Building composite decking is a crucial task. Aside from beautifying your garden or lawn, composite decking will add value to your compound. But adding value to your compound does not come automatically. You have to use high-quality, decking material to build your decking. Aside from that, you have to ensure that you follow all the steps when building your decking. Following all the steps means that you must use the right substructure or joists for your composite decking foundation. But if you use the wrong joists, it will rot. So, how do you keep your composite decking joists from rotting?

What Is a Composite Decking Joist?

The joists are also the substructure of your composite decking. Your substructure or joists consist of several planks joined together to form a single frame. This infers that the joists of your composite decking are the foundation of your decking. It is what holds your wood plastic composite decking to the ground.

Of course, you will not place your joists directly on the ground. You have to fix your composite decking joists to the posts that you will cement to the ground. So, the joists and the posts are what we refer to as the foundation of your decking.

What Material Can You Use for Your Composite Decking Joists?

There are several materials that you can use to build the joists of your composite decking. You can use wood or wood material for your wood plastic composite decking joists. Aside from wood, you can use composite boards for the joists of your wood plastic composite decking.

Wood or Wooden Joist

Keep Wooden Joists From Rotting

Wood joists are made from natural wood. This means that when you use wood joists to build your composite decking, you are using wood. But natural wood is not too good for building composite deck joists. This is because of the problem associated with wood joists. As a natural fibre material, wood will decay or disintegrate easily.

This infers that when you build your composite deck joists with wood, it will not last long. Lumber joists are susceptible to rot and will rot easily. A rotting joist is not a good thing because your composite decking can collapse under its weight. Aside from rot, wood joists will absorb moisture and swell. This also will make your composite decking joist to rot.

Composite Boards Joists

Another alternative to wood joists is composite boards. Unlike wood joists, composite boards joist is not a natural material. The boards are synthetic materials made in a factory. Composite boards are stronger than wooden joists and will not disintegrate easily. This infers that composite boards will last longer.

Regarding rot, composite board joists will not rot like wood joists. And these boards will not absorb moisture like wood. This makes composite boards a joists material that will not decay or rot like timber. Since your composite decking will last for a long time, using wood is not too good a choice because the wood will not last as long as composite decking. That is why you should use composite boards for your joists.

Preventing Your Composite Decking Joists from Rotting

When you build your composite deck, the joists which serve as the foundation of your decking will be closer to the ground. This makes it susceptible to rain splash or water. Water or moisture can make your joists to rot. This is true if you use the wrong joists material. If you use wood joists, you have to stop them from rotting.

One way you can stop the wood joist from rotting is by using pressure treated wood as the substructure of your composite decking. Treated wood contains chemicals that prevent moisture absorption. Also, treated wood is firm and stronger than untreated wood. Even when you use treated wood, you have to seal the wood, so that moisture will not enter it. Sealing your composite deck wooden joists will prevent them from rotting.

If you don’t want a joist that will rot quickly, you can use composite deck joists. You don’t have to treat your joists to make it strong. This is because composite boards will not rot because it is a synthetic material. So, if you desire to build good joists that will not rot, you should consider composite boards instead of wood that will rotten.


You can keep your composite deck joists from rotting by using pressure-treated wood instead of untreated wood. Also, you can use composite boards as the joists of your decking.

Show CommentsClose Comments

Leave a comment