What’s The Harm In Screwing Composite Decking?

When installing composite decking, it is essential that you get it right the first time. Making mistakes during the installation can result in costly repairs or can damage the decking boards.

Investing in high-quality composite deck boards can ensure you enjoy a high-quality finish that is long-lasting and can also add value to your home.

Professional installation will help you achieve a great finish and safe decking for you and your family to enjoy. Alternatively, you will be able to carry out the composite decking installation yourself if you have the skills and experience.

One important decision you will have to make is whether you plan to use screws to secure your decking or go with an alternative method.

This guide will take you through all the information you need to make an informed decision that results in a safe decking area that looks great.



Screwing Down Composite Decking Boards

There are many reasons that people might choose to use screws on composite deck boards.

Screwing boards in place is relatively quick and straightforward for those with experience.

It can allow professionals to complete the job more quickly and reduce labour costs.

Composite decking screws are readily available and low-priced, making it an attractive proposition for anyone looking to lower the cost of their decking.

Three-inch decking screws should be used to guarantee a secure hold. Composite deck screws have a reverse thread to cut off the mushroom head that can be created when composite lumber is screwed into.

While screws offer a convenient option, there are a number of significant disadvantages that can affect decking. It would be best if these are considered before making your decision.


Why Screwing Down Composite Decking Can be a Bad Idea

When thinking of installing composite decks, most people will automatically think screwing the deck boards down will be the best, most secure option. After all, this is the most common method for securing a wood deck.

You might have started to look for the most suitable screw options to blend in with your decking, including composite screws, wood screws, or other special screws that are marketed as being suitable for decking.

In reality, screwing composite decking can be a bad idea. The following reasons demonstrate why you may want to think twice about screwing down composite material.


Cracked Boards

Using screws to secure deck boards can cause the boards to crack or warp. This is because composite boards are made of reclaimed wood fibres and recycled plastic.

The different materials in this type of board mean it can behave in a different way to wood in different temperatures.

Expansion and contraction can cause pressure to build up around the screw holes leading to the boards cracking or warping. We recommend fixing the composite deck boards with our hidden T-clips, Locking clips or Start/finish clips. On deck boards, fascia or trims where a special clip can’t be used, we would recommend pre drilling and counter sinking screws, this can be done in a way where the screw has a little bit of movement as the hole is larger than the screw.


Invalidate the Warranty

Following the supplier’s instructions is essential when building composite decking.

Different suppliers will create different composite options. The parts supplied and instructions are designed specifically for this composite, and straying from these instructions can lead to safety or performance issues.

Deviating from the supplier instructions can invalidate a warranty should it cause issues with the deck boards.

When you purchase your decking from Ecoscape, you will be supplied with starter and finish clips, hidden T-clips, locking clips, and the screws needed to attach these to joists.


Damage Boards

Using screws to fasten composite decks will lead to warping or cracking. The screw holes you make when installing the decking also make it difficult should you change direction and decide against screws midway through a job.

Allowing boards the space to expand and contract naturally is essential. Screwing a deck board directly to a joist won’t stop contraction and expansion, but it will pin it in place.

Preventing room for boards to expand or contract means that the area around the screw will have unnecessary pressure put on it, resulting in damage.


It Requires Skilled Professionals

Screwing composite boards is not as straightforward as screwing wood decking.

You might need a professional to ensure they do a good job. This will increase the cost of the decking project.

Buying decking from Ecoscape means you will be provided with the decking components and accessories, so avoiding screws can also save you money.


Alternatives to Screws

Using the components and accessories the supplier provides is not negotiable, and failure to do this will result in invalidating the warranty.

This makes things easy for anyone who plans to install their own decking boards as everything needed is provided.

The following provide excellent alternatives to screws when installing composite decking materials.


Starter Fasteners

Starter deck fasteners are used to secure the first and last deck boards to the subframe joists, providing safe and secure outer decking that will last a long time.


Hidden Deck Fasteners

Hidden fasteners are designed to secure the boards in place, clipping to the individual deck boards and being screwed into the joist beneath the deck.

Hidden fasteners also help to keep a set gap between the boards, helping with drainage and ventilation.

Hidden fasteners have several great benefits, including;

  • The clips provided by Ecoscape are designed for our decking. This guarantees a secure fit.
  • Because the clips are screwed to the joist and clipped to the board, it allows for expansion and contraction without the risk of damaging the deck board like screws.
  • Hidden fasteners also provide a cleaner finish. Thanks to this concealed fastening option, your decking will look better than ever. Screws can affect the overall appearance of a completed deck, and leaving the visible part of your decking untouched can be a vast improvement.
  • Holding your decking in place with clips minimises the risk of damage that screws can pose. Warped or split decks can happen when you screw them into the joists directly and screwing a clip that holds the deck board is a much safer option.
  • It can be hazardous if a nail is not screwed down enough. This can make your decking dangerous for children and pets, cause a trip hazard, or be dangerous for bare feet.
  • If a screw is screwed too far and the finish isn’t flush, it can cause water to pool in the indentation. Pooled water and prolonged exposure to moisture can result in mould, a slippery surface, or the accelerated degradation of your decking.
  • Hidden fasteners also have the benefit of a built-in spacer. This allows you to space your deck boards out an appropriate distance easily. This improves drainage and ventilation, minimising the risk of mould and mildew.



Can composite decking be laid on wooden joists?

Yes, you can lay composite decking on wooden joists. Because composite is a heavier decking material than timber, joists should be spaced together more closely.

Double joisting the butt ends of composite deck boards is also necessary, ensuring each board benefits from as much support as possible. It also helps with drainage, please refer to our installation guide.

