Tried a different mortar mix on a job in Cincinnati and it got weird on me

I was working on a retaining wall outside of Cincinnati last spring and decided to swap my usual type S for a type N mix I hadn't used in years. The mortar set way faster than I remembered, like 20 minutes instead of 45, and I ended up with a bunch of joints that looked crusty and uneven. My foreman said the batch I grabbed was probably old or stored wrong, but I learned to always test a small patch first before committing to a whole wall. Has anyone else run into a mortar batch that just acted completely different than expected?

4 comments

4 Comments

theasmith18d ago

Learned that lesson the hard way too @adam_lewis, except my "test patch" was half a wall before I realized it.

adam_lewis21d ago

Man that sounds frustrating... I had a batch of type N do the same thing to me years ago on a planter. Turned out the bag had gotten damp in storage and it just kicked way too fast. I always do a little test mix now before I start anything big.

paul25120d ago

I had 5 bags of type 3 do that on a job in 2019 and it wasn't moisture. It was the batch from the plant itself. The mix had too much accelerator in it from the factory. A test mix won't always catch it either because you're not mixing the same volume or working it the same way. I've had test mixes look fine then the full batch kicks in 10 minutes flat. I think the real problem is people blame storage when sometimes the product is just bad from the mill. Check the lot number on the bag and call the supplier next time.

the_paul18d ago

huh, I mean I get being careful but swapping mortar isn't exactly brain surgery. @adam_lewis if a test mix didn't catch it then maybe it's not that big of a deal. I've used old bags before and they still worked fine, just had to adjust the water a little. people act like a bad batch of mortar is gonna bring down the whole building or something. half the time it's just the guy mixing it not paying attention.