On two outside walls we had a tide mark of damp above the skirtings. We removed the skirtings and found a rotten joist, woodworm etc. We have dealt with the wood problems and injected a DPC, replastered using render type plaster and the wall seemed dry. When we place the skirtings up to the wall, they get wet behind them with an increasing level of height over time. One of the internal walls is some 2 feet above ground level and the wet is at this height and higher internally. It seems like condensation but it is strange. Any help appreciated.