Mortar Types N, O, S and M: Which One Belongs on Your Chicago Wall
Mortar types N, O, S and M differ by how much lime is in the mix. The strongest one is almost never the right one, and on an older wall it is the expensive mistake.
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Mortar types N, O, S and M differ by how much lime is in the mix. The strongest one is almost never the right one, and on an older wall it is the expensive mistake.
A stone sill that slopes back toward the wall feeds water into the masonry. BIA lists neutral or negative slope on sills as a structural indicator.
The crown is the slab across the top of your chimney. It is the smallest piece of masonry on the building and the one holding the most water off everything below it. Here is how to read it, and what a correct one has that a failed one does not.
A weep hole is the exit door for water already inside your wall. BIA anticipates that maintenance work will seal them shut. Here is how to check yours and what to do.
The tool that cuts your joints open decides how much of your brick survives the repair. NPS and BIA both draw the same line, and it runs through the head joints.
The lintel is the steel angle carrying the brick over your window. When it corrodes it expands, and the wall above it has to move. Here is how to read it.
Sealing brick is the most commonly sold masonry upsell in Chicago and the one both NPS and BIA spend the most words warning about. Here is what the standards actually say.
A spalled brick face is not the start of the problem. It is the end of one. What matters is which of the four causes put the water there.
On almost every Chicago quote, tuckpointing and repointing are one repair with two names. The mortar going back in is the decision, not the word at the top.
Chicago permits filed in 2025 report a median tuckpointing job value of $15,000. The spread around that number is set by joint condition, not by wall area.
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