Spray Foam Insulation in Windsor Heights, IA

A small city with an old, uniform housing stock

Windsor Heights is a small city of about a square mile and a half, surrounded by Des Moines, West Des Moines, Urbandale and Clive, centered on University Avenue and 73rd Street. It was built out in one burst after World War II. The Census Bureau's 2020-2024 American Community Survey shows a median year built of 1960 for its roughly 2,400 housing units, with about 70 percent built before 1960 and only about 7 percent since 2000. Nowhere else in the metro is the postwar era so dominant.

That makes the insulation picture unusually predictable. Story-and-a-half Cape Cods with knee-wall attics and sloped ceilings. Single-story ranches with low-pitch roofs and shallow eaves. Block foundations with an open rim joist. A few inches of original insulation, often rock wool, with maybe one blown-in top-up decades ago. Bath fans added later and vented into the attic. Recessed lights from a kitchen remodel. Almost none of it air sealed.

The Cape Cod problem

The story-and-a-half is the classic Windsor Heights house and the classic ice dam house. The finished upstairs has knee walls with a small triangular attic behind them, a sloped ceiling section with two-by-six rafters, and a flat attic above the center. Heat and air leak through the knee walls and the top of the sloped section, warm the roof deck right above the eave, and the dam forms there every winter. The fix is to air seal the knee wall floor and the back of the knee wall, get real R-value into the sloped bays (which usually means closed-cell foam because the space is shallow), and seal and insulate the flat attic above. It is a detailed job and the scope will lay it out section by section.

Ranches and rim joists

The single-story ranches are simpler: a low attic that needs its floor sealed and blown to depth, eave baffles where the pitch allows, and a block foundation where two inches of closed-cell foam across the rim joist and the top course of block closes off the coldest spot in the basement. Many of these houses have had a basement finished at some point with fiberglass against the block; if that wall is being redone, foam is the right replacement.

Because Windsor Heights houses are so alike, we can usually tell you what the scope will look like from the street. The assessment confirms it and finds the surprises.