Cracked chimney masonry repaired in Beulah

Reading the damage pattern before any repair

A worn joint, a cracked brick and a section that has shifted are three different findings, even when they sit side by side. We look at the whole chimney before deciding anything, because the pattern of damage says more than any single crack.

Where the damage sits, which way cracks run and whether anything has moved out of line decide the repair. A joint problem gets joint work, broken units get replaced, and movement gets a closer look before anyone reaches for mortar. Your estimate explains which of those your chimney shows.

When joints need to be cut out and repointed

Five conditions, listed in brick industry guidance, call for repointing rather than surface treatment. We check for each of them during the inspection, joint by joint, on every face of the chimney we can reach.

• Mortar eroded back more than about a quarter inch
• Mortar that crumbles when scraped
• Voids in the joints
• Hairline cracks in the mortar
• Cracks between the brick and the mortar

How deep old mortar has to come out

Deteriorated mortar should be removed, per Technical Note 46, to a uniform depth of no less than twice the joint width, which usually works out to about three quarters of an inch, or until sound mortar is reached.

Shallow work is the usual reason a repointed joint pops out again. New mortar laid over a skim of old material has little to grip. We cut to the depth the guidance calls for, clean the joint and only then start filling it.

Rust stains on chimney masonry

Rust streaks on masonry usually start at metal parts, such as a cap, a bracket, an old fastener or steel inside the masonry. The stain points to the source but does not say how serious it is.

We find where the rust is coming from. A surface stain from a cap is a small matter, while rust from steel inside the masonry can be a structural concern, and the estimate explains which you have. Surface staining can often be cleaned once its source is dealt with, using a product made for brick and tested on a small area first.