Preventing Condensation

[shaunaustin]

Hi everyone. I live in an end-terrace house which I estimate was build around 1920. Like most old houses, it's been modenised to have central heating, double glazing, wall insulation etc.

The problem I have is that the house suffers from terrible condensation in the downstairs lounge. The condensation settles on both the exteria walls and the windows. The usual answer to this is 'ventilation - open your windows', but with Winter coming and a very young family this isn't practical. I invested in a 'lofty condenser' on the advice of a damp proofing company (to the tune of nearly £500!!!!) but all this does is blow cold air around my house, and doesn't seem to have helped the condensation at all.

I had various experts out and no-one has managed to give me a workable solution for this. The condensation is causing mold on the walls and although having the heating on should help, I really need a solution to this.

Any advice at all would be gratefully recieved.

Thanks

Shaun

 

[JohnD]

You have a 1920's house which was constructed with open fireplaces, draughty windows, bare ground floor boards - so when it was built it had plenty of ventilation. this has now been blocked up.

When it was built, it had no shower, and people had infrequent baths. I expect you now have lots of hot baths and showers, thus creating a large moisture load.

When it was built, the housewife used to do her washing once a week, with the kitchen door open to let the steam out, and dried it on a line in the back yard.

For all I know you wash every day, and drape wet clothes about the house or use an unvented drier.

So, you have reduced ventilation and increased moisture load. You are bound to get damp and condensation.

Things you can do to reduce moisture load:
Use an extractor fan in the bathroom, and run it all the time the bathroom is occupied, plus 20 minutes after each bath or shower, and al the time you have wet towels in there.

Use an extractor fan or hood in the kitchen whenever you are boiling vegetables, washing up etc

Open the trickle vents on all your windows

Never ever ever leave wet washing draped about the house. If you do this the house will be damp and there is no way it will ever be dry.

Never ever ever put anything on a radiator to dry

If you have a tumble drier, make sure it is vented to the outside.

Have a look at the airvents/airbricks in the outside wall which are intended to take damp air from under the floor and ventialte it away. If these are blocked, choked with dirt and cobwebs, or have been built over, the damp air can only escape into the house. If they are working, there will be enough aircurrent from one side of the house to the other to blow smoke from a cigarette at all times.

 

[disinfo]

I'm sorry to break this to you but the solution really is ventilation.

Do your dobule glazing windows have trickle vents in them? Do you have any other kind of passive air vent installed in the room?

We suffered a similar problem, installing trickle vents sorted it in our case.

 

[str]

ventilation definitely the key here.

Most people thinks its odd to put the heating on in winter to warm up their house with opening the windows - but the warm air needs to escape as it cools - it gets attracted to the colder surfaces, ie the windows and inside face of external walls and continues to cool, reverting back to moisture and hey presto, you have condensation.

The other posts say it all, make sure there is ventilation

 

[JohnD]

In the mornings, when you have been breathing all night and the bedclothes are warm and humid, open the bedroom windows while you air the bed. This will ventilate out the excess moisture that builds up overnight, and you will not be in the room to feel cold. Turn the bedroom radiators down, as you do not need to heat them when you have got up and have the windows open.

During the day, when the sun is shining, open all the small windows. leave the trickle vents open all the time. This will gradually reduce the moisture that has built up in the house.

You do not have to fling the windows open at the very moment you turn the heating on.

BTW I would be very interested to know if you are in the habit of draping wet washing about the house.

More on //www.diynot.com/wiki/building:condensation_in_houses

BTW heating does not reduce condensation. Quite the reverse.

 

[Bilioustrumpstaine]

A bit more info here.

http://www.leicester.gov.uk/your-co...-services-branch/housing-repairs/condensation

 

[shaunaustin]

Thanks everyone for the responses.

John - The answer to you're question 'do we dry clothes on the radiators', is 'Yes'. We don't do it in the room where the condensation occurs for the very reasons you said we shouldn't, however we do it in other rooms. I have a 11 month old baby which means washing and drying clothes on a daily basis. Clothes are usually queued up waiting to go on the radiators to dry. We have a condensing tumble dryer (i.e. no vent, but it does produce alot of heat!) but most clothes can't go in this because of their material, which leaves the radiators as the only choice.

From looking at everyone's comments, it seems there's quite a few things I can do. Opening windows in the bathroom and kitchen when showering / cooking would seem like an easy one. Fitting extractor fans is an option but i'm reluctant to go to this expense because the house is actually up for sale.

Can I clarify one point - Obviously during the winter the central heating will be on. I would normally keep interia doors closed to keep the heat in the room we're in, but would I be better off leaving the doors open to allow the warm air to circulate, and thus reduce condensation?

Thanks

 

[shaunaustin]

I don't have trickle vents on any of my windows. This may be a daft question but can these be fitter easily to existing windows? Are they likely to cause a noticeable draft when they're open?

 

[disinfo]

regarding trickle vents,

They were quite easy to retro-fit on my windows, but it all depends on the construction of your double glazing. Also, it would obviously void any warranty you still have.

With regards to draught, trickle vents are simply a hole in the window frame when open, so if the wind is blowing in the right direction there will be a draught.

A modern passive ventilation system is apparently draught free, someone posted a link on here a while ago i'll try and find it.

**edit** Here you go, //www.diynot.com/forums/viewtopic.php?p=1019922#1019922

Look at woodys link to a passive vent kit, im tempted to get one of these myself.

 

[JohnD]

would I be better off leaving the doors open to allow the warm air to circulate, and thus reduce condensation?

leaving interior doors open alllows damp to spread more easily throughout the house.

to reduce condensation you have to take the damp outside the house.

An unvented tumble drier emits a surprising amount of steam inside the house, as well as costing more than a vented drier.

When you pick up an armful of wet washing, and it weighs a pound more than the dry washing off the radiator, that's three quarters of a pint of water you have added to the air. You might as well throw a bucket at the walls. Sorry, but it's true. If you drape wet washing about the house and on top of radiators, it will be damp, mouldy and suffer condensation. No-one can help you.

An extractor fan costs less than a Lofty.

What can you tell me about washing lines?

 

[shaunaustin]

What can you tell me about washing lines?

We used them in the summer when it's practical to. I've tended to not use them in the Winter because of the weather, although thinking about it, it's no more unpredictable than the summer whether is.

 

[Bilioustrumpstaine]

Thanks everyone for the responses.

John - The answer to you're question 'do we dry clothes on the radiators', is 'Yes'. Clothes are usually queued up waiting to go on the radiators to dry.

You will be putting so much moisture into the air. All the moisture in the clothes is going straight into the atmosphere of your house when the air can carry no more it will offload onto your walls, this will be in the coldest point, usually a corner with two outside walls.

If you are moving and want to keep your spending to a minimum buy a washing line and dry your clothes outside. You could buy a portable dehumidifier which can go with you to your new home. When you are drying clothes on a rad keep the door shut and the window open, use a fan to move the air about.

Nothing more likely to put buyers off than a hint of dampness on the walls.
Hide the dehumdifier when people are viewing

 

[chezzer0361]

I have exactly the same problem and I live in a end terrace built in the 1920's

My advice is paint stain block on all the damp patches on the walls, it smells disgusting but it works, you may have to do it a few times as it will come through in different places, maybe if the room is not too big paint the whole wall.

It is not cheap and smells terrible but after you have done everywhere once you will not have to do it again and you will see a marked improvement in the damp patches.

Also get a large tumble dryer and put all most everything in, forget what the labels say, they are only a guide line, I wash things all the time that say Dry Clean Only, just wash them on a 30 and not much spin. Also get it so the pipe goes outside not a condensing one they are useless.

If you can not, try one of those walk in green house and just put the washing in there to dry outside, it will be sheltered and they keep the heat in suprisingly well.

When you can leave the windows open a tiny bit as much as you can, only has to be a inch or so.

You will see a great inprovement

One other thing, check the pointing on the front of the house, it may need re-doing, my other half is half way thorough the front of my house and you can see already the imporvement.

 

[shaunaustin]

We have a portable dehumidifier which we used to dry out the walls when we had rising damp problems. It makes sense to use it whenever we have clothers on the radiators (better than opening the windows in winter!!).

I've got some mould killer for the walls and hopefully this clears the current mold and if we 'change our ways' we will stop any more (although as I type I can feel the walls are wet!!).

We had the pointing done not too long ago so this shouldn't be part of it. By the amount of water on the surface, it must be condensation. Which is good in the sense that there isn't a rising damp problem (at least on that wall -- there is on others!!!) but bad in the sense that there isn't a practical solution to condensation. Except that is, to revert my house back to how it was 100 years ago!!!!

I think the big problem we have is that because we want to move, we're reluctant to take the steps that could ultmately solve the problem, i.e. extracter fans, trickle vents on windows, vented tumble dryer etc...

Thanks everyone for your advice.

 

[JohnD]

or to look at it another way, you want to sell your house, and it is going to go up for sale with damp running down the walls, which will discourage buyers and put the price down.

You are going to continue living in a damp and mouldy home, the reason being that you don't want to do the things that will cure the problem