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Hi All

I have a house in France that we are currently restoring. Like most old houses it has no DPM or insulation under the floors or DPC around the walls. My question is I am planning on digging out the floor to add insulation and a DPM (makes sense too). I have no DPC in the wall so moisture will be pushed into them right? I thought about adding an injection layer to the walls (chemical DPC). However i think the walls are solid stone, i need to confirm this by removing some render. I have fixed the roof and gutters that were causing water issues. I plan to put a French drain around the house next to the walls. The attached photo shows there is a issue with damp in the external gable end wall, maybe caused by bad drainage and poor guttering?

What would you recommend in terms of tying the DPM to a DPC if one can be retrofitted? Or is there another way to approach this? I plan to insulate all internal walls so want to sort any problems out rather than cover them up until later.

Thanks

Chris

It is difficult to come up with a plan as there are a number of variables. The ground water table will have an input as through the seasons the ground water level will go up and down. This will contribute to the moisture under the house and dealing with the exterior wall face may help with moisture transfer from outside but it will not help beneath, even with a good membrane. There will always be a degree of porosity in the walls and that is why a DPC barrier through the wall is best. Injecting a seal might not work in stone as the barrier solution may not uniformly penetrate the stone. Not much help I am afraid.

DWD