Loose chimney brick and open joints repaired in Lancaster Park

Signs that point past routine masonry repair

Brick Industry Association Technical Note 46 lists conditions that are structural rather than routine maintenance, and says they generally warrant investigation by a professional engineer.

When we see any of them, we tell you before quoting a repair, because patching a crack that is caused by movement tends to crack again.

• Cracks wider than about 0.075 inch, or 2 mm
• Cracks that pass through several bricks
• Cracks that follow a stepped or diagonal pattern
• Widespread spalled brick
• Masonry that has moved out of plane

Fireblocking where the chimney passes floors

Section R1003.19 of the residential code calls for the spaces between a chimney and the floors and ceilings it passes through to be fireblocked with noncombustible material, securely fastened in place.

It is easy to overlook because it is hidden. When the attic or a ceiling opening lets us see it, we note what is there, and missing or combustible material is written up as a separate finding with its own recommendation. It sits outside the masonry repair itself, but it is part of the same chimney, and we would rather you know about it.

Loose courses at the top of the chimney

The top courses of a chimney take the brunt of the weather and carry little weight above them to hold them in place. When their joints fail, bricks can loosen and fall.

If you see loose brick at the top, keep people and vehicles clear of the area below, and do not climb up to check. We inspect from a safe access point, remove material that could fall, and then plan the repair or rebuild of that section.

Keeping brick faces clean during pointing

Mortar smeared across brick faces during repair is hard to remove once it sets and can leave a haze that outlines every repaired joint.

We work neatly at the joint, clean excess mortar from the faces before it hardens and brush the finished joints once they have firmed up. Brick industry guidance even suggests masking or a template for face grouting, for the same reason. Clean faces are also why the finished joints read as a single, even repair rather than a series of patches with haze around them.