Slight damp in poor circulating area

Oh - I thought he was taking the pee! Never heard f it and it sounded like sky hooks r a glass hammer. Sorry Joe!

How does it work? Just adhere to the wall and paint over? Does it require maintenance / replacement?

Goes under the wallpaper.

http://www.wickes.co.uk/Wickes-Polystyrene-Veneer-Lining-Paper-White-10m/p/105968#

There is no wallpaper - any other option?

You know the cause is poor air circulation - why not use a small fan to eliminate this? It does not need to be heated, powerful, noisy or large, or on all of the time.

It just needs to be able to create changes of air in the affected location when the ambient temperature outside is much cooler than inside - for instance when you need to have the heating on, and especially when the heating goes off, but the outside continues to cool, e.g. at night in the winter.

Typically, a USB powered fan would provide sufficient airflow. You can also get "bladeless" fans which will not cost a fortune, e.g.: http://www.amazon.com/Laptop-Buddy-Bladeless-Cooling-72-0607/dp/B005SCYHYU

Thanks for the advice but I'm unsure on the cause now as I thought the notion of poor circulation had been rubbished.

Is a vented grille likely to fix the issue?

The consensus seems to be condensation on a cold wall in the absence of any obvious water infiltration.

If you increase local air circulation, any condensation there will evaporate, drying out the area, inhibiting mould growth, and the temperature of the wall will rise to become the same as the inside air.

If there is no temperature difference then there will be no condensation.

You have a fan for hot summer days don't you? You asked for other suggestions - try it out. If it works, consider getting a little fan for just this purpose, as a big fan is overkill.

Don't forget to clean off the mould first - you don't want to disperse all those spores. Some would recommend a proprietary mould remedy.

(I would use neat thick bleach in that situation, painted (not scrubbed) directly onto the black mould with a synthetic bristle paintbrush, and left to dry. The mouldy area should lose all the colour of the fungus and leave the wall colour clean. It may need another application. Don't rinse with clean water, just wipe with a slightly damp cloth afterwards.)

Thank you.

An issue I have is that I rent the room out and can't rely on the tenant to use the fan. I need something that doesn't rely on them to do anything.

Is my suggestion of adding an air brick or creating an opening going to work? I appreciate its more intrusive than using a fan but it seems more suitable based on use of the room.

Looking again at your photographs, it appears that you have exactly the same sort of construction around the front door that we have. The wall at the right hand side as you go over the threshold is a single brick thickness internal wall, yet being exposed to outside temperatures.

In other words, this causes a cold bridge, which could be overcome by moving the position of the front door forwards to the outer aperture of the entrance.