NY State code requires that new homes be built and tested to a maximum air leakage rate of 3 air changes per hour at 50 pascals of pressure.
If you are planning on using tradition batt insulation, there are a handful of critical air-seal details that must be followed to insure a continuous air barrier.
- All penetrations through the building envelope need to be sealed. In most cases, required fire-caulking provides the seal. Usually, it’s the larger penetrations (like fireplace flues, dryer vents, and range hood ducting that causes most of the problems.
- The MOST CRITICAL SEAL is the connection between the top plates and drywall anywhere that the ceiling meets the attic. Mismatches in the plates, hurricane strapping, wire protectors, nail heads, etc. along with shrinkage of the wood itself leave a gap between drywall and wood. Attic air drops down into the wall through this gap and then leaks into the room from electric boxes, low voltage penetrations, and especially from under the baseboard moldings since the same gaps occur at the bottom of the wall also.
- It’s also important to have effective sweeps under doors, and gasketing around attic scuttles and stairs.
Below is a useful downloadable whitepaper of further air sealing potential issues and guidance
