Spray Foam Insulation in Oshkosh, WI

Spray foam insulation is mixed at the spray gun and expands into the cracks and cavities it hits, bonding to wood, concrete and steel. It does two things loose fill and batts cannot: it seals air leaks completely and, in its closed-cell form, it resists moisture. Around Lake Winnebago, where winters are long and many basements sit in clay that stays damp, both of those matter.

Closed cell

HomeGuide rates closed-cell foam at R-5 to R-7 per inch. It cures hard, adds rigidity, slows vapor at normal thickness and does not absorb water. That makes it the go-to for rim joists, foundation and crawl space walls, floors over cold spaces and steel buildings. It is the more expensive of the two per square foot.

Open cell

Open-cell foam is soft and expands much more. At R-3.5 to R-3.7 per inch it needs more thickness for the same R-value, but it costs less and fills irregular cavities well. It also dampens sound. We use it in interior walls and roof lines where a vapor plan is in place, never against concrete or below grade.

Where foam pays off

Foam earns its cost where air leaks are concentrated or space is tight: rim joists, cathedral ceilings, kneewalls, walls in additions and new construction, and outbuildings. Over a big open attic floor, sealing the leaks and blowing loose fill usually gives more R-value for the money, and we say so on the quote.

Before spraying

We check for moisture, old wiring, roof or plumbing leaks and heat sources. Foam is kept away from flues and hot fixtures, and exposed foam in living areas usually needs a fire-rated covering. All of that is written down before we start.