Decking screws are timber screws with a torx drive and a countersinking thread that pull the board down flush for a clean deck surface, while spengler roofing screws have a bonded sealing washer that makes the fixing watertight in sheet metal and roofing. Decking screws are optimised for holding timber to timber, whereas roofing screws are made to fix and seal metal sheets, cladding and flashings. Both are corrosion-resistant, but each is shaped for a different material and job.

As a rule, choose a screw about 2 to 2.5 times as long as the thickness of the board or part you are fixing, so enough thread anchors into the material beneath. Decking screws are commonly 4 to 6 mm in gauge and 40 to 80 mm long, while lighter fixings use finer gauges; a torx drive gives better grip and less cam-out than a slotted or pozi head. Leave the screw long enough to bite firmly into the sub-frame without breaking through the far side.

Stainless steel screws offer the highest corrosion resistance outdoors and are the safest choice for wet, coastal or tannin-rich timbers like oak and cedar. Galvanised and organically coated screws are also weather-resistant and suit most general exterior use at lower cost, but their coating can wear at the drive recess over time. For permanent structures and hardwoods, stainless is the most durable; for standard softwood decking and fencing, coated or galvanised screws are usually sufficient.

The GeZu Impex fasteners range includes decking and terrace screws with a torx drive, spengler roofing screws with sealing washers, and fixings for construction, roofing, decking and general DIY. The screws are corrosion-resistant and come in a range of lengths and gauges to suit timber, sheet metal and outdoor use. Choose by material, board thickness and finish, matching the head, thread and coating to the job.