Climate Zones (U.S.) and required exterior insulation

A chart shows the minimum exterior insulation required by code.

The chart shows requirements for Marine zone 4, Zone 5, Zone 6, and Zones 7 and 8 of the U.S. (zones displayed in next image). It then displays the code minimum R-Value and thickness of rigid foam sheathing for external insulation for both 2×4 walls and 2×6 walls. The right most column shows percentages of “the wall’s total R-value that needs to come from the rigid foam layer.”

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