Undermined footing

[MHaines]

I have a project I am working on here in which we have a continuous footing that is undermined by 1 foot perpendicular to the footing. It was done for the plumber to install his piping. I think that this is a relatively small issue, however, can become a big issue in the future. I am needing to know what would be a fast, simple, and cost effective fix for this. I was thinking possibly placing a flowable fill below the footing. I also thought of a helical pier but I do not believe this would be a cost effective solution. Any suggestions?

 

[JedClampett]

Do you mean a continuous trench one foot from the footing? Or a trench under the footing one foot wide? The perpendicular term throws me.
However, flowable fill is like duct tape. It tends to fix foundation screw ups whatever they are. I'd say you're on the right path.

 

[MHaines]

A trench under the footing 1 foot wide.

 

[PEinc]

Backfill the 1' wide trench under the footing with crushed stone and compact it the best you can. Pack the stone under the footing. Flowable fill sounds good but you need too little of it and it shrinks a lot.

http://www.PeirceEngineering.com

 

[cvg]

you can use a pourable, non-shrink grout which will completely fill under the foundation, require no compaction and give over 5,000 psi compressive strength. Alternatively you can mix it stiff and pack it in.

 

[oldestguy]

Don't get excited now. This happens all the time when plumbers install their pipes into residential and other buildings. Usually the design of the footing is such that no problems occur.

However, for restoring support to what was there before, the post from PEinc does the job nicely. I've even done this for a footing 4 feet wide, ramming in granular fill from the side, horizontally. Use a 2 x 4.