Spray Foam Insulation in Johnston, IA

Johnston's housing in numbers

Johnston lies northwest of Des Moines, bounded roughly by the Des Moines River and Saylorville Lake on the east, Camp Dodge on the north and Beaver Creek on the west. It grew fast from the 1990s on. The Census Bureau's 2020-2024 American Community Survey shows a median year built of 2004 for the city's roughly 9,700 housing units, with about 63 percent built since 2000 and only about 4 percent before 1960. The older pockets sit near the original town along Merle Hay Road and NW 62nd Avenue.

The result is a city of two-story and story-and-a-half houses with walkout or daylight basements on the rolling ground toward the river, many of them finished or about to be.

The walkout basement question

Johnston's terrain toward Saylorville produces a lot of walkout basements, which means one or two basement walls are framed above grade while the others are poured concrete below grade. The above-grade framed walls need to be treated like exterior walls; the below-grade concrete needs foam against it before finishing. Getting both right, plus the rim joist that runs continuously around the top, is the core of a Johnston basement scope.

We also see many bonus rooms and finished upper floors with knee-wall attics behind them. The flat attic over the main house may be well insulated while the knee walls and the sloped ceiling between them are barely touched, which shows up as a cold room over the garage and an ice dam right above it.

Outbuildings and acreages north of town

North and west of Johnston toward Polk City and Grimes there are acreages with pole buildings and shops. Closed-cell foam on the steel roof and walls stops the winter condensation drip and makes a shop heatable. If that is your building, tell us how you use and heat it and we will scope the thickness to match.