Does Composite Decking Warp and How to Fix It?

By Galen |

Picking the ideal deck material for your outdoor living space can be challenging. This is because there are many different types and prices of deck trim materials available on the construction market today. Since there are many factors to consider, it is important that you have a basic understanding of these deck materials. The kind of deck you select will depend on your budget. But understanding the additional advantages of each material will guide your decision.

Recently, composite decking has gained popularity as a fantastic substitute for conventional wood decking. Composite decking has a lengthy lifespan of roughly 25 to 30 years when installed correctly. Compared to natural wood decks, composite decking boards require far less upkeep because they typically don’t split, splinter, or warp.

The primary reasons for warping composite decking, strategies for reducing the risk, and solutions will all be covered in this article.

Reasons for Warping Composite Decking

Composite decking is composed of wood fibers and recyclable polymers. Thanks to the properties of these materials, composite decking material has the best of them all. That’s why composite decking has the look of solid wood and superior mold and water resistance.

On the other hand, manufacturers are also required to provide their customers with capped composite decking that offers even better performance. These capped composite decking have a polymer shell, which makes it more robust and aesthetically pleasing.

Natural wood decking typically warps when left in a humid atmosphere for an extended length of time. Of course, composite decking is an exception to this. A properly installed composite decking will not warp. Composite decking boards are at risk of warping if any of the following occurs.


Inaccurate Spacing

For several reasons, the distance between composite decking is crucial to the installation process.

Decking boards that are positioned adjacent to one another won’t drain as well as boards that are spread apart. Each composite deck must have a drainage gap to prevent too much moisture or water from accumulating under the deck.

Mold can grow in poorly drained regions, which can also cause composite decking boards to become discolored and slick. Air movement via the decking gaps between boards aids in the appropriate drying of the deck surface.

A sealed deck creates moisture underneath the composite decking, which further deteriorates the subframe and joists. This may accelerate their breakdown and lower the deck’s level of safety.

The planks must also be spaced sufficiently apart to allow for natural expansion and contraction in response to temperature variations. The deck planks will collide if they are not correctly spaced apart. The reason composite decking boards bow is because separate boards collide with one another.

Deck boards positioned against a wall should have room between them for the same reason. If enough room is not permitted, the composite decking may bend out of shape as a result of the decking boards’ thermal expansion pushing against the wall.


Composite Decking Fixed too Tightly

When installing composite decking boards, a lot of people think about screwing the boards into position. However, they are unaware of the potential drawbacks of doing so.

Many people believe that this is a quick, simple, and inexpensive method of laying a deck. Since composite decks tend to expand and contract, this can lead to a number of situations. And screwing composite decking too tightly can lead to problems.

They stay in place when composite wood decking is screwed into place. But when the boards swell, they overpressurize the screws. Composite decking may warp as a result.

How to Avoid Bending Composite Decking

There are many tips to prevent composite wood decking from warping. You can ask the composite deck manufacturer how to avoid the warping or bending of these decks.

These are the simplest methods for stopping the warping of composite decking boards.

Outdoor Dining Area

Allow for proper clearance

Proper spacing between composite decks facilitates air circulation and drainage. Also, these gaps prevent the warping of composite wood decks.

It is advised that you let these deck boards sit for roughly a week before beginning your composite decking installation. This will lessen the issues brought on by thermal expansion and contraction and allow the composite decking boards to become acclimated to the local humidity and temperature.

Follow the installation guidelines supplied by the composite decking manufacturer when doing the composite decking installation. Pay close attention to the installation guidelines, which often call for an 8 mm space between decking boards.

You can inquire with the composite decking manufacturer if you reside in a region with more harsh temperatures. Utilize them to learn how big of a gap to leave while constructing composite decking.

Employing Hidden Fasteners

With the help of hidden fasteners, you can easily secure the composite decking. and you also don’t have to worry about the problems that can occur when using screws. You can install composite decking safely and without having to worry about it warping if you use hidden fasteners.

