Foundation Failure/Repair 1

[Struct1206]

I was recently asked to assist a local foundation repair company with a house that is experiencing foundation settlement issues. The northwest corner of the house was underpinned (think PermaJack) approximately 19 years ago but it appears the settlement is continuing. The house is two stories with a basement that retains soil on the front but quickly slopes off at both sides. On the west side of the house there is a garage with a concrete floor slab on metal deck supported by steel beams. The steel beams bear on the west wall (front of the house faces south). The west wall is settling and rotating at the bottom, the garage slab is drifting to the west and the floor system is pulling the interior bearing wall out of plumb. The west wall now slopes out from the foundation up to the garage floor and then slopes back in up to the roof level. I feel they need to install additional underpinning to stop the settlement but I'm concerned with the hinge that's been created in the wall at the garage floor level. I'm worried that if the put upward pressure on the footing the wall will continue to rotate outward. I feel like we need to tie the floor and walls together to keep the wall from buckling out of plane or possibly tie the upper and lower walls together somehow to make it more of a continuous wall. Then, install underpinning. Has anyone dealt with a similar situation? Does anyone have any thoughts on remediation?

 

[oldestguy]

First thing, you need to know the soil conditions both under and alongside. Underpinning with something that jacks up the foundations, etc. may not be suitable, as apparently happening to previous work. At that time you plan what to do. Much also depends on the overall value of the property. For instance would a Cadillac fix cost be considered for a house not very valuable? Engage a geotech and his recommended exploration company.

 

[GeoPaveTraffic]

Questions that need to be answered before trying to find a solution.

Why is the wall/corner/footing moving?
How much and in what direction is the footing moving?

If the movement is settlement (vertical), then well designed and installed underpinning often works to stop the movement. However if the movement is a combination of settlement and lateral movement, then underpinning will rarely work.

Given your description, I expect there is some lateral movement occurring.

Either way, you need to get an experienced local geotechnical engineer involved with the project.

Best of luck.

Mike Lambert

 

[SLTA]

Totally agree with the above. Get a geotech involved post haste and figure out why everything is moving. Otherwise, it's like throwing money into a fire.

Please remember: we're not all guys!