STAINLESS STEEL DECKING SCREWS

SPAX Decking Screws

Decking Screws are made for fixing timber decking boards, where the fixing is permanently exposed to weather, standing water and foot traffic, and where the head needs to sit cleanly without becoming a trip or splinter point. They use a cylindrical head, the T-STAR plus drive and the 4CUT point, and are stocked in both A2 and A4 stainless from 5.0mm to 6.0mm diameter in lengths from 40mm to 80mm.

Materials Stocked in A2 (304-equivalent) for general decking work, and A4 (316-equivalent) for coastal and salt-exposed sites. An Antique wood-tone finish is available on selected A2 sizes for decks where the fixing should visually recede into the board rather than read as bright metal.

Choosing A2 or A4 For an inland domestic deck, A2 is the normal specification. Specify A4 where the deck is coastal or estuarine, exposed to sea spray, near a swimming pool, or subject to de-icing salts. The cost difference is real but so is the exposure difference, and a failed decking fixing is disproportionately expensive to put right once the boards are down.

Head and finish The cylindrical head is shaped to seat cleanly into the board face and, on a timber deck, to sit at or just below the surface without tearing the fibres around it. The Antique finish option gives a darker wood tone that is less visually obtrusive across a large deck area than bright stainless.

Sizes Diameters of 5.0mm and 6.0mm, with lengths from 40mm to 80mm. Length selection depends on board thickness: the screw needs sufficient penetration into the joist beneath while leaving the point short of breaking through.

FAQs

What length decking screw do I need? Take the board thickness and allow for roughly twice that again into the joist as a working guide. For a typical 25mm board that puts you at 60mm or thereabouts; for a thicker 32mm board, 70mm to 80mm. Check the joist depth so the point is not breaking through the underside.

Should decking screws be pre-drilled? In most softwood decking the 4CUT point makes pre-drilling unnecessary. In dense hardwood decking, and when fixing within about 50mm of a board end, pre-drilling will prevent splitting. Hardwood decking generally benefits from pre-drilling as standard.

Can I use A2 screws on a coastal deck? It is not advisable. Chlorides are the specific thing A2 handles poorly, and a coastal or estuarine deck will see them continuously. A4 contains molybdenum, which is what gives it the additional chloride resistance, and it is the correct specification for that exposure.