Masonry is defined as the building of structures from individual units laid in and bound together by mortar. Inspectors find both solid masonry walls and veneer masonry in the houses they inspect. Each has a number of common defects.
Solid Masonry Walls
Many older homes throughout the country are constructed of full-thickness brick masonry or stone. Newer homes in the south often are constructed of concrete masonry units (blocks) at the first floor and wood frame at the second. In both cases, cracks are common. Almost all masonry will crack. Typically, cracking is due to shrinkage in the mortars and normal settling of the house. The inspector must determine whether or not the cracks are defects. Of course, large cracks or cracks with movement are candidates for further evaluation because they allow water to intrude and have the potential for structural consequences.
Generally, most inspectors believe cracks larger than 1⁄8 to 1/4 inch in masonry walls should be evaluated further. Additionally, a number of small cracks that add up to 1/4 inch or more may indicate more than usual movement. Any cracks with lateral (horizontal or vertical offset) movement should be investigated by a professional such as a structural engineer.
It is important to be observant for other evidence of movement that may be causative or consequential to the cracking observed in the masonry wall. This may include wracking of window frames or door frames, trimmed or rubbing interior doors, interior cracks, sloping floors, etc. These indicators, plus consideration of the age of the home and material being inspected, may indicate more than normal movement and require the services of a structural engineer.
Bulges are easier than cracks to assess because any bulge in a masonry wall is evidence of movement; therefore, due to the potential for dramatic failure, further evaluation is recommended as soon as possible.
Other areas to inspect closely in solid masonry walls are penetrations, such as windows and doors. Most solid masonry walls are not barrier walls. In other words, they will allow some moisture penetration, and they depend on the multiple wythes to allow water to drain to the bottom and escape. Due to this characteristic, any horizontal interruptions in the wall, such as the top frame of windows or doors, can cause moisture to slow in its downward path. This slow-moving moisture will be absorbed by wood frames, leading to their deterioration. Also, some moisture may enter the interior. In solid masonry walls, check closely the top of window and door frames, looking for deterioration and/or evidence of water penetration into the house.