Fire-Rated Drywall Layer Calculator
Estimate how many layers and sheets of Type X drywall a fire-rated wall assembly needs.
Fire-rated assemblies are built around layers of 5/8" Type X gypsum board rather than the framing itself — a typical 1-hour rated wall uses a single layer of Type X per side, while a 2-hour rating generally requires two layers of Type X per side. This calculator estimates sheet counts from that rule of thumb, but the exact layer count, screw pattern, and joint treatment for a given assembly must always be verified against the specific UL or GA fire-rated assembly listing your local code official requires — this tool is for material estimating, not code compliance sign-off.
Frequently Asked Questions
How many layers of drywall does a 1-hour fire rating need?
Most 1-hour fire-rated wall assemblies use a single layer of 5/8" Type X gypsum board on each side of the framing, though the exact assembly must match a tested UL or GA design listing.
Does a 2-hour fire rating just mean double the drywall?
Generally yes — a common way to achieve a 2-hour rating is two layers of 5/8" Type X per side instead of one, though staggered joints and specific fastening patterns from a tested assembly are also required, not just the extra layer alone.