Best Way to Solve Crumbling Mortar

LESLIE: Ben in Minnesota has some crumbling mortar. How can we help you today?

BEN: I have a really old house, kind of like what you guys have, and built in the early – probably early 1900s. Don’t know exactly. But it’s got a rock foundation and we’re in southwest Minnesota, so the ground does freeze pretty deep.

And basically, the mortar between all of the rocks has pretty much turned to sand. Some places, they worked on re-tuckpointing it here and there. But it’s all kind of coming apart again and some of the rocks, especially on the corners, are even tipping out a little bit. So I’m trying to figure out what I need to do to fix that, if I need to dig down. I have access to equipment. I work in the HVAC business, so we have lots of equipment and I do lots of stuff on my own. So, just seeing if you guys had any pointers for me.

TOM: So, the foundation is damaged or you’re just concerned about the rocks that are sticking out from the crumbling mortar?

BEN: Yeah, well, the foundation isn’t particular damaged; it’s actually pretty solid. It’s just that the mortar – since it’s so old, the mortar between all of the rocks has deteriorated to the point where it’s almost like sand. You know what I mean? And it just falls out from between the rocks.

TOM: So what you need to do is simply to repoint or replace that mortar. Pointing is the act of mixing up new mortar and pulling out the old crumbling mortar and then pressing new mortar into place.

And the type of mortar that you use for repointing is a little stickier than the mortar that would have been done originally. Usually, it has a bit more lime in it, which tends to make it a bit gooier and it sticks to the old stuff pretty well.

So, what you do is you work one section at a time. You do remove all that loose stuff and then you repoint it up with new mortar. And that’s pretty much normal maintenance with a 1900 foundation. You do have to eventually repoint a foundation like that; it’s not unusual. You can slow it down with proper drainage and things like that but essentially, that’s what we would expect, OK?

BEN: Right, OK. Perfect. Hey, thanks so much for your time and the advice.

TOM: You’re very welcome. Thanks so much for calling us at 888-MONEY-PIT.