What screws do I use for decking?
For wood decking, use #10 × 3″ exterior-grade coated or Type 305 stainless steel deck screws. For composite decking, use composite-specific screws — standard wood screws can mushroom or crack composite boards.
Wood decking screws
Deck boards expand and contract seasonally, so screws must resist corrosion and pull-out:
- #10 × 3″ — standard board-to-joist connection for 5/4″ (1″ actual) deck boards.
- #10 × 3-½″ — for thicker 2× boards.
Coating matters: Modern pressure-treated lumber uses ACQ (alkaline copper quaternary), which corrodes ordinary zinc-coated screws rapidly. Look for screws rated for ACQ or use 305-grade stainless steel.
Drive type
Deck screws are available in Phillips, square drive (Robertson), star drive (Torx), and combo. Star drive is preferred — it reduces cam-out, especially when driving at angles.
Composite decking screws
Composite decking (Trex, TimberTech, etc.) requires screws with a smaller-diameter head and a specially shaped tip that cuts cleanly into the material without creating a raised "mushroom" around the head. Most composite manufacturers specify their own screw line or a compatible option.
For hidden fastener systems (Trex Hideaway, Ipe Clip, etc.), the board edges clip into a track and no face screws are visible — follow the manufacturer's fastener spec exactly.
Predrilling
Always predrill within 2″ of a board end. A pilot hole slightly smaller than the screw's root diameter prevents end splits in both wood and composite.