Found out my mortar mix was off by a weird stat I read online

I was looking up why my last wall had some cracks showing up after two weeks. Turns out I was using too much Portland cement in my mix. A bricklaying forum from 2019 said the ratio should be 1 part cement to 4 parts sand for most residential work. I had been doing almost 1 to 3 because I thought stronger was better. That extra cement makes the mortar too rigid and it can't handle movement. Now I'm redoing that section with the right mix. Has anyone else messed up their ratio and seen cracking later?

2 comments

2 Comments

drew_thomas92d ago

Gotta disagree a bit with @the_nina on that one. Yeah sand type matters but if you're getting cracks after two weeks the ratio is almost always the culprit, not the climate. I've seen guys in Arizona use 1:4 with no issues and guys in Oregon use the same mix and it holds up fine as long as it's not too wet when you lay it. The real problem is people thinking more cement means stronger mortar when really it just makes it brittle and prone to cracking from any tiny ground shift. I messed up a whole retaining wall once using that 1:3 ratio and it looked like a spiderweb after a month. Live and learn I guess.

the_nina2d ago

Actually that 1:4 ratio is more of a general starting point. Depending on your sand type and climate, you might need to tweak it a little still.