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?

2 comments

2 Comments

danielr9910d 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.

taylor95710d ago

Totally agree, had the same exact wakeup call on an old church.