How to Fix and Prevent Cracks on Composite Decking

Learn how to effectively fix and prevent cracks on your composite decking. Discover tips for repair, maintenance, and prevention to ensure the longevity and appearance of your deck.

3 min read

Composite decking offers numerous advantages over traditional wood decking, including durability, low maintenance, and resistance to rot and insect damage. However, like any outdoor surface, composite decking is susceptible to wear and tear, including cracks. In this article, we'll discuss how to effectively fix and prevent cracks on your composite decking, ensuring its longevity and appearance.

gray wooden bridge
gray wooden bridge

Understanding Composite Decking Cracks

Causes of Cracks

Several factors can contribute to the development of cracks on composite decking:

  • Temperature Fluctuations: Extreme temperature changes, especially during freeze-thaw cycles, can cause composite decking to expand and contract, leading to cracks.

  • Improper Installation: Incorrect installation techniques, such as inadequate spacing between boards or improper fastening, can create stress points that result in cracks over time.

  • Heavy Loads: Excessive weight or pressure on specific areas of the deck, such as furniture or heavy foot traffic, can cause stress fractures and cracks.

  • UV Exposure: Prolonged exposure to sunlight can degrade the surface of composite decking, making it more susceptible to cracking and fading.

Types of Cracks

Cracks on composite decking can vary in severity and appearance, including:

  • Surface Cracks: Superficial cracks that affect only the top layer of the decking material, often caused by minor impacts or temperature fluctuations.

  • Structural Cracks: Deeper cracks that penetrate the entire thickness of the decking board, compromising its structural integrity and stability.

Fixing Cracks on Composite Decking

Surface Crack Repair

For minor surface cracks on composite decking, follow these steps to repair:

  1. Clean the Area: Remove any debris or dirt from the crack using a brush or compressed air.

  2. Fill the Crack: Apply a composite deck repair filler or epoxy resin into the crack, ensuring it fills the entire space.

  3. Smooth the Surface: Use a putty knife or scraper to smooth out the filler and remove any excess material.

  4. Allow to Cure: Allow the filler to cure according to the manufacturer's instructions, typically 24 to 48 hours.

Structural Crack Repair

For more significant structural cracks on composite decking, professional assistance may be necessary. Contact a decking contractor or composite decking manufacturer to assess the extent of the damage and recommend appropriate repair solutions.

Preventing Cracks on Composite Decking

Proper Installation

Ensure proper installation of composite decking by following manufacturer guidelines and recommendations. Pay attention to factors such as board spacing, fastener placement, and support structure to minimize stress points and prevent cracks.

Regular Maintenance

Perform routine maintenance on your composite decking to keep it in optimal condition:

  • Clean Regularly: Sweep or rinse your deck regularly to remove dirt, debris, and organic matter that can contribute to cracking.

  • Inspect Periodically: Check your deck for signs of damage, including cracks, splinters, or discoloration, and address any issues promptly.

  • Apply Sealant: Consider applying a protective sealant or coating to your composite decking to enhance its durability and resistance to cracking.


While composite decking offers many benefits, including durability and low maintenance, it is not immune to cracks. By understanding the causes of cracks, implementing proper repair techniques, and taking preventive measures, you can keep your composite decking looking great and structurally sound for years to come.

vacant white and brown sectional sofa in room
vacant white and brown sectional sofa in room


  1. Q: Can cracks on composite decking be repaired?

    • A: Yes, cracks on composite decking can be repaired, depending on their severity. Surface cracks can often be filled with a composite deck repair filler, while structural cracks may require professional assistance.

  2. Q: What causes cracks on composite decking?

    • A: Cracks on composite decking can be caused by temperature fluctuations, improper installation, heavy loads, and prolonged UV exposure.

  3. Q: How can I prevent cracks on my composite decking?

    • A: To prevent cracks on composite decking, ensure proper installation, perform regular maintenance, and apply protective sealants or coatings as needed.

  4. Q: Are cracks on composite decking covered by warranty?

    • A: It depends on the manufacturer and the terms of the warranty. Some warranties may cover certain types of damage, including cracks, so it's essential to review the warranty details before making any repairs.

  5. Q: Can I use wood filler to repair cracks on composite decking?

    • A: It's not recommended to use wood filler on composite decking, as it may not adhere properly or provide adequate durability. Instead, use a composite deck repair filler designed specifically for this purpose.