Decking & Timber Screws

The Right Screw for Every Timber and Decking Job

Selecting the correct decking screws or timber screws is one of the most practical decisions on any outdoor build. The wrong fixing length can result in boards lifting, timbers pulling apart or surface damage that is difficult to repair once the project is finished. This collection brings together the sizes most commonly specified by landscapers, joiners, groundworkers and self-builders throughout the UK.

Every screw in this range carries an exterior-grade green coating, compatible with pressure-treated and tanalised timber, and designed to resist corrosion in exposed outdoor conditions for the lifetime of the structure.

Decking Screws

Our decking screws feature a countersunk head that sits flush with the board surface after driving, leaving a clean finish without the need for further preparation. The self-countersinking point reduces splitting in softwood and hardwood boards, and the coarse thread provides reliable pull-down force that keeps boards seated firmly against the joist.

We stock the following lengths, each linked directly to the relevant product:

Composite Decking Screws

Fixing into composite decking demands a screw with a head profile that cuts cleanly into the board surface without cracking the capping layer or causing delamination around the fixing point. Our composite decking screws are designed specifically for this purpose, with a self-countersinking head that produces a flush, tidy finish that does not lift or telegraph through the board surface over time.

Composite boards vary in thickness between manufacturers, so always confirm the board depth before selecting a length. As a general rule, the screw should pass fully through the board and engage at least 35mm to 40mm into the supporting joist beneath. For most hollow-core and solid composite boards used in the UK, our 50mm decking screws and 75mm decking screws cover the majority of installations.

Timber Screws

Our timber screws are heavy-duty structural fixings for posts, beams, pergola frames, raised beds, fencing and landscape construction. They are engineered to drive without pre-drilling in most softwood and medium-density hardwood applications, which saves significant time when working through thick sections of timber.

The hex flange head is driven with a standard impact driver and hex bit, giving greater torque control than Pozi or Torx drives when working in dense or knotty timber. Both lengths available are exterior coated and suitable for permanent outdoor structures.

Timber Sleeper Screws

Railway sleepers and heavy landscape timbers place greater demands on a fixing than standard decking boards. Timber sleeper screws must penetrate deeply through dense, often very dry timber and hold firmly without working loose as the sleeper expands and contracts with seasonal moisture changes.

For standard raised bed walls and garden steps built from single sleepers, our 200mm timber screws provide the depth and pull-out strength required. Where sleepers are stacked two courses high or where additional structural assurance is needed, the 250mm timber screws are the recommended choice. Both sizes carry an exterior green coating that is fully compatible with the preservatives used in treated sleepers.

Choosing the Correct Screw Length

As a practical guide, a deck screw should pass through the full thickness of the board and penetrate the joist by at least 40mm to 45mm. For a 28mm softwood board, that means 75mm decking screws are the correct size. For a 38mm board, 100mm decking screws give the necessary penetration depth. For composite boards at 20mm to 22mm, 50mm deck screws are the standard choice.

For structural timber connections, the minimum recommendation is that the screw engages at least half its total length into the receiving timber. A 200mm timber screw through a 100mm post, for example, will engage 100mm into the receiving member, which is sufficient for most landscape and garden structure applications.

Trade Stocked, Next-Day Delivered

JALFT supplies decking screws and timber screws to builders, landscapers, joiners and self-builders across the UK. Every product in this range is held in our UK warehouse and available for next-day delivery on orders placed before 2pm. Products are available in trade boxes and contractor packs, with pricing structured for professional volume requirements.