Installing composite decking is simple and quick, whether you do it yourself or work with your usual installer. This guide takes you through the job step by step: from choosing the sub-base to laying the joists and the boards, the cuts, the steps and the finishing trims.
With the Quick-Fix® system, which uses a single screw per board, installation is up to 3 times faster than with a traditional system.
See CDECK composite decking
Before you begin, make sure you have the latest version of the CDECK® Technical Data Sheet and Installation Manual and read them carefully from start to finish.
Don't lay the decking at temperatures below 5 °C, in humidity above 90% or in snow.
Store the boards flat at the installation site for at least 48 hours, protected from the weather and from direct sunlight.
The surface must be flat, stable and have a minimum fall of 5 mm/m for water run-off, in the direction of the joists and the boards.
The gap between the boards and the ground must be kept clear at all times to allow ventilation and prevent water from collecting, particularly inside the boards.
Use CDECK® accessories only and follow the instructions in this manual. Failure to follow these instructions voids the warranty.
To lay your CDECK® deck, you'll need:
The type of sub-base determines the installation method. CDECK® covers three types.
Find your sub-base in the table to see which installation applies.
| Your sub-base | Installation type | In short |
|---|---|---|
| Concrete slab or solid cement base, regular and drillable | Type 1 | PVC joists fixed to the ground and supported along their full length. |
| Drillable base, but irregular or uneven | Type 2 | Structural aluminium joists, with a maximum span of 500 mm between supports. |
| Waterproofing membrane or compacted ground that can't be drilled | Type 3 | Cross structure of aluminium joists and tubes, fixed to each other. |
| Surface that needs raising | Type 3 | Cross structure combined with height-adjustable CDECK® pedestals. |
| Soft ground or soil | Type 3 | Compacted ground, geotextile membrane and a cross structure of aluminium joists and tubes, fixed to each other. |
The joists form the base of the deck and are fixed to the ground with screws and plugs.
Once the structure is up, lay the boards. Each board is fixed with a starter clip at the ends and intermediate clips along the middle section.
These gaps are not optional. Composite expands with changes in temperature and humidity and, if they aren't respected, the boards can distort or break.
To trim the boards, use a circular saw with a wood blade. Wear the appropriate personal protective equipment, work outdoors or in a well-ventilated space and make the cuts on a stable surface.
The CDECK® stair nosing piece creates a continuous transition between different levels. Installation follows the same principles as the rest of the deck, with a few adjustments.
Two types of accessory finish the edges of the deck: the fascia boards and, in the case of hollow boards, the end caps.
The Quick-Fix® PRO Intermediate Clip allows a board to be lifted out without taking up the whole deck, which is particularly useful for maintenance or for reaching services underneath.
No. You must leave an air gap between the boards and the ground by using Quick-Fix® joists.
The joists must be fixed to the ground or to other profiles forming a structure fixed to itself, always following the instructions in the Technical Data Sheet.
Yes. You need a structure fixed to itself (Type 3), the ground compacted at the support points and the air gap under the deck kept clear, for example by using a geotextile membrane.
No. The gaps specified must be respected: a minimum of 6.5 mm between board ends and 15 mm from fixed elements. If they aren't, the deck can distort, lift or break.
Just one, fitted in the clip closest to the centre of the board and driven at 60° with the CTOOL. Never screw the clips into the joists.
No. CDECK® is designed and tested as a complete system. Use CDECK® accessories only to keep the warranty valid.
Yes. Anyone with some DIY experience and the right tools can install CDECK® by following the Technical Data Sheet and the installation videos.
Yes. Leave them at the installation site for at least 48 hours before you start. Don't lay the decking at temperatures below 5 °C or in humidity above 90%.