Plastering over brick is one of the most stylish looks you can give your walls. Many people like the brick look without the actual brick appearance. Once the plastered is covered, it can be painted in a variety of colors or decorated with various wall decorations that accentuate the plastering over the brick.
You can use plaster over brick on both interior and exterior walls. While the process for both will be similar, there are some things you must consider when plastering over brick outside. The weather and other outdoor elements can affect your walls and weather down the plaster coating. Moisture can seep between the brick and plaster layers if the job is not done properly causing cracks in the plaster and the necessity to recoat the wall.
Inside your house, you may have problems with moisture, but it will not be as intense a problem as it can be outdoors, since it will have the indoor protection from the weather.
Tools and Wall Preparation
Decide which wall you plan to plaster over the brick on and then choose the right kind of plaster to get the job done. For a brick wall, we suggest a structure-lite plaster. You can find this type of plaster at most building and home supply stores.
You may be applying plaster straight to brick or you may be applying it to a thin coating of plaster that is already present. The most important thing to do at this point is to make sure that the wall is smooth. Any debris or tiny particles of dust on the wall can interfere with the plaster. You can use a shop vac to remove anything that is on the surface. Once you have a clean surface to work with you can start plastering over the brick.
Depending on the surface of the brick, a bonding agent may or may not be necessary. For outside walls, you will not want to use a bonding agent. Often, the bonding agent will soften the plaster as it dries and it will be more likely to crack and flake. However, on interior walls you should be fine to apply a light coating of a bonding agent.
Regardless of whether you are using a bonding agent or not you should wet the brick prior to the application of the plaster on both interior and exterior walls. Dry walls are often softer then wet walls, especially if they are older. When the plaster dries, it has the potential to capture moisture and this can cause the plaster to settle incorrectly.
Apply the Plaster
You will want to apply the plaster in a smooth layer over the brick wall. The thicker the coating the less visible the appearance of the brick will be behind the plaster. If you want the shape of the bricks to be more prominent, use a thinner coating of plaster over the bricks.
The plaster will need to dry before you can apply a second coating. Make the second coating thinner than the first coating. Once the second layer of plaster has dried, you should add a finish and water trowel. The trowel is used to coat the plaster so it is water resistant.
Tips for Repair
If your plaster over brick has settlement cracks or is crumbling in any place there are a number of things you can do. You can use a joint compound or a little bit of real plaster to fill in spaces and gaps. You can also use a wire lath and bonding agent around windows though sometimes, a metal lath can cause settlement cracks if too much is applied.