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How to Replace Wood Joints in Patio Concrete

By F.R.R. Mallory ; Updated September 21, 2017

Concrete patios, driveways and sidewalks are frequently installed with wood expansion joints. These joints allow the concrete to expand and contract and the assist in reducing the amount of concrete cracking. Over time the wood in the expansion joints will decay and weeds and missing material will make the joints unsightly and a trip hazard. Replacing the expansion joints is good maintenance.

Step 1

Remove the existing rotting wooden expansion joint with tools like a pry bar, putty knife, crow bar, flat shovel, chisel and hammer. Replace all of your joints at the same time to provide a consistent finished appearance.

Step 2

Clean your open joints using a garden hose with a focused sprayer. Any weeds or other debris should be removed so that the concrete joints are as clean as possible.

Step 3

Cut your foam backer rod with a utility knife and insert the rods into the patio expansion joints using a putty knife to press the rods to the bottom of the joint. The rod fills up the space in the joint to keep the sealant closer to the surface of the joint.

Step 4

Apply tape along both sides of the joint to create clean lines when you apply the sealer.

Step 5

Fill the joint with a self-leveling expansion joint sealer. Use a caulking gun if your particular product dispenses by caulk tube. Some products may be applied with a putty knife or other method. These sealers are often elastomeric polyurethane products that remain flexible enough to allow the concrete to expand and contract easily. This product is available in many colors to match your patio finish. Allow the sealant to dry for 24 hours before removing the tape and walking on the joints.

 

Things You Will Need

  • Pry bar
  • Putty knife
  • Crow bar
  • Flat shovel
  • Chisels
  • Hammer
  • Garden hose with sprayer
  • Painter's tape
  • Backer rod (foam)
  • Utility knife
  • Elastomeric polyurethane sealant
  • Caulking gun

Tip

  • Well-maintained concrete joints will extend the life of patios, sidewalks and driveways. Once decay is noted in an older joint, all of the joints of that same age should be considered to be in replacement condition. It is easier to replace all of the joints at the same time for a consistent repair appearance.

About the Author

 

F.R.R. Mallory has been published since 1996, writing books, short stories, articles and essays. She has worked as an architect, restored cars, designed clothing, renovated homes and makes crafts. She is a graduate of the University of California at Berkeley with bachelor's degrees in psychology and English. Her fiction short story "Black Ice" recently won a National Space Society contest.