Got shown a mortar mix trick on a retaining wall yesterday

I was working on a retaining wall in Akron and a guy I met showed me how he mixes his mortar a little drier than normal for the first course. He said it keeps the bricks from sinking down when you lay them on soft ground. I tried it and the difference was night and day, the whole wall stayed level. Has anyone else played around with the water ratio for different parts of a job?

2 comments

2 Comments

angela_coleman1mo ago

Question why you'd want your first course sitting on drier mortar. That seems backwards to me. If you've got soft ground, the real problem is the ground, not the mortar. A drier mix doesn't have the same stick and it might not bond to the base as well, especially if the ground shifts a little over winter. I've always found a wetter mix on the bottom gives you more time to level things out, and it lets the bricks settle into the mortar rather than fighting them to stay put. Making the mortar drier just means you're fighting the mix instead of working with it, and you end up with cracks later because the mortar didn't really grab the bricks tight. You might have gotten lucky with the soil conditions on that job, but I wouldn't count on that trick holding up long term.

wrenstone1mo ago

Actually, the mortar being drier isn't about fighting the mix. It's about preventing the first course from sinking into a wet base before it sets. A wetter mix on soft ground can actually let the bricks settle unevenly overnight, and then you're leveling twice. Drier mortar also helps control how much water gets sucked into the bricks, which matters for strength later. I've seen jobs where a standard wet mix on unstable soil just turned into a mess after a freeze.