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MoisTURe management. Code Minimums for Exterior Foam. Zone 6 2x4 walls: R-7.5 1.25” polyiso @ R-6/in 1.875” mineral wool @ R-4/in 2x6 walls: R-11.25 1.875” polyiso @ R-6/in 2.812” mineral wool @ R-4/in. GWP. Source: Avoiding the Global Warming Impact of Insulation
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Code Minimums for Exterior Foam Zone 6 • 2x4 walls: R-7.5 • 1.25” polyiso @ R-6/in • 1.875” mineral wool @ R-4/in • 2x6 walls: R-11.25 • 1.875” polyiso @ R-6/in • 2.812” mineral wool @ R-4/in
Source: Avoiding the Global Warming Impact of Insulation Posted June 01, 2010 03:20 PM by Alex Wilson, buildinggreen.com
Interior Management Strategies • Dehumidifiers • Bath fans • Range hoods • Sump pits • HRVs/ERVs • Target: < 45%
Exterior Management Strategies • Overhangs • Gutters • Rainscreens • Thick foam and NO POLY • Plywood
Follow These Guidelines: • Air leaks are bad. • Air-permeable insulation is risky. • The thicker the wall, the colder the sheathing, and the riskier your wall. • Rainscreens are good GREAT. • Avoid OSB if possible where it’ll get wet. • Exterior foam? Make it thick. • Reverse laps are bad. Source: How Risky Is Cold OSB Wall Sheathing? Posted on Nov 5 2010 by Martin Holladay, GBA Advisor