Other materials to consider for joists include aluminium, plastic, and composite. These options offer greater protection against the elements and different levels of strength.


How much does it cost for professional composite decking installation?

The average cost of composite decking installation in the UK is between £400 and £600.

Professional installation costs will vary depending on the installer and location, and installation in the UK typically costs around £200 per day.

Composite decking will typically take between 1 and 3 days to install, depending on the decking area size. Assuming the deck is between 10 – 30m2 and isn’t complicated design.


Why is it important to leave gaps between deck boards?

Leaving gaps between decking is an integral part of the installation process. Gaps between composite deck boards allow easier drainage and minimise pooling.

As well as leaving gaps between deck boards, the decking should be laid with a slight gradient of around 1.25% to allow the water to run off naturally.

The gradient won’t be noticeable to anyone using the decking, and decking grooves should run with the gradient.

Gaps between decking also improve ventilation, allowing boards to dry more quickly and minimise the risk of mould or mildew growing.


How much does composite decking cost?

Ecoscape Clarity composite decking boards cost £41.55 per square meter. The cost to deck a small 15 square metre area in a garden would be £623.25.

Ecoscape Forma composite decking boards cost £66.12 per square meter. The cost of deck materials for a small garden with a 15-square-metre deck would be £991.80.


Can anyone install a composite deck?

While composite decking is relatively straightforward to install, only professionals or those with adequate experience should lay composite decks.

Proper installation is essential for the warranty and to guarantee the safety and longevity of your deck area.

The following tools are recommended for carrying out composite decking installation;

  • Pencil
  • Tape Measure
  • String-line
  • Set Square
  • Spirit Level
  • Protective goggles and Personal Protection Equipment
  • Hand Drill
  • 3mm and countersink drill bits
  • Jig Saw
  • Mitre Saw
  • Circular Saw


Only commit to a composite decking project if you are confident you have the experience to install composite decking safely and securely. Repairing poorly installed decking can be expensive and time-consuming.


Final Thoughts

Using screws on composite decking offers a level of convenience but can cause long-term issues.

When you weigh the pros and cons of using screws on composite decking, there is only one real winner; using hidden fasteners.

Hidden fasteners allow composite deck boards the freedom to expand and contract naturally without being pinned into position.

The irreversible damage caused by using screws on a composite deck is not worth the time you will save in the short term.

The cost and time of repairing or replacing damaged deck boards in the future should be considered when installing your deck.

The fasteners provided by Ecoscape are designed specifically for Ecoscape products, ensuring the perfect fit for a safe and secure deck.

You should always use the parts provided by suppliers and follow directions for the best performance, a long-lasting deck, and to avoid invalidating the warranty.

Gary is the founder and CEO of Ecoscape UK. Gary graduated from Liverpool JM University in 2007 with a 2:1 in Economics. A passion for innovation, design and sustainability, Gary has put to market numerous wpc products/systems, some of which have UK and European registered designs. Outside of work Gary enjoys spending time with his family, the great outdoors and watching Manchester United.


Comments (07)

  1. Paul Lane
    April 23, 2024

    Great article! It’s important to consider all factors when installing composite decking, including the method of securing the boards. Using screws may be a quick option, but it’s crucial to make sure they are high-quality and properly installed to avoid damage and costly repairs. As someone who has installed composite decking myself, I highly recommend investing in professional installation or taking the time to research and properly install the boards yourself. Thanks for the informative read!

  2. Guy
    April 23, 2024

    “Great article highlighting the importance of proper installation for composite decking. The potential harm and costly repairs that can result from mistakes make it crucial to invest in high-quality materials and consider professional installation. The information provided on using screws versus alternative methods is helpful, but I’m curious about where to purchase the decking boards. Overall, a valuable read for anyone considering composite decking for their home.”

  3. Darren Musgrave
    April 23, 2024

    Great article on the importance of properly installing composite decking. It’s important to consider the long-term effects and potential damage that can occur if the installation is not done correctly. It’s also helpful to know the options for securing the decking, whether it be with screws or alternative methods. However, I have a question about where to purchase high-quality composite deck boards. Can anyone recommend a reliable source for these materials?

  4. Dominyka
    April 23, 2024

    This article provides valuable information on the importance of proper installation when it comes to composite decking. It highlights the potential harm that can result from mistakes during installation and emphasizes the benefits of investing in high-quality materials. The decision to use screws or an alternative method is also discussed, providing a well-rounded guide for readers. However, I am left wondering about the availability of these composite decking screws and where to purchase them. Overall, a great read for anyone considering composite decking for their home.

  5. natasha stanbury
    April 23, 2024

    Great article! As someone who is considering installing composite decking, I found this information very helpful. I didn’t realize the potential harm in using screws and now I know to carefully consider my options. I would love to know more about where to purchase high-quality composite deck boards and what to look for in terms of durability and safety. Thank you for sharing this valuable information!

  6. James
    April 23, 2024

    Great article! It’s important to get the installation of composite decking right to avoid costly repairs and damage. I agree that investing in high-quality boards is key for a long-lasting and valuable addition to your home. I appreciate the information on using screws for installation, but I’m curious about alternative methods. Do you have any suggestions or recommendations on where to purchase high-quality composite decking? Thank you for sharing this informative guide.

  7. Malcolm Hoe
    April 23, 2024

    “Great article on the importance of proper installation when it comes to composite decking. It’s true that using screws can be a quick and cost-effective method, but it’s crucial to use high-quality screws and follow proper installation techniques to avoid any potential damage or costly repairs. As someone who is considering installing composite decking, I appreciate the detailed information provided in this article. I do have a question about where to purchase the best composite decking screws. Any recommendations? Thanks!”

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