Choosing the Right Drywall for Your Job
7 min read · Updated 2026
Most jobs get hung with whatever board the crew always buys, and most of the time that works out. The times it does not — a garage ceiling that sags, a shower wall that turns soft, a fire-rated wall that fails inspection — are expensive, and they all trace back to the same thing: picking a board by price instead of by what the wall is being asked to do.
This guide walks through the drywall types we stock, what thickness to use where, and how to spot the two or three walls on any given plan that need something other than standard board.
The four boards that cover almost every job
Drywall is gypsum core wrapped in paper or fiberglass facing. What changes between products is what is mixed into that core and what the facing is made of.
| Board | What it is | Where it goes |
|---|---|---|
| Regular (white board) | Standard gypsum core, gray back / ivory face | Interior walls and ceilings in dry, conditioned space — the majority of any house |
| Moisture-resistant (green board) | Core and facing treated to resist water absorption | Bathrooms, laundry rooms, utility areas — behind the sink, not inside the shower pan |
| Mold-resistant / paperless | Fiberglass facing instead of paper, so there is nothing for mold to eat | Wet-prone walls, slab-level rooms, anywhere humidity swings hard |
| Type X (fire-rated) | 5/8 in. core with glass fiber reinforcement, rated 1 hour | Attached garage walls and ceilings, common walls, anywhere code calls for a rated assembly |
Green board is water-resistant, not waterproof. Inside a tub or shower surround you want cement board or a proper tile backer — not moisture-resistant drywall.
1/2 in. vs. 5/8 in. — thickness by location
Half-inch board is the default for interior walls and it is what goes on the vast majority of the sheets we sell. Five-eighths is heavier, stiffer, and quieter, and there are three places it earns its extra weight.
- Ceilings framed at 24 in. on center — 1/2 in. will sag between joists, especially under blown insulation. Use 5/8 in., or 1/2 in. board specifically rated for ceilings.
- Fire-rated assemblies — Type X is a 5/8 in. product. There is no 1/2 in. substitute for a 1-hour wall.
- Walls where sound matters — bedrooms off a living room, offices, shared walls. The extra mass measurably drops sound transmission.
Edge profile, length, and why sheet size matters
Tapered long edges are what let you bed tape flush; that is the standard board and what you want on finished walls. Square-edge board shows up in specialty applications where the joint gets covered by something else.
On length: longer sheets mean fewer butt joints, and butt joints are the hardest thing in the trade to hide because they have no taper. A 12 ft sheet across a 12 ft wall gives you zero butt joints. That is worth more to the finish than almost anything else you can buy.
The tradeoff is handling. Twelve-footers are heavy and awkward in a remodel with tight stairs. On new construction with open access, run the longest board that fits.
What this means in a West Texas house
Our climate is dry most of the year, which takes some pressure off moisture-resistant board in ordinary rooms — but bathrooms and laundries still swing hard, and a slab-level utility room can hold humidity longer than people expect. Spend the money there.
The attached garage is the wall that most often gets the wrong board. If living space sits above or behind that garage, the separation wall and ceiling need Type X. Inspectors check it, and re-hanging a garage ceiling after the fact is miserable work.
Ordering: what the counter needs from you
Bring square footage by room, ceiling framing spacing, and a note on which walls are rated. From that we can split the order into regular, moisture-resistant, and Type X, add the right screw count and joint compound, and set a delivery day.
Frequently asked questions
- Can I use 1/2 in. drywall on a ceiling?
- On joists 16 in. on center, yes. On 24 in. on center, use 5/8 in. or a 1/2 in. board specifically rated for ceiling application — standard 1/2 in. will sag between joists over time, and blown insulation above makes it worse.
- Is green board required in a bathroom?
- Codes vary, but it is standard practice on bathroom walls and it is cheap insurance. What green board is not is a shower backer — inside the tub or shower surround you need cement board or a tile backer designed for direct water contact.
- What is the difference between Type X and Type C?
- Both are fire-rated. Type X is the common 5/8 in. 1-hour board. Type C has additional additives that hold the core together longer under fire and is specified for certain rated assemblies, usually in commercial work. Check the assembly listing on your plans.
- How many screws per sheet of drywall?
- Plan on roughly 32 screws for a 4x8 sheet on walls at 16 in. on center, and more on ceilings. A 1 lb box covers a few sheets; for a whole house order screws by the 25 lb bucket and do not run short mid-hang.
Need the material, not just the theory?
Bring your numbers to the Seminole counter or send us the plans — we will price the package and set a delivery day. Free Delivery on Qualifying Orders. Call for details.
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