Rubblestone Foundation

[CT18fireman]

I have a small excavation needed for an addition onto a small barn. The Barn is set on an dry laid stone foundation. Other than just ebing careful anysuggestions on keeping the foundation solid?

I have though of building a temporary wall on the inside against the foundation with 2Xs and Plywood. Not sure about the outside.

I have done lots of work near buildings but never loose foundations.

 

[Cat420]

I would first dig very carefully to get a feel for how much variation in width the wall has. Then I would dig within 4-6 inches and scrape the rest off by hand. I recently dug a trench for water lines on a house with a cemented stone foundation and I noticed that a few stones fell off even though I never touched them. The temporary wall on the inside sounds good to me. Is it possible to do something similar on the outside? Any rough drawings or pictures of the job might also be nice to see.

 

[CT18fireman]

I will try to throw a sketch together and also scan in a few pics of the job.

Not doing it till the spring so I have time to plan (he is waiting for permits). Just wanted to get some ideas and layout before the snow falls.

 

[digger242j]

A number of years ago we did a lot of work in an area that had once had quite a few old houses on it. Consequently, I had to dig through a large number of old stone foundation walls. They're pretty sturdy, even once there's no longer a structure sitting on top of them. (Note that the walls in question were of limestone, anywhere from fist sized up to a couple of feet long and a foot thick--in your part of the world they might be something different, and consequently, act differntly.)

Actually, there's some advantage to working around those old dry laid stone walls, in that there's no mortar to crack. Hit a brick or block wall and it's evident right away. Hit an old dry stone wall and you might chip a stone, but other than that it won't look damaged, and unless you've really whacked it hard enough to displace it, it won't really be damaged. As for the loose stones that Cat420 mentions, it would seem to me that if they were bearing any of the weight of the structure, or the wall itself, they wouldn't fall out.

If the foundation is sound right now, and you're not going to be pushing on it, I wouldn't worry too much about it.

 

[cat320]

A while back i had to dig in that loose ruble foundation stone boy was it fun put the 12" bucket on and dug very careful.I had to put a door in . I think i even amazed myself when i pulled a huge base sone out that needed to come out and never moved any other stones above it .