Roofing
Eave
The lower edge of a roof that overhangs the exterior wall, providing protection from rain and directing water away from the foundation.
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In the Field
Eave overhang dimensions are specified by the architect and affect ice dam protection, wall drainage, and sun shading. Deeper overhangs in hot climates reduce cooling loads; in cold climates, adequate overhang helps keep water off walls.
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Rule of Thumb
A minimum 12-inch overhang protects wall surfaces from direct rain. Eaves of 18–24 inches significantly reduce wall wetting and extend the life of paint and siding.