Material guide
Drywall & plaster
What works on drywall and plaster: the right bit, cutting method, anchor, adhesive and sanding grit, plus how to keep the dust down.
Quick facts
- What it is
- Drywall: a gypsum core between paper faces (ASTM C1396). Older plaster: hard coats over wood or metal lath.
- Best cutting tool
- Utility knife: score, snap, then cut the back paper
- Panel screws
- 1-1/4 in Type W screws, up to 16 in apart on walls and 12 in on ceilings (USG, wood framing)
- Heavy loads
- Into a stud, or a heavy-duty toggle (1/2 in hole, walls 3/8 to 3-5/8 in thick)
- Sanding grit
- 150-grit paper or 220-grit mesh on joint compound (USG)
- Dust hazard
- Joint compound dust can contain silica. NIOSH found sanders at up to 10 times the dust limit.
Drywall is a sheet of gypsum pressed between two paper faces. It's soft, cheap and easy to cut. Many older homes have plaster: hard coats troweled over wood or metal strips called lath.
Each one is tricky in its own way. Drywall is weak. A screw in plain drywall holds very little, so anything heavy needs a stud or an anchor. Plaster is hard and brittle. It can crack or let go of the lath when you drill or cut it.
Both walls hide things. Pipes and wires run behind them, often right where you want to drill. Cutting and sanding both make a lot of fine dust.
So start by finding out what you have. Tap the wall and drill a small test hole in a hidden spot. White powder and paper mean drywall. Hard, gritty dust and wood strips behind it mean plaster on lath.
Drill into drywall & plaster
Drywall drills easily with any sharp twist or brad-point bit at low speed. Plaster is harder: use a carbide-tipped masonry bit with hammer mode off, and light pressure. Check for pipes and wires first.
What to use: Twist bit for drywall; carbide masonry bit for plaster
Guides
- What happens if you drill into a gas pipe? What to do right now
- Drill into plaster without cracking or crumbling (coming)
- What size drill bit for a drywall anchor (chart by anchor type) (coming)
- Where pipes and wires run in walls: the danger zones before you drill (coming)
Cut drywall & plaster
Score the face paper with a utility knife, snap the panel, then cut the back paper. Use a jab saw for outlet and pipe holes. Skip the circular saw: it makes a cloud of dust. For plaster, use an oscillating tool with a carbide-grit blade.
What to use: Utility knife and jab saw
Guides
- Can you cut drywall with a circular saw? You can, but you shouldn't
- How to cut drywall: straight, openings, and curves (coming)
- Oscillating multi-tool: what it's for and how to choose blades (coming)
Glue drywall & plaster
Panel adhesive can help hold drywall to studs, but USG still calls for screws or nails with it. Don't glue a hole shut. Patch it with joint compound and tape, or a patch, then sand.
What to use: Drywall screws plus panel adhesive; joint compound for repairs
Guides
- Will construction adhesive hold on drywall? (coming)
- Remove construction adhesive from drywall, concrete, and wood (coming)
- Adhesive hooks vs anchors: what actually holds on tile and painted drywall (coming)
Screw or anchor into drywall & plaster
Drive into a stud whenever you can. Between studs, pick a hollow-wall anchor rated for the weight. Use toggles for heavy items. In old plaster, pre-drill and use a toggle long enough to clear the plaster and lath.
What to use: Stud first; heavy-duty toggle between studs
Guides
- Screw won't go into the wall? Find the cause and fix it
- What is a nailer board? (Framing term explained)
- Wall anchor types explained: which one for which wall and weight (coming)
- Drywall anchor weight limits: what 9 anchors actually held (coming)
- How to hang heavy things on drywall without a stud (coming)
- Toggle bolt vs molly bolt vs snap toggle: which holds more (coming)
- Best anchors for plaster and lath (and why drywall anchors fail) (coming)
- How to find a stud (with and without a stud finder) (coming)
Sand or finish drywall & plaster
Sand joint compound, not the paper face. Use 150-grit paper or 220-grit mesh, or finer. A pole sander keeps dust farther from your face. A vacuum sander cut dust 80 to 97% in NIOSH tests.
What to use: Pole or vacuum sander, 150-grit or 220-grit mesh
Guides
- Sand drywall with almost no dust (coming)
- Sandpaper grit chart: which grit for which job (coming)
Safety basics
- Check for pipes and wires. Code calls for steel plates where cables pass within 1-1/4 in of a stud's face, but older walls may not have them.
- Keep the dust down. Score and snap instead of sawing. Pole or vacuum sanders cut the dust you breathe. Wear a respirator for big jobs.
- Test old walls first. Paint in homes built before 1978 may contain lead, and some older joint compound contains asbestos.
- Wear safety glasses. Plaster chips and grit fly when you drill overhead.
Sources
- Sheetrock Brand UltraLight Panels Mold Tough submittal sheet: gypsum core, score and snap, ASTM C1396, fastener spacing over wood framing, adhesive with nails or screws (USG)
- Sheetrock lightweight topping joint compound data sheet J965: sand with 150-grit paper or 220-grit mesh, avoid scuffing paper (USG)
- Control of Drywall Sanding Dust Exposures, DHHS (NIOSH) Publication 99-113
- SNAPTOGGLE heavy-duty toggle bolt: compatible surfaces, drill hole size, wall thickness range (TOGGLER)
- DT20717 oscillating carbide grout removal blade: slits in plaster (DeWalt)
- OSHA 29 CFR 1926.304(d): guarding of portable circular saws
- NFPA 70 (National Electrical Code), Article 300.4: protection of cables near framing edges
- EPA: protect your family from sources of lead (homes built before 1978)
- EPA: learn about asbestos (joint and patching compounds)