What kind of pipe would be best to go through a slab for water supply to a house? And is some sort of sleeve or protection advisable? Due to the difficulty of access, I would favor the most durable solution in this situation. Homemart recommends PE pipe for burial.

With hot water, if you are thinking of also putting in a boiler (hot water tank), do the plumbing now. Getting copper pipes done is almost impossible in Thailand, well possible but difficult to find. I ended up using gal-pip, this should be insulated when in the wall or the slab as it can get very hot and expand, the insulation offer expansion room as well. You can get the same stuff they use on air-con pipes from global, or even inside pvc pip will do the trick, eg gal-pip inside bigger pvc pipe.

When water pipes are in the ground under the slab, bury them in sand, as the often clay in Thailand soil expands and contracts in dry and wet season the sad acts as a buffer a little bit, also avoid rocks touching the pipes.

As for the short verticle section penetrating through the slab into the bathroom floors etc no sleeve was used for cold water. I have never seen a sleeve used in this case for cold water.

We have the Homemart recommended PE pipe coming through our floor slab and ten years on it's still seems to be OK, had I been here at the time I would not have buried any pipes permanently.

If you have clear and easy access to both ends put a four inch pie in the concrete and run your pipes through that . any time time you have a problem you can cut the ends pull the pipe and replace it. Obviously only works with a straight run and no right angle turns.