Replacing Foundation & Saving Chimney
We’re hoping to add second floor onto our one-story 800 sf house built in 1920s. Unfortunately foundation was constructed without footings and has settled significantly over years. Whether we build up or not, foundation needs to be replaced. There’s also a chimney/fireplace involved. It’s an exterior chimney.
What I’d like to know is whether or not chimney needs to come down? Ideally I suppose house would be raised foot or so and then there’d be room to demo old foundation, form and pour new foundation. But that’s not really possible is it with chimney sitting alongside house? But if you only raise house enough to secure it how do you pour concrete into new forms?
Replies
You can shore the house in place (not raise it) and remove and replace the foundation. It usually takes some creative digging and forming. If there are NOT going to be pony walls--i.e. the joists are going to sit right on the mudsill--it makes formwork and concrete placement more difficult. If at all possible you would leave some room for a pony wall on top of the mudsill so that you don't have to pour right up to the house. Any space is better than none.
If you raise the house, you probably need to remove the chimney. You can raise the chimney too but it's a job for pro house movers, involving some serious digging and some serious danger. The cost of rebuilding the chimney new might be less than the cost of raising, lowering, and repairing it.
Old houses are often built quite low. Ours was about 15" off grade and I raised it to 36" so I could get myself in there to repair framing, plumb, wire, insulate, and especially get all the rabbits outta there. The two chimneys (poor condition) had to come down. I'm making a brick stair landing out of some of those bricks right now.