Ground settling under block wall

[Guv Bob]

I have a 5-foot by 40-ft block wall. A 5-10 feet section at one end is not supported due to ground settling and the mortar has given way. Both pieces are still solid. My concern is that the top portion is not supported and would be more likely to break in a wind or earthquake - or if some fat guy tried to jump over it to get at the apples on the other side. Not mentioning any names. LOL!

First thought was to dig down, jack up the sunken part (or leave it in place), pour concrete underneath, then fill in the cracks. The blocks are an old style and it would be impossible to get new ones close to matching them.

Anyone ever had this happen and can tell how you fixed it?

A sketch is here:

[philoÂÂ]

I had an old-style cement block pillar for my porch give way...

I hired a mud-jacker to shore it up.

If you can pour cement under there yourself, you should be OK

[Tekkie®]

Guv Bob posted for all of us...

And I know how to SNIP

Like Philo said. Mud-jacking.

The only other alternative is to cut the wall at a seam and install a proper foundation and re-lay weaving with the reused block.

[nestork]

I don't know if mudjacking would work on a concrete block wall.

Mudjacking is where they pump some kinda slurry under a solid slab to level it once again. It works because they pump the slurry in under pressure, and that pressure acts on the entire area of the underside of the slab. So, even if you have a 10 foot by 10 foot slab of concrete weighing 100 pounds per square foot, a slurry pressure of 100/144 or less than 1 psi acting on the underside of that slab will lift it. While some of the slurry will undoubtedly spill out from under the slab all around the perimeter of the slab, as long as you can compensate for that by pumping enough slurry under the slab to maintain that 1 psi pressure, you can lift the slab.

But, pumping a slurry under a concrete block wall is an entirely different situation. The slurry is going to rise into the cavities of the block wall and fill up the block wall with slurry before it lifts the wall. There may be a way to do it, but I'd talk to some of the mudjacking companies before I assumed this could be done with mudjacking. Even if the blocks were solid, I'd still think that mudjacking a concrete wall would be far more difficult than mudjacking a concrete slab just because of the leakage rates and pressure requirements in each case.

[bob haller]

disassemble wall one block at a time, carefully. clean block, install proper footer. rebuild.

A retired brick layer told be you can match any brick or block, they can be made to order.

truly though people shouldnt build retaining walls or any walls for that matter without a footer

[hrhofmann]

What Philo said, and I would also use some good construction adhesive to fi ll in the cracks in the wall as you are jacking it up, let it cure for at l east a day before starting to push in the new footing-type concrete. The c onstruction adhesive will help hold the wall together against futue crackin g due to settling. That stuff is amazing.