Winter Damp Solutions?
October 24, 2012 2:26 AM   Subscribe

Damp Mouldy London Flats: Cheap simple solutions? We moved in to a new flat in May and now that the could winter is coming the flat seems to be getting rather damp and there are some mould (mold) issues. What do we do?

Does anyone have experience with any of the following:
- Electrical Dehumidifiers; How do they work? are they very effective?
- buckets of dessicant / moisture absorbing substance?
- turning up / turning on the radiators?

In the mornings the windows are usually covered with condensation (whereas none of the neighbours flats are).

We don't really use the radiators much as the flat is not double glazed so it seems wasteful. So most days lately the ambient temperature inside is around 18C - 19C inside. I know this will result in a higher relative humidity. What temperature to people usually maintain indoors in winter?

Due to the damp / condensation there seems to be a bit of dark mould starting to grow in the corners of the sash windows, would treating those areas with anti-bacterial type stuff kill off the mould?
posted by mary8nne to Home & Garden (18 answers total) 5 users marked this as a favorite
Yes, dehumidifiers work. Mine removes a few litres a day when it is humid, assuming I remember to empty it. An explanation here. The best ones are made by ebac but for £1 you can get a trial to Which? and, as long as you remember to cancel it, you can see their full reviews.

Dessicants are better than nothing for places where you either don't have power, don't want a dehumidifier humming along or don't have the space. IMHO they aren't really a proper solution to damp though. I used some cheap ones for a while and they were crap. If you are going to buy them, buy decent ones.

You can get specialist mould removers rather than the antibacterial/mildew products. You need a proper anti-fungal application. If you own the place, and are therefore inclined to do some painting, I'd highly recommend getting some mould-proof paint in damp rooms. I used to have a mould problem in my bathroom due to poor ventilation and I sugar soaped it so it was clean and then painted on the mould proof paint. No less damp, but no longer mouldy.
posted by MuffinMan at 2:52 AM on October 24, 2012 [1 favorite]

Water is condensing on your windows because they're single-glazed. Glass has virtually zero insulating value, so its interior surface is about the same temp as outside. When moist indoor air hits that cold surface and cools, its RH jumps and the water condenses out onto the glass.

Turning up the heat would make the air feel generally drier, but you'd still get condensation on the windows because they would still be cold. A little mildew on the windows (which can be easily cleaned up with a bleach-based cleaner like the stuff sold for cleaning tile) isn't the end of the world.

Electric dehumidifiers work but are expensive to run. Similar to an air conditioner, they blow air over a cold surface so that moisture condenses there and drips into a reservoir that you have to empty periodically. And, again like an air conditioner, this requires a lot of electricity. Unlike an air conditioner, they also vent their waste heat into the living space so that they end up warming the room slightly.

The desiccant solution works for one-time events and small, contained spaces like a closet or chest, but is not practical as an ongoing solution.

If the dampness is evident everywhere, not just on the windows, I'd look for unusual sources of moisture getting into the building, like a small roof leak or foundation drainage problems. If it's just the windows, I'd simply live with it, or maybe put plastic film over them to simulate double glazing. Any time the indoor temperature is higher than outside, you should not need to worry about dehumidification.
posted by jon1270 at 2:58 AM on October 24, 2012

Having just moved into a place where the previous tenants clearly did not ventilate properly - you want to make sure you don't let the mould spread. If you're renting, any cleanup the landlord has to do after you move out will probably come out of your deposit - in our case, a couple of walls will have to be repainted. Yeah, dehumidifiers cost money (as does the running of them), but it's probably a wise investment. If you're renting, I'd almost expect the landlord to help you out with one, since they have a vested interest in keeping the place mould-free.

One thing you can do is to leave a window cracked open during the night - this will reduce condensation. Also, get a nice absorbent cloth and wipe the windows and window sills in the morning. Obviously don't dry that cloth - or anything else - inside without proper ventilation.

There's some very basic advice about things you can do to reduce the risk of mould everywhere here and here. From the second link:

Always try and keep some background heating on in the house to maintain warmer surfaces and help control condensation

It sucks that it costs more to run dehumidifers and radiators and whatnot to keep after the mould, but as someone who's developed pretty serious mould allergies, I'd say it's most definitely worth preventing it from taking hold.
posted by harujion at 3:18 AM on October 24, 2012

Reduce the humidity with dehumidifiers (run mainly when you aren't home if they're noisy) and by venting bathroom, kitchen, and clothes dryer to the outside. If there are no vents, slide the window open a crack when you're showering, cooking, or doing anything else potentially steamy.
posted by pracowity at 3:27 AM on October 24, 2012

Friends in your situation bought some purpose made cling film type thing (something like this) that you can put over the window frame on the inside and then hairdry into flatness. They said it made a big difference.
posted by emilyw at 3:47 AM on October 24, 2012 [6 favorites]

I lived in a basement apartment for a year and a half. I am very familiar with that.

