Damp/Mould Problem

[Badger1oo]

Hello, and a Happy New Year to everybody. I am looking for some advice please. We live in a small terraced cottage circa 1850. Our Main bedroom (first floor) suffers really badly in winter with damp on the outside wall. The wall is 9" solid wall with brick on the outside. Our dressing table we keep about 4" from the wall, yet behind it, from the skirting to about 30" up the wall goes black with mould. Similarly the wall behind the mirror above the dressing table goes the same way. We do not have excessive heat in the room, because the wood burner in the room below keeps the bedroom warm enough. The bedroom radiator is very rarely on. The bedroom window is left almost permanently open to try to air the room, but this also fails to alleviate the problem. Any suggestion as to how to combat this problem would be much appreciated.

Suffolkman

 

[Newboy]

turn the radiator on in the room and ventilate

 

[Badger1oo]

The temperature in the bedroom over the winter ranges between 17-20 C. Do you think the problem could be helped then by increasing the temperature ?. The room is already ventilated, the window is open 99% of the time. I am thinking the damp must be coming through the external wall. I was wondering about a water seal sprayed on to the external brickwork as a start. Secondly, how about a a foil backed plasterboard over the existing inner wall ?. Anyone else have a view please ?

Suffolkman

 

[theprinceofdarkness]

Increasing the insulation will do the job. The real problem is the fact that your nice warm air in the room does not warm up the wall behind the dressing table. Its a very common problem in bedrooms, behind the headboard, when it up against an outside wall.
With better insulation, the cold wall will not be so cold so will not suffer so badly from condensation. The next problem is that the room will now be losing less heat, so the heating is turned down. This leads to this corner still being the coldest part of the room and so would still be the most likely to suffer from condensation.
The real solution is to make this corner thermally part of the rest of the room, say with a fan. This is clearly not practical. You could try to encourage the air to circulate better, such as removing any modesty panel to allow air to get to the wall, or raise the dressing table of the floor with blocks to allow air to get under it. A very low wattage (and safe) heater, say 10 W might be enough but I can't think of one ( fish tank heater?).
A passive heat conductor might do the trick, such as a strip of aluminium that goes right around the corner and sticks out say, 6" from each end. The theory being, that the ends of the ali, get warm from the room so this heat is then conducted right behind the dressing table causing convection air currents which could be enough to clear the condensation.
I have actually used this method with great success. Imagine a long thin kitchen, across one end there is a 2m wide double glazed window. Because the window would not fill the vertical space above there was a long thin single glazed pane, say 2m long and 6" high. In the winter the single glazed pane would get misted up. I put in a long strip of ali, covering the top of the double glazed window frame but extending about an inch beyond it. Because of its height, you did not notice it because you were normally looking at the edge of it. Worked like charm. But I do not think its right for this problem.
You said that you use a woodburner in the room underneath. I wonder if you either put a large piece of ali under the carpet with a decent turn up on the two edges next to the skirting board, it would pick up a bit of extra heat from underneath and direct it to the wall?
Do let us know how you cure this problem, there are millions of homes suffering the same fate!
Frank

 

[Badger1oo]

Thank you for taking the time to give me your comprehensive views. Sorry for the delay in replying to you. My plan at the moment is to leave it until the spring. Then to line the wall with foil backed plasterboard and skim. It would be good to batten the wall first to leave a small cavity behind, but we really cannot afford to lose a couple of inches on the room.
Your idea of a small fan or heater is good, but not really possible in this application. I had considered putting some vents in the ceiling of the lounge below, then vents in the bedroom floor above. Sounds simple, but a lot of work, and no guarantee of success. Next winter I will let you know how it works out, thanks again.

Suffolkman

 

[AronSearle]

Wasting your time with foil backed plasterboard, it will make almost no thermal difference and it is the thermal value you need to raise.

Use insulated plasterboard where the issue is occuring or the whole wall/ceiling or don't bother.

Ventillate more (instead of opening the window 99% of the time, just remove it).

Move furntiture several inchis away from the wall (which will just have the same effect as using insulated plasterboard).

Or increase heat output in total or locally and help your energy company make more profit for the bosses.

 

[nebjamin]

We had a similar problem behind a bookcase.

We've insulated the wall now, but for a while I used one of these heaters:

https://www.cupboard-heaters.co.uk/

and it did the trick.

 

[Badger1oo]

Thank you Aronsearle, Will check out insulated plasterboard, I wasnt aware there was such a product. We do not really wish to raise the temperature of the room, the temp at present is about where we like it. The dressing table is kept well away from the wall, to try to give some air circulation. Meantime I will check out the small closet heater as suggested by Nebjamin (thank you too ).

 

[tony1851]

Those cupboard/wardrobe heaters do work. It's not just the warmth, but the air movement they encourage as well.

 

[tony1851]

Ventillate more (instead of opening the window 99% of the time, just remove it).

Won't burglars get in if they remove the window?