Mould in the loft

[swampydrill]

Going to decorate my daughters room and i see a patch on her artexed ceiling which looks like a water stain.

i looked in the loft directly above and i find that there is a type of mould on the otherside of the plasterboard. Sitting directly above on the joists is the water tank, there doesn't seem to be a leak because i have put a bowl under there for 3 days and yet nothing, if there was small drops before then surely they would have dried up fairly quickly,

is it possible to get mould some other way and what is the best stuff to put on it both in the loft and on the painted ceiling before i repaint it, should i put pva on it?

 

[HERTS P&D]

Wash the ceiling/mould with a solution of water and bleach, say 10% bleach, then once dry apply an oil based paint. Normally white undercoat.

As for the cause, make sure your float valve is correctly set and your overflow pipe is sealed against the tank.

These are for starters.

Andy

 

[roughcaster]

I'd agree with Hearts-D',, use oil based undercoat to seal it all in before you emulsion. "Never use pva as a sealer on walls/ceilings" if you're going to emulsion over it,,,,, problems ahead otherwise!!!

 

[swampydrill]

Thanks guys, thing is where the mould is is right underneath the middle of the main tank so any overflow would be below the perimeter, not sure where it is from, it is obviously under the wood that the tank sits on and i wondered if it was a lack of air circulation, there is no loft insulation in that area, just the plasterboard

 

[JohnD]

the loft needs to be well-ventilated, with airflow from one side to the other.

Common sources of condensation in lofts are holes in the ceiling, especially of bathrooms, where warm moist air can rise up. Often around downlighters, pipes, and ill-fitting hatches.

When the loft tank is full of cold water it will attract condensation if not encased in n insulating jacket

If the house is damp, e.g. from draping wet washing around, or failing to use extractor fans in bathrooms and kitchens, you will always get condensation.

If the loft has been plasterboarded this will interfere with ventilation.