If you plan to build your composite decking yourself, you can save some cash by doing that. But building your composite decking comes with lots of experience. This infers that you have to have an accurate knowledge of what it takes to build your decking. One thing you must know about decking installation is how to build the foundation. The kind of foundation that you build for your decking affects how long it will last. You must build or install a solid foundation if you want your decking to stay long in the ground. So, how deep is the composite decking foundation?

Type of Decking Foundation

There are different types of decking foundation. There is the elevated decking and the ground-level decking. Ground-level decking is closer to the soil or ground. The top or the surface of the decking is not far from the ground. To climb ground-level decking, you don’t have to raise your feet much. The other type of decking foundation is elevated decking. 

This type of decking foundation requires posts. The posts used to raise the decking are high enough to lift it from the ground. Elevated decking needs a deep or solid foundation for it to be strong. This implies that you must sink the posts deep inside the ground and cover them with cement to get a solid foundation. So, if you are building composite decking, you must give it the right foundation. 

How Deep Is Composite Decking Foundation?

Building Your Decking Foundation

If you are building ground-level decking, you don’t need a deep foundation because your decking is not far from the ground. For this kind of decking, what you have to do is give it a simple foundation. Look for short posts or concrete blocks. If you are using posts, dig small holes and put part of the posts in the holes. 

Then cover the holes with cement and wait until it dries. When the cement is solid, then you can start fixing the substructure. You should do the same if you are using concrete blocks. Put the blocks at the corners of your decking and ensure that you fit them to the ground with cement. When the structure is dried, you can start building the frame of your decking.

Building an Elevated Decking Foundation

An elevated decking foundation is different from ground-level decking. To build an elevated decking, you have to clear the area you will install it. After that, you have to ensure that you level it to get straight decking. Then, you should start planning for the foundation. You will need posts. The posts you will use for your composite decking foundation should be long. 

Depending on how high you want your plastic wood decking to be, you can use long treated wood. If you have money to spend, you can use metal as the posts instead of wood. The posts should be at least 90 cm long. After getting the woods that you will use as the posts, then you have to dig holes. You will put the wooden posts of your plastic wood decking in the holes. This is where skill is required.

Holes deep holes determine the strength of your decking foundation. If you dig holes that are not too deep for your posts, then your decking’s foundation will not be solid. But if you dig holes that are deep, then your decking foundation will be solid. Look for a digger and start digging the holes. The holes of the foundation of your decking should be at least 30 cm deep.

 This implies that if your posts are 90 cm long and the holes are 30 cm deep, you will put 30 cm of the posts inside the ground. After digging the holes, you should put the posts inside the holes and cover the hole with cement. Cement and deep holes will contribute to a deep foundation when you build your decking.

Fixing the Decking Boards

After building a solid foundation, you can start fixing or arranging the composite boards on the frame. You have to attach the frame of your decking to the posts first before fixing the boards. When you build a good substructure, your decking will last longer than one that doesn’t have a good structure.


The foundation of your composite decking must be deep so that your decking will last longer. Ensure that you use long posts for the foundation so that you will put it deep in the ground.

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