Has anyone seen someone in the Bangkok area who performs slabjacking or mudjacking? I need this for my add on kitchen.

Thank you in advance.

A slab on grade without walls or columns on it? unless it is really well reinforced, jacking will likely destroy it. It may be cheaper, and best, to just demolish and pour a new one - this time over precast hex-piles to support it.

This is a slab which was poured without tying it into the main slab. the columns they have for tile roof were in footers 5 feet deep. The floor was poured around them As it is now, the back is tilting down causing the rolling doors to be out of square as well as the top of the kitchen to break away from the house.

I was looking to mudjack or I may tear it down and rebuild, this time tying it into the main slab of the house.

Hmm, you could maybe hammer-drill a few holes in the slab along the house side edge, hand excavate out a bit & dowel-in some rebar lengths into the house grade beam, and then pour some spots of concrete just under the existing slab. This will create a series of concrete shelves (that are tied to the main house structure via the dowels). Then you will have stopped the differential settlement, and can pour a topping if need be to attain good slope to the finish floor. Or just wait fo rthe outboard edge of slab to drop down (assuming its not doweled to the column footings)

May I ask is it the columns which are sinking?

The slab sinking?

Or both?

Both. I was actually looking at both suggestions. I was looking to mud jack and then dowel it in.

if the columns at the outboard corners, away from house, are also sinking, don't tie your slab to them - let the slab float independently. DO tie yr slab to the house via dowels/conc ledger shelves as per above post, and slab will hinge down over time.

I believe the colums at the outboard corners are intact, it is the 3 in the middle. They only footed them down by 2 meters as we could not get a machine to put in the hex cast as the house was already built. I need to find a reputable company to come out and look at it to see what can be done. I have used several contractors in the area and had to redo the work every 12 months.