Humidity Humidity everywhere

movingon

Hi, I have small bedroom, which is furnished but unused. Since we moved in it has always smelled and I have found mould growing on the bed and chairs. Recently the paintwork on one wall had eroded altogether at the bottom 12 to 18".

The bedoom appears to have possibly been used originally as an outbuilding or perhaps a bathroom. it has its own self contained attic, but built on stone or concrete, ie there is no downstairs below. the carpet has always been dry. The attic is well insulated. The external walls are made of stone and the room has three external walls. At the rear of the 'bad' wall is a steep slope of vegetation. My OH then dug out the land immediately behind the wall and put up an extra concrete retaining wall,against the house wall to stop the land coming right up to the wall.

That did not make any difference so I bought a dehumidifier, and it collects loads of water and the smell and signs of damp are gone.

So to cut a long story short, is there anything else I can do to reduce the humidity as I am worried re running costs. There is a radiator in the room- should this be on or off? If I dont want to run the dehumidifier 24/7 is it better at night or during the day?

Thanks for reading

jimbo_the_jetset

Do you own the property? It sounds like the problem is not going to go away so I'd recommend getting an expert in for a survey (make sure it is a consultant, not a contractor i.e. someone who is not going to make money out of repairs)

See http://www.bwpda.co.uk/ and the link to http://www.property-care.org/find_member.asp. We used this http://www.pdoyle.net guy who we found from the site to get a survey before we purchased our property as the building survey noted high damp meter readings, in the end there was nothing of bother in our house besides a leaky stop tap.

It might cost a few hundred quid for the survey but in the long run it should be worth it in terms of maintenance and piece of mind

alanobrien

The best thing to reduce humidity is ventilation.
Do the windows have vents or better still can you put in air bricks.
They would help reduce the problem.

We used to have horrendous humidity issues with old aluminium windows and had to run a dehumidifier for hours every day. We replaced with windows with vented UPVC and have not needed to use the dehumidifier since.

movingon

The windows are UVPC with vents, but the vents are closed because we were trying to stop the cold air getting in and condensing on the cold walls

alanobrien

movingon wrote: »

The windows are UVPC with vents, but the vents are closed because we were trying to stop the cold air getting in and condensing on the cold walls

Then you do have a problem. Air bricks will of course let cold air in. Its about balance. One other option would be to line the walls with something warm to stop cold air condensing. I recall some years back using rolls of polystyrene under wallpaper for this purpose, not sure if its still available though.

TimBuckTeeth

movingon wrote: »

The windows are UVPC with vents, but the vents are closed because we were trying to stop the cold air getting in and condensing on the cold walls

I would open the vents to improve the ventilation. Cold air doesn't carry much moisture, it is the warm air from inside your house that carries the moisture and condenses on the cold walls. Try to open the window and one in another room to get a through airflow for at least a few minutes every day to allow humid air out and fresh less humid air in.

movingon wrote: »

So to cut a long story short, is there anything else I can do to reduce the humidity as I am worried re running costs. There is a radiator in the room- should this be on or off? If I dont want to run the dehumidifier 24/7 is it better at night or during the day?

It would be best for the radiator to be on as it will raise the temperature of the walls slightly and combined with ventilation (or dehumidifier) will help dry the room out.
Dehumidifiers do not work well below about 10C room temperature.
It depends on a few factors whether it is best to run a dehumidifier at day or night. If there is someone sleeping in there then that will produce extra moisture in the air, so in theory could be a good time to run it, but in practice the noise would be a problem, and if the air becomes too dry can cause a dry throat.

dan1979

^ What he said: you definitely want the outside air coming in.

My kitchen is usually about 60% humidity at this time of year, if I open the windows it drops to about 48% within ten minutes.

willowthecat

Hi

I need a dehumdifier for a small room, so a mini one would be sufficient. I've seen them for about £50 in Argos but I was wondering if anyone could point me in the right direction if they know where I could get one cheaper.

darich

movingon wrote: »

My OH then dug out the land immediately behind the wall and put up an extra concrete retaining wall,against the house wall to stop the land coming right up to the wall.

That did not make any difference so I bought a dehumidifier, and it collects loads of water and the smell and signs of damp are gone.

Did your other half put a waterproof membrane between the concrete and the existing wall?
was the concrete simply poured against the wall and allowed to go off?
is there a waterproof membrane between the new concrete and the soil leaning against it?

The wall was probably not designed to be a retaining wall so the load of the outside material plus the concrete would be a concern to me.
Also, if there is no waterproof membrane between the house and the concrete then it could be that it's not condensation but dampness seeping through the old walls. I presume they're old if you think it was originally an outhouse or even an outside bathroom.
If it's made of sandstone then it would be vital for the waterproofing membrane to be in because sandstone is porous and water will leech through in time - especially if there is ground built up against the wall.

MRSTITTLEMOUSE

I had this problem with one of my unused bedrooms,mould under the wallpaper and everything.After drying it out initially with a dehumidifyer for a couple of months,I now open the window daily.You just need it open slightly and I use two trays of those water absorbing crystals which I change once a month.It's fine now but the ventilation is realy important and I think is probably more important than anything.

catford

alanobrien wrote: »

Then you do have a problem. Air bricks will of course let cold air in. Its about balance. One other option would be to line the walls with something warm to stop cold air condensing. I recall some years back using rolls of polystyrene under wallpaper for this purpose, not sure if its still available though.

You can still get the polystyrene--I saw it in my local focus diy store just a week ago--I think it was called warmawall or something like that.:D