ray356•2d ago

Why does nobody talk about how bad rapid set mortar is for large walls?

I was up in Spokane last month helping a buddy on a 40-foot retaining wall job. Everyone was pushing rapid set mix saying it saves time, but I watched three guys struggle to tool the joints before it crusted over. We lost almost 10 feet of wall to cracking because the stuff set unevenly in the summer heat. Am I the only one who thinks regular portland cement is still the way to go for anything over 20 feet?

3 comments

3 Comments

tarabell2d ago

Funny you mention Spokane, I had a crew out there last summer on a patio job where the homeowner insisted on using leftover rapid set from a previous project. We mixed it up, and by the time we got it in the wheelbarrow it was already turning into concrete crumble. Had to chip it all out and start over with standard portland, which took twice as long but at least didn't fight us the whole way.

kelly3852d ago

Oh man, that's rough! I totally get the homeowner wanting to save a buck by using leftover materials, but rapid set is one of those things that's either perfect or a total nightmare. @tarabell The thing people don't realize is that leftover rapid set can be way more finicky than fresh stuff, especially if it's been sitting in a damp garage or shed. It's like the moisture in the air starts activating the chemicals, so by the time you add water, it's already got a head start on you. That's why I always tell folks to either use the whole bag in one go or just buy fresh for small jobs, because the headache of chipping it out just isn't worth the few bucks you'd save.

knight.dylan2d ago

I mixed some rapid set for a small garden wall and ended up with a modern art sculpture instead, not my finest hour.