The cavity wall in my lounge around the fireplace appear to be filled with concrete or cement. My neighbour asked if I had problems with damp a while after we moved in and then told me that one of the previous occupants had poured concrete into the void around a flu and it had gone everywhere.
I've opened a few bricks and had a feel around inside the cavity and it appears to be the case - the void is breached in a number of places and completely blocked - I have sever and persistent damp in patches across the wall.
How can I remedy this?
