Six Insulation Spots for Vented Crawl Spaces

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Ever wondered why your floors are cold despite having insulation in your crawl space? The secret lies in understanding exactly where and how to insulate properly. Most builders miss critical spots, leaving your home vulnerable to energy loss, moisture problems, and pest infiltration.

Crawl space insulation isn't just about stuffing fiberglass between floor joists. As Michael explains in this eye-opening episode, there are six specific areas that require attention in a ventilated crawl space: rim joists, sill plates, subfloor penetrations, the subfloor itself, ductwork, and water pipes. Each area demands different techniques and materials to create an effective thermal and moisture barrier.

The rim joist—that wooden frame around the perimeter of your floor system—represents what building scientists call a "critical seal." Yet most homes have this area either completely uninsulated or poorly insulated with compressed fiberglass. Michael walks through the superior foam board and spray foam method that creates a true thermal break. Similarly, the often-overlooked subfloor penetrations from electrical, plumbing, and HVAC installations create significant pathways for air leakage that must be properly sealed before insulation is installed.

Perhaps most surprising is Michael's breakdown of common insulation mistakes, like compressing R19 insulation into smaller cavities (reducing its performance to R13) or creating moisture traps by installing vapor barriers in the wrong locations. These practical insights come from decades of crawl space experience and will help you make informed decisions about your home's insulation strategy.

Whether you're a DIY homeowner looking to improve energy efficiency or simply trying to understand your options before hiring a professional, this episode provides clear, actionable guidance for properly insulating a vented crawl space. Subscribe to our channel for more expert advice on creating healthier, more efficient homes from the ground up.

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