does composite decking expand and contract
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Ryan Coyle
Ryan Coyle

With 20+ years of experience in the landscape, decking, and construction industries, Ryan is one of the top deck designers in the central Indiana area. He and his companies have garnered several awards for their designs.

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Does Composite Decking Expand and Contract?

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Before building a deck, you need to choose a durable material that lasts for years with minimum maintenance. Composite decking ticks every box, providing you with extreme durability, longevity, and less maintenance than a natural wood deck. Among many other questions, homeowners often wonder, “Does composite decking expand and contract?”

The simple answer to this question is yes, though composite decks are more stable than regular wood decks. Find out how composite decking material expands and contracts with the best composite decking contractor in Fishers, IN.

What Is Composite Decking?

Composite decking boards consist of a mixture of wood and recycled plastics. This composition of materials creates sturdy boards that are extremely stable and resistant to damage from the elements, fire, and insect infestation. Many homeowners choose composite boards over wood because they want a longer-lasting deck that requires little maintenance, with most composite decks lasting at least 50 years.

While composite decking withstands the seasons much better than natural wood, the material does experience some of the expansion and contraction that affects wood boards. Understanding what causes those conditions and how to avoid them can extend your composite deck’s lifetime by years, if not decades.

does composite decking expand and contract

What Affects Composite Decking Expansion and Contraction?

Many factors affect how composite decking will expand and contract, so take these aspects into consideration when choosing composite boards for your deck construction. 


Any material, including composite decking, left under the changing seasons, rain, and sunlight will eventually shrink and warp. However, professional deck builders know the best construction techniques to help your deck stand the test of time. Proper installation methods and regular maintenance can help you keep your boards from warping or buckling over the years.


While composite decking can withstand more moisture than wood, too much humidity can cause the boards to swell, making them more vulnerable to warping. Without enough moisture in the air, the boards will contract, possibly causing cracks or buckling. Over the years, the cracks may soak up more moisture and further weaken your composite deck.


Composite decking will expand during warmer weather and contract during colder temperatures, with both extremes leaving the potential for damage to your boards. Dry, cold months can cause cracks to form in the boards and reduce the deck’s durability over the years. Warm weather brings higher humidity levels along with sweltering temperatures, both of which contribute to expansion gaps in the composite material.

To better define the difference that temperature makes in your composite boards, during installation, consider that at 110 degrees Fahrenheit, a gap might measure 1/32 of an inch. That same gap will shrink to 1/4 of an inch when temperatures drop below 35 degrees Fahrenheit.

UV Light Exposure

Quality composite decking materials have UV-resistant materials in them, helping protect the boards from sun damage. As time progresses, regular maintenance and cleaning can help you keep your deck from fading or suffering UV damage. The heat combined with UV rays can cause boards to contract and dry out, forming cracks and weakening the stability of your deck.

Board Color

You probably wouldn’t expect the answer to, “Does composite decking expand and contract” to include the idea that the color could affect longevity. Composite decking boards come in various colors, allowing you to create the deck of your dreams without worrying about staining and painting. However, boards in darker colors tend to absorb more heat, leaving them vulnerable to expanding and contracting.


Shade can prove both helpful and detrimental to the durability of your composite decking. Natural shade from trees may keep harmful UV rays off your deck but will still allow rain and snow to fall on the boards. Since the shade will stop the sun from drying out your boards, you’ll have to practice extra care to keep your deck in good condition.

A roof, pergola, or other deck covering can make your outdoor space more comfortable while adding an extra layer of protection for your deck. Deck covers prevent the sun from cooking your deck and rain or snow from dousing the boards in water.

How Do Composite Deck Installers Take Expansion and Contraction Into Consideration?

Installing a new composite deck requires knowledge of how to properly handle the material to provide the safest deck possible while taking weather and humidity changes into account. All decks need wiggle room to allow for safe expansion and contraction but should have proper construction that discourages warping, bowing, or buckling. Professional deck builders use expert methods to construct a composite deck, such as:

  • Choosing light-colored boards that will last longer in the sun
  • Building in the morning while the material remains easy to work with
  • Arranging parallel boards with a gap for deck drainage
  • Leaving gaps between board ends for expansion

Thorough knowledge and understanding of board expansion and contraction are crucial in constructing a safe composite deck. Homeowners wanting to ensure proper construction and installation should look to professional deck builders who know the science and measurements of proper composite board placement. With proper construction, expansion and contraction won’t affect the lifetime or durability of your composite deck.

does composite decking expand and contract

Enjoy Your Composite Deck with Custom Design Options in Fishers, IN

Building a composite deck has many benefits that make it a better option than wood, including its durability and variety of colors. While composite materials last a lot longer than natural materials, understanding the answer to, “Does composite decking expand and contract,” helps you know how to increase your deck’s lifetime. Instead of trying DIY deck building and risking cracked or warped boards in a few years, turn to professional deck builders to take the guesswork out of composite construction and to save your valuable time and energy.

With our expert deck builders at Artisan Outdoor Craftsman, you’ll enjoy the ability to create your custom deck designed to your specifications. To learn more about composite vs wood decking and how our designers and builders can bring your ideal outdoor living space to life, contact our construction team at Artisan Outdoor Craftsman in Fishers, IN, at (317) 813-9669.