Dehumidifiers work.
My place was damp enough in the summer that I was emptying it usually twice a day (in the morning and when I got home from work) I only had one for my whole apartment, but I would rotate it around the rooms during the week. At least one day a week I would lock it in my bedroom with the door shut all day while I was at work. Kept my bedroom from getting too icky. I gave the bathroom some dedicated dehumidifier time often.
posted by PuppetMcSockerson at 4:15 AM on October 24, 2012

I live in a damp, mouldy, London flat, and getting a dehumidifier changed my life. We got this one and it pulls litres of water out of the air daily; in addition to the reduction in window condensation and mould, it helps dry our wet laundry much faster. The slight increase in electricity consumption has been totally worth it. (We also had double-glazing installed this year; hopefully that will make difference during the winter too.)
posted by hot soup girl at 4:16 AM on October 24, 2012 [2 favorites]

A dehumidifier made a big difference in my parents' basement, which was always damp and moldy because their house is near a stream. Most models have a removable reservoir, but some also have a hose outlet. Put the dehumidifier somewhere high and have the hose drip down into a sink, and you don't have to worry about emptying it.
posted by 1adam12 at 4:33 AM on October 24, 2012

Mrtarium and I live in a damp London (basement) flat. Mould has plagued our house, to the point of spreading all over clothes and shoes in a wardrobe closest to the outside wall. I nth above suggestions for dealing with this as soon as possible - which we did not do!

Ventilation is important, agreed, but in our situation, for a variety of reasons, we couldn't leave a window open all the time etc. As a temporary stop-gap, we used a cheap dessicant box thing placed in the worst areas (for us, the wardrobe). Turning up the radiators didn't help too much, but seemed to delay the inevitable spread.

I bought a special anti-mould cleaner and tackled the mouldy walls/window areas etc. head on with this, very thoroughly. It does not smell like it's very good for your lungs, but certainly got all the stuff off. However, this only worked for a few months and we were back to mould-ville after a rainy spell.

The thing which has changed our mouldy life for the better is the landlord using specialist anti-mould paint wherever there's need, applied liberally, AND putting in a ventilation point in the wall. Now, we have no mouldy wardrobe. Dehumidifiers sound like a great idea too, but really attacking the problem with the assistance of a landlord or the like should sort it out for good.
posted by thetarium at 5:25 AM on October 24, 2012 [1 favorite]

I lived in the San Francisco Bay Area and in Florida, and what I don't know about interior humidity and damp, isn't worth knowing.

Your radiators will dry your house out like nobody's business. The air was so dry in my flat that I used to put wet towels on the rad just to put humidity IN the air.

Electric dehumidifiers work amazingly well. My parents had one in an apartment they had and the thing would extract gallons of water daily.

The dry dessicant stuff, it's okay for small, dampish areas (under sinks, or under-stair storage) but just can't handle a lot of damp in room sized areas.

Turn the rads on first (since that's the option of least resistance) if that doesn't take care of it, look into a dehumidifyer.

I too would recommend mold-resistant paint. It stinks like crazy but works really well.
posted by Ruthless Bunny at 5:56 AM on October 24, 2012

I live in a ground floor flat (in Leeds) and the landlord had provided a dehumidifier. It works great and we run it nearly daily. (I want to let it run all night because it should be more effective extracting water from cool air than warm air but my girlfriend thinks it needs to rest) It has made a huge difference and when the clothes in the wardrobe were starting to get damp I shut it into the bedroom and left it running while we weren't home. It was pulling out a full storage tank per day and over the course of a week the humidity went down to under 40% after running during the day. The clothes were noticeably less damp as well. We have some of the dessicant that we had tried also, but there was so much water in the air that the dessicant would just dissolve in a couple of days and be useless while the dehumidifier could get emptied and would start immediately working again.
posted by koolkat at 6:24 AM on October 24, 2012

My coworker lives in a basement apartment, so I asked: a dehumidifier, desiccants in closets/under sinks/other small closed areas.
posted by nile_red at 7:17 AM on October 24, 2012

My bathroom gets a lot of condensation and I bought this to suck the excess water off the shower enclosures and get the steam off the windows. It's surprising how much water it sucks away. It'd work on condensation on windows.
posted by essexjan at 10:17 AM on October 24, 2012

Response by poster: To those using a Dehumidifier on a regular basis. How expensive is the electricity costs on that? About how much energy do they use?

More than a Refrigerator?
posted by mary8nne at 2:27 PM on October 24, 2012

We worked it out a couple of years ago and I think the energy consumption was a bit less than a small fridge.
posted by hot soup girl at 3:25 PM on October 24, 2012

(We run it almost 24/7 in the winter.)
posted by hot soup girl at 3:26 PM on October 24, 2012

Ebac claim their dehumidifiers can cost as little as 2p per hour.

Also FWIW - my first dehumidifier was a Delonghi and it broke just after a year. My Ebac comes with a 5 year warranty and is going strong.
posted by MuffinMan at 4:56 AM on October 25, 2012

Response by poster: I bought one of these Argos Value range ones: which seemed not obscenely expensive compared to some of the others.
posted by mary8nne at 5:12 AM on October 26, 2012

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