Spray Foam Insulation in Oshkosh, WI

Spray foam insulation in Oshkosh often goes into older houses. The city has six historic districts and 33 National Register listings, and much of the north side was rebuilt after an 1875 fire destroyed about 500 homes. Those houses commonly have empty walls, thin attics and stone or block foundations, and they lose a lot of heat through a winter that brings about 39 inches of snow and January lows near 10°F.

Rentals

Census QuickFacts lists a 55% owner-occupied rate, and UW Oshkosh serves about 15,000 students, so many houses near campus are rentals. Landlords usually want to cut heating costs and tenant complaints without major remodeling. Attic sealing, rim joist foam and dense-pack walls in the coldest rooms fit that well.

Clay and water

The state geological survey describes the red, clay-rich lake sediment under much of Winnebago County as relatively impermeable. Water collects against foundations, and in April 2026 the National Weather Service reported prolonged flooding along the lake's west and north sides affecting Oshkosh. We check every basement for moisture before insulating below grade.

Code zone

Winnebago County is in Climate Zone 6A, where Wisconsin's code summary lists R-49 ceilings and R-19 cavity or R-15 continuous basement walls.

Costs

HomeGuide lists attic jobs at $1,000 to $2,700, rim joist foam at $2,000 to $2,500 and dense-pack cellulose at $1.60 to $4.20 per square foot. We price each area in writing after a visit.

How a visit goes in an older Oshkosh home

We start in the basement, checking the foundation for water marks and the rim joist for gaps, then go to the attic to measure depth and find bypasses. In homes with plaster walls we look for knob-and-tube wiring before planning any wall work. If vermiculite shows up in the attic, we stop and recommend testing. The written quote lists each area with material, thickness and R-value, so you can do the attic and rim first and plan walls for later.