I have been having a few problems with damp in my house. I have posted before about this but have come up with some more info (different) so I thought I'd post new. I have read some other posting on this but could not find an answer
I Live in an end of terrace which I bought only a while ago. There is an alleyway one side of my house - hence end terrace. When I had the house surveyed, I was told there was damp on the end terrace wall (the one on the side of the alleyway). I was told this was due to the floor level of the alley way bridging the dpc. Solution from him was to lower the floor level of the alleyway to 2 brick lines below the dpc. I originally posted about this is and the generally opinon was that the floor level was too high and I needed to lower it.
Another solution offered was to use a disc cutter and cut out a channel 6 inches away from the wall, along the full length of the wall and dig down to the correct level. Create soak away and filling the channel with gravel.
I have spoke to a few builders about this and from them I have discovered sometihng else.
The whole wall externally is painted black (all the way to the chimney stack). I originally thought this was just exterior paint (weatherproofing), however one builder told me that it looks like bitumen paint. He says it may have been put there to prevent damp getting in, but in reality perhaps it should not be there as by default it also prevents the wall from breathing and could be the cause of damp problems internally. So here are my questions:
How can I tell its bitumen paint
Is he right in saying that it may be causing problems. Could it be causing the damp I am getting on the ground floor (ie on the internal walls I see bubbling of the plaster, loose bits flaking off and small bits of black mould in the corners. I also have some mould appearing in one of the bedrooms upstairs on the inside of the same wall)
Shoud I remove it, and if so how?
Once removed do I need to do anything to the newly exposed wall (pointing, coating with something else etc)
I will not be doing the work my self, but want to get an idea of what could be the cause of my damp problems before I get anyone to start any work