filling under slab on grade 1

[SLTA]

Boy do I get the interesting ones...

See the pics. 20 year old house - for some reason the contractor either didn't install the last course of CMU at the lower level deck or cut it away. I'm fixing the deck, no troubles, but the remaining gap between the lower CMU and the higher slab on grade for the house floor is letting the gravel and soil between leak out. How do I get at that to fill the void, block the hole, or otherwise fix it, without taking off the lower level of the deck? And what do I use to fill the void?

Please remember: we're not all guys!

 

[MotorCity]

You could fasten plywood to the foundation wall and the underside of the deck and use it as formwork. Then drill holes in the deck joists for grout holes and pump grout until the void is filled.

 

[SLTA]

Excellent idea. Thanks.

Please remember: we're not all guys!

 

[msquared48]

SLTA:

You still need to keep a separation between you infill concrete and any untreated wood or it will rot, and the deck members do look untreated...

I would make the form easily removable, leaving at least a 1/2" gap between the infill and the end joist.

Mike McCann, PE, SE (WA)

 

[SLTA]

Thanks, Mike. It may be the color of the pics but I do need to recheck that!

Please remember: we're not all guys!

 

[oldestguy]

If I was asking the question and the reply was as above, I'd say "how to pump"? Most of us don't have a grout pump, but probably require some one who does. Suppose a common slab mud jacker is contacted and lifts the slab (not wanted) as a result?

I'd do the blocking off of the opening and drill a hole or two through the slab and have an EXPERIENCED SLAB JACKER" do the job.

I've had this question, or similar, when on a big job as an engineer. I had the contractor's ready mix guys come with a concrete pump and a load of grout. The pressure needed was not much and with one hole through which to get under the slab it was done in 10 minutes.

I think working from above will offer the best job and is easiest to do.

 

[SLTA]

If we work from above, it will mean messing with the interior finishes in the house. That is a thought, though.

Please remember: we're not all guys!

 

[Ron]

The area doesn't seem that large and is "non-structural" so I would clean it out a bit and fill with foam.