Just found out my mortar mix has been wrong for 3 years

I was reading an old masonry handbook from 1982 I found at a thrift store in Portland, and it said the sand-to-cement ratio I've been using is way off for structural walls. Turns out I've been adding too much sand, which makes the joints weaker over time. Has anyone else had to re-learn a basic thing like this after years on the job?

2 comments

2 Comments

iris_ellis1mo ago

That 1982 handbook was probably written for proper Type S or N mortar too. I bet your mix has been closer to Type O or worse, just straight sand and cement with no lime. The joints might look fine now but freeze-thaw cycles are going to wreck them in a few winters. Portland rain is no joke on weak mortar either.

the_robert1mo ago

Hang on... is it really that serious for a DIY wall or a garden structure though? I've seen old farm walls with way more sand than that stand for fifty years without crumbling. Portland rain is rough but if the wall isn't load-bearing and drains okay I don't see it falling apart overnight.