umac71•3d ago

Appreciation post: The day my mortar mix nearly caused a wall collapse

I was working on a garden wall in Austin last spring, about 4 feet high and 20 feet long. Mixed my mortar a little too wet that morning because I was in a hurry. By noon, the whole middle section started bulging out maybe 2 inches. Had to tear down 12 courses and start fresh with a stiffer mix. Took me an extra 6 hours and a load of new bricks. Has anyone else had a batch go bad on them mid-project because of water content?

2 comments

2 Comments

the_kevin3d ago

The water content thing always messes people up but nobody talks about how the temperature that day factors in just as much. If you mixed that mortar at 7am when it was 60 degrees and by noon it was 85 with that Texas sun beating down, the water was evaporating way faster than you planned for. That's why the middle section bulged while the ends held fine. I started checking the forecast and adjusting my mix for the hottest part of the day instead of just morning conditions. Saved me from a few more do-overs.

ray3243d ago

Read somewhere that a guy actually tests his mortar slump on a scrap brick before starting. Sounds dumb but I tried it after my second wall started going south like yours. You mix it up, grab a brick, butter it, set it in place and see if it holds. If the brick slides down in the first five seconds your mix is too wet period. Saved me having to tear down a whole section later on. Temperature thing the_kevin said is real too. That Texas heat cooks the water right out of your mix before it even sets up proper.