Flagstone floor advice

[evolvoordie]

Morning all, I have had lino down on my kitchen floor for many a year, but I was thinking about having it tiled.
I decided to lift the lino and found some more lino underneath. I lifted the second layer of lino and have revealed the original floor, which consists of the original flagstones but they have had a screed/self levelling compound put on top of them.
It`s an old Victorian house, so it probably does not have a damp proof membrane. There was black mould on the underside of the second layer of lino.
My question: Is there a product that can be applied to the floor to seal it prior to tiling?
Kind regards: Sean

 

[Qwerty]

Your original floor was designed to breath as there was no dpm underneath. A liquid dpm may be suitable such as Tilemasters one coat membrane or @Mapei UK Marketing aquaflex system . I successfully used the latter to treat my whole ground floor of my property 10 years ago as my dpm had failed in a number of places. A great product. Speak to their technical support departments before buying though