Condensation – Is this a go od solution? - Advice Sought

[Robin Smith]

I have a first floor flat, with an entrance hall downstairs on the ground floor. The flat has gas central heating and radiators in all rooms except for the downstairs entrance hall. The downstairs entrance hall smells musty and is cold and I have to regularly clean to door as mould starts to form.

At first I thought the problem might be with the damp proofing, done some 5 years ago. So I called in the damp proofing company to inspect under their guarantee. They confirmed that the damp proofing course was fine, but that the problem was due to condensation produced by washing machine, dishwasher, cooking, clothes drying etc.

The recommended solution is to put in an extractor fan that detects when the level of moisture is high, and then extracts this to outside. So far so good! The damp proofing company has recommended that this extractor fan is put in the upstairs kitchen (which is some considerable distance away from the downstairs entrance hall), the rationale being that this is where most of moisture in the air comes from.

As the work will cost £300, I just wanted to double check here with the experts, that an moisture triggered extractor fan in one room, will sort out the problem for the whole house. I'd appreciate a second opinion.

Has anyone else had experience of such a solution, or can offer any advice.

Thanks in advance for any advice given.

Best Regards,

Robin

[Christian McArdle]

It may or may not. Assuming that penetrating and rising damp is definitely not a problem, then the basic problem is that the downstairs entrance hall has cold, wet air. The extractor fan will hopefully reduce the moisture, but the real difference between that part of the flat and the rest is that there is no heating.

As the wet air tumbles down the stairs, it gets progressively colder. Cold air can't hold moisture, so it condenses out onto the walls.

It is certainly a very good idea to have a kitchen extractor anyway. I would be inclined to see if it helped before determining if another cause is indicated, as you should have one anyway.

Other things you should be checking are that you do not have flueless gas heating and that you don't dry clothes by putting on a radiator, or use a vented tumble dryer with no vent.

Christian.

[Michael McNeil]

please note!) How much will it cost to open the windows now and again?

[Robin Smith]

Hi Christian,

Thank you for your response.

I had a Valiant Gas Boiler installed recently, which I guess is properly vented - it certainly has a vent to the exterior wall.

I do indeed dry clothes in the hall, not by putting them on a radiator, but by using a Victorian clothes dryer. I suppose this cannot help. I also have a washer/dryer (a Bosch Classixx Wash and Dry) with no apparent external vent. Combining this with a dishwasher, and cooking, I guess that (as you say) an external kitchen extractor would be no bad thing, so think I will go ahead and get that fitted, and see whether the downstairs mustiness goes away.

I guess it might not, but I suppose that it may be general consequence of the poor design of what is a converted house rather than a purpose built flat.

Thank you again.

Robin.

[derek]

Sorry, missed the first part of this thread.

If you are drying clothes in the house, all the moisture in the clothes (think of the weight of a wet sweater/pair of jeans, etc) ends up in the atmosphere.

If you have damp problems that's just a No-No.

I'd suggest you vent the kitchen with a (not the smallest) ventilator, and same with the bathroom. And you dry your clothes in there, and keep the door shut.

Search the web for "Airflow".

DG

[Peter Taylor]

Robin Smith wrote

Robin, in what way you think the design of your flat is poor?

If you're hanging out clothes to dry indoors, and your washer-dryer is evaporating all the moisture that it doesn't pump down the drain and then blows the vapour all over the flat, what do you honestly expect? As a building designer I can (at grossly uneconomic cost) insulate every surface so that condensation is less likely to form, but without ventilation the vapour will then just build up and up in the air until it reaches saturation point like a steam bath, and then you'll have *everything* going damp and mouldy. The vapour has to be able to escape out of the building.

Yes, the builder should have ideally put in an extractor fan, and if it's controlled by a humidistat so much the better. But I don't think this will solve it completely. You have to play your part as well by airing the flat as often as possible - it's vital you open a window when you have a shower, or when you're using the tumble drier or drying clothes, so that the vapour can escape and ultimately return to the sea from whence it came :o)

All the best Peter

[Velvet]

Yeah, have to agree somewhat with this. Downstairs has the same sq footage as me, drylined like mine (previously it wasn't) and part dg (I'm fully, apart from front door). They have a huge condensation problem even on the dg windows. I don't. I have a window cracked open almost permanently, and open others as necessary depending on what I'm doing.

I dry clothes inside, though I do put some through the condensing washer/drier (which is why there's no vent for it, it condenses internally then gets pumped out the normal washing machine drain, just for info) when there will be more needing drying space than I have space for.

I have quite a lot of plants, which pushes up the humidity indoors. I also have a fish tank, which can evaporate reasonable quantities of water.

Yet because the place is rarely sealed up tight (the kitchen window is almost always open slightly) I only get condensation on the windows if it's very very cold outside and I've been creating a lot of steam (cooking, normally) - and even then it's not a lot.

The trick is to open the windows you need open when you're creating the damp. Open the windows during cooking (it really doesn't get THAT cold if you have them open just a bit, but makes a big difference to the amount of damp in the air), don't shut the place up totally if there's lots of damp washing, etc.

Velvet

[Niall]

Might be a good idea to ask someone other than the company which installed it. This is not the first instance I've heard of where this sort of work has been done, the problem has persisted but apparently the cause has miraculously changed after the work has been done.

[Scott Mills]

Try opening the windows. Since it is damn cold at the moment the outside air will be pretty dry. Let some of that in and see how you go. I personally have the window in the bathroom open all the time, and kicthen whenever I cook. I don't get too much condensation...

Although I did the other day when I had the windows shut, the heating on and I washed 18sqM of tiled floor. Not really surprising...

Scott

[Brian S Gray]

Is the entrance hall 'airtight'? If so, would a little ventilation their help in addition to an extractor fan in the kitchen?

[Peter Taylor]

Velvet wrote

This is a real problem for people living in ground floor flats. You're out at work all day and you have to keep the place secure. A fan running at trickle speed 24/7 does help a lot.

I looked at Robin's Bosch Classixx on the web. It didn't say anything about condensing, but maybe that's a given.

Yes - it's just common sense when you think about it.

We're not designed to live in a sealed environment. Besides washing and cooking etc, we're all giving off moisture all the time just breathing and sweating. It used to be the case that the Building Regs were part of the Public Health Act, but I can't see how the recent regs requiring sealed buildings can be good for people's health.

Peter

[Harry Ziman]

Try a dehumidifier - they can work wonders in reducing condensation and so on without sucking all that expensively heated air out of the house. They are a lot less than £300.

[Dane Koekoek]

How well do they work in practice? How noisy are they?

Dane

[Harry Ziman]

They work pretty well in my experience. You do need to empty them about once per day. They do make some noise depending on the fan speed. About the same as a PC computer fan at low speed, but bear in mind that they need to situated in a place with free air movement - they can't be tucked away in a distant corner of a closed bedroom and expect them to dry the whole house.

A time-clock can be used so they only work while you are out, although one may need a little more power. Also I only bother running ours in winter when there was a condensation problem, not in summer.

If the humidity is high, I would give it a go if you can.

[Bob Smith]

In my last house, before I had the damp proofing done, I was pulling the 5 litre bottle out once a day.

After all the new plaster had dried, it was probably about once a fortnight.

Mine is not too noisy, and although it is fairly small, the instructions say it will dry the whole house if doors are left open.

Infortunately, mine is buggered. Anyone know how to fix the refrigerator side of a dehumidifier?

Bob.