Building Envelope Solutions
Air sealing comes before insulation
Most drafts, cold floors, hot upstairs rooms and high bills come from air moving through the house, not through the insulation. Warm air rises and escapes through the top of the house, and cold air is pulled in at the bottom. Insulation slows heat, but it doesn’t stop air. That’s why we seal the leaks first, then insulate.
Signs your home needs air sealing
- Drafts near outlets, baseboards and windows
- Cold floors over a basement, garage or crawl space
- Upstairs rooms that are hot in summer and cold in winter
- Dust lines on carpet edges or insulation that has turned dark
- Ice dams on the roof edge in winter
- A boiler or furnace that runs a lot more than it should
Where we seal
- Attic floor and roof edge: top plates, wiring holes, recessed lights, chimney and flue gaps, and the attic hatch.
- Basement and crawl space: rim joists, sill plates and pipe and wire holes through the foundation.
- Walls and floors: plumbing chases, dropped soffits and gaps behind tubs and kitchen cabinets.
- Party walls in row houses and brownstones: the gaps where cold air moves between houses.
- Multifamily and commercial: roof edges, shafts and gaps between floors that drive stack effect.
We use foam, caulk, sealant and rigid board depending on the gap and the fire rules for that spot.
Air sealing and insulation together
Sealing and insulating are usually priced and done in the same visit. In attics we seal the floor, then add blown-in insulation. Where we use spray foam, the foam is the air seal. Both often qualify together for utility programs. See our NYC insulation rebate guide.
Common questions
Can a house be sealed too tight? Older NYC homes are rarely close. When we seal a lot, we check that bathrooms, kitchens and gas appliances vent properly.
How long does it take? Air sealing a typical home takes part of a day, and it’s usually done alongside the insulation.
Do you do larger buildings? Yes. We air seal walk-ups, apartment buildings and commercial spaces, and it can help with Local Law 97.