Hello, I've been reading many threads tonight on this topic. Of course, not every situation is the same.
I have an old barn with a dirt cellar and stone foundation (largish boulders. I'm undertaking some structural repairs myself and am trying to work out the big plan. One of the walls seems to have no mortar for the most part. Two seem to have the remnants of a half-assed patch job ... all crumbling ... looks like "cement" to me. The wall with nothing needs some work, pushing the stones back up under the sill. I then want to bond them in place.
During the massive storms we've had recently in Boston it takes on *a lot* of water (3 feet of standing). The house sump is quite active, as well, or the house would also take on this water. The water table is so high here, I'm skeptical that much can be done to avoid the standing water down there. I mention this so you know what the moisture situation is. Normally, it's dry down there.
If I have to dig externally on the small section that's leaning in, I can do that, but overall, I'm looking to do these repairs from the inside. So ... given the fact that there's water at times, that this is unheated (therefore considered entirely exterior?), that I'm in New England ... what would you do? Lime mix? Mortar? I assume I'd be trying to force this as deeply as I can between the rocks. There are big spaces, plenty where I could fit my fist inside. Actually, even bigger than that. Would it be stupid to think about setting sections of rebar between the rocks "randomly" before packing it all?
Before researching this, I called the local lumber yard and they suggested mixed mortar. Since I don't seem to have existing lime, I suspect this may be an option, but I'm still a bit confused, frankly.