Masonry chimney repair in Hibiscus

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.

Looking at the chimney between visits

Periodic inspections of brick masonry, preferably each season, are what brick industry guidance suggests, with binoculars to see upper areas at close range.

You can do a simple version from the yard. Look for missing mortar, cracked or displaced brick, new stains and anything that has changed. If something looks different, let us know. Comparing what you see with the notes from our last visit tells us a lot before we even climb. A note on the calendar after storms and at the change of seasons is enough for most homeowners.

Pieces of masonry on the roof or ground

Brick fragments, mortar crumbs or grit in the gutter or at the base of the chimney tell you something above is letting go. The pieces themselves can help show where.

Leave them where they are if it is safe to do so, and tell us where you found them. We match the material to its source on the chimney, which can separate a failing joint from a spalled brick face or a crumbling crown. A piece of smooth, curved clay often came from the flue tile, a rough gray chunk from the crown, and a brick face from the masonry itself.

Questions worth asking before you approve masonry work

A sound masonry proposal should answer each of these clearly. If one gets a vague answer, ask again, since each affects how the repair performs and what it includes.

• What is causing the damage, and is it fixed by this repair?
• Where exactly does the repair area start and stop?
• Which mortar type is proposed, and why?
• How close will the brick and mortar match be?
• What happens if more damage turns up?
• Which separate repairs, if any, are recommended?