Spalling, brick

Brick spalling is damage to brick masonry that is the result of improper pointing or moisture trapped into mortar joints.

Spalling is the cracking of the outer face of a masonry surface.

The picture below shows an example of a brick kneewall where the specific brick units have spalled. The faces of those brick units have cracked off and fallen away.

By using improper mortar, the common type of mortar sold on the shelf at big box stores such as Home Depot and Lowe’s, for pointing and brick restoration, historic bricks will fail.  This mistake is easy to prevent, however the vast majority of contractors of construction workers in the historic neighborhoods of Washington DC and surrounding areas are untrained and unknowledgeable about the proper methodologies for historic masonry restoration.  Understanding the key characteristics such as compressive strength and moisture retention capacities requires knowledge and experience. Most of the Masons in this area lack that knowledge.

Using hard mortars, such as the Portland mortars sold at the big box stores, causes pressure points in the masonry walls.  Bricks are generally heavy and hard, but they are not hard enough to withstand the pressure points caused by improper mortar at the outer edge of the joints. Using improper mortar or pointing improperly will cause brick spalling. Spalling may happen overtime and can actually take years to occur but can cause extremely expensive damage.