Tips on drying out An Enclosed Area.

bellevueace

Im just looking for any tips on a problem im having at the moment. I live in an end terrace built in the late 1800,s and have recently had a new kitchen, bathroom, and dining room. The kitchen and dining room was taken back to brick as the plaster was very old and had blown mainly due to bad outside maintainance , the whole out side was repointed before doing the work. The rooms were completed using the dot and dab method and dried out after a few days of leaving the heating on, using a fan, and a dehumidifier. With it being an old house under the stairs is an enclosed area that would at one time have been a larder, there was no outside ventilation when I moved in just an air brick low down on an internal wall, as there was a musty smell due to the house being empty I put in an outside air vent on the gable end and this cured that problem. As I had some plasterboard left I decided to take the larder area back to brick as the plaster was shot and board it using dot and dab with a quick skim. After the plaster dried out I painted a mist coat and an undercoat, after a few weeks I noticed damp marks coming through the boards and a couple of areas of mould. Ive been using a dehumidifier for a week even though no mould has returned im emptying about 4 pints of water out every 24 hours,, I realised I didn't use the anti damp membrane in this area so could that be the problem and if so would that mean removing all the boarding? Or could it be the dehumidifier is just taking the moisture out of the air and not drying the walls due to no heat being in the area? Would it be better to use an oil filled radiator to supply some heat and the dehumidifier the then remove the moisture from the air thus actually drying out? Any ideas would be welcome as I don't really want to strip all the walls again. The main area that is the problem is the inside wall the backs onto the dining room, ive checked for central heating leaks but the system isn't losing pressure, and the floor is solid concrete. I know on the road I live there is a stream under the road so some houses suffer a lot with damp but this seems to have arose since boarding out.
Many Thanks ( Sorry for the long post).

JimmyChanga

Have you checked moisture content of the concrete flooring? If that's okay I'd suspect you will need to strip the walls again.

What is this anti-damp membrane you're using? Where does the water go to?

bellevueace

No ive not checked the floor will do that, ive put an oil filled radiator in there now as there has never been heat in this space, already its starting to feel better, the anti damp membrane is something I hadn't heard of but found out a lot of companies now use it a lot of people I know have had it fitted, as an after thought I wondered if putting the fridge in there could contribute to the problem?