Chimney Services
The parts of a masonry repair in Forest City
The masonry details we watch for in Forest City, with the guidance behind them.
Why stronger mortar can harm old brick
Using the hardest mortar available sounds sensible, but guidance from the National Park Service and the Brick Industry Association points the other way. Repair mortar should be softer and more vapor permeable than the bricks it joins, and no harder than the mortar already in the wall.
Hard, dense mortar leaves moisture and stress nowhere to go except into the brick faces, which can crack or pop off at the edges. Keeping the joint as the weaker part of the wall means future wear shows up in mortar, which is far easier and cheaper to renew than brick. Our masons match the mix to the chimney for that reason.
Hairline cracks in mortar joints
Not every crack needs cutting out. For fine hairline cracks in otherwise sound mortar, the Brick Industry Association describes face grouting, where a fluid grout is worked into the crack to seal it against water.
There is a visible trade-off. Grouted joints look slightly wider and smoother because the sand in the mortar no longer shows. We point that out before recommending it, and where the joints are worn deeper than a hairline, we price proper joint repair instead. Either way you choose with the difference explained, and the inspection that finds it costs nothing.
Rusting steel hidden in the masonry
Steel set into or supporting brick, such as a lintel over an opening or a support angle, grows as it rusts. The Brick Industry Association lists accumulated rust on lintels and shelf angles among the conditions it treats as structural, since the swelling steel pushes on the masonry around it.
That pressure can crack and lift the courses above, and patching the brick alone will not stop it. If we find rusting steel behind the damage, we explain what cleaning, treating or replacing it would involve before any brick goes back, and whether an engineer should weigh in first. You decide with the full picture in writing.
