Stumbled on some mortar mixing numbers that made me rethink everything

I was reading through an old trade journal from 2019 and found a stat that said using too much water in your mix can drop compressive strength by up to 30 percent. That got me thinking about how I've always just eyeballed it on site, adding a splash here and there to keep things workable. On the other hand, a dry mix is a pain to lay and can cause weak bonds if it sets too fast. So where's the line between workable and waterlogged? Anyone else ever tested their mortar slump or just go by feel like me?

2 comments

2 Comments

knight.xena23d ago

Oh man, I remember reading something about this too... saw an old interview with a mason from back in the 70s who said he'd squeeze a handful of mortar and if it held its shape but crumbled when poked, that was perfect. Always stuck with me. I tried it once on a retaining wall job and honestly it worked way better than my usual eyeballing. Ended up with fewer cracks and less dusting on the surface later. Kinda makes you wonder if all these fancy calculators are just complicating what old timers already figured out with their hands.

paul_webb4523d ago

Nah I just go by feel too. Used a water to cement ratio calculator once and it told me my mix was way off, but I still prefer the eyeball method. Got lucky so far I guess.