Before attaching any permanent fixtures to a composite deck, some pre-thought and planning should take place to avoid potential damage to the composite decking. Many a tradie has come unstuck by treating composite materials just like timber. Composite materials have their own unique qualities and you must understand the material to gain its full potential.

It is well known that all composite materials expand and contract with temperature changes, more than conventional hardwood decking timbers. When installing fixtures onto a composite deck this needs to be taken into account and adequate measures need to be made to allow for this natural movement. Most commonly fencing and balustrading is attached to composite decking often around a pool. If installed incorrectly it can cause the decking to either crack or distort over time.

Some points to consider when installing a fence to a composite deck.

  • Pre-planning

When setting out the decking sub-frame it is important to understand what the finished area will look like. What non-fixed heavy items, fencing or other fixtures are planned to be attached or placed on to the finished deck. Adequate sub-structure blocking needs to be fixed into the correct positions. Often a fence installer is a different contractor to the deck builder so preliminary consultation is required to ensure suitable fixing point provisioning – in the correct positions!

  • Composite decking is not a structural material

Much like cladding, composite decking is not designed to add any additional structural strength to an area. Any external fixtures must be fixed directly to the timber or steel sub-structure below and not the decking boards. An unusual amount of flexing or movement of fence or balustrade posts can cause damage to the decking boards below.

  • Attaching fence footing screws through a composite deck

Pre-drill a pilot hole through the decking as large as the footing cover plate will allow. A minimum of 2mm larger than the screw gauge being used is recommended. Where the design layout allows, it is preferable to use a Poliwood Solid Single Groove Decking Board in positions where a fence or other fixtures are being attached.

So remember, pre-planning the layout, adequate frame support and understanding the nature of composite decking will ensure a successful decking project.

This information is intended as a guide to the best practice for installing fixtures to a composite deck and should always be considered in conjunction with our installation guide and engineering or building contractor’s recommendations.

If unsure about any of the information provided here please contact

Poliwood Composite Decking

(03) 90847426