Spray Foam Insulation in Des Moines, IA

Spray foam insulation in Des Moines usually means working on older houses. Point2Homes' summary of Census data puts the median year built in the city at 1961. About 26.7% of homes went up before 1940, another 7.4% in the 1940s and 14.8% in the 1950s, so roughly half the housing stock is more than 65 years old. Many of those homes were built before anyone thought about air sealing, and most have had only patchy insulation upgrades since.

What we find in pre-war houses

Foursquares, bungalows and story-and-a-half homes from the 1910s to 1940s tend to share the same problems. Walls were often balloon framed, with studs running from the sill to the roof and nothing blocking the cavity, so warm air rises inside them into the attic. Attics have a few inches of old loose fill or matted batts. Kneewalls in upstairs rooms are thin or bare. The rim joist sits on a block, brick or stone foundation with gaps all around. The most useful work is usually capping the tops of open walls, sealing chimney and plumbing chases, foaming the rim and kneewalls, and blowing the attic floor to depth.

Post-war ranches

The 1950s ranches and small two-stories that fill many close-in neighborhoods have simpler framing but similar gaps: a bare rim, a shallow attic with settled insulation, and leaks around ceiling fixtures and the hatch. These jobs are often finished in a day.

Winters and summers here

Wikipedia's Des Moines climate table lists a January mean low of 13.8F, a July mean high of 85.6F and about 36.5 inches of snow a season, with records of -30F and 110F. A leaky house pays for that range twice: heating in January and cooling in July. Sealing the attic floor and rim joist helps in both seasons.

Basements and the 1993 flood

The 1993 flood put the Des Moines Water Works under water on July 11, 1993, and about 250,000 people went without running water for 12 days. A levee broke again in June 2008. Most basements in the city never saw river water, but many have had seepage in wet years. We check for it before insulating and use closed-cell foam on rims and walls where damp is possible.

A typical Des Moines plan

Take a 1920s two-story with a stone or block foundation and an attic that was last insulated decades ago. We would seal the attic floor around the chimney, plumbing stack and light fixtures, cap the open tops of the wall cavities, build a dam around the hatch, and blow cellulose toward R-49. Downstairs, closed-cell foam goes around the full rim. If the walls test empty, dense-pack fills them from small holes. Each of those is a separate line on the quote, so you can do the whole house at once or start with the attic and rim.

What it tends to cost

HomeGuide's national figures put air sealing at $350 to $3,000 and a rim joist foam job at about $2,000 to $2,500. Older Des Moines houses often sit toward the top of the air sealing range because there are more open chases to close. We show you the leaks we plan to seal, so the price is easy to follow. Get a free estimate