Carbon steel screws

SPAX screws are self-tapping screws to be used in a wide field of applications such as timber structures, wood-based applications such as windows, doors, furniture, general joinery or carpentry applications and renovation.

They shall be threaded over a part or over the full length providing certain tip geometries such as 4CUT. The screws shall be produced from carbon steel wire and have a nominal outer thread diameter of 2,5 mm to 12,0 mm in lengths from 12 up to 800 mm (see different EPD for SPAX stainless steel screws). A hardening process provides the desired strength to penetrate different timbers or wood-based panels without pre-drilling. The screws have different head shapes such as countersunk head, raised countersunk head, Pan Head and others equipped with different recesses such as T-STAR plus or conventional PZ or PH. Usually, a coating e.g. electro-galvanized zinc plating is applied to serve as corrosion protection during transportation, storage and final use in products or buildings. An additional lubrification layer might be applied to provide easy installation and reduce drive in torque and friction. In protected, unweathered or dry indoor conditions the coated screws are assumed to last for decades. For exterior and weathered conditions SPAX screws made of different stainless steel grades are available (see different EPD for stainless steel screws).

The screws are driven into the timber or wood-based material either by using manual screwdrivers, but mostly by using battery screw driver tools or similar equipment. Collated screws mostly provided with plastic strips allow for faster installation of high numbers of the same screw size, but their share in sales volume is small, just as the range is small itself.

For environmental reasons and ease of recycling, SPAX screws are predominantly packaged in cardboard boxes (82%). Whereas retailers require plastic packaging with transparent lids for product presentation on store shelves. SPAX is aiming to reduce the share of plastic in the boxes within the next years, and has recently launched the first carton based alternatives. See SPAX’s environmental report published on spax.com for details.

At the end of their life cycle SPAX screws can be easily recycled as scrap metal. The product can be reused if there is no damage caused by corrosion or deterioration during lifetime, false assembly or unprofessional disassembly. However, SPAX screws are usually used once, as reuse is generally uneconomical for the small screw dimensions and the time being. But developments on enhancing deconstruction capabilities for timber structures and re-use are a future target for SPAX, including refurbishing services allowing for re-use and a second lifetime (to meet the Green Goals of the European Union) and a more sustainable building sector.

For the use in load-bearing timber structures SPAX screws are regarded as a building product, and they fall under the European Construction Products Regulation (EU) No. 305/2011. Screws’ mechanical properties (called essential characteristics) are documented in European Assessment Document ETA-12/0114 or ETA-16/0617 and they bear a CE-Marking on the labels of the packaging to show conformity (see picture above). A Declaration of Performance DoP can be downloaded on the website spax.com

Specification of the intended use as a building product according to ETA-12/0114 or ETA-16/0617:

The screws are used for connections in load bearing timber structures between members of solid timber (softwood), glued laminated timber (softwood), cross-laminated timber, and laminated veneer lumber (softwood), similar glued members, wood-based panels or steel. The screws are also used for connections in load bearing members of solid timber (hardwood), glued laminated timber (hardwood) or laminated veneer lumber (hardwood). SPAX screws with a thread over the full length are also used as tensile or compressive reinforcement perpendicular to the grain or as shear reinforcement in softwood members. Furthermore, SPAX screws are suitable for fixing on-roof insulation.