How to Fit Composite Decking

What is Composite Decking?

Composite decking is a modern alternative to traditional wooden decking. It’s made from a blend of wood fibres and plastic, creating a durable and low-maintenance outdoor surface. Composite decking has gained popularity for its ability to resist the elements, requiring less maintenance compared to natural wood. It is available in a variety of finishes and colors, allowing homeowners to achieve the look of wood without the upkeep.

Where Should I Lay My Composite Decking?

When deciding where to lay your composite decking, it’s essential to choose an area that is flat, level, and free from any obstructions. Your decking will need to have proper drainage, so avoid areas that collect water. If you’re laying your deck over soil, make sure the ground is prepared to provide stability and support. Avoid areas prone to flooding or excessive moisture, as this could cause damage to the decking over time.

Is Composite Decking Easy to Install?

Installing composite decking can be straightforward for someone with basic DIY skills, but it does require attention to detail. While composite decking is easier to install than traditional wood decking because it doesn’t require staining or sealing, it still involves preparing the ground, assembling joists, and laying the boards. If you’re confident in your ability to follow instructions and have the right tools, you can install it yourself. However, if you’re unsure, hiring a professional installer can save time and ensure a high-quality finish.

How Do You Prepare the Ground for Fitting Composite Decking?

Before you start laying your composite decking, the ground must be properly prepared. Begin by clearing the area of any debris, plants, or obstacles. The surface should be level and stable, so if the ground is uneven, you may need to add a layer of gravel or sand. This helps with drainage and prevents moisture from collecting underneath the decking. If you’re building over soil, you may want to lay a weed barrier to prevent growth under the deck. Once the area is cleared and leveled, you can begin assembling the joists.

Assembling the Internal Joists

The joists are the structural framework that supports your composite decking. They should be spaced at regular intervals (typically 40-50 cm apart) to ensure the deck is sturdy and stable. Start by laying the perimeter joists and then work your way inward, attaching them securely to the frame. When assembling the joists, ensure they are level and that they provide the proper slope for water drainage (approximately 1-2 cm per meter). This will help prevent water from pooling on your decking and promote long-term durability.

Fixing the Noggins in Place

Noggins are short pieces of timber used to connect the joists at regular intervals. They provide additional support and help maintain the spacing between the joists. Once the joists are in place, fix the noggins in between, ensuring they are securely attached. This will help prevent any sagging or movement in the decking boards and ensure that your deck remains stable over time.

How to Lay Composite Decking

When it comes time to lay the composite decking boards, start at one end of the deck and work your way across. Lay the boards perpendicular to the joists for maximum strength. Composite decking is usually installed with hidden fasteners, which means you won’t see screws on the surface of the boards. These fasteners fit into grooves on the edges of the boards and are fixed into place with screws that attach to the joists below. Be sure to leave small gaps (around 5-6mm) between each board to allow for expansion and drainage. Continue this process until all the boards are in place, ensuring they are aligned and level as you go.

What Are Butt Joints?

Butt joints are a type of joint where two decking boards meet at a straight angle. Unlike miter joints, which are angled, butt joints are simple and straightforward, where the ends of the boards are lined up next to each other. This type of joint is commonly used when joining two ends of decking boards to extend the length of the deck. It’s essential to ensure the butt joints are flush and aligned properly to avoid any gaps, which could allow water to enter and cause damage over time. For a seamless finish, you can use a trim board to cover the edge of the joint.

Tools You’ll Need

When installing composite decking, having the right tools is essential for a successful project. Key tools include a measuring tape to ensure accurate spacing and alignment, a saw—preferably a circular saw or miter saw—to cut composite boards to the correct size, and a power drill and driver for drilling holes for screws or fasteners. A level is also necessary to ensure the decking frame and boards are perfectly level during installation. For maintaining uniform spacing between the joists, joist spacers can be very useful. Don't forget safety gear, such as safety goggles, gloves, and a dust mask, especially when cutting and drilling.

Leave Room for Expansion

Composite decking has a tendency to expand and contract with temperature changes, so it’s crucial to leave proper space between the edges of the boards and around the perimeter of the deck. You should also leave small gaps between each decking board to allow for expansion. A gap of around 5-6mm is typically sufficient for both the edges and between the boards. This ensures that your decking remains in good condition and doesn’t warp over time.

Use the Right Fasteners

While you can use screws to attach composite decking, hidden fasteners offer the best results. These fasteners clip into the grooves along the edges of the boards, creating a clean, screw-free surface that not only looks better but also reduces the risk of moisture damage around the screw holes. The use of hidden fasteners ensures a more secure attachment and a longer-lasting deck, as there’s less chance of water weakening the composite material.

Install Decking at a Slight Angle

To encourage water drainage, it’s advisable to install your decking at a slight angle. A gentle slope of about 1-2% will ensure that water doesn’t pool on the surface, preventing potential water damage over time. This small slope, which is roughly 1-2 cm for every meter, helps to keep your deck dry and enhances its longevity.

Trim the Edges for a Clean Finish

After installing the composite decking, you may notice that some of the edges are uneven. To achieve a professional and clean finish, it’s worth trimming the edges of the decking using a circular or miter saw. Additionally, many composite decking systems come with trims or fascia boards that can be added around the perimeter of the deck to provide a neat and polished appearance.

Allow Time for the Boards to Settle

Before beginning the installation, it’s important to allow the composite boards to acclimatize to the outdoor temperature. This is particularly crucial if you live in an area with significant temperature fluctuations. By letting the boards sit outside for 24-48 hours before installation, you ensure that they won't expand or contract too much once installed, which can lead to gaps or misalignment.

Consider Drainage

Proper drainage beneath your decking is vital to prevent moisture buildup. If you’re laying the deck over soil or grass, you should consider adding a weed barrier and gravel to improve drainage. This will help reduce the likelihood of mold, mildew, and weed growth under the deck. Some installers even choose to incorporate drainage systems beneath the deck to help channel water away from the surface, further protecting the structure.

Cleaning and Maintenance After Installation

Once your composite deck is installed, regular cleaning will keep it looking its best. While composite decking is low-maintenance, it still requires occasional cleaning to remove dirt, debris, and leaves. You can wash the surface with soapy water or use a pressure washer to remove built-up grime. It’s important to avoid harsh chemicals, as they can damage the surface. Composite decking is resistant to staining and mold growth, but periodic cleaning will help maintain its attractive appearance over time.

Check for Manufacturer’s Warranty

Before starting your installation, take the time to review the manufacturer’s warranty. Many composite decking products come with warranties that cover defects in materials or workmanship. Understanding the terms of your warranty can help you address any issues early and ensure long-term satisfaction with your deck.

Summary

By following these guidelines, your composite decking installation will be both easy and durable. With the proper tools, preparation, and maintenance, composite decking provides a lasting, beautiful addition to any outdoor space.