Basement and crawl space insulation on Long Island

Basement and crawl space insulation

Cold floors, damp basements and drafts at the baseboard usually start below the house. The rim joist, where the floor framing sits on the foundation, is one of the leakiest spots in a home.

Most Long Island homes have full basements, and many have crawl spaces under additions. Near the shore, damp is part of the picture.

What we insulate

• Rim joists: foam around the band on the foundation.
• Basement walls: for heated or finished basements.
• Crawl spaces: under additions and sunrooms.

Why closed-cell foam

Closed-cell spray foam seals and insulates in one layer, and it doesn’t absorb water, so it suits concrete, block and stone foundation walls. Where a space needs a fire-rated covering, we tell you before we start.

Rebates

On Long Island, gas is mostly National Grid and electric is PSEG Long Island. Depending on your home and what is funded this year, that can open National Grid, PSEG Long Island or NYSERDA programs. For 2027, Con Edison and National Grid plan one joint weatherization program for market-rate homes and apartment buildings. We check what is open for your address before we price the job. See the rebate guide.

Common questions

Do you insulate the basement walls or the ceiling? If the basement is heated or you use it, the walls and rim joist. If it is cold storage, sometimes the ceiling instead. We decide after we see it.

Is the estimate free? Yes. Call (347) 200-5089.