In this episode of The Build Show, Matt demonstrates how exterior mineral fiber insulation can dramatically improve a home’s fire resistance while delivering year-round energy benefits. He compares PowerWool’s Class A, non-combustible mineral fiber board to traditional foam insulation, showing how foam quickly melts, burns, and drips under a propane torch, while mineral fiber withstands over 2,000°F with minimal surface change. Wrapped around a monopoly-framed wall assembly, the two-inch PowerWool layer prevents heat from penetrating the sheathing, which stays near room temperature even after a full minute of direct flame. Matt also highlights mineral fiber’s additional advantages: vapor permeability, moisture safety, acoustic performance, dimensional stability, and resistance to insects, rodents, and decay. He explains how it supports best practices in fire-zone construction, especially when paired with Class A roofing and siding, and how ember-resistant screening may be needed in rainy climates. Overall, Matt shows why mineral fiber acts like a fire blanket for modern homes.

Huge thanks to our episode sponsor, Powerwool. Watch more of Matt's episodes and follow him on Facebook and Instagram.
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