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attaching composite decking directly to concrete

Composite decking has gradually evolved into a more popular choice for outdoor construction. Because of its better durability, low maintenance, and aesthetic appeal. If you have decided to install composite decking in your outdoor space. You may be wondering can composite decking be installed over concrete. In fact, the most common material used to support frames for decks and outdoor spaces is concrete. Many builders use concrete because it is economical and more durable. In the next article, we will discuss can composite decking be installed over concrete and how to install composite decking over concrete.

Can you attach composite decking directly to concrete

In most cases, you can attach composite decking boards over concrete. But it is important to remember that you must build a substructure that allows airflow and drainage. A concrete surface provides a dry, durable, and sturdy area that is friendly to your deck. And using concrete as a base has the following benefits:

  • Easier installation: An already existing base can save you more time on deck installation. Because you don’t need to spend time installing the base.
  • More aesthetically pleasing: If your concrete deck cracks and wears out, there is no need for new maintenance and upkeep. Install composite decking over concrete and you will have a beautiful and durable deck.
  • Decking is easy to maintain: Concrete decking can be a pain and requires regular repair and maintenance. But installing composite decking on concrete can solve this trouble. COOWIN offers composite deck boards that can withstand extreme weather conditions. And are more durable, not easily cracked, worn, and warped.
  • Concrete is drier: Compared to some gravels and sands, concrete is drier and does not easily have wet floors.
how to install composite decking over concrete

Pre-installation considerations

Installing composite decking over concrete is a very simple project. However, in some cases, you cannot install over concrete. And there are some precautions you need to strictly follow during the installation process.

Beware of sinking decks

In most cases, you can install decking on concrete very easily. However, it takes several years for the concrete to be fully set. Installing composite decking boards during this time may cause the deck to sink along with the concrete.

To avoid this, you can take precise measurements to see if your concrete deck will sink. Draw a horizontal line near the surface of the concrete foundation and record the vertical distance from the mark to the concrete. Measure every month and compare if there is movement or sinking.

Make sure the door is not blocked

Installing composite decking over concrete will raise the surface of your deck by 2-3 inches. If there is a door near the deck, make sure that the deck will not block the door frame after installation. To avoid this, build a temporary deck to test and see if the new deck will have an impact.

If your door frame will be blocked by the composite decking, it does not mean you cannot install the new deck over the concrete. Although this can be very tricky to install, you can still seek the help of professional composite deck installers. They can design a more reliable solution to your needs.

Repairing damaged areas

If your concrete deck is broken and cracked, repair your deck before installing composite deck boards. Make sure the concrete is flat, structurally sound, and free of any damage or cracks during the installation process.

can composite decking be installed over concrete

Repairing broken concrete is accessible by purchasing a self-leveling concrete repair product. Placing it on the uneven or broken deck allows it to dry and set. This will complete the concrete patio repair project.

Tools and protective gear needed

Before installing composite decking, make sure you have the right clothing and equipment to protect yourself, including:

  • Gloves: Heavy-duty gloves with good friction will protect your hands from injury during the installation process. Especially when you build a deck to fit the installation.
  • Goggles: They can effectively protect your eyes from particles and debris. Goggles or safety helmets are especially important when sawing decks.
  • Long sleeves: Long sleeves can protect your skin from scratches or sunburn. Be sure to keep your sleeves away from the saw during the cutting process.
  • Installation tools: circular saw, electric drill, tape measure, rubber hammer, and measuring tape.

How to install composite decking over concrete

If your precautions and preparations have been completed. You are ready to begin installing your new composite deck, here are the steps that must be followed:

Step 1: Clean the surface

Thoroughly clean the surface of the concrete deck to remove any dirt, debris, or other contaminants that may interfere with the composite decking installation. Use a pressure washer and cleaner to ensure the surface is clean and free of any residue.

Step 2: Apply bonding agent

To ensure better adhesion between concrete and decking, apply a bonding agent to the surface. This is a special bonding agent for composite decking. Apply the bonding agent in a thin, even layer and follow the instructions for application and use.

Installing composite decking over concrete

Step 3: Install the sleeper system

When installing composite deck boards on a concrete deck, a sleeper system must be installed. The sleeper system is a grid of support beams, which allows a gap to be created between your deck and the concrete surface. The gap ensures air circulation and moisture drainage at the bottom of the deck. Preventing the collection of moisture that can cause deck rot. It also ensures gaps between composite deck boards, allowing your deck to circulate air better.

Step 4: Install the deck

After the sleeper system is installed it is time to lay composite decking. Start the installation from one end of the sleepers and lay the deck perpendicular to the sleepers. Use hidden fasteners or screws to secure the deck in the sleeper system. Be sure to leave gaps in the installation of the decking to allow for thermal expansion and contraction of the deck.

Step 5: Adding Trim

After the deck is installed, you can add some decorations such as railings, stairs, and other accessories. To complete the look as well as the function of your outdoor space.


In conclusion, attaching composite decking directly to concrete is possible if it is thoroughly prepared and installed correctly. Installing decking over concrete is very easy and has many more benefits. It will make your composite decking more durable and save you more money on installation costs.

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