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I finally switched from lime mortar to Type N after that library job in Portland
I was always a lime mortar purist, figured it was the only way to go for old brick. Then I did a repoint on that 1920s library downtown last month and the lime just kept crumbling in the freeze-thaw. A structural engineer on site told me 'you're fighting 100 years of weather with a prayer' and showed me how Type N would actually breathe better there. Made me rethink my whole approach, especially for exterior work in cold climates. Has anyone else had to change their mortar mix based on a specific building's history?
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danielr992mo ago
Looked into the aggregate type on that job? I had a similar wake up call on a 1910 school last winter, turned out the original sand they used was way coarser than what I was buying. Switched to a sharp concrete sand mixed with a little masonry sand and the Type N held way better than my old go-to blend ever did. Makes me wonder how many failed repoints are actually a sand problem dressed up as a mortar problem. Nobody talks about the aggregate enough, it's always lime vs cement but the grit really changes everything.
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taylor9572mo ago
Totally agree, had the same exact wakeup call on an old church.
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