Concrete to Stone Foundation Connection
My wife and I are planning to expand our 100+ year old Victorian style house by bumping out the back of the house to add a 14ft x 18ft addition. This will be a full basement, first and second floors. Being 100+ years old the house has a mortared stone foundation. My question is what is the correct way to tie a new concrete foundation to the existing stone foundation? I’m clearly nervous about any digging around the existing foundation. I won’t be doing this myself a contractor will but having absolutely no building experience I would like to know that the approach to be used is the correct one. Thanks for any information you can provide.
Replies
You don't.
No matter what the soil conditions are, concrete and stone will behave differently over time.
Some sort of bond break is in order, I would look at butyl.
Far more important than the foundation connection (or lack thereof in this case) is the structural relationship between the old house and the addition.
Your architect or designer has probably accounted for this, if not, they need to.