Composite decking is a popular choice for homeowners looking for a low-maintenance, durable, and aesthetically pleasing outdoor space. However, like any installation process, there are common errors that can compromise the quality and longevity of your composite decking. Avoiding these mistakes will help ensure your deck is built to last and performs well over time. Here are the most common composite decking installation errors and how to avoid them.
1. Acclimation & Storage
Composite decking boards should be placed on-site for 48 hours prior to installation. This allows the boards to settle in the environment and will help ensure consistency throughout the installation process. Boards should be stored flat, covered and protected from the elements until ready for installation.
2. Board Arrangement
Lay out your boards and check for any subtle grain or colour variations prior to starting installation. This can help to create a more professional and aesthetically pleasing final result.
3. Not Allowing for Proper Expansion and Contraction
Composite decking materials, like wood, expand and contract with temperature changes. Failing to leave adequate space between the boards can cause them to warp, buckle, or even break over time. To prevent this, always follow the manufacturer’s recommendations for spacing between deck boards. Typically, you should leave a gap of at least ¼ inch (6mm) to allow for expansion and contraction.
4. Perimeter Expansion Gap
An expansion gap between the house, building or wall and the decking itself should be present to allow for expansion, drainage and air circulation. We recommend a gap between 10mm – 20mm. Without this expansion gap, the decking will be liable to cracking during the warmer months. This would both invalidate your warranty and lead to costly repairs.
5. Failing to Check for Proper Joist Spacing
The spacing between the joists is critical to ensuring the composite decking is properly supported. If the spacing is too wide, the boards can sag or become unstable. Always follow the manufacturer’s guidelines for the recommended joist spacing, which is typically 12 – 16 inches (approx 400mm) apart. This will ensure that your deck is structurally sound and safe to use.
6. Not Installing Decking on a Slight Gradient
Composite decking should have a slight slope to allow for water runoff. If the decking is installed perfectly flat, water can pool on the surface, possibly leading to mold, mildew, and potential damage over time. Make sure the deck is installed with a slight gradient away from the house to direct water away from the structure. A slope of about 1/8 inch per foot is ideal.
7. Incorrect Clips Use
Using the wrong type of clips (also known as fasteners) can lead to weak and unstable deck boards. Ensure you are using clips specifically designed for composite decking. Stainless steel or coated deck screws are best because they resist rust and corrosion. Avoid using nails, as they don’t provide a secure hold and may lead to boards loosening over time. We always recommend using the clips supplied or recommended by the manufacturer of your particular decking brand.
8. Poorly Secured End Cuts
End cuts on composite decking must be properly sealed to prevent water from penetrating and causing damage. Many people make the mistake of leaving end cuts unsealed, which can lead to moisture seeping into the board, causing swelling or warping. Use a composite decking end sealant to protect these areas and ensure long-lasting durability.
9. Installing Without Ventilation
Proper ventilation is key to maintaining the longevity of your composite decking. If the decking is installed in a way that restricts airflow around or underneath, it can trap moisture and promote mold or mildew growth. Ensure there is adequate space between the deck boards and the ground to allow air to circulate. This will help the deck to dry out more quickly and prevent moisture buildup.
10. Ignoring Manufacturer Instructions
Each brand of composite decking comes with its own specific installation instructions. Failing to follow these guidelines can lead to errors that affect the appearance, performance, and longevity of your deck. Always carefully read the manufacturer’s instructions before starting the installation process to ensure you follow the proper procedures for your specific decking.
11. Not Using the Right Tools
Using the wrong tools during installation can lead to improperly fitted boards or damage to the material. Make sure to use tools that are designed for composite decking, such as carbide-tipped saw blades and screwdrivers or drills with the correct torque settings. Avoid using power tools that could overdrive the screws or cause the boards to crack.
12. Over-tightening Screws or Clips
While securing the decking, it’s important not to over-tighten the screws or clips. Over-tightening can cause the composite material to crack or deform, leading to unsightly marks and potential structural issues. Tighten the screws just enough to secure the boards without compressing them too much. Most composite decking materials have a specified torque limit for screws, which should be followed carefully.
13. Neglecting to Clean the Deck
Although composite decking is low-maintenance, it still requires periodic cleaning to maintain its appearance and prevent buildup of dirt, debris, or algae. Many homeowners make the mistake of neglecting cleaning altogether. Regularly sweep the deck and clean it with a dedicated composite decking cleaner or mild soap solution (washing up liquid) and a soft brush to keep it looking like new. Avoid harsh chemicals, bleach or abrasive materials that could damage the surface.
14. Incorrect Framing for Elevated Decks
For elevated decks, it’s essential to have the correct framing sub-structure. The frame and joists must be level, secure, and strong enough to support the weight of the decking and anyone who will use it. Improper framing can result in an unstable deck that is unsafe to use. Ensure your framing is properly constructed and meets local building codes to guarantee stability.
15. Overlooking Proper Drainage
Inadequate drainage can lead to moisture buildup beneath your composite decking, which can affect its longevity. Make sure that water can easily flow away from the deck and that the space underneath remains dry. Install proper drainage systems such as gravel or perforated drains if necessary to ensure that water doesn’t collect underneath the decking.
Conclusion
By avoiding these common composite decking installation errors, you can ensure your deck is built properly, lasts longer, and requires minimal maintenance. Take the time to plan, use the right materials, and follow the manufacturer’s guidelines, and your composite deck will provide a beautiful and durable outdoor space for years to come.
FAQs
1. How much gap should I leave between composite decking boards?
Leave at least a ¼ inch (6mm) gap between composite decking boards to allow for expansion and contraction.
2. Can I use regular wood screws for composite decking?
No, always use screws specifically designed for composite decking to ensure a secure hold and prevent damage. Speak to your supplier if you are unsure.
3. How can I prevent water pooling on my composite deck?
Install the decking with a slight slope of about 1/8 inch (3mm) per foot to allow water to drain away.
4. Is it necessary to seal the end cuts of composite decking?
Yes, sealing end cuts prevents moisture from penetrating and causing damage to the boards.
5. What tools should I use to install composite decking?
Use carbide-tipped saw blades and the correct torque setting for your screws to avoid damaging the decking.