Reoccurring mold. Does the wall need treatment?

Hi,

I am desperately trying to get rid of this mould (pics should be attached) but as much as I wipe and spray with treatment. It keeps returning. I vacuum all the windows and open during the day however I can't stop it.

Do I need to do some sort of treatment on the wall externally?

Any advise would be greatly appreciated as my asthmatic son is really struggling :'(

Thanks!

Looks like mould and fungal decay caused by moisture.

Eliminate the moisture, which I suspect is caused by condensation (search the forum for lots of info on that).

Any treatment is a sticking plaster.

What is on the other side of the wall? What is under that carpet?

Thanks for the replies. They are under wardrobes and beds which makes it difficult to treat. I'm going to check the guttering when it rains to see if moisture is coming in through the walls as it is occurring in the corners of the house.

They are external walls. The carpet was only fitted a month ago. There is only unlay under it I think.

Thanks again for the replies

It's condensation mould, and your vacuum might just be recirculating the spores if it's not got a HEPA filter.

Use a spray fungicide on the walls, skirting and carpet edge.

You may also need to deal with the condersation you are producing. Read the standard advice on here or Google.

It is common to have black mould spots around the bedhead, lack of air flow and adults breathing out a pint of water a night. Try more ventilation and try to get it where it is needed (not easy!). The other place is in the lower corners of the room - no moving air. I have to admit, that "bubble" right down at the carpet level looks like some other problem, like rising damp?
Frank

Are your walls solid or cavity? First or ground floor?

Could it possibly be rotting timber? Reason I say that is on the last picture the black mark on the right looks suspiciously like 'feelers' a rot would 'send out'.
Is there anyway it could be getting wet underfloor if it is a first floor?

Thanks for the replies

I am going to try a cold air fan to circulate the air as it is under our beds and wardrobes so even with the windows open, air doesn't easily get there.

I'm unsure about the walls, a neighbour was saying about theirs being solid so ours could be too. It's a detached bungalow that we have so no 1st floor but it is affecting only the back of the house, on the external walls.

Thanks again, I appreciate all the help

the damp is at skirting level. Do you have a concrete floor? Roll back the carpet and look for signs of damp. Especially near to a window or to plumbing pipes, for example close to a radiator or adjacent to a bathroom or kitchen.

Also go out on a rainy day and look for a wet wall due to spilling gutters, leaking downpipe, or puddles against the wall, especially if the ground level has been raised by paving or flowerbeds and is no longer 9" below the dpc.

DCoops said:

I am going to try a cold air fan to circulate the air

Click to expand...

Be careful with that.

A normal fan will move air too fast, cooling the air and actually making the problem worse by causing condensation. If you do want to try this, you would be better off using the fan on its lowest speed, on the other side of the room, and with it facing away from the problem area or vertically.

The fan won't cool the air so much as the enhanced evaporation will cool the surface as water takes in heat to vapourise. With a constant play of air, the surfaces will dry faster - like the droplets on the windows of a moving car after a shower disappear quite fast, but hang around if the car is stationary. Warmer air flowing over an evaporating damp surface will never cause condensation in the way that stationary air will drop out condensation onto cold surfaces. That's why dew forms on still nights, but not on breezy ones.

After the surfaces are dry, they come up to the same temperature as the air.

If the heating is on, the thermostats will detect that the temperature is lower as heat from the air is lost to evaporation and the heating system will work a little harder to maintain the flow temperature.

I'd use neat thick bleach painted (not scrubbed!) onto the mouldy areas with a nylon paintbrush, and left to dry. Don't dilute the bleach, it becomes less effective as a biocide if dilute, and just adds additional water to the problem areas. Used like this, bleach will not damage the paintwork on skirtings, or walls and will not harm polyester carpets like yours.

You need to increase room ventilation to remove the chlorine smell, and the use of fans will be more effective than dehumidifiers, and don't increase the room temperature, which will make the condensation worse, better to keep the bedrooms a degree or two cooler. Make sure bedroom doors are shut to prevent warm moist air from downstairs rooms from going into them.