Mould at cold spot

nialldinho

Hi

I've been told that my bedroom has a cold spot in the corner at the external wall. Over the winter mould forms on the walls in the very corner.

I scrubbed it off with disinfectant today and then sprayed bleach on it and left it for an hour before rinsing off.

I intend to paint the room soon but I'm not sure what to do to prevent this happening again. I'll try to keep the room well ventilated and open the window to let fresh air in but can you recommend any primer I can use before going ahead with the painting?

Thanks

BryanF

'the cold spot' is the problem - paint won't solve the fact that moisture will always form on a surface that is cold, allowing mould to grow
the question is how would you insulate the 'cold stop' - the best option would be to externally insulate, other options would need more info

nialldinho

BryanF wrote: »

'the cold spot' is the problem - paint won't solve the fact that moisture will always form on a surface that is cold, allowing mould to grow
the question is how would you insulate the 'cold stop' - the best option would be to externally insulate, other options would need more info

Thanks.

The problem is that I'm in an apartment so I can't do anything externally.

I got Homebond to look at it and they said that it was just a cold spot and they won't do anything.

So, I think my options are quite limited..

BryanF

nialldinho wrote: »

I got Homebond to look at it and they said that it was just a cold spot and they won't do anything.

was this explanation given in writing by homebond? what about giving us a picture(include something to scale)

nialldinho

BryanF wrote: »

was this explanation given in writing by homebond? what about giving us a picture(include something to scale)

Yes, I think I have it in an email somewhere.

Can't find any photos I might have of it now though. And I just cleaned it this evening so nothing really to show at the minute!

I'd say it got about six inches down the join of the walls in a V shape. It was quite dark possibly black. Nothing really on the ceiling though.

MicktheMan

You probably have excessive moisture (high relative humidity) in the room and an external corner (probably on the north or east side of the apartment block). A number of things are at play here:
1. The temperature in the corner is lower by about a couple degrees than the rest of the wall due to the geometry and heat loss on 2 walls in close proximity. This temperature is lower than the dew point of the air for long periods resulting in regular condensation allowing the mould to thrive.
2. because there is v little air movement right in the corner, there is little drying opportunities.
3. high moisture content in the air raises the dew point making 1 & 2 above worse.

BryanF is right, no amount of surface treatment will solve the problem.

Is there an ensuite off the bedroom with an extractor fan? Is the fan effective, used? Are clothes drying indoors? Is there an extractor fan in the kitchen and is it effective, used?

You must increase the temperature of the walls (better insulation possibly but not drylining, more heating on), reduce the moisture load (see above) and most importantly a constant ventilation system or strategy be employed. What ventilation system is there now and is it used?
Buy a humidity monitor and try to keep the RH below 65%.
Btw, all the above is valid during the heating season.

nialldinho

Thanks guys.
Yeah, there's an en suite with shower but the fan works and it comes on automatically with the light. I will open it up and give it a good clean anyway.
There are vents above the window but i think they were closed during the winter as the room was very cold even with the heating on.
I do air clothes in the apt too but not in this bedroom.
I'll look for a humidity monitor anyway and see how it goes.