Drywall Types & Thickness Guide
Standard Drywall (White Board)
Regular drywall is suitable for most interior walls and ceilings in dry, conditioned living spaces. It comes in 4×8, 4×10, and 4×12 sheets. Choosing the right thickness matters for both performance and code compliance.
| Thickness | Application |
|---|---|
| 1/4″ | Resurfacing over existing walls. Not for structural use. |
| 3/8″ | Curved walls and arches. Light-duty only. |
| 1/2″ | Standard interior walls with 16″ o.c. framing. Most common. |
| 5/8″ | Ceilings over 24″ o.c. framing. Fire-rated assemblies. Commercial. |
Moisture-Resistant Drywall (Green Board / Blue Board)
Has a moisture-resistant facing. Suitable for bathrooms, laundry rooms, and kitchens — but not as a tile backer in wet areas like shower surrounds. Use cement board or glass mat tile backer in direct-wet applications.
Mold-Resistant Drywall (Purple Board)
Has additives that resist mold growth. Recommended for Eastern WA basements, bathrooms, and any area with potential humidity issues. More expensive than green board but significantly better protection.
Type X Fire-Rated Drywall
5/8″ Type X is required by code in specific locations:
- Garage-to-living space wall (garage side)
- Garage ceiling below living space
- Furnace/mechanical room walls (check local code)
- Between dwelling units in multi-family buildings
- Certain commercial applications
Always confirm requirements with your local building department — Spokane County, Stevens County, and Ferry County may have specific requirements.
Cement Board (HardieBacker / USG Durock)
Not drywall, but often confused with it. Cement board is the correct backer for tile in wet areas. Available in 1/4″ (floors) and 1/2″ (walls). Heavier and harder to cut than drywall — use a scoring tool or carbide-tipped blade.
Tips for Hanging Drywall
- Hang ceilings before walls — allows walls to support ceiling edges.
- Stagger joints — never line up vertical joints on adjacent sheets.
- Use ring-shank or coarse-thread screws — avoid smooth-shank nails for better hold.
- Leave a 1/8″ gap at the floor — allows for settling without cracking.
Questions on your drywall project? Our team can help you calculate materials and find what you need.