Ground settled under garage floor

[derwiener]

My 4" concrete two car garage floor was poured in 1978 and has no cracks. I believe the concrete was reinforced with whatever type of metal mesh was used back then. When replacing the concrete driveway, the area where the driveway meets the garage floor showed there were areas under the garage where the earth had settled and there was no apparent support for that part of the floor. I don't know how extensive this is. In a couple of areas I can push a stick several feet under the floor, a tight fit, however. Cinderblock prevents me from investigating more extensively. Question: is this a concern, given the fact that here are absolutely no cracks in the floor after 34 years? If yes, I understand that holes can be drilled through the floor and a concrete slurry pumped in. Is this correct, or is there a better repair method?
Thank you!
Paul

 

[hidollartoys]

You are correct, sir.

 

[derwiener]

Hi hidollartoys: Thank you for the reply, but what is correct - I should not worry about the floor or there is a better repair method than concrete slurry.
Thank you.

 

[rsanter]

For long term durability you need to do a concrete slurry so fill the space and support the floor. More important I would start to look for why it happened so it does not happen again. Do you have water issues around the foundation? Did a pipe break at one time under the foundation?

Bob

 

[rasit]

but what is correct - I should not worry about the floor or there is a better repair method than concrete slurry.
Thank you.

Yes and no. You should not worry about the floor unless you are planning on changing the way you have been using the garage in the past (such as adding a lift), and there is no better repair method.

 

[Big-Foot]

Not knowing where you're located makes a bit of a difference...

When I lived in Texas, there were a bunch of companys that did what was called mud-jacking. They would us a pump to push mud (clay?) underneath foundations, driveways and such. They could raise them up or just add support..