sister wall against old stone foundation - bonding agent?

tcook555

Good Afternoon everyone! Despite my best efforts to "do my homework" I have some lingering questions that I hope someone can help me with. I have a 200+ year old New England farmhouse with a dirt floor basement and an old stone foundation. I want to build a sister wall on portions of the inside foundation walls where it is beginning to bow in, crack, etc.. The sister walls will be reinforced with rebar, but how to tie them into the existing stone foundation?? I really don't want to send any vibrations through the existing walls by drilling holes, so would a bonding agent be better for this?? Furthermore, the rocks are large and appear to be coming loose, so tying rebar to one rock won't necessarily mean it's tied to the wall. Can I simply pour the new concrete against the existing stone wall without doing anything else and still get the reinforcement I want?? (pics are attached)

Thank You for you time and any feedback anyone can give!!

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Daniel Holzman

I am not really sure I understand exactly why you want to build a new wall, and why you want to tie the old stone wall into it. Let's start by assuming you are concerned that the old wall is failing, and you want to support the house on the new, reinforced concrete wall. That would require major framing work, since you would need a new sill around the house, the old framed walls (if that is in fact what you have) would not line up with the new wall etc.

So maybe your plan is simply to install a new wall with the goal of supporting the existing stone wall foundation to prevent it from moving. Perhaps your plan is to leave the existing sills in place, and reinforce the existing wall.

You should first verify that the old stone wall is in fact failing. This usually requires very careful measurements to determine if there is evidence of movement. Pictures are never definitive, but I did not see evidence of substantial bowing and failure as you indicated, but due to the construction method, it is hard to tell.

Construction of a reinforced concrete wall to fix the old stone wall is going to be expensive and pretty difficult, due to the need to pump concrete inside the basement. Before I expended that kind of money and effort, I would have an experienced mason look the wall over, maybe it isn't so bad, its been there a long time, and might just need some repair.

tcook555

First, Thank You Dan! This is in fact my plan/goal. I want to prevent further failure/movement so that I won't have to jack the house and replace walls in the near future. I believe the foundation walls are not failing YET, but I am concerned because there is some bowing, cracking, and shifting of the house, that has taken place during the last 200+ years of it's existence. Nothing major, but I am the paranoid type, and I want to make sure this foundation is solid. I just want to give it some reinforcement, and give myself some peace of mind. At the same time, I am building piers at various points to take some of the load off the foundation walls and provide even more support of the house, and at some point afterwards a concrete floor will be poured, but that's for another post! Right now a solid foundation is my top priority with this house, and I have all the materials on hand to complete this project. Just trying to figure out how to tie the new wall to the existing wall so they don't become separated years from now and give me another headache to deal with! Thanks again for your help!

joecaption

The way your suggesting fixing this is just not going to work out in your favor.
http://www.basement-repair.com/found...ing-walls.html