Typically the only time a homeowner thinks about an expansion-joint is when they find out the reason their patio, driveway or garage floor cracked is because the expansion-joints were in severe disrepair. expansion-joints come in many forms, commercial use expansion-joints are made of metal and resemble a teeth like system or a straight line metal gap. Residentially, an expansion-joint is made of wood, rubber, foam or caulking. These joints regardless of what they are made of allow for expansion and contraction between concrete slabs. expansion-joints are used so the concrete does not crack under the pressure of expansion and contraction. If a concrete slab is too large and no expansion-joint is made, over the course of time the concrete will crack, especially in areas that are subjected to freeze thaw cycles. Residentially you will find expansion-joints used in concrete driveways, patios, sidewalks, the area the patio, stairs or walkways meet the foundation of the house along with many other concrete structures. Due to weather conditions, age and accidents, expansion-joints can be damaged and destroyed. It is necessary to repair and replace them. If the gap between concrete is left open water will seep inside and under the concrete and displace or crack it, especially if the water freezes. Weeds and trees can begin to grown in between the slabs and the roots will also lift and displace the slabs. Fortunately, repairing or actually replacing expansion-joints is an easy do it yourself repair.

Removing the Existing expansion-joint

Use a hammer, chisel and pliers to break out, lift and pull up the old expansion-joint. Remove all pieces of thhe old expansion-joints to avoid further joint damage which will lead to concrete damage.

Use a shop vac to vacuum out dirt debris and pieces of wood or old expansion-joint caulking. You can also use a leaf blower to blow the debris out of the gap.

Installing a New expansion-joint

Measure the length and width of the expansion-joint and not the measurements.

Buy foam backer-rod equally the length plus 1 to 2 feet extra -- just in case. Buy the foam backer-rod slightly wider than the width of teh expansion-joint.

Forcefully press foam backer-rod into the expansion-joint as far as you can push it in by hand. Foam backer-rod is a thick, durable foam that allows for expansion and contraction between concrete slabs due to the heat or cold. Foam backer-rod is much more durable than wood expansion-joints and the preferred method of re-jointing. Foam backer-rod can be purchased at home improvement stores, hardware stores and some masonry supply houses.

Place a piece of wood equal to the size of the expansion-joint on top of teh foam backer-rod.

Tap the wood with a mallet to force the backer-rod deep in between the concrete slabs. Move the wood along the expansion-joint and continue tapping it in place with the mallet until the foam backer-rod has been inserted between all concrete slabs.

Use a caulking gun loaded with a tube of self leveling urethane expansion-joint sealant.

Squeeze out a thick layer of the sealant into the expansion-joint from one edge of the joint to the other.

Build the sealant up until it sits just barely below the concrete surface.

Allow the sealant to dry completely before walking on it or driving on it. Typically the sealant requires eight to 10 hours to dry.


Inspect the expansion-joints on concrete patios, driveways, walkways, sidewalks and elsewhere every fall and every spring.

Remove the existing expansion-joint material at the first sihgn of cracking, chipping or lifting.

This is a very easy and inexpensive repair job which can be successfully accomplished by a homeowner without any professional help.