Concealed fasteners are clips that screw into the joists and secure them to the deck. Suppliers that customize the screws and clips for their products can guarantee a safe installation. The deck boards won’t be screwed through by them. Rather, they will provide support, enabling the deck to flex and contract.

When composite decking boards expand, they have nowhere to go if the screws are driven straight through them. As a result, some board components are more movable than those that are fastened by screws.

Spacers are also included with T-clamps to help hold the composite decking firmly in place. They also permit the boards to swell and preserve proper drainage and air circulation.


How to Fix a Warped Composite Decking

You can replace certain pieces of the decking to restore it, depending on how severe the warpage is. If the warping is too bad, you might need to hire a qualified contractor to help you out more. A deck may occasionally need to be rebuilt if repairs are not possible. As a result, doing the installation correctly is crucial.

The damaged sections must be located by first taking a close look at the complete composite decking. Remember to account for the trim board depth when measuring the area. It is necessary to cut and push the damaged deck boards off the deck. Installing the new composite decking boards comes next. To secure the deck if you’re utilizing hidden fasteners, you’ll need to get to the underside of it.

To keep your existing decking boards intact, you can also clamp a straight board to a crooked board. Composite decking boards that are drooping can also be taken out and laid level on a hard surface so that the head of the board touches the ground.

This is a difficult step. But you can carefully remove damaged boards or place flat boards on top.


Although it is less frequent than with wood decking, warping of composite decking is nonetheless possible. Preventing the warping of composite decking boards is the easiest approach to handle the issue, and it’s not difficult to do so. Making sure you adhere to the installation instructions provided by your supplier ought to assist with this problem.

It is recommended that you use parts and accessories supplied by the manufacturer of your composite decking. You should also adhere to the terms and conditions of the warranty. You might not be eligible for the warranty if you use other tools and techniques and the composite decking still warps.

If you can install a composite deck correctly, it is far less likely to have problems. The composite decking may distort if there is insufficient space for it to expand and contract thermally.



Why Does Composite Decking Sag?

The reason composite decking sags most often is that the joists are spaced too far apart. Composite decking is substantially heavier than wood decking. As a result, it requires shorter joist spacing.

By pulling the joists closer together and installing double tenons at the end of each composite deck, the deck will have the support it needs. Verifying that the joists are correctly supported is also crucial. The composite wood decking will break if the joists are not adequately supported, causing them to sag.

What Is the Long Life of Composite Decking?

Composite wood decking can endure twenty to thirty years with proper maintenance. The majority of composite decking producers normally provide a 15–20 year warranty.

The warranty must be used with the recommended accessories and installation techniques in order to be valid. Certain other situations may potentially shorten the warranty’s validity. Such as using the wrong cleaning products on composite decking.

Is It Possible to Power Wash Composite Decking?

On composite decking, power washing is an option. However, before use, read the supplier’s instructions. This is because the use of power washing composite decks usually cannot be higher than 3100 psi or the deck surface may be damaged.

You should clean the deck piece by piece by following the grain of each board rather than scrubbing it horizontally. By doing this, you can reduce scuffs and protect the deck’s surface.


Which Kind of Framing Is Best for Composite Decking?

While inexpensive, wooden underframes are not as durable as those composed of more durable materials. Because it is sturdy, long-lasting, and performs as well as composite decking, aluminum is a good option.

Composite material frames are reasonably priced and simple to deal with. It’s long-lasting and waterproof, which also makes it a good choice.

Does Sunlight Cause Composite Decking to Fade?

Composite decking will not flex due to sunlight. Nevertheless, if you select the incorrect kind, it can fade. Not all combinations are created equal. Every supplier has special qualities and benefits of their own.

UV inhibitors are typically present in COOWIN composite decking, allowing it to withstand prolonged exposure to sunshine without fading.

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Galen Content Writer
Galen is a content creator and decorator with five years of experience designing home decor. In his daily life, Galen is constantly on the lookout for the latest, great examples of house design and further optimizes his solutions. Additionally, he writes articles related to outdoor design, interior design, and architectural decorating materials to help brands build more engaging relationships with their audiences.

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