damp walls when it rains

[joanne78]

Please help - this is really starting to get me down.

We moved into a ground floor 4 in a block flat last year. however, this winter we've noticed that whenever it rains or the weather is particularly cold, the bottom corner of our (internal) bedroom wall gets wet. We've tried damp seal paint (before we papered the room) but it still gets wet and now there's black mould on the wallpaper. We opened up the wall a little to see if it was wet and it's bone dry (it''s a cavity wall) what can we do to stop this - would a dehumidifier help? the flats were built in the 80s and we have electric heating and double glazing. Could it be caused by condensation?

 

[big-all]

heeelllooo j 78 and welcome

youl need ventilation of some sort a window ajar for an hour or so would help
if there is anything in front off the mouldy patch try putting it somwhere else or move it away from the wall a bit
if all these measure fail to reduce or stop the problem you have damp from somewhere

 

[Santorium]

I have the same problem. Solution was a de-humidifier

 

[joanne78]

thanks so much - it was really depressing me I thought about a dehumidifier yesterday when I saw them in B&Q. Did you ever find out what caused it? It's only in the one room

 

[masona]

would a dehumidifier help?

Up to a point it does but blow out hot mositure which in turn make condensation !
Check the outside walls for any bad pointing, rendering cracks, is downpipe or gutter blocked, overflow pipe etc. Sounds like from what you're saying is known as "condensation trapped" due to poor ventilation with no air flow in the room, As big-all said move all furniture away from the wall for the time being as this will give a air pocket for condensation. One of the biggest problem is double glazing trapping the moisture in the room !

 

[joanne78]

there isn't any furniture in front of it now and we keep the window open during the day while we're at work. Do we need more ventilation? Maybe an air vent or something in the room??

 

[masona]

Have a read at this and this.

 

[oilman]

I have the same problem. Solution was a de-humidifier

Sorry, but I couldn't disagree more. Ventilation is the solution, dehumidifiers do not work well at low temperatures and only extract lots of moisture when humidity is high, and needs electricity. Ventilation works at all temperatures and humidity and doesn't need a power source.