IDEAS

Brick Basics

by John Cluver, AIA
Senior Associate & Director of Historic Preservation

Even those who are not fortunate to have a building built of brick know well its benefits, such as its durability, its beauty, and its apparent lack of maintenance requirements. Those who are responsible for maintaining brick buildings, however, know that despite its benefits, brick, just like any other material, is not maintenance free. The following is a brief discussion of several common issues that any one trying to maintain or repair a brick building may encounter.

1. My brick has lots of cracks in it, is this a problem?
There are several types of cracks that can appear in a brick or brick wall. The most common, especially with older brick (before the 1870s) is a series of smaller, seemingly random cracks across the surface. These are a product of the way the molds for forming the bricks were packed, and in general do not present a problem.

Another type of crack is a diagonal crack near the corners of the brick. These can form when the mortar between the bricks is made of strong cement, which prevents the brick from expanding as it needs to when it gets wet. This type of crack will get worse over time. The third type of common crack is the crack that runs up a wall, stepping along the edges of the brick. This indicates a past or current shift or settlement in the wall, and it should be checked out by a structural engineer.

2. Some of the mortar between the bricks is falling out, what should I do?
While brick walls should last as long as the building is being used, the mortar between the bricks needs to be replaced periodically. Due to growth and shrinkage in the brick (from water absorption, thermal expansion) and the freezing of water that collects in cracks between the mortar and bricks, the mortar in the joints crack and come loose over time. When the mortar has reached this state, it needs to be repointed (or tuckpointed). Basically, the existing mortar is removed to a suitable depth, then new mortar is inserted in the joints.

It is very important that this work is performed by an experienced mason using the proper type of mortar. Work that is sloppily done or using the wrong type of mortar can actually damage the brick and shorten its lifespan. One way to ensure a good compatibility between the brick and mortar is a mortar analysis, which is a test that determines the composition of materials in the mortar to help determine what the composition of the new mortar should be.

3. My brick is dirty, can I clean it?
Yes, but this is a job best left to professionals. There are many different types of stains that can appear on brick, and each one is cleaned a different way.

Regardless of the stain, however, sand blasting and power washing should never be used on a brick wall. These highly abrasive cleaning approaches “clean” the brick by taking off the surface layer, exposing a fresh face that is not as durable as the original.

4. Speaking of stains, what is this white stain under my windows?
It is most likely one of two things. The first could be chalking from the oil-based paint on the windows or shutters, which is washing off the surfaces and being absorbed by the brick.

The second is efflorescence, which is a salt deposit formed when water that has leaked into the brick is later evaporated. This is common with new brick and newly repointed brick, but it is also found if there is a leak somewhere in the wall.

5. I don't like how my brick looks. Can I paint it?
Technically, yes. Should you do it? No. Painting brick actually increases the long term maintenance of the brick, since the paint can trap moisture in the wall and will peel over a few years.

Paint also covers up the unique aesthetic and sense of pattern that is part of the beauty of a brick wall. Cleaning and repointing can go a long way to improving the look of a brick wall, and offer a more durable result!

Please note that this is only a brief overview of issues related to brick construction, and is intended only to provide a general introduction to the topic. The information contained within this article should not be construed as architectural advice or guidelines for work; specific situations should be evaluated by a properly trained professional prior to any work being performed. The author and Voith & Mactavish Architects LLP will not be liable for any loss or damage suffered by a user through the user's reliance on information and advice gained through this article.