Interior vs. exterior grade materials: what NYC code requires
A material rated for indoor use isn't automatically safe outdoors — and code doesn't treat the two the same. What the grading actually means.
Materials are engineered and tested for specific exposure conditions, and code enforces that distinction more strictly than most people realize.
What 'exterior-rated' actually tests for
Freeze-thaw cycling, UV exposure, and moisture resistance — exterior-grade materials are tested against conditions an interior-rated product was never engineered to survive.
Where the code line gets strict
Facades, balconies, roofing, and anything exposed to weather has to meet exterior specifications the DOB will check against filed drawings — substituting an interior-rated product here isn't a shortcut, it's a rejected inspection.
Getting the spec right the first time
We match every material to its actual exposure condition at the drawing stage, so what's filed, purchased, and installed all agree — no surprise substitutions discovered at inspection.
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