Fixing Cracks In Composite Decking


Technology gets to work on your backyard with composite decking. 

Wood byproducts are combined with plastic and resins under high pressure to make a wood-like composite that is durable and rot-resistant. Each board is straight and uniform, so you can paint or stain it easily. Cracks are unlikely to appear in the deck when it has been designed and built properly. However, a crack could occur if it is placed on a settling foundation or there are design issues. Cracks may occur from simple wear and tear, as well as from faulty pieces. In order to patch cracks in composite decking, manufacturers have developed special products for the purpose.

Here are the steps you need to take to fix the cracks in your composite decking:

  1. Whenever possible, use a drill/driver to unscrew the cracked board from below and screw it back into place upside down. If individual composite boards are cracked on both sides, then this approach won’t work.
  2. If the board cannot be reversed, blow air into the crack using an air compressor. Remove any twigs, debris, chips, or dust from inside the crack with an air nozzle. Putty knives can be used to cut through the debris if it has become stuck, and then re-apply the compressed air to remove it. 
  3. Use mineral spirits dampened on a cloth to clean out the crack. Allow the mineral spirits to dry. 
  4. Place masking tape strips as close as possible to the crack without actually covering it. 
  5. Open a 1/4-inch hole in the end of a tube of composite filler by cutting the end at a slight angle with a utility knife.
  6. Place the tube tip at one end of the crack. As the tube moves along the crack, squeeze the tube to inject the filler into the crack. Using a putty knife, push the filler into the crack deeper. When applying filler with the putty knife, if the crack has a small depression, put more filler on the crack and repeat until it is flush with the surface. Let the filler dry for at least 12 to 24 hours – as described in the manufacturer’s instructions.
  7. The crack and filler should be sanded with a 100-grit sandpaper using a hand block. Sand the filler flush with the crack surface by using strokes parallel to the board. If the composite filler shrinks and leaves a depression, fill the depression with more composite filler and let it dry. Using 100-grit sandpaper, sand it smooth.
  8. Stain the sanded area matching the stain color.

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