Black colouring in corner of Ceilings

masterK

For the past few years during winter I've been getting a very dark mould like colouring in the corners of the ceilings in some of my upstairs rooms. It is really bad in the en-suite, even though the shower has not been used in some time. It's now getting really bad in one of the bedrooms. It only occurs at the corners adjacent to outer side wall of the house.

Also in the wardrobes that back onto the outer wall there is a build up of what looks and smells like dampness to me.

Any ideas/advice on where to start to track down the cause of this problem?

Gurgle

Your roof leaks.

dubtom

Generally blackness like you describe is from lack of ventilation in the rooms which can be fixed by opening the vents/windows in the room and letting air circulate.Seeing as the damp only seems to be on external walls I'm guessing that the guttering is leaking, or possibly blocked with moss/ dirt,water dripping down the walls in winter, with little drying time can accumulate and seep into the brick or block.If it's any of the above it would be a good idea to seal the external walls in summer after a good spell of dry time.

crosstownk

Sounds like bad ventilation coupled with unwanted water ingress. You need to check and see where this dampness is infiltrating. Try opening as many windows and doors as possible to allow for good ventilation. There are products that you can buy to stave off the growth of mildew.

Avns1s

Bad ventilation and check that your insulation extends PROPERLY into the corners. A 'cold' spot will cause this where there is condensation even from normal use of a room particularly a bedroom for some reason.;)

squarecon

That is due to the warm air in your house which contains moisture (from the kitchen usually) travelling to the cold area of your house, (exposed external walls) and condensing, much the same as how rain falls. A small heater combined with unblocking your vents in the rooms(which some people used to block up fearing loss of heat)

Viking House

One of my Scandinavian builders told me today that the Irish are very busy building "Mushroom Houses", referring to the standard non breathable building systems we are using in Ireland that promote fungus and mould growth.
A Sweedish Architect who works in Wales told me last week that Wales is now on the top of the list as the Nation with the highest incidence of Asthma in the World, we are not too far behind here.
Now don't start blaming the "Damp Irish" weather because if you wash your floor when it is raining outside it still dries quick enough when you open the window, the biggest problem is moisture generated by the occupants inside the house and from cooking.