Spray Foam Insulation in Oshkosh, WI

Spray foam insulation in Oshkosh has two jobs: keeping heat in through a long winter and dealing with the moisture that comes with living on a big lake. January lows average about 10°F here and the city gets around 39 inches of snow a year, while much of Winnebago County sits on dense red lake clay that holds water near foundations. We are spray foam insulation contractors who also blow loose fill and remove old insulation, so each part of the house gets the material that fits it.

The houses we see

Oshkosh has six historic districts and a large stock of older homes, many rebuilt after the 1875 fire that burned 500 houses north of the Fox River. Those homes often have empty walls, thin attics and stone or block foundations. Postwar ranches have shallow attics and bare rim joists. Newer homes in Algoma, Neenah and the edges of the city have better attics but still leak at the rim and over garages. Rentals near UW Oshkosh are a big share of the market, too.

Closed cell vs open cell

Closed-cell foam, rated R-5 to R-7 per inch by HomeGuide, is dense and slows vapor at normal thickness. It is the right choice for damp basements, crawl spaces, rim joists and steel buildings. Open-cell foam, at R-3.5 to R-3.7 per inch, is lighter and cheaper per square foot and works in interior walls and roof lines where moisture is planned for. Loose cellulose (R-3.1 to R-3.8 per inch) is the usual choice over a sealed attic floor.

Code targets

Winnebago County is in Climate Zone 6A. The Insulation Institute's summary of Wisconsin's Uniform Dwelling Code lists R-49 for ceilings, R-20 or R-13 plus R-5 continuous for wood-frame walls and R-19 cavity or R-15 continuous for basement walls in Zone 6. Existing homes are not required to meet them, but they are useful targets.

Spray foam insulation cost

HomeGuide's national range for installed foam is $1.50 to $5.00 per square foot: open cell $1.50 to $3.50, closed cell $3.00 to $5.00. For about 1,000 square feet, it lists $1,500 to $5,000; Fixr lists $3,150 to $7,500 for an existing home. Rim joists alone typically run $2,000 to $2,500. Your written estimate is the price.

Hiring insulation contractors

Whoever you call, ask which product goes where and how thick, how they handle ventilation and how long you stay out (HomeGuide advises at least 24 hours), what they do about damp walls and old wiring, and whether the quote shows R-values for every area. Specific answers matter more than the lowest number. Get a free estimate

Rebates and timing

Focus on Energy, the statewide program run with Wisconsin utilities, has published rebates for attic, wall, foundation and sill insulation, with air sealing rebates tied to insulation installed by its registered Trade Ally contractors. Terms change, so check the current offer before you plan around it. Fall is the busiest season; attic and basement work can be done any time of year.

We work in Oshkosh and the communities around it: Neenah at the north end of the lake; the towns of Algoma and Clayton just outside the city; Omro and Winneconne up the Fox and Wolf rivers; Fond du Lac and North Fond du Lac at the south end of the lake; Ripon, Berlin and Waupun to the southwest; Chilton to the east; and New London up the Wolf. Many of these places sit on low ground near water, and several saw flooding in April 2026, so basement moisture is a bigger part of the conversation here than in most markets. The older river and lake towns have a lot of pre-war housing; Algoma, Clayton and North Fond du Lac have grown faster in recent decades.