Scandinavian pine 105×105, glued squares, class B
On request
Deck joists & substructure
A deck lasts only as long as its substructure. Our selection covers WPC composite joists (Hartika, 4DECK) for maintenance-free projects, and timber joists (Siberian larch, thermo-treated pine, Scandinavian spruce) for traditional substructures.
32
products
Scandinavian spruce 69×69, planed square, class AB
On request
45×70 Scandinavian Spruce CONSTRUCTION TIMBER C14/V+
On request
Scandinavian spruce 34×70, planed, class AB
On request
Edging/terrace beam 45×70 Siberian larch class AB
On request
Thermo Pine Square 42×68, NATUR class
On request
Scandinavian pine 105×150, glued squares, class B
On request
Thermo Pine Square 42×140, NATUR class
On request
Our range by material
- Hartika WPC composite joists 4.8 × 2 cm and 4.8 × 3.8 cm in 4 m lengths — wood-polymer composite, unaffected by moisture, use class 4. Ideal for poolsides, concrete slabs and public buildings.
- 4DECK composite joist 3 × 4 cm in brown, 4 m lengths — the budget option.
- Siberian larch decking, smooth, 4.5 × 14.2 cm, grade AB — substructure or solid decking boards.
- Thermally modified Scandinavian pine and planed spruce 3.4 × 7 cm, grade AB — lightweight joist frames.
Sizing and installation
Joist spacing depends on the thickness of the boards: 40 to 50 cm for 2.6 cm boards, up to 60 cm for thicker sections. Raise the frame at least 4 cm on PVC pedestals or rubber shims to preserve the ventilated air gap — the one condition on which longevity depends.
Fixings: A2 stainless steel, or A4 on a seafront elevation. For composite joists, use the dedicated fixing clips (4DECK, Hartika) — never nails driven straight through.
Help & advice
Frequently asked questions
Everything you need to know before ordering. Another question? Contact us.
The WPC composite joist is unaffected by moisture, does not rot and needs no treatment — ideal beside a pool or on a concrete slab. The timber joist feels warmer, is breathable and more environmentally friendly, but calls for a durable species (larch, thermally modified) and careful ventilation.
Recommended spacing 40 to 50 cm. Reduce to 30 cm on cantilevered sections or in heavy-traffic areas.
Always use the dedicated fastening clips for the system (4DECK, Hartika, etc.). A screw driven straight through means a loss of watertightness — and of the warranty.