Endless Dampness on External Walls

[Trinity1832]

We moved into our house approx. 2 years ago. The house was built in 1832 and is Grade II Listed. We had a Full Building Survey undertaken which confirmed what we expected, that there was dampness would be present in the house. This was expected given the age of the property and the fact that it was empty for sometime prior to us moving in. One room in particular was very damp with dampness visible on the walls up to approx. 3-4ft above the floor. This is a second sitting room and rarely used and therefore dampness can't be attributed to occupancy or use of the room. There is an open fire place with a functional chimney. 2 of the four walls are external wall, which are of solid brick construction c. 15-18" thick. There are no air / brick vents and ventilation through the windows is negligible given secondary glazing units have been fitted.

We installed electro osmosis damp proofing to the full perimeter of the house in Nov 2009. Drying out of dampness was expected to be and has been very slow. In an attempt to speed things up I bought a Ruby Dry Portable Dehumidifier in Oct 2010. This is running 24/7 with some exceptions - basically when I get fed-up emptying the bloody thing. The dehumidifier has a 6 litre reservoir which I empty daily!
That's somewhere in the region of 1000 litres of water. Is this normal, is there that much volume available within the walls to store such a quantity?
I have a 'cheapey' dampmeter which seems to give quite high readings (60-80%) similar to those when we first moved in.

Can anybody shed any light on this matter?

 

[^woody^]

Who talked you into the electro-osmosis scam? It rarely works, and then is only for specific circumstances.

You need to determine if the damp is coming up due to high pressure (very damp ground) or just due to very absorbent masonry.

Then you will know if the damp problem is treatable, or if you need to mask it and just deal with the eventual humidity.

You can do treatment work, but will need planning permission, and they wil want to agree the scope and type of the work - you will normally need a specialist report (not just a normal damp survey), and the report will detail why a particular treatment method is required