damp wall-flaking paint

purerandom

hi guys,
I blocked up the fireplace 2 yrs ago as there was no need of it. it was bricked up, then plastered, then painted.
last week i noticed that the paint was starting to 'rise' and the wall felt a bit damp.
I fear that there is a build up of water in the chimney or something and was wondering what can i do to sort the problem?

any advice is appreciated.
sorry if this is the wrong forum for this query

slavetothegrind

i'm guessing you didn't leave a vent at the base of the bricked up fireplace?

also coould be damaged flashing at the chimney stack on the roof

purerandom

No i didnt leave a vent!
If you have the time would you mind explaining what you mean by 'damaged flashing at the chimney stack on the roof'?
Sorry for my lack of knowledge here and thanks for the reply.

Billy Bunting

More likely the lack of a vent at the fireplace. Bad flashing tends to show higher up the chimney.

purerandom

ok thanks for that, just to be precise the flaking and dampness is occurring about 4 feet from the floor, does this indicate bad flashing?

Buford T Justice

No. If it was an issue with the flashing the dampness would be visible from the top of the wall downwards.

Was the chimney sealed off at the top when the fireplace was blocked up?

purerandom

no, i never sealed it off!
schoolboy error methinks.
I should seal it off and put in vent where the open fireplace would have been. would that be correct?

Buford T Justice

No point in a vent if you seal off the top. Did it in our house years ago. Bricked up the fireplace, capped the chimney and never had a problem.