Brick is one of the most attractive and durable finishes for interior or exterior surfaces. Bricks are joined together using a mortar, a combination of sand and cement. Unfortunately, over time, the mortar joints tend to deteriorate. This is especially true in ocean climates where salt eats away at them. There are several measures that can be taken to maintain both the aesthetic and structural integrity of the brick and the mortar joints.
A white powdery substance called efflorescence frequently is seen on bricks. This results from mineral salts in the mortar or other cementicious material leaching through to the surface. While efflorescence is not particularly destructive it is unsightly and in some cases results in flaking or minor deterioration of the surface.
A solution of vinegar and water is all that is generally required to remove the efflorescence. Stubborn or more extensive areas can be cleaned using a wire brush along with a light acid washing. A 10-percent solution of muriatic acid should do the trick. Caution: working with acid can be dangerous. Always wear safety goggles, rubber gloves, protective clothing, and have plenty of ventilation.
Once the majority of the efflorescence has been removed by the wire brush, apply the solution with a nylon brush. The area should be thoroughly rinsed with fresh water. More than one application might be required. The acid washing should improve the appearance of both the brick and mortar joints.
In some cases cleaning might be only the first step in the restoration of a brick wall. Cracked and deteriorating mortar joints are not only unsightly, but they diminish the integrity of the surface as well, and can allow water to get behind the brick causing major damage. This can be avoided by pointing the brick. Simply stated, pointing is the removal and replacement of cracked or missing mortar between the bricks.
This is a project that is best left to the professional if the area involved is large and the damage is extensive. On the other hand, if the area is manageable, the task can be performed by a do-it-yourselfer.
The first step in the pointing process is to chip away cracked and loose mortar using a slim cold chisel and a hammer. Be sure to wear safety goggles to avoid stopping a piece of flying mortar with your eye. Use the cold chisel slowly and carefully so as not to damage the surrounding brick. Remove the existing material to a depth of approximately 1/2 inch. Clean up all of the loose material and dust, using a brush, after the chiseling is done.
Before pointing, brush the joints with fresh water. This will remove any remaining dust and prevent the existing mortar from drawing all of the moisture out of the new mortar. Otherwise the mortar can be difficult to apply and will most likely crack.
Mortar can be purchased pre-mixed, or you can create your own batch using one part masonry cement and three parts fine sand. In either case you'll want to add enough water to create a paste. It's best to keep the mix on the dry side. If it is too runny it will be weak and will run down the wall making it difficult to apply and will cause stains. Allow the mix to set up for about five minutes before beginning.
Apply the mortar using a pie-shaped trowel (a pointing trowel). Force the mortar into the vertical joints first and remove the excess using a brick jointer. The brick jointer will help create a smooth and uniform finish. Once all of the vertical joints are completed, go on to the horizontal ones.
Avoid performing this task in extreme weather conditions as the mortar will not properly set up when it is either too hot or cold. In warm weather it's a good idea to lightly spray the wall with water for several days to assist the curing process and prevent the material from cracking.
In a week or two, after the mortar has had the opportunity to cure, apply a coat of high-quality acrylic or silicone masonry sealer. The entire surface (brick and mortar) should be sealed. The sealer will prevent water damage. This is especially true in areas of the country that get particularly cold. Unsealed brick and mortar will readily absorb water which will freeze in cold weather. The water turns to ice and causes the material to expand and crack. Periodic sealing will prevent this from occurring.
One of the simplest methods of applying a sealer is with a pump garden sprayer and a brush.