Type X drywall is 5/8-inch gypsum board with a glass-fiber-reinforced core that provides a 1-hour fire rating when properly installed. It is required by Texas Residential Code in specific assemblies, and it is the single most-failed inspection item we see on residential remodels and additions. This article walks through every place R302 requires Type X, why each requirement exists, and what gets you flagged on inspection.
Garage-to-Living Separation (R302.6)
The most common Type X application. Any wall separating an attached garage from living space must be 5/8-inch Type X on the garage side. Any ceiling separating an attached garage from living space above must be 5/8-inch Type X on the garage side. The supporting structure for that ceiling (joists or trusses) must also be protected per the same code — usually by extending the Type X up the structural members.
Dwelling Unit Separation (R302.3)
Walls and floor-ceiling assemblies between dwelling units in townhouses and duplexes require a 1-hour fire separation, which is most commonly achieved with Type X on both sides of the assembly. Sound assemblies (STC 50) are often a separate requirement that stacks on top.
Furnace and Boiler Rooms (M1306)
Mechanical rooms containing fuel-fired equipment must have Type X protection on the walls and ceiling unless the equipment itself is listed for direct-vent installation. This is increasingly relevant as more Longview-area homes add tankless gas water heaters and high-efficiency furnaces.
Stairs and Egress Paths
Walls supporting required egress stairs in multi-story dwellings often require Type X, depending on building height and exit path classification. Single-family residential typically doesn't trigger this, but garage-apartment and accessory-dwelling-unit projects often do.
What Goes Wrong on Inspection
Standard 1/2-inch drywall installed instead of 5/8-inch Type X — easy to spot because the board is labeled and the thickness shows on the cut edge. Type X installed but joints not taped to maintain the assembly rating — Type X with untaped joints does not provide the rated assembly. Penetrations through Type X (recessed lights, electrical boxes) not fire-stopped — every penetration must be sealed with rated firestopping or it breaks the assembly rating. Wrong fastener spacing — Type X assemblies typically require fasteners every 8 inches on edges and 12 inches in the field; standard residential spacing won't pass.
Cost Difference
Type X material costs about 40% more than standard 1/2-inch drywall — typically $14 vs $10 per sheet. On the labor side, Type X is heavier and harder to cut, adding roughly 15% to install time. For a typical Longview garage conversion, the Type X requirement adds $300 to $700 to the drywall scope — a tiny number compared to the cost of a failed inspection and a tear-out.
Get It Right the First Time
Every garage conversion, attached-garage addition, ADU, and townhouse build we do includes Type X in the right assemblies, taped, fastened, and firestopped to pass inspection on the first walkthrough. If you're considering a project that involves any of these assemblies, get a contractor who can talk fluently about R302 — and never let anyone tell you 'we'll just use 5/8 standard, the inspector won't know the difference.' They will, and the rework is yours to pay for.