flag stone flooring

[owensinger]

what is the best base for flagstone flooring in a kitchen? Currently, and for the last 300 years dirt ie the ground has been working ok. I would like to lift them ,level the floor a bit and seal them with something to reduce the amount of dust that is produced. any suggestions on sealant as well?

[buildersmate]

Since you are going to the trouble of lifting them, its well worth putting a damp proof membrane under (thick plastic sheet). Dig down a bit - say 30mm - put plastic down, fill with sharp sand/cement wet mix. These flags will be different thicknesses, which you have to roughly level by having different thicknesses of screed under each one. I'm assuming the soil base below the floor is nice and stable.