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What Size Screw for 1/2 in Drywall?

Short answer

What size screw for 1/2 in drywall? On wood studs, use 1-1/4 in coarse-thread drywall screws (Type W, usually sold as #6). On steel studs, use 1 in fine-thread (Type S) screws. Building codes require screws to reach at least 5/8 in into wood or 3/8 in into steel. Space them up to 16 in apart on walls with studs 16 in on center, and 12 in on ceilings.

Screws for 1/2 in drywall by framing

FramingScrew typeMinimum penetrationMinimum length for 1/2 in boardScrew to buy
Wood studs or joistsType W, coarse thread5/8 in (16 mm)1-1/8 in (29 mm)#6 x 1-1/4 in coarse-thread (32 mm)
Light-gauge steel studsType S, fine thread3/8 in (10 mm)7/8 in (22 mm)1 in fine-thread (25 mm)

Drywall screws for gypsum board are covered by ASTM C1002: Type W (coarse) for wood, Type S (fine) for steel. Building codes accept either type in wood as long as it reaches 5/8 in into the framing.

Minimum screw length for other drywall thicknesses

BoardWood framing (board + 5/8 in)Steel framing (board + 3/8 in)
3/8 in1 in3/4 in
1/2 in1-1/8 in7/8 in
5/8 in1-1/4 in1 in

Round up to the next length you can buy. The wood-framing minimums are the ones building departments quote from the International Residential Code (IRC). The steel-framing column applies the same 3/8 in penetration rule. Two-layer and fire-rated walls have their own fastening rules, so check the assembly's spec.

How far apart to space screws (1/2 in board)

WhereFraming spacingMaximum screw spacing
Walls16 in on center16 in
Walls24 in on center12 in
Ceilings (board either direction)16 in on center12 in
Ceilings (board perpendicular to joists)24 in on center12 in

These are the maximums in IRC Table R702.3.5 for a single layer, as published by several building departments. Your local code may amend them, and fire-rated walls follow the fastening schedule of their tested assembly.

How to drive drywall screws

  1. Find the framing. Mark stud and joist centers on the floor and ceiling before the board goes up.
  2. Drive square to the board with a drywall screw gun or a dimpler bit, so the head sets just below the surface.
  3. Don't break the paper. Building codes require that screws not tear the face paper. If one does, drive another screw nearby instead of driving it deeper.
  4. Keep edges and ends on framing where they run parallel to it.

Common mistakes

  • Coarse-thread screws in steel studs. Type W screws are made for wood. Use fine-thread Type S in light-gauge steel.
  • Screws too short. A 1 in screw in 1/2 in board on wood only reaches 1/2 in into the stud, under the 5/8 in minimum.
  • Overdriving. Screws that tear the face paper don't meet code. Set the head just below the surface.
  • Too few screws on ceilings. Ceilings need closer spacing (12 in) than walls.
  • Missing the stud. A screw that only holds in drywall does nothing. Pull it and patch the hole.

Hanging something on the drywall instead?

That's a different question: it depends on the weight and whether you hit a stud. See how to install a drywall anchor or mount a TV on the wall. Not sure what screw you're holding? Snap it next to a ruler and Mechy tells you the size, thread and length. Identify a screw from a photo.

Questions

What length screw for 1/2 in drywall?

1-1/4 in on wood framing (the minimum is 1-1/8 in) and 1 in on light-gauge steel studs (the minimum is 7/8 in). Screws must reach 5/8 in into wood or 3/8 in into steel.

Coarse or fine thread drywall screws?

Coarse thread (Type W) for wood studs and joists. Fine thread (Type S) for light-gauge steel studs. ASTM C1002 defines both types.

Can I use 1-5/8 in screws for 1/2 in drywall?

Yes, on wood framing. A 1-5/8 in screw goes 1-1/8 in into the stud, well past the 5/8 in minimum. 1-1/4 in is enough and drives faster.

How far apart should drywall screws be?

For 1/2 in board: every 16 in on walls with studs 16 in on center, every 12 in on walls with studs 24 in on center, and every 12 in on ceilings.

What size screw for 5/8 in drywall?

At least 1-1/4 in on wood framing (5/8 in board + 5/8 in into the wood), and at least 1 in on steel studs.

Sources

  1. GA-216: Spacing and Installation of Fasteners (preview) – Gypsum Association
  2. Drywall Inspections (IRC R702.3.5 / R702.3.6) – Town of Cave Creek, AZ
  3. Gypsum Wallboard Installation Handout (IRC Table R702.3.5) – City of Grand Rapids, MN
  4. Sheetrock Nailing Patterns (IRC Table R702.3.5) – Franklin County, WA
  5. ASTM C1002: Steel Self-Piercing Tapping Screws for Gypsum Panel Products
  6. Grip-Rite 114CDWS5 #6 x 1-1/4 in Coarse Drywall Screw – AIH
  7. Simpson Strong-Tie DWC114PS #6 x 1-1/4 in Drywall Screw – EMI Supply

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