On foundations bitumen is used, its applied to the walls and floor etc. This prevents water seepage and same...
Exact process of applying I am not aware of but the magic ingredient is bitumen.. it looks like Tar but is kind of different scientifically...
Secondly when everything is done then you place a plastic sheet and do kacha floor on that. Due to this Samme if it even occurs does not climb the walls.
Termite proofing is necessary too in this stage and later on it happen when laying kaccha floor