New foundation wall tied into old stone wall!
Can someone give me advice in trying to replace a length of foundation wall that is collapsing. It is a 1850 house with a stone wall foundation. A 20′ length of wall has collapsed and needs to be replaced, but I am unsure as to how to properly tie a new length of wall into the existing. The client is requesting a monolithic concrete foundation wall for the new portion. I feel that this section of wall has collapsed partially due to water pressure coming down the adjacent slope which will be relieved with proper draingage.
Any thoughts out there may help.
Replies
At first, I assumed your problem was easy. Here in California, we just bust out sections of the foundation while supporting the home just to the inside of the rim joist, say 20 feet at time. Then dig footings, pour concrete for the same, and use CMU walls with rebar to rebuild the foundation. Simpson anchors, required by Code out here, finish the job, along with a shear wall.
But if you are having water problems, don't get any advice here, except one piece--hire a civil or structural engineer and get plans from him. If this thing goes South on you, you want the protection of engineered drawings.
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934
Are you asking how to deal with the 'raw' ends of the remaining stone wall?
Or how to repair the collapsed section?
csnow,
thank you for responding - raw ends is the real question.
dominic
If the remaining stonework is in good shape, and you are not in an earthquake zone, I'm not sure that any special linkage between concrete and stone is necessary.
That old structure probably has massive sills that are strong enough to span large gaps in the foundation anyways.
I wonder if you could simply run the forms up near the stone, then fill the gap with stones and mortar as needed.
My parents remodeled an old ca 1905 farmhouse with a creekstone foundation many years back. They had the foundation rebuilt by a local guy who specialized in creekstone work. In this case the foundation was largely just sitting on the ground, and it had survived in fairly good shape because it was at the top of a hill and the ground remained dry most of the time. (A concrete porch, on the other hand, was disintegrating and sagging.)
The main problem you have is minimizing the tendency of the two foundations to move differently. You're probably required by code to put the new foundation at proper depth, even if the old one isn't, and concrete will be less flexible than the stonework. This could result in considerable stress at the junction between the two, possibly causing the adjacent stonework to fail.
It might be best to have some sort of non-rigid joint between the two, and you should attempt to design the structure above so it won't be terribly "upset" if the two foundations move differently.