I was dead wrong about lime mortar. Here's why.

I've been laying brick for almost 15 years, and I always swore by standard portland cement mortar. Thought lime mortar was just for old buildings and purists. Then last spring I took a job restoring a 1920s church downtown, and the specs called for a NHL 3.5 lime mix. I grumbled through the whole first week, but then I noticed something. The stuff was way more forgiving on the old soft brick, didn't crack near as much, and even in the heat it held up fine. Three months later I had to repoint a small section of my own driveway that I'd done with portland, and it was already crumbling. The lime work on that church still looks perfect. Has anyone else switched over and dealt with the longer drying time?

3 comments

3 Comments

reese_garcia1mo ago

Start paying attention to how lime mortar handles moisture movement in the wall. Portland locks everything in tight, so water finds the next weak spot and pushes through, while lime lets the whole assembly breathe and dry out naturally. Have you noticed less spalling on the brick faces since you switched over?

mila_reed1mo ago

You're totally right @reese_garcia! The difference is night and day once you see how lime handles moisture. I had a section of wall that kept getting those damp patches in winter with Portland mortar, and after repointing with lime it dried out evenly and stayed stable. The brick faces on that wall look way better now, no more chipping or flaking like before. It really makes you wonder why modern houses don't stick with lime from the start.

stellas562d agoMost Upvoted

Wait wait wait, hold up. You're saying you actually saw lime dry out evenly on a wall that had damp patches? I gotta tell you, that sounds almost too good to be real. I've seen so many old houses where they slapped Portland on brick and it just turned into a mess, but hearing you say the brick faces came out better is wild. So you're telling me that after repointing, the chipping just stopped like that? Man, that's the kind of result I'd need to see to believe if I hadn't already heard it from a few other people too.