stone walls and damp

[Robbox]

The question is, what to expect?

After the huge rains early this year, we had parts of the stone walls weeping water inside. Some of the interior walls are exposed stone and other parts are plaster.

After the rains, we decided to repoint outside and use a sealant product.

I have had a dehumidifier going for several hours a day after the rains finished, then during the recent warm weather I turned it off.

I borrowed a damp meter recently and there are still patches of 30-50% dampness. These can be exposed stone and plaster areas. The readings are not consistent across the walls.

Is this to be expected with an old rubble wall? Should I expect the walls to take quite some time to go down into the low teens readings?

What about paint on the walls, will this slow down the drying process a lot?

 

[stuart45]

Stone walls take a long time to dry out, especially in Somerset. Make sure you repoint with lime and use breathable paints when it's dry.

 

[Robbox]

I was also wondering if when the salts come out of plaster, they give a higher reading because salts are so hygroscopic and create a more electrical conductive substance.
There are a couple of areas, around an internal chimney stack that was leaded and rendered on the the outside this year, where the plaster is very soft and it gives a 50% reading. Since we haven't had that much rain since the stack was waterproofed, it seems odd.

 

[stuart45]

Salts will attract condensation, and give a high reading on the meter.