If you are unfamiliar with composite decking, you may assume it to be placed in the same way that wooden decking is. Composite decking expands and contracts differently than wood. This discrepancy must be recognised during installation to avoid costly repairs and unsightly decking.
To avoid issues, prepare and plan the composite decking installation. If not, you might have warping, standing water, or a collapsed deck. These faults degrade deck look and strength. So, how can you deck safely? Failure to follow the manufacturer’s installation instructions may void your warranty, which you do not want. Here are our common mistakes people make often when installing composite decking:
1. Insufficient expansion spaces between the decking butts
The plastic component of composite deck boards causes them to stretch and compress more than wood decking. We recommend deck boards end-on at the appropriate distance (*1mm if the temperature is over 26°C, 3mm if 4°C – 25°C, 6mm if below 4°C). This will provide enough expansion area without bending or twisting the boards.
2. Insufficient ventilation below the deck
Composite decking absorbs moisture because it is semi-organic. Rotting occurs when wood is exposed to water for an extended period of time without drying. A 35mm gap should be left between your foundation, concrete, slab, or grass and the bottom of your deck boards to enable composite wood joists and deck boards to drain and dry.
3. Installed on a substandard timber subframe
Subframes exist, as the term indicates. Standing water and erosion might cause joist damage if the subframe is not correctly installed. Composite decking requires more support than wood. Five joists is inadequate.
You may add joists to the existing subframe, replace it with new wood joists, or create a composite subframe. Plastic lumber subframes are ideal for decks in high-water locations or floodplains since they do not rot.
4. Installation on Larger Joist Centres
The joist centres on timber decks are generally 500mm. It may make sense to repurpose wood subframes. Composite decks need more support than wood planks, therefore this is improper. This is because composite lumber has a lower tolerance than wood. Timber planks flex naturally. Composite deck boards are more flexible, but not weaker, owing to the plastic component, and need more support. To accommodate this, composite deck subframe joists should be spaced 250-350 mm apart.
5. Using an alternative. Suppliers’ Composite Deck Clips
When doing something you’ve done previously, it’s natural to assume you know best. However, composite responds differently than wood, so what works for wood may not work for composite. Superdeck is responsible for designing, manufacturing, and supplying our proprietary goods.
Our clips work best since they are specifically designed for our decking. Decking is flexible and expands as it changes shape.
6. Directly attaching to decking without clips.
Our decking clamps allow boards to expand and contract with temperature. Screw holes may split and shatter when the decking pushes on the screw during expansion and contraction, rendering them less secure. Our clip system works seamlessly with Superdeck products, allowing boards to stretch and compress without constraint.
7. Not Treating Timber Joist Cut Ends
Timber used to construct a decking subframe should be properly treated. Top, bottom, sides, and ends. This is a simple, common mistake that we encounter often. The main reason ends are overlooked is because painting joists placed on posts is easier since you can paint both top and bottom without drying. This makes the exposed ends butted against a wall or fence difficult to access and may be overlooked.
8. Do not construct twin joists where two boards connect.
A sturdy base is required for decking. Double joists should be used when deck boards are butted together on a deck longer than 3.6 metres. Planks must be supported at all junctions to prevent splitting and slippage. Install deck boards with an expansion gap according to the fitting temperature.
9. Using Alternative Supplier Methods
If you have previously worked with composite timber, it may be tempting to follow the supplier’s fastening approach. All composites are not made equally. Each composite is unique in composition and design, necessitating a different technique. We worked hard with our design team, skilled installers, and customers to understand Superdeck Composite Decking’s tolerances and provide an installation guide that is appropriate for our product.
10. Insufficient Slope Drainage
Any handyman with a spirit level expects a level surface. This may cause standing water to remain on your deck for an extended period of time, preventing proper drainage. To ensure proper drainage, let 1% (1:100) to fall. In truth, your deck should slope 10 mm away from your house for every metre. This will be small enough not to be detected while allowing water to drain away, preventing slippery surfaces and rotting.
11. Specifying an Unsuitable Product
There are four different Superdeck composite decking products. They function differently and have diverse goals. The Essential and Advanced pieces are somewhat hollow for simple installation. These should not be used in high-traffic areas, commercial settings, or load-bearing applications. Classic and Deluxe boards are durable and suitable for such applications.
12. Use Low-Quality Subframe Material
A wise man once said, “Only a fool builds his house on sand.” Decking is just as solid as its foundation. Before putting boards, make sure the base is well prepared. Choose the subframe material wisely. Steel subframes anchor themselves, making them excellent for roof terraces and balconies. Instead of wood, use plastic lumber near water or a high water table since it does not degrade. A traditional subframe requires seasoned wood that can withstand extensive use.
