Is Composite Wood Waterproof?

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water proof decking material

Moisture can Damage Decking Boards.

Water alone can be destructive. Just like the climate, hot tubs and swimming pools are equally destructive to wooden decks and sometimes more destructive because of their chemical content. We may be wondering how water destroys wood. Wood, even after it has been sawn down and cut into boards, stores water in them. Twenty per cent of a dimensionally stable wood board contains moisture. When moisture reaches 30 per cent of the weight of the board, that means that the water is already between the board and not in its fibres anymore. That’s when problems arise. A freezing climate can make it even worse. If water expands between the fibres, fungi and other microbial life will soon grow. The more water is intruded into the fibre, the more it encourages other organisms to move in.

Choose the Correct Decking 

When choosing a decking material, it’s important to know that all decks use treated lumber for framing. This is the structural part of the deck that is not visible. Thus, deciding on the material of your deck relies solely on what the decking surface and its railings are made of. Deck material can either be natural wood or man-made products. These are the two main categories to choose from. Wood products can be treated lumber and cedar, while man-made deck material products are those that include composite, PVC and vinyl.

Most decks built today are made up of wood simply because of their low cost; however, those who choose composite decking think of the low maintenance it requires. You will be asking a lot of questions before deciding. Consider how the deck will be used. Will it be built in a shaded area? Do you plan to use this for a long time? Are you up to doing maintenance yourself? Or will you be hiring a company to do it for you?

Composite Decking is Made from Recycled Plastics and Wood Fibres 

Composite wood decking is made up of recycled wood chips and plastics, making it eco-friendly. If you are a person who follows a house theme, this comes in different styles and a variety of Earth tones. You can easily match it with your furniture or home. Aside from spending very little to no maintenance, composite dicking is friendly to the environment with its recycled materials.

Composite decking offers very minimal water absorption when compared to wood. When moisture gets trapped under the decking and on top of the wood joists, it stays there and keeps it from drying properly. This is different from wood which is more susceptible to rot and decay when not properly dried. If you are looking for quality waterproof composite decking materials, you should be very sceptical. The first-generation composite decking was made up of shredded plastic bottles and sawdust. They weren’t waterproof boards. Earlier, composite boards like these fell apart. It may also be dangerous during the rainy season, as it gets slippery when wet.

Homeowners looking for waterproof composite decking materials should look for those with special features. 2nd generation decking boards are surrounded with full capping (shielding) with a layer of waterproof material. This makes it fully protected. The capping material should provide a non-slip surface, making it safe even when wet. However, caution should be taken with any underfoot surface that is wet.

How do you make your Decking Boards Waterproof for Longer? 

The co-extruded capping is extruded together with the board as it leaves the mould to ensure that the capping and the core form a single unit. When the capping is not bonded to the core, it can crack or peel and could make the board vulnerable to water intrusion. There are no screws that were pierced into the board to resist moisture better. Hidden fasteners are inserted at the side of the board and are screwed into the substructure of the deck. This also creates a smooth look and feel as there are no screw heads to worry about.

decking material

The Signature collection of Wood Plastic Composite (WPC) boards from Ultra Decking benefits from Ultra Shield Technology. The Signature composite decking boards are more resistant to UV fading*, staining, mould, and mildew, giving them a life span of 25 years or more. It creates a natural look with its natural wood grain finish. Many customers described it as fabulous indoor flooring with all the benefits of outdoor protection.

2nd generation composite decking has eliminated several issues compared to first-generation WPC like fading, staining, mould spots, mildew, cracking, crumbling and warping. 2nd generation composite decking includes a plastic layer or capped shielded technology covering the entire composite decking board. This also guarantees that your decking colour stays for a long time and prevents dust and liquid from reaching the core of the composite decking boards.


The 25-year warranty makes it all worth it. Ultra-Shield technology guarantees ultra-low maintenance decking. Since the board absorbs almost no water, you don’t have to worry about liquids, drinks and spills. You simply wipe them away! It is also a protection against natural elements such as mould and mildew. An additional feature would be its surface texture which is almost indistinguishable from real wood.

Also read: How Do You Remove Rotten Decking Boards


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