Will a Composite Decking Board Rot?

M. John
Learn Decking
Will a Composite Decking Board Rot?

Will a composite decking board rot? In short no. Wood will rot if you expose it to moisture. Unlike wood, composite decking boards do not rot. Composite decking is resistant to rot even if exposed to moisture. This benefit of composite decking is a distinct advantage over wood decking. To understand why a composite board does not decay, let’s see what composite decking is.

What is Composite Decking 

The word “composites” mean a combination of two different materials. Ultra Decking composite boards consist of two different materials. It is not like wood decking that is pure wood. Composite decking contains wood fibres and recycled plastic material. The combination of these two materials makes composite decking boards superior to wood decking.

Composite decking floor installed beside a small garden

A Brown composite decking project, installed beside the garden without fear of rot.

Wood is naturally beautiful, and so is composite decking. But a composite board is more durable and can be beautiful for decades longer than wood. It is stronger and resistant to splintering or cracking and will not warp like wood.

Composite boards are also easier to maintain than wood. If you have a composite deck, you can easily maintain it without spending too much money. With wood, you have to sand it before treating it with sealers and stains to prolong its lifespan.

Lastly, wood can rot or decay over a short period if not maintained regularly.

Why Composite Decking Does Not Rot

Composite decking is durable and resistant to water or moisture. A composite decking board consists of wood fibres and recycled plastics. These materials are combined with a bonding agent to form a durable composite decking board. The wood in the decking gives the decking board its strength, while the plastic in the decking board makes it resistant to water.

Wood decking, unlike composites, will swell if it absorbs water or moisture. And will eventually rot over time.

In the presence of water or high humidity, wood will eventually rot and decay.

Types of Composite Decking Board

However, there are two types of composite decking material you can use in building a deck. There is capped and uncapped composite decking board.

Capped Composite Decking

Capped composite decking boards have higher water resistance. This is the most common type of composite decking homeowners prefer. One reason is that the capped composite decking has a plastic coating on its outer layer. The plastic coating around the capped composite decking board makes it difficult for water or moisture to penetrate it.

Because they have high resistance to water or moisture, the capped composite decking board is suitable in high moisture areas. You can install it by the dockside or by the poolside without worrying that the decking will swell.

Uncapped composite decking

The uncapped composite decking board differs from capped decking as it does not have a plastic coating around it. Uncapped composite decking boards are less resistant to water than capped composite decking. They are not suitable for use in places with high moisture. But this does not mean that the uncapped decking will not last long. They are also durable and less resistant to moisture and water penetration compared to wood and will last for a very long time.

However, the uncapped composite board is suitable in areas with less moisture. So, if the place you want to install your deck is dry, the uncapped composite decking board will be suitable for building a deck. Also, if you are planning to build the decking over a shaded area, you can use the uncapped composite board. The shade will protect the decking and keep it from absorbing water.


Will a composite board rot? No. A composite decking board is resistant to water and moisture absorption which stops the board from rotting.


Leave a Reply

Your email address will not be published.