How to install Composite Decking

12th Feb 2024

A guide to installing composite decking

Are you prepared to enhance your outdoor living area with the exquisite and long-lasting option of composite decking? Whether you're an avid DIY enthusiast or a newcomer to the realm of home improvement, our comprehensive guide is available to assist you throughout the entire process. Composite decking is widely recognized for its durability, low maintenance requirements, and appealing aesthetics, which have made it a favored selection among homeowners. Join us as we guide you through the initial stages, providing valuable advice and knowledge to guarantee a seamless installation. Let's convert your backyard into a stunning and practical sanctuary!
FEB, 2024


Selecting the correct composite decking is crucial. Consider the color, texture, and durability that will best suit your outdoor space. High-quality composite decking may come with a higher upfront cost but can save you money in the long run due to its longevity and low maintenance requirements. Additionally, you'll need to decide on the type of fasteners – hidden or visible – based on the finish you desire.

Measure twice, cut once – this old adage holds particularly true when it comes to decking. Accurate measurements are essential to ensure you purchase the right amount of materials, preventing wastage and additional costs. Plan your deck's layout carefully, considering the size and shape, as well as any unique features such as railings, stairs, or benches, as these will impact the quantity and type of materials needed.

Before installation begins, preparing the site is a key step. This includes clearing the space of any debris, rocks, or vegetation that could interfere with the decking foundation. If you're replacing an old deck, make sure to remove all remnants of the previous structure. Ensure the ground is leveled and firm, and if necessary, consider laying a weed barrier to prevent growth under the deck. For those planning to install over an existing patio or concrete, check for drainage issues or uneven surfaces that may need to be addressed beforehand. With the area prepped and materials at hand, you're now poised to start your composite decking installation.

Installation process

Before laying your composite decking boards, the foundation or joists must be correctly installed. Begin by ensuring your ground is level and firm. When setting up the joists, keep them at a maximum distance of 16 inches apart center-to-center for standard composite decking. This provides the necessary support and prevents sagging. Use corrosion-resistant screws or brackets to secure the joists in place. Remember to include a slight slope away from the house to allow for water drainage.

Once your joists are in place, it’s time to start laying your composite deck boards. Start from the outer edge of the deck and work your way in. This step ensures that the final board width does not end up too narrow. Make sure to leave a gap of at least 1/8 inch between each board for expansion and contraction as well as drainage. Some composite boards come with their own spacing tools, but if not, a set of spacers can be a handy tool to ensure consistent gaps.

To secure the decking boards to the joists, you can use hidden fasteners or deck screws. Hidden fasteners give a clean look as they are not visible on the board's surface, while deck screws are more traditional and require pre-drilling to avoid splitting the composite. Whichever method you choose, ensure that the boards are securely attached to each joist for a sturdy finish.

The deck frame provides the structural integrity of your entire deck. Construct the frame using treated lumber or metal framing for longevity. The perimeter of the frame must be securely attached to each joist and the house, if applicable, to ensure stability. It's essential to double-check measurements and level throughout this process to avoid any issues later on.

After all the boards are securely in place, inspect your deck for any uneven boards. Using a planer or sander, smooth out any uneven surfaces to prevent tripping hazards and ensure a pleasant aesthetic. Remember to follow the grain of the composite material to avoid damaging the boards.

Finishing Touches

Fascia and trim not only add aesthetic appeal to your deck but also protect the deck's structure by covering exposed joists and framing. Measure accurately and cut the materials to fit around the perimeter of the deck. Secure these with screws designed for composite material to ensure a long-lasting finish.

The final touch for many decks is adding post caps on any exposed deck posts. Not only do they provide a finished look, but they also offer protection to the posts from weather elements. Post caps are available in various designs and can easily be installed with adhesive or screws, depending on the type.

Completing your composite decking project may seem daunting at first, but with careful planning and attention to detail, you can create a beautiful and lasting outdoor space. Regular maintenance and cleaning will ensure your deck remains in top condition for years to come.

Maintenance and care

Maintaining your composite decking is key to ensuring it looks fantastic year after year. Even though composite materials are designed to be lower maintenance than traditional wood, they still require some care to stay in tip-top shape.

Cleaning your composite deck is straightforward and doesn’t require any special tools. A simple solution of soap and water, applied with a soft-bristle brush, is often all you need to remove dirt and grime. For tougher stains, there are specific composite deck cleaning solutions available. Remember to clean your deck semi-annually to maintain its beauty and integrity. Avoid using a power washer as it can damage the decking material.

Composite decking is designed to resist mold and mildew, but no outdoor surface is entirely immune. To prevent these unwelcome guests, keep your deck clear of leaves, twigs, and other debris that can hold moisture. Ensuring proper drainage and air circulation around your deck can also help keep mold and mildew at bay. If mold and mildew do appear, a deck cleaner designed for composite materials is your best solution for removal.

While composite decking is engineered to minimize fading and staining, it's still important to take precautions. Spills should be cleaned up quickly to prevent staining. For added protection, consider applying a composite deck water sealant. This can help to further protect your deck from the elements and prolong its life. However, make sure the sealant you use is compatible with your decking material.

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