Mould growth

[Karen2005]

How do we eradicate mould growth from our bedroom wall?  We have a ground-floor maisonette with a deep porch.  The mould is growing on one section of the wall - the outside of which is the porch.

We have double-glazing, but no vents.  We can't keep the windows open during the day to ventilate as we are at work all day.  We use a dehumidifier during the evenings, but don't want to keep it on during the day and it would be nice not to have to need it!

Will getting an air brick fitted be the answer?  Another suggestion someone gave us was to fit another door to the porch, so the wall no longer is "outside".

Any suggestions welcome! Thanks.

[Lindy Loo]

Hi Karen. I do sympathise with your problem. Had a similar one myself years ago in semi basement flat.

First of all is the mould the result of condensation or rising damp? It's important to find the cause before you can cure it!
It may be that this part of the wall has a defective damp course which when repaired will 'cure' the mould problem.

It the problem is condensation, then airbricks would help, but there are a couple of other things that can be done to help and they are probably cheaper than having a new porch.  Unfortunately both mean redecorating!! 

1) Putting up 'warmer line' will insulate the walls (a thin polystyrene sheeting that is put up like wall paper, and can be papered over)
2) Try using a product called 'Thermilate'. It is a powder added to any paint and once dry, creates a 'thermal' lining over the wall. I have recently been recommended this for use in my bathroom which gets soaked with condensation despite ventilation 24/7, and certainly intend giving it a try. It can even be used on exterior walls!!

The company's website is www.thermilate.com and well worth a look.

Hope you find a solution.

[Didwot]

A good thorough answer Lindy Loo. The only things you did not mention are extractor fans and heating. Extractor fans can be set to operate when the humidity level gets too high so that they are not on all the time.
Condensation occurs when warm moist air meets a cold surface, allowing the water vapour to condense. and is a function of heating and ventilation. The solution is to get the right balance of ventilation and heating.

[Hammer]

Ventilation, heating and the sources of the humidity are definitely the key. Give them both a bit of thought and you will certainly improve things.

Is the bedroom near the bathroom? If so, make sure you always use an extractor fan or leave the window open when in the bath or shower, and keep the bathroom door shut to stop the humidity spreading throughout the house. Same goes for the kitchen when cooking.

Do you have a tumble drier without an outside vent, or do you leave damp clothes to dry in the house? Both of these will considerably add to your problems.

Make sure the bedroom is kept nice and warm. Cold air can hold less water vapour, so deposits in on the walls and windows.

We had a similar problem, and putting a bit of thought into these things made a huge difference. It has been said that if there are two houses, one with condensation problems and one without, if you swapped the occupants of the houses then the problem would move with them!

[Karen2005]

Thanks for your answers.  I've got a feeling it's condensation, rather than rising damp as the window tends to get covered with condensation, especially in winter.  Well, we have to redecorate anyway once we've had a full re-wire done!!! 

Just remembered that when we get the re-wire done we'll get a better extractor fan fitted in the bathroom, so that might help too.

[steevee]

We had a similar problem for many years in a north-facing bedroom. The walls, particulary in the corners at the ceiling, would grow a black mould which was impossible to remove. The only answer was repainting every spring. Then a neighbour recommended a special mould-inhibiting paint, not the usual stuff from the DIY shed, but from a builders' merchant. I can't remember the name but it comes with a small bottle of mould-killing liquid which you wipe over the wall first, and then use the paint. This has been totally successful and there hasn't be a hint of mould for the past five or six years. Another good tip is to use a dehumidifier in the room as well � you'll be surprised at the amount of water it removes from the air! The paint comes as a standard white but you can have a colour mixed in.