CMU Foundation Repair Suggestions

Yikes,

removal and replacement of those blocks would be my recommendation. Sorry, but any other fix just won't do.

You could, slide some reinforcing into the cores and form it up and pour it full of concrete. The hard part is determining how much concrete to order. I wouldn't recommend site mixing as you'll need quite a bit I'd bet once you get going.

I've never seen something like that. What would cause the CMU to deteriorate like that?

Was the corner grout filled or hollow?

Thanks Jay. These blocks are from the 1940's and they no longer make blocks in this size (believe they are 6x24, unsure of width). One foundation repair contractor said he would form out the corner (this was before I removed the rest of the parge coat on the wall as shown in the 3rd photo), stuff empty concrete bags in the voids and fill with concrete. I'm not sure if this is a great approach because of the added weight onto possibly compromised blocks, concerns about having a solid block of concrete without reinforcement, and not having a structurally sound surface at the bottom for the concrete to adhere to.

The second foundation contractor I talked to said he would just pump concrete down to the footings. I like this better, but not so much the 5k price tag for the pump truck. After calculations it should be about 1.5 cu yards of concrete. I have a few other calls out to concrete pumping companies for comparison but am thinking this is a better approach.

Unfortunately I decided to take on this project in the fall and winter is just around the corner (no pun intended). I bought the house earlier this year and couldn't see this damage with the parge coat over it. There were major cracks in the parging that I sealed a few months ago that water had to have been entering in through. Eventually I'll be getting drain tile installed also.

Hi Joel - I'm not positive but am guessing it's due to water infiltration. I haven't seen water enter in through the basement. My guess would be grading issues, lack of maintenance, damage from freeze/thaw, and soil/hydrostatic pressure. New gutters were added a few years ago but I don't know if there were gutters in place before that. I also found some pretty big tree roots around this corner (two large silver maples are nearby) and I believe this is the side where the water main enters.

This will be a tough job for DIYers. Looking for an experienced contractor, and see if the procedure below is feasible:

1) Shoring the outer shells the best you can. Some chipping is required to provide stable support.
2) Grout the open and reachable CMU cores to the ground level.
3) After the grout is set and hardened, chip and remove the broken/loose CMU remains, and build small piers in between the space.
4) Chip out remaining deteriorate CMU wall, at a staggered manner, to expose CMU cores.
5) Repeat steps 2-4 until the entire wall is repaired solid.

5k for a pump truck? That is ridiculous (at least in my area). Should be able to find a Mayco pump for 1/4 of that price. They could also just bring in a mortar mixer and just mix on site.

I agree with jayrod here - those blocks need to go and be replaced. You may not be able to find exactly the same blocks, but you should be able to get something that will function well. Shore up the floor underneath, remove the blocks, and rebuild the wall. Anything else is likely be a really expensive patch job.

Thanks everyone. I went around the foundation company and got a quote for $750 for the pump truck...they just require the site be prepped first.

I should mention the foundation company said any jobs that require a pump truck start at 5k and the truck is 2500 of that.

My thoughts are having a foundation company come to prep the site, shore the wall, and replace the 3 courses of damaged blocks. Then have it pumped with concrete. I’m questioning how metal reinforcement can be added without creating a giant mess in the basement and compromising the integrity of that side of the block. Thinking run a bond beam through the top course of the new block? Then somehow get vertical support down the cavities. I just don’t know how that would be possible without ripping the whole wall down. The blocks under the damaged courses appear to be fine and don’t seem to be blocked with any rubble which makes me think the wall below grade is still usable.

I'd not be surprised if the walls below grade are still in good shape. You should be able to slide reinforcing down from the top on the outside based on the pictures.

In my experience a pump is around $500-750 for mobilization and then you get charged per cubic yard/metre and for standby time. To minimize the cost of the pump, you need to be ready to go the second the pump is on site. Also, make sure you have enough concrete ordered to prime the pump and cover any additional you may need. Concrete is relatively cheap, so ordering a bit more to make sure you're covered is cheap insurance.

Make sure you shore the inside of the wall as well if you're going to dismantle the top of the wall. You need to shore the floor, and the wall. Or else you could have the remaining wall fail from the soil pressure.

Hiring a local structural engineer to take a look and detail the repair would be money well spent, too.