Before beginning work                                                               

Having taken delivery of your composite decking boards, we recommend you allow them a day to adjust to your local temperature and conditions before starting work. We do not recommend installing your deck in cold weather. Your composite decking boards can be worked with normal woodworking tools. We recommend using a wood saw with a fine-tooth blade to cut boards to size. When cutting, care should be taken to ensure that boards are properly supported. As with other building work it is important to work safely and to take suitable safety precautions including the wearing of protective clothes, gloves, safety goggles and dust mask.

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Building your new deck

1: Build a supporting substructure

Make sure that the base is flat and stable. Decking boards must not be laid directly on the ground but should be fixed to joists of a suitable supporting substructure. This will vary, for a domestic patio deck we typically recommend a simple concrete base and our own WPC joists.

The concrete base should be at least 10cm thick and have a slight slope – we suggest a gradient of 1 in 80 – that runs away from the property to allow for the run-off of water that collects under the deck.

The WPC joists should be fastened to the concrete base using screws through the joists and plastic raw plugs in the concrete base. They should be fixed so as to create parallel, regularly spaced rows in-line with the slope of the concrete base, again to allow for the run-off of water.

The maximum recommended space between joist rows depends on the angle at which you intend to lay your boards in relation to the joists, but should never exceed 40cm, please see diagram below.

A gap of at least 8mm should be left between the ends of joists and a fixed object such as a wall and of at least 10mm between the ends of joists at butt joints. These allow for proper drainage and temperature expansion

Remember the suitable supporting substructures for your deck will vary with the circumstances. 

2: Fix decking boards to joists

Our compsite decking boards are easily fastened to the joists of a supporting substructure with the help of our stainless steel screw and plastic T-Clip system.

Start at the outside of the area to be decked. Place your first board and screw it into each joist it crosses with a countersunk decking screw of suitable length. Then fit T-clips into the groove along the side of the board and screw them into each supporting joists with the screws provided, one T-Clip for each supporting joist

Fit your next board by sliding it onto the T-Clips used to secure the first board and fitting another set of T-Clips to secure the opposite side of the board, again one T-Clip for each supporting joist. Follow a similar process to fix subsequent boards attaching the final board in a similar manner to your first.

As an alternative to using T-Clips, our boards can also be screwed straight into supporting joists using decking screws through the center of each board. Unlike timber, composite decking only requires one screw in the center of each board as they do not warp or bow.

Decking boards must be properly supported!

The ends of boards must be fully supported. No overhang or cantilever is allowed. At butt joints – where the ends of two decking boards meet, this may mean doubling up on supporting joists.

Minimum spacing requirements

It is recommended that a gap of at least 7mm is maintained between the sides of adjacent boards to allow for drainage and expansion due to temperature increases. The use of plastic T-Clips helps ensure these gaps are maintained.

Gaps of 8mm at butt joints – where the ends of two boards meet, and of 15mm between the edges of boards and objects such as wall should also be observed for similar reasons.

3: Finish your deck

Having fastened your boards all that remains is to tidy up the sides of your new deck with our WPC skirting and corner trims which can be used to hide the unfinished end of boards and supporting joists.

Start at the outside of the area to be decked. Place your first board and screw it into each joist it crosses with a countersunk decking screw of suitable length. Then fit T-clips into the groove along the side of the board and screw them into each supporting joists with the screws provided, one T-Clip for each supporting joist

Our skirting trims can be screwed directly into joists with wood screws. A gap of at least 8mm should be maintained between skirting trims and the ends and sides of boards to allow for expansion due temperature increases.

Corner trims can be applied subsequent to skirting trims to achieve a finishing touch by screwing them directly into decking.

We recommend that you do not fully close your deck to allow for the free circulation of air and drainage.

Job Done!