussed measures we have taken to reduce thermal transfer and maximize space for insulation.
At this point framing is complete, roofing installed, windows and doors installed and we are tight to weather.
Soon the insulation and then drywall will be installed closing in the wall cavities. Prior to that occurring we have full access to the inside of the wall cavities and an opportunity to seal any areas that could potentially allow unconditioned air from outside the house to enter into the conditioned space of the building envelope.
Areas of concern are: the sill plate to concrete floor connection (even though we utilized sill seal foam during construction), all sheathing panel edges and perimeter openings for windows and doors(even though we taped all seams from the exterior with DOW Weathermate tape), and wall plate seams and penetrations.
DOW professional expanding foam sealant is utilized extensively in these areas and will dramatically improve how much (or how little) air infiltration can occur.
We also seal any penetrations left behind from our platform staging and penetrations from plumbing and electrical rough ins.
These efforts also keep any air trapped within the wall assembly (once they are closed in) from circulating and causing convection which can create drafty conditions inside the house.
To conclude, there are many areas that can potentially leak air into the building envelope if left unsealed. Each area sealed collectively helps to “tighten” the house helping to improve energy efficiency, sustainability, and comfort for its occupants.