Under the KP2 window console
12,13 € HT14,55 € TTC
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.
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products
45×70 Épicéa Scandinave BOIS DE CONSTRUCTION C14/V+
On request
Lame de terrasse composite WPC 2,3 × 14,6 cm brossée rainurée – Teck doré, Sapin argenté, Sapin graphite
78,63 € HT94,35 € TTC
Starter kit for composite decking boards 2.3 x 13.8 cm 4DECK Premium – 4 colours
23,71 € HT28,45 € TTC
Composite decking board 2,3 × 13,8 cm 4DECK Premium – 4 colours
103,87 € HT124,64 € TTC
Plinthe composite HARTIKA rainurée 1 × 7,5 cm x 4 m
35,67 € HT42,80 € TTC
Composite decking joist HARTIKA 4,8 x 3,8 cm – 4 m
46,33 € HT55,59 € TTC
WPC composite decking joist 3 × 4 cm brown 4 m
19,51 € HT23,41 € TTC
Solive de terrasse composite HARTIKA 4,8 cm x 2 cm x 4 m
36,06 € HT43,27 € TTC
Thermo-treated pine square timber 4,2 × 4,2 cm, natural grade
On request
Thermo-treated Scandinavian pine cladding 4,2 x 9,2 cm class NATUREL
On request
Square Siberian larch joists 4,5 x 4,5 cm class AB
6,18 € HT7,42 € TTC
Thermo Sosna 42×140 decking board, NATUR class
On request
Scandinavian pine 105×120, glued squares, class B
On request
Scandinavian spruce 70×70, planed square, class AB
On request
Scandinavian spruce 90×90, planed square, class AB
On request
Scandinavian pine 105×180, glued squares, class B
On request
40×60 LEGAR Exotique for terraces
On request
Scandinavian pine 105×210, glued squares, class B
On request
Planed squared timber Thermo Abachi (Ayous) 40×40, NATUR class
On request
40×60 Exotic Glued LEGAR for terraces, class FJ
On request
Scandinavian pine 94×94, glued squares, class A
On request
Planed board Thermo Sosna 42×117 S4S, NATUR class
On request
Scandinavian pine 94×94, glued squares, class B
On request
Top sellers in this category
Under the KP2 window console
12,13 € HT14,55 € TTC
45×70 Épicéa Scandinave BOIS DE CONSTRUCTION C14/V+
3,30 € HT3,96 € TTC
Lame de terrasse composite WPC 2,3 × 14,6 cm brossée rainurée – Teck doré, Sapin argenté, Sapin graphite
78,63 € HT94,35 € TTC
Composite decking board 2,3 × 13,8 cm 4DECK Premium – 4 colours
103,87 € HT124,64 € TTC
Starter kit for composite decking boards 2.3 x 13.8 cm 4DECK Premium – 4 colours
23,71 € HT28,45 € TTC
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.