The connection between the block or concrete foundation and wood framing of the home is referred to as the rim joist or sill box. This is the most-often overlooked source of infiltration in the home, even though the air lost in this connection is very significant.

As indoor air is heated, it rises and escapes from the home, leaving an area of low pressure behind in the basement. Here, cold outdoor air is drawn in through leaky rim joists. This air not only cools the basement; it also taxes the heating equipment. St. Croix Energy Solutions is here to make sure your rim joists are properly sealed and insulated.

Spray Foam: The Top Choice for Rim Joists

Fiberglass batts are often haphazardly stuffed into these cavities. Unfortunately, batts are largely porous, so they do little to slow heat loss or prevent air leakage. Our team chooses closed cell spray polyurethane foam (SPF) for use around rim joists, the best choice for sealing and insulating these spaces.

As it is applied, SPF expands to seal every nook and cranny, eliminating infiltration in the basement and curing to an thermal resistance value of about R6.5 per inch (twice that of fiberglass!). Spray foam also has peripheral benefits: as it seals the rim joist from air leakage, it also creates a barrier against pests and critters.

Contact us to learn more about sealing up rim joists, and schedule your insulation and air sealing appointment today!

Contact UsEnergy Assessments for $450 or less

Schedule your FREE Home Estimate

Start Now

Testimonials

John Williams, Hudson, WI

They came out and used spray foam insulation along our entire rim joists. They also foamed the holes in the attic where air is escaping, covered recessed lights with boxes and then blew in additional cellulose insulation to reach a final value of R60.
They were very professional. They came in at the time they said they were coming. They went right to work. The work went smoothly and ended before their estimated ending time. They even came back out a couple of times to help touch up some areas and help with a particular problem area that air was leaking through. We finally stopped the draft and we are very satisfied with the work that was done. Our house feels much mo... (read more)