Spray Foam Insulation in Scranton, PA

Spray foam insulation goes on as a liquid, expands into every gap and cures in place, so one layer stops air and slows heat. In Scranton's older houses, that makes it the right tool for some spots and the wrong one for others. It shines on stone and brick foundation walls, sills and rim joists, kneewalls, cathedral ceilings and roof bays with no room to vent. It is usually not our first choice for plaster walls in balloon-framed houses or for a wide-open attic floor.

Closed cell vs open cell

Closed-cell foam cures dense and rigid. HomeGuide lists it at R-5 to R-7 per inch, and at normal thickness it slows vapor and does not soak up water. That suits foundation walls, sills and rims, where cold surfaces meet damp basement air. Open-cell foam is softer and expands more, at R-3.5 to R-3.7 per inch. It seals air and quiets sound, but vapor passes through it, so in Zone 5 it needs a vapor retarder or a design that lets moisture dry out.

Stone and brick foundations

Many valley houses sit on fieldstone or brick foundations with a wood sill on top. Cold air leaks in at the joints between stone and sill and around every pipe and wire. Closed-cell foam sprayed over the sill, the rim and the upper part of the wall seals all of it. Old foundations can let some water through, so we check for dampness first and leave the lower wall alone where it needs to dry.

Attic floors and kneewalls

In the attic, we use foam to seal the tops of open wall cavities, the gaps around chimneys (with metal and fire-rated sealant at the chimney itself), plumbing stacks and light boxes. Then cellulose goes on top to depth. Story-and-a-half houses get foam on kneewalls and the short attic floors behind them.

Roof bays and porch roofs

Attic rooms, finished third floors and enclosed porches often have roof bays only a few inches deep. Closed-cell foam reaches a useful R-value in that space without needing a vent channel. We check the roof for leaks before we cover the deck.

When not to use foam

Foam should not go over live knob-and-tube wiring, untested vermiculite, wet wood or a leaking roof. In plaster walls, dense-pack cellulose usually does the job for less and lets the wall dry. We tell you which parts of your house are worth foaming.

Curing and safety

We cover and mask the work area and ventilate it. HomeGuide advises staying out for 24 hours or more while foam cures. Foam needs the surface and material within a working temperature range, so cold attics and porches in a Scranton winter may need added heat or a milder day.

Rebates

PPL's rebate form for June 2026 through May 2031 lists rim joist insulation at 75% of cost, up to $500 or $200 depending on heating type, and requires spray foam or rigid foam for the rim. Get a free estimate