How to Stain Masonry Brick Joints

Staining mortar joints.

There is not a fast method of staining mortar joints, but a determined homeowner can change the color, one brush stroke at a time, to create a completely different look.

1. Clean the surface of the brick and mortar joints with a power washer and allow them to dry overnight.

2. Test a mortar joint for absorption by applying brick stain to it, or by just spraying water at it. Look for beaded stain or water. This will indicate the presence of a sealer on the joints, which means an acid etching solution will need to be applied prior to staining.

3. Put on safety goggles and rubber gloves before working with an acid product. Pour a pre-mixed etching solution into the pump-up sprayer. Set the spray nozzle on the pump-up sprayer to emit a narrow stream; apply the solution and scrub it into the joints. Allow the etching solution to set for the recommended amount of time; rinse thoroughly with water. Let the masonry joints dry overnight before applying stain.

4. Thoroughly stir the brick stain before using it. Stain pigment settles to the bottom of cans when they have set for any prolonged amount of time. Some brick stains are two-part formulas that consist of stain and polyurethane. Mix both together in a separate bucket.

5. Apply the stain to each mortar joint with the 1-inch brush, or use an artist’s brush. Work from the top down so that you can catch drips as they occur, and you do not lean into joints that you have already stained.

6. Moisten a rag with paint thinner or water and keep it with you while you are working. The stain you use will determine whether you use paint thinner or water to wipe off the edge of the brick or to wipe off drips. Oil based stain will have to be cleaned up with paint thinner, and latex stains are cleaned off with water.

Tip

You can clean the brick and mortar joints just by using a power nozzle on a garden hose and scrubbing the surface with a scrub brush. It is best to use a stain with a sealer already mixed into it. Staining mortar joints is a slow job, and using a stain/sealer will eliminate the need to apply a separate sealer.