That lime mortar kickback story had me rolling my eyes until it bent my trowel

I always thought the old guys who swore by lime mortar were just stuck in their ways. Then I had to repoint a 1920s brick wall in Denver last spring. The modern Type N I used turned the face of the soft old bricks into powder after one freeze-thaw cycle. Went back with a lime mix and it held perfect. Is there anyone else who thought a traditional method was overhyped then got proven dead wrong on a specific job?

2 comments

2 Comments

wells.reese1d ago

Type N turning old brick to powder" - sounds about right, those old soft bricks just laugh at modern cement mixes. I learned that lesson the hard way myself on a 1908 church wall, now I just keep a bucket of lime putty ready and let the old timers have the last laugh.

noahpark1d ago

Went back with a lime mix and it held perfect" - yep, that's the exact moment it clicks. Here's the trick I learned after ruining a whole side of a 1910 building in Chicago. You gotta match the mortar's strength to the brick, not the other way around. Soft old clay bricks need a mix that's weaker than they are, usually around 1 part lime to 3 parts sand with just a tiny pinch of white Portland if you need it to set faster. I keep a bag of hydrated lime on my truck at all times now specifically for pre-1930s work. Test your brick first by scratching it with a key - if it leaves a white mark, you're dealing with soft stuff that will get wrecked by Type N. The old timers weren't being stubborn, they just knew that lime mortar flexes with the brick instead of fighting it.