If you have an old concrete slab in your backyard and you don’t want to tear the surface away, you can make a beautiful backyard by learning how to fix composite decking to concrete. This write-up explains in detail how the best practice you should follow when building your composite decking project on an existing concrete slab.

Why Do I Need A New Composite Decking In My Backyard?

You will ask that question if you have a backyard that is beautiful or perhaps, you have a good and durable decking in your garden. If you have installed concrete, you will notice that with time, that beautiful concrete slab is no longer attractive. It could be that the concrete top has worn out or there are holes or cracks on top of your concrete slab. The pits and cracks will distort the surface of your concrete and make your backyard less beautiful.

 When this happens, you will want a new flooring material in your backyard. There are several decking materials that you can use to floor your garden. One of them is wood decking. Aside from wood decking, there is composite decking. Of the two, composite decking is the best. This is because composite decking is durable, strong, easy to maintain, and it will last longer than wood decking.

 Aside from composite decking, there is PVC and aluminium decking. Composite decking is better than the two because it can be customised to look like wood decking. This is because homeowners prefer the traditional wood look of wood decking. So, this makes composite decking the better alternative to wood decking.

Fixing Composite Decking to Concrete

It is crucial to know that we do not recommend that you fix composite decking joists directly on the concrete. The reason for this is simple. Your composite decking will block the flow of water. When this happens, the joists or frame will absorb water or moisture. 

Moisture will weaken the frame or substructure of your composite decking. When this occurs, your decking can collapse under its weight. Note that before you install your composite decking, you have to gauge it to determine the extent of the damage. If the cracks are not deep, then there is no need for you to worry.

Step One – Install the Sleeper System

The sleeper system is the right solution to the problem. So, instead of fixing your composite decking directly on the ground, you will fix the joists on the sleeper system. What is a sleeper system? A sleeper system is a substructure made of treated joists that sits on the surface of the concrete. The sleeper system creates a space between the concrete and your composite decking boards. Remember that we mentioned earlier that if your composite decking absorbs moisture, the moisture will weaken your decking. 

So, the sleeper system creates a space so that moisture and water will not get to your decking surface. Also, the sleeper system allows for air circulation under your composite decking. Since you will install the sleeper system in such a way that it runs in the direction of water flow, your sleeper system will allow good drainage. 

So, to build the sleeper system, you have to use treated wood for the substructure. Arrange them in the direction of water flow so that they will be straight to the wall of your house. You will need lots of treated planks for this task.

Step Two – Protect the Sleeper System

After you have installed your sleeper system, you can then proceed to install cover the edges with tapes. You don’t need to do this, but this will go a long way to protect your planks from moisture and prevent it from rot.

Step Three – Install Your Joists

Now that you have installed your sleeper system, you can install your joists. You should use treated planks for the frame of your substructure. The best practice is to start installing your composite decking joists from an edge. Make sure that the space between the joist should not be more than 16 inches. Also, tilt your joists slightly so that it will allow water flow when you have finished installing your composite decking boards. 

Step Four – Install Your Composite Decking Boards

outdoor decking on concrete

After installing your joists, you can start installing the composite decking boards. You should use starter clips and intermediate clips to install your composite decking boards. When you are done, you should cover the edges with fascia so that your decking will look beautiful.


You can fix composite decking boards on concrete. This process is easy, and you can do it yourself.

Leave a Reply

Your email address will not be published. Required fields are marked *

Your email address will not be published. Required fields are marked *