Chimney repointing and mortar repair across Hillsboro Pines

Joint conditions that call for repointing

Brick industry maintenance guidance lists the joint conditions that usually call for repointing. We look for each of them on every face of the chimney.

When a face shows these conditions, we mark the area and explain whether the damage is local or spread across the chimney. The pattern also hints at where water is coming from.

• Mortar eroded back from the brick face
• Mortar that crumbles or has voids
• Hairline cracks through the joints
• Cracks where mortar has separated from brick

Comparing mortar samples wet and dry

Mortar changes color as it dries. Brick industry maintenance guidance suggests comparing new samples with the existing mortar while it is wet, then again when both are fully dry. A match judged only when wet can end up noticeably lighter.

We mix sample batches when the finish matters and compare them against the chimney before committing. That takes a little time, but it avoids a whole face of joints that looked right on the day and wrong once it dried. Several batches may be needed to reach a match.

Why staining new joints is not the usual fix

It can be tempting to stain new mortar to match weathered joints straight away. Federal preservation guidance generally advises against it. Stained and unstained mortar can weather at different rates, and some staining mixes introduce salts into the masonry.

We would rather get the match right in the mix and let the joints weather. If a contrast remains that bothers you, we discuss options openly. One is repointing a larger area, so the difference sits at a natural boundary rather than in the middle of a face.

Water repellents come after the joint work

Brick industry guidance puts repairs before coatings. Cracked and deteriorated joints are repointed first, then the chimney is given time. The same guidance suggests waiting several months to see whether a water repellent is needed at all.

Often the repairs solve the water problem on their own. If a repellent is still wanted, it should let the masonry release water vapor, and it will need reapplying over time. We discuss it as a separate item once the joints have settled, not as part of the repointing price.