THIS is Why Your Heat Bill is So High! Rim Joist Insulation Technique!

Summary by Krater

An experienced renovator compares three methods of insulating rim joists in a basement—fibreglass batt, rigid foam with spray foam, and two-component spray foam kits—explaining R-values, thermal bridging, air sealing, and cost.

From the video

Answers: How do I insulate and air seal basement rim joists?

• basement rim joist insulation
• thermal bridging in framing
• air sealing rim joists
• spray foam kits

What it concludes

• Two-component spray foam kits provide the best air seal and R-value for rim joists, eliminating the need for separate vapour barriers and thermal breaks.
• Using fibreglass batts alone in rim joists leaves the home vulnerable to cold air infiltration and high energy costs.
• Applying spray foam in layers not exceeding 2 inches prevents overheating and combustion during curing.
• Purchasing two-component spray foam kits for DIY application is cost-effective for full-basement insulation compared to hiring contractors.