How to Install Expansion Joints in a Concrete Driveway

Driveway in front of a house
What You'll Need
Ready-made expansion joints or thin slats of wood
Jointing trowel
Cement saw
Eye protection

It doesn’t take a lot of experience to tackle building your own concrete driveway. The challenge is building it so that no cracks will develop in your finished project. If you do not add expansion joints, cracks typically develop as a result of temperature changes or from the concrete shrinkage during curing. But, there is a way to minimize or prevent this cracking. There are joint strips made from cork, rubber, or even thin wood slats that absorb the expansion of concrete from heat and cold. They are not hard to install and they require very little material or experience.

Prepare for Your Joint Installation

When preparing to pour your slab, use ready-made joints. They will need to be the same height as the thickness of the slab you'll be pouring. The same is true with wood joints. Cut them, or buy them, at a height that will match the thickness of your concrete.

Add Joints During Slab Pour

pan spreading concrete as it pours out of a truck

The easiest way to add expansion joints is to do it during the pouring of your cement slab. As you finish pouring each section of your driveway, slip an expansion joint into the form between the section you've just poured and the section you are about to pour.

Position it along the edge of the form, so that it will be in a vertical position when concrete is poured against it. With the joint in place when the concrete hardens, a slight drop in the driveway slope will not cause a crack in the concrete.

Use a Joint Trowel

spreading concrete with a trowel

When pouring and troweling your concrete slab, use a special trowel called a joint trowel, to create a narrow space between slab sections. This space will allow expansion or contraction, just as a rubber joint would. This method of creating joints is typically used for more narrow concrete surfaces such as sidewalks.

Although one of these joints made from a joint trowel doesn't extend completely through the thickness of the slab, there is enough space in the top part of the joint to absorb most of the expansion or contraction that will happen. But if your concrete slab is to be used as a driveway your best bet is to use the ready-made joints.

Use A Concrete Saw

If you need to add an expansion joint to a driveway after it has been poured and has cured, you can use a cement saw to cut the joint. First, snap a chalk line across your driveway slab and follow this line as you cut. Make sure the line is as perpendicular as possible and take all appropriate safety precautions including eye protection when operating the saw.