Help with condensation

[gg]

I hope someone can help, and has time to read my post...which is quite long...!

Info first!

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We live in a 3-bedroomed semi detached circa 900 Victorian house. It has brick walls, DOES have a cavity but too small to insulate so our rooms are often chilly in the morning in winter without heating etc (eg 15/16deg)...Rooms (inc kitchen and bedrooms) are generally large 6 x 7 mtrs and 3m hig ceilings.

House has concrete floors downstairs and fully UPVC double glazed, has recently has new loft insulation has GCH (approx 12 rads) and is generally good state of repair. Next door (attached) however has been empty for some time and thus is not heated (this may be relevant!)

Every winter or on colder periods I experience condesation in the form of:

1) Water dripping down windows in main bedroom and often downstairs rooms in the morning (which all clear mid day) 2) Damp feeling (and often slight mould growth in exposed corners) in back bedroom (this room unused but see below) 3) We have a hygrometer that reads generally around 60-70% normally in most rooms, but often over 80% in the back bedroom at times - its never below 60% anywhere in the house 4) Slight mould growth in the bathroom (directly above the shower) 5) Dampness INISDE the cupboards of the front bedroom (these are directly built onto the outside wall of the front bedroom). We had the same in the back bedroom, but have removed the cupboards here... 6) Condensation in the back downstairs toilet (but only on the tile floor) 7) We have solid wooden 'firedoor' type doors which always start to 'stick' (due to high moisture?) but then shrink back later in the year!

I have read LOTS of posts regarding similar problems from many others, and here are my conclusions to the causes and possible solutions....I might be WAY off line and missing something obivous here, but here goes

Causes?

1) We DONT have any extractor fan in the bathroom (which is situated between the main and back bedrooms) 2) We DONT have any extractor fan in the kitchen, where we do the cooking, etc 3) Wife tends to dry washing near the radiator (front bedroom near window!) rather than put in tumble dryer (which IS vented outside!) 4) UPVC windows DONT have trickle vents and are NOT left in the vent positon (security) and not in the front bedroom for noise reasons 5) The front bedroom cupboards are lined with about 2mm of polystyrene (but this doesnt seem to prevent condensation forming on top of it occasionally)

So, from all of the reading I have done here...this is my plan (in order!)

1) Install decent extractor fan (with timer shutoff, connected to lights) - in the KITCHEN and BATHROOM - Can anyone recommend a decent one? Is it worth paying the extra for a humidistat model?

2) Line the cupboards in the front bedroom with 25mm polystyrene, put carpet on the bottom (just floorboards at the moment) - hopefully this will stop coldness coming in from the wall on which cupboard is built on - as the back of the cupboard is just the wall/polystyrene - Ill probably 'no more nails' the 25mm polystyrene sheets on top of the 2mm (its not near any electrics)

3) The back bedroom seems to have slight mould/most damp in the extreme corners (bottom) where the corners are external walls when the outside temp is cold - as this wall is exposed (and has the window). I am also seeing small damp patches in the bottom corners of the wall inside of the window? - I plan to accompany the exisitng GCH rad with a smaller elelctric fire which I will place near one of the problem corners, facing the other...so hopefully the additional heat from here will help warm the cold air from the outside walls/window

Oddly this back bedroom all year round has a slight 'wet plaster' type smell, but has NO signs of dampness anywhere at the moment. It was replastered (and a new UPVC window) last year..so we thought it was still drying! Roof has been checked, and there are no problems with guttering...maybe its just as its next to the bathroom and never used

- and the install of extractor in bathroom/extra heat in winter will help

We have a 6ft by 9ft 'box' room (has no window and no heating in it) - which is currently just used for junk/storage - we dont have condensation problems in here!. Would I bet better off hanging 'wet washing' in here along with a demudifier (and close the door!) - Some items cant be tumble dried, so is this better than 'drip drying' on a radiator?

Hopefully Ill see a difference with the extractor fans in the kitchen/ bathroom and if I insulate the cupboards better, possibly the bedroom temprature will stay higher in the winter to prevent condensation.

I also plan to leave the heating on ALL OF THE TIME in winter and set the room stat to 17-19 (any guide on whats best?) so the house never gets below this (as often we wake and the rooms are 14-16)...we have a fairly new condensing boiler so hopefully wont cost too much!

Some people have commented on installing noiseless extractor fans in the bedrooms also (that run all day) - Ive never heard of these, and hopefully wont come to that, but if anyone can recommend anything else (especailly if youve had any of my experiences) - I would be very grateful

Also, dry lining walls has been another recommendation to keep the heat in...but unless we are decorating rooms from scratch, I dont think this is an option at the moment either.

Thanks - J

[Graham]

More Edward the Elder than Victorian. Sure its not listed?

-- Graham.

[dennis]

Why is the cavity too small? How small is it?

Lack of ventilation.. main cause of condensation.. most UPVC suffers from a lack of ventilation IME.

Buy a dehumidifier or three. They reduce damp and recover heat so keep you warmer. The alternative of more ventilation will cost more in heating.

[Andrew Gabriel]

I suspect you have correctly identified the causes.

You need to get more ventilation in the house.

Open bedroom windows, except when you're sleeping in there. Open other windows when you're in the house. Dry washing outside, or in the tumble trier, or make a small drying room or cupboard using a dehumidifier...

the built-in cupboards, take the polystyrene off (fire hazard) and line the external walls with 25mm Cellotex or Kingspan. You could plasterboard over this if you want.

You might find that the extractor fans are not necessary if you do just these things.

[gg]

Thanks for replies, please see below

Oops, it was built 1900 not 900...sorry for typo

When we had the roof insulation work done, we also had 2 x quotes from Cavity wall people - both probed the wall with a measuring tool and both said that the cavity was too small to fill...

I dont know the exact cavity size, but from memory (after a brick was removed) it was about an inch - inch/half

Only problem we have then is heating? - If we open windows in winter (when condensation worse) - the house will get very cold and the heating bill going up! - I will try to use the night vent setting on the upstair windows though

Im not a great DIY'er...are these Celotex boards easy to fit? The cupboards arent easy to navigate inside...I could just about stick polystyrene sheets to it (once cut to size!) - can anyone tell me if the Celotex/Kingspans can be cut also?? - Do I have to make a wooden frame to fit them inside, or could I 'no more nails' them??

I take on board the fire hazard comment, so would probably prefer another method like this!

Im surpised at this as nearly everyone Ive spoken to (builders, plumbers etc) and a lot of people on the groups have said no.1 priority should be extractors to aid air movement and to retain warmth (dew point etc)

Seems Im learning more, so thanks for replies so far.

[Chris George]

On 22 Jul, 12:13, " [e-mail]" wrote:

Dear J You appear to have got all the correct data. Most impressive. Item 1 is I suspect you sleeping and producing water from breathing I agree with the post saying to avoid extractor fans unless you are scrupulous about having them on a timer you control. It is cheaper to remebmer to open and shut the bathroom/kitchen windows! I would consider some form of trickle vent capacity so water vapour can get out of the "sealed" (now that you have so well sealed the Victorian house with double glazing) rooms which it can do when the vapour pressure is higher inside than outsite. This can be done in adjacent masonry rather tnan your new windows. It is not critical to do this because the right way forward is to identify the activities that are causing water production and eliminate or reduce them. What are they? Well simply breathing can produce 1.5 odd litres overnight so, contrary to advice of others and on good health grounds for other reasons, I would sleep with the windows slightly (or fully if you want to consider yourself a hardy type!) open and turn the heating down only to come on just early enough to warm the place up as you wake up. Bathrooms Avoid usual issues of drying washing over the bath and hanging out wet towels etc ie eliminate production of water. Bathrooms rarely cause condensation unless in multiple continuous use so simply opening and shutting windows is all that is needed Kitchen This causes a lot of condensation and perhaps an extactor here could be useful. Make sure it is not left on too much - only when needed. I personally would use windows or dehumidifiers. Often the problem here is stupidity - not putting lids on saucepans. SWMBO (of so 35 years) still will not put lids on pans and has them boiling away on full gas in the vain hope of raising the temperature above 100! Cleary, despite having done Physics to A level standard not remembered her pressure Temp laws! (nuff of that) All the advice to date from others on de-humidifiers is excellent and I endorse it all Drying clothes will be a large part of the problem. I suspect were you only to do one thing - buying a dehumindifer that had proper controls would be the best solution to the problem if you are not happy to change life habits. Cupboard I endorse not useing polystyrene Apart from that suggested by others there is also Wedi board (expensive) and better still British Gypsum reveal boarding (if you want to lose less of the cupoard I would put on 25 Kingspan myself Re Item 2 mould growth Is this black coloured? probably Aspergillus niger if so. Typical location for condensation. Suggest solution is to combine removal of water sources first and see if that fixes it general de-humitification failing those anti condensation paint failing that dry lining to make dew point better with yukky polystyrene wall paper (LAST resort!) dry line the whole wall with reveal board and replaster If there is a cornice a detail can be made at the top to appear ok and skirting can be removed and replaced or simply lost

3) is the other major cause of the problem - SWMBO medicine required... best suggest de-humid cupd on basis of cost but dont envy you this attempt at persuasion. Could bang on about the mould growth being not good for lungs so she must not contribute to cause... Good luck Chris

[Peter Parry]

On Sun, 22 Jul 2007 05:17:49 -0700,

Polystyrene wall tiles in a cupboard are not a significant fire hazard, replacing them will achieve little.

Yes - but it isn't addressing the real problem so I wouldn't bother with it.

The priority should be on ventilation not just extraction. Extractor fans only work if there is fresh air coming from somewhere and in a totally double glazed house with possibly blocked chimneys it isn't easy to control where the air comes in. Opening windows isn't really suitable as a long term solution as it increases noise and draughts.

It doesn't take the brains of a dried prune to recognise (as you already have) that the way you are living is putting gallons of water a day into the house. If you don't get rid of that water vapour the problem will always remain - it will just move around a bit.

Extractor fans are better than nothing if carefully planned and installed, but they would need to be running non-stop in your situation. It may be more appropriate to look at a whole house ventilation system with the amount of water you are evaporating.

Have a look at

the short term a couple of dehumidifiers, one upstairs and one down would certainly help a lot.

[John Rumm]

I take it you mean 1900...

Short of not breathing you can't stop the source of that. Using the trickle vent position on the window would help though if it does not make the noise too bad.

Humidistat controlled extractor is well worth having in rooms with a shower - especially if you have a high pressure shower. Having the extraction point in the ceiling directly above the shower is the most effective.

As others said a foil covered PIR foam product like celotex, kingspan etc. This can be cut with a sharp knife and is not much harder to work with than polystyrene. You can also get plasterboard sheets with this stuff pre bonded to the back of them - very good for dry lining walls etc.

A ducted cooker hood will make a big difference here. Also stops the room getting quite so hot in summer, and reduces the amount of grease that ends up covering surfaces.

This is a big no no! in your circumstances.

2mm is not really enough...

I have found the manrose ones to be ok. It is worth having the humidistat in the bathroom. TLC do a standalone humidistat that can be used to control ordinary fans - handy when you want them installed remotely in loft spaces etc for ducted operation (which reduces fan noise as well).

Yup, PIR foam and carpets.

A bigger rad would be cheaper to run. Or perhaps a fan assisted rad since these distribute the heat more widely and quickly than ordinary convector rads.

Here sounds like a good place you build a drying cupboard with a dehumidifier.

A programmable thermostat is the way to go here. You can then set different temperatures for different times of day (you leave the heating set to run full time, and let the stat take care of the actual requirements). That way it only kicks the heating in should a minimum temperature of your choice be reached at any point in the day.

[gg]

Thanks Chris/Pete, more suggestions for me to take in.

I already one de-humidifier that tends to get moved about, and it does extract a fair amount of water, so Im sure that we are producing a lot of water (and there are only 2 of us!)

We laundry usually once a day/every other day and at least a shower each etc so a lot of water is being produced.

Also Chris re "mould growth Is this black coloured?" - the mould isnt REALLY bad, it seems to be smal black specs that start to appear after the wall has had damp patches where the condendation falls' quick wipe with some 'de moulder' and its gone. We get small black spots on the seal around the windows also, but again seems to be where the water droplets fall...

I think I will start with the extractor fans, and then persuade the wife to dry the clothes in the tumble drier (which is vented to outside). We can leave the bathroom and back bedroom windows on night vent (locked) in the daytime this may help

As for the cupboards...I have mixed responses...

Clearly, due to the dripping windows in winter and the condesation in the cupboards which in the top/unused cupboards sometimes is wet to touch, the front bedroom is an annoying problem...I had hoped that insulating the bottom cupboards (which have only a 2mm polystyrene roll type covering) and top cupboards with 25mm poly or kingpsan would help insulate the bedroom and thus help the the condensation

The top cupboards are just bare wall (with a lot of crappy old plaster) - so these get REALLY cold.

As well as insulating the cupboards (trying to stop cold walls and draughts etc) should I look at putting ventlation grills in a couple of the doors on the cupboards to aid circulation? The wife has more clothes than Victoria Beckham and are all taightly jammed packed in the wardrobe which Im sure is also contributing to restricted air flow no doubt

I have a question..couple of our friends have 'new' houses, that are ultra insulated (cavity wall, upvc, loft, no chimