New Floor on top of Flagstones

[kb1904]

I’m in the process of replacing the floor in the basement kitchen of my Georgian town house. Currently the floor is covered with ceramic tiles which has trapped the damp with the usual undesirable effects. The original flag stones are under the tiles but are in a poor condition; I therefore plan to install a new limestone floor to allow the floor to breathe. Being situated in the basement I want to keep the increase in floor height to a minimum so as not to lose any ceiling height.

Can anyone advise me if I would be best to remove the flags and construct a ‘breathable’ floor from scratch, or if a thin layer (1 inch) of a suitable screed (e.g. limecrete) can be laid directly on the flags followed by the new limestone?

Many thanks

Kieran

 

[inwood]

I'd be sceptical about the ceramic tiles trapping the damp. Ceramic tiles are breathable (unless they were sealed) so should allow any damp to evaporate.

I would suggest improving ventilation first to see if that drys out the original flags that you've uncovered. If it doesn't then it would be pointless installing a new limestone floor as this will only absorb the excess damp.

You may need to find methods of solving the cause of the damp before installing a new floor - you don't want to do all that work and then find out you've still got a problem.