To guarantee optimal results, we recommend that you hire professionals and only use high-quality materials.
The wood professionals who design and build wood decks comply with the rules, recommendations and requirements of the GUIDE DE CONCEPTION ET DE REALISATION DES TERRASSES EN BOIS (Guide to Wood Deck Design and Construction) jointly published by the FCBA and ATB. It contains detailed information on the technical practices and solutions deemed acceptable by the experts who helped write the guide. In the absence of a DTU (Dossier Technique Unifié-Unified Technical Document), the guide is the only reference document that specifies best practices. The writers ensured that the guide is technically consistent with the content of the future DTU 51.4 (Deck boards) and related product standard (French standard on deck boards).
Wood boards should be stored, preferably bundled, in a well-ventilated shed indoors or outside under a tarpaulin. Direct exposure to sunlight should be avoided.
Before starting, ensure that the supporting structure is stable, solid and flat. Allow a minimum slope of approximately 1cm/m away from the house to ensure proper water drainage. Cover the ground with a geotextile fabric to prevent weeds from growing.
Joists are pegged, screwed down or sealed onto plates and levelled.
Installation of joists and fasteners on adjustable PVC blocks (8 blocks/m2)
To avoid differential settlement of the deck in this type of design, the joists all rest on foundation blocks to ensure equal distribution of the load-bearing capacity in relation to the ground.
Apply, compact and level a layer of sand or gravel. Install concrete slabs or blocks to support joists (in general, 1 block every 50 cm). Verify plumb and level. Attach joists to blocks (screwing down, pegging).
Joists should be sealed, screwed down or secured to the base to prevent premature warping due to sagging. We strongly recommend that the type of wood used for the joists be at least of the same density and durability as the wood boards (for example, treated or untreated fir should be avoided due to its low density and lower durability). When aligning joists, ensure that proper spacing is maintained between supports based on board strength and width (e.g., for a 21 mm x 140 mm exotic wood board, the centre-to-centre distance between joists should be a maximum of 51 cm).
Maximize your material usage with an accurate layout. For installations with hidden joints, allow between 5% and 10% additional surface area. For installations with cuts at a 45° angle, curves or regular joints, allow between 15% and 20% additional surface area.
DThe spacing of supports for a standard load on a residential deck depends on the width and thickness of the boards.
It is important to adjust the screwdriver torque and rotation speed to avoid breaking or damaging screws during the installation. High speed and low torque are the ideal combination. Impact drivers should be avoided. Be sure to test the screwdriver on a piece of scrap board first.
The moisture content of deck boards should always be tested prior to installation using a properly calibrated probe moisture meter. Among other things, it will determine the board spacing required during installation to allow for expansion and contraction between wet and dry periods.
Humidity is the key factor to monitor when using wood. It is one of the keys to the durability and dimensional stability of the components installed.
To maintain optimal stability of wood deck boards (reduce the cupping effect), allow for proper ventilation (minimum of 10 cm between the ground and joists).
Wood boards should be installed with sufficient spacing between them to allow for contraction and expansion.
hardWood Clip™ spacer tab fasteners, which are designed to control spacing based on the moisture content of the wood, space boards automatically to avoid abnormally large gaps or having boards abut against each other.
Expansion of KD boards with the ExtremeKD™ fastener
Contraction of AD boards with the Extreme™ fastener
See "Principles of deck installation using hardWood Clip™ fasteners and the downloadable instruction sheet.
There must be a fastener at every bearing point where boards touch on supports, whether in the middle or at the end of the board, regardless of board width.
Separate the ends of two boards placed end to end to prolong the lifespan of deck boards.
Place a fastener at each end of the boards while ensuring that the screw is at least 20 mm from the end to prevent the wood from splitting. Consider pre-drilling the holes if necessary.
Do not fasten adjacent board ends with only one fastener (Fig. B)
