Hi, The inner walls of our fireplace gets damp with black mold growing on it. This has caused severe condensation inside so we have to keep a dehumidifier running day and night. Can we fix the issue by painting the wall with damp seal paint or does it need a more intrusive solution ? Thanks in advance for your help. Please see the photos Thanks
Unfortunately paint will work for a few months but won't fix the issue. Determine the cause of the problem and fix that. It could be anything from outside wall brickwork or faulty render, leaking drainpipes, internal pipe leak, under floor damp etc. The solution won't necessarily be expensive but it will be messy. Does the damage continue behind the stove?
Hi. Thanks for your reply. No it doesn’t continue around the stove. On your point about pipe leak, it is possible. There is pipe running alongside the outside wall (soak away).I have added more photos of the outside wall . Do you think the wall needs to be demolished?
I'm speaking as a fellow victim rather than as a builder so I can't advise on structure. It seems that the damp zone corresponds with the corner edges of the box structure which could mean there are are hairline cracks along the joint or rising moisture from underneath caused by the French drain. Next time it rains, look at where the water gathers or channels as it could be the water is just sitting in the drain for a long period and seeping in to the box wall. Also, look up and see if there are there any leaks from drainpipes which you don't notice in dry weather. I had a damp problem caused by an overflow pipe dripping on to a hairline crack in the outside wall render.