I’m in a bit of a pickle. I bought a house built in 1964, poured concrete walls, the front of which is in 2.75" at it’s worst, about 20 foot of the 50 foot wall is in need of repair. I hired a very reputable foundation company to install 6 helical tiebacks across the front of the house, in addition to digging out the front wall, backfilling with 80% rock, applying a waterproof membrane, and new drain tile daylighting out the side of my house. My house is on a fairly steep grade making a sump pump unnecessary.
The company has so far dug out the front wall down to the footing, but when they went to install the tiebacks they hit some rock about 8 feet out from one of the holes. This caused the poop to hit the fan. They tried one more hole with a smaller diameter pier, getting it out to 23 feet, but then decided that since the one hit a rock we needed to rethink our strategy. They have given me new options for the repair, which vary from less than original contract to almost double. To complicate issues, the portion of the house opposite the problem wall is a wood wall, everything other than that 20 foot section is poured concrete. It ranges from installing steel ibeams on the inside wall, which they won’t warranty because it’s a walkout portion which they say shouldn’t be used, installing carbon fiber straps on the inside and outside of the house which they also refuse to warranty, or for double the price, drill into the rock 6 feet and anchor to that. The wall would be brought back plumb before they do any of these repairs.
Obviously the rock anchors being twice the price blows my budget out of the water and isn’t viable. I’m not sure if the carbon fiber or ibeams will work, they act like it will push the house out of wack and refused to warranty their work on these repairs. I will have a structural engineer hired in the morning, but wanted any advice and opinions I could get.
The structural engineer will be able to give better advice while at your property than any of us here, reading your narrative which has no pictures, and some opinions stated as facts. I wish you luck on your project. I hope the Structural engineer is able to offer some economical and safe alternatives.
Gotta say, your description is inadequate for me to understand what the problem is. What does the 2.75" refer to?
Tieback? You mean your problem is… what’s the problem other than drilling for helicles hitting rocks? You said concrete walls, but then it’s wood walls?
Man, I have no idea what you’re talking about. What Bert said
They probably want to grout the tie backs into the rock, which is what this situation calls for. And they are correct that both the steel beam pilasters and the carbon fiber are wrong for the situation. It sucks, but grouted tie backs are what’s needed here.
For the heck of it, you should find out what the price of replacing the wall would be. He’s already got it dug out. I kind of doubt it’s cheaper, but with drilling rock, you never know.
You should also ask them or their (or your, hopefully) engineer if a wale (also known as a soldier beam) could be installed to eliminate the one tie back with the rock. But the wale itself could be just as costly as grouting the one tie back.
I’m also curious, are you saying the cost of the entire job (6 tie backs) doubled because they need to grout just one of the tie backs into rock? That doesn’t sound right.
Yes, they think that since we hit rock on one tieback that they will all need grouted now. I don’t understand that really, because I watched them install a different tieback to pressure at 23 feet out with no issues. I asked them to try installing the tiebacks into the other 4 slots to see how many hit rock before reaching the proper torque pressure, but they keep assuring me they will all need grouted now, without knowing that to be the case.