I have a slab on ground patio at my house. It's slowly sinking due to sub standard (normal Thai buildling standard??) construction and non compacted soil under it - it would appear.

I don't want to destroy it and start again for various reasons.

There is a process called underpinning which could be the solution.

Anywhere/anybody in Thailand do this?

gotta admit had to google it..seems to me that concrete work is so cheap here that replacing or just overlaying would work..I am just replacing our forever rotting wood deck with concrete and tile ..just rubble and about 200m of footing with 50mil concrete..we will see...lol

Yes I know it's cheap but that patio joins an existing part of the house which is built on solid footings/foundations and where there are no problems. Would be difficult to replace just the patio in this case but you may well be correct in that it's better just to replace it.

Next problem would be finding matching tiles which will not be possible.

Yes I know it's cheap but that patio joins an existing part of the house which is built on solid footings/foundations and where there are no problems. Would be difficult to replace just the patio in this case but you may well be correct in that it's better just to replace it.

Next problem would be finding matching tiles which will not be possible.

just get contrasting tiles..buy a few samples and compare..just a thought..good luck

There are Thai building companies that would undertake to do underpinning if it cannot be carried out by a local builder but you won't get them cheap.

When you say sinking, in what way, pictures posted are always a good way to go.

Maybe will be best to have it reconstructed but the original sorce of subsidence will still have to be dealt with.

OK thanks

OK thanks

Just another thought if you cannot do it yourself a good (maybe) local builder could jack it up, dig down and pour making more concrete reinforced piers.

Again without seeing it, it's difficult to help and not know whether the subsidence was cause by settlement or what they call liquid faction from flooding.

I would think you could do it yourself:

try mini piles...

cus some holes in the cement and drill down maybe 2 m into the soil and then fill the holes with grout

OK thanks

Just another thought if you cannot do it yourself a good (maybe) local builder could jack it up, dig down and pour making more concrete reinforced piers.

Again without seeing it, it's difficult to help and not know whether the subsidence was cause by settlement or what they call liquid faction from flooding.

This is the answer I was looking for. I know the process involved. Just wondered if it was common in Thailand and whether there is any contractor that could do it in Chiang Mai?

I will start looking.

OK thanks

Just another thought if you cannot do it yourself a good (maybe) local builder could jack it up, dig down and pour making more concrete reinforced piers.

Again without seeing it, it's difficult to help and not know whether the subsidence was cause by settlement or what they call liquid faction from flooding.

This is the answer I was looking for. I know the process involved. Just wondered if it was common in Thailand and whether there is any contractor that could do it in Chiang Mai?

I will start looking.

When we were able and successful in jacking up subsided houses I don't mind commiting myself to say it is very possible as long as your original floor slab is strong there should not be a problem.

I don't think a Thai slab on grade will have reinforcing enough to hold together under jacking pressure ...and [how shall i say this?] procedurally I don't see it going off well in LoS `:]

ONLY IF you MUST save the slab, you might want to jackhammer out openings in a gridwork of about 1M x 1M and get a crew to drive down the hex-shaped precast conc piers used for driveways. Then hand dig out under the slab around each hole about 600mm diameter x 150mm high - enough to slide in a tight gridwork of rebar under the slab & over the hex piers. then pour/stuff w/shovel & rod a conc "shear cap" under the slab & over the hex piers. Make it a stiff mix, not the Thai garbage. This will help distribute the load and give you a chance at saving your slab.

No promises, as we have no idea what your slab and geotechnical conditions are capable of.

I agree wit the previous post, underpinning a pation slab is just not sensible in Thailand for a whole host of reasons.

Well I say, still give it a try, as said we do not know the make up of the slab, maybe OP does.

If it doesn't work then he can start looking forward to replacing it.

Is the slab on a beam and the beam sinking?

It won't actaully be that heavy.

You can dig out alternate sections, say dig two feet lengthways then leave two feet and so on repeating.

Make sure you make the footing wider to spread the load sideways with some rebar to help do this.

The combination of wider footing and some concrete weight to compress the ground should be enough.

So you do the odd two foot lenghts, then when they're cured dig out the even two foot lengths and do them.

Cheeryble