STAINLESS STEEL TIMBER CONSTRUCTION SCREWS

SPAX Timber Construction Screws

Timber Construction Screws are the heavy-duty screws in the SPAX range, intended for structural timber work: framing, joists, rafters, posts, and timber-to-timber connections carrying real load. They use a washer head, which spreads bearing load over a wider area than a countersunk head and seats on the timber surface rather than pulling into it, and are stocked in A2 stainless from 6.0mm to 8.0mm diameter in lengths from 60mm to 220mm.

Materials Stocked in A2 (304-equivalent) stainless steel with a plain finish. Stainless is specified here not only for corrosion resistance but because structural timber fixings are frequently inaccessible once the structure is closed up, so the fixing needs to outlast the access to it.

Head and drive The washer head presents a broad flat bearing face, which both spreads load and prevents the screw pulling through softer timber under tension. The T-STAR plus recess on these larger diameters takes the upper end of the bit range, generally T30 to T40, which is what allows the higher torque these lengths need to be driven without the recess rounding out.

Sizes Diameters of 6.0mm and 8.0mm, with lengths from 60mm to 220mm. The 6.0mm sizes cover framing and lighter structural connections up to 140mm; the 8.0mm sizes extend to 220mm for deeper connections, post fixings and heavier timber sections.

Structural use and declared performance Where these screws are used in a load-bearing application, the governing document is the Declaration of Performance for the specific product, issued against the relevant European Technical Assessment. Design values, edge distances, spacing and minimum timber thicknesses should be taken from that document and the manufacturer's technical literature rather than assumed. If you need the DoP for a specific size, ask and we will supply it.

FAQs

Do I need to pre-drill for a timber construction screw? Often not, thanks to the 4CUT point, but it depends on the timber and the position. Pre-drilling is advisable in dense hardwoods, close to the end of a member, and where edge distances are tight and splitting would compromise the connection. Follow the manufacturer's guidance for the specific product where the fixing is structural.

Why a washer head rather than countersunk? A countersunk head pulls into the timber, which is what you want for a flush finish but not what you want in a structural connection, because it reduces the effective bearing area and can crush fibres under the head. The washer head seats on the surface and spreads the load, which is why it is the standard head form for timber construction screws.

Can these replace a bolted connection? Sometimes, and that is a common reason for using them, but it is a design decision rather than a like-for-like swap. Screwed timber connections behave differently from bolted ones in stiffness, in how they fail, and in their tolerance of timber movement. Work from the declared performance data for the specific screw and, on anything load-bearing, have the connection designed.