Damp in a stone built cottage

[cairnhill]

We are currently doing up our 100+ year old stone built cottage and have just discovered there is damp around where the floor and wall joins, the floor has a concret screed while the walls are the originals stone/mortar can anyone suggest an easy fix, something that doesn't require major machinery work to cut out slots in walls to fix membranes etc.
The walls are solid stone approx 300mm thick and the stone is not uniform in size or shape.

[stoneyboy]

cairnhill,
If you can see a DPM lapped up to the surface of the screed then you could have a silicone DPC injected in the walls.
end

[cairnhill]

Stoneyboy, thanks for your reply, things just got a lot worse today.
We uncovered the original stone fire place and were removing the rubble put in their by a previous owner when a lump of the existing floor concrete came up. Underneath is what looks and feels like soil, sand and stones mixed, no damp proof membrane to be seen anywhere, if this is what's under the whole floor downstairs I guess we are in for an expensive floor replacement project. At least we now know where the damp is coming from.
Only upside is that this only effects about a 35 square meter area but will mean tearing down a couple of stud walls including the bathroom.
Happy days :(

[stoneyboy]

cairnhill,
Looks like you will have to recast the floors but incorporate a DPM. You will probably still have to form a DPC in the walls by injection. If the stone is non-porous the silicone should be injected into the mortar courses.
At least you will have plenty of rubble for the sub-base.
end