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!

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Testimonials

Adam F., River Falls, WI

Call St. Croix Energy Solutions if you care about saving money, energy and the planet. The company recently insulated my 100-year-old farmhouse, and now it feels like someone placed a warm blanket over the whole place. I called because with my first child on the way, I was concerned about the temperature in our upstairs bedrooms. We do not have duct work upstairs and rely on baseboard electric heaters in the winter. Since St. Croix Energy completed their work, I've rarely had to turn the electric heaters on at night, and that's despite temperatures plunging to zero degrees. If your home is old, drafty, or simply costing you a bundle on heating and cooling costs each mon... (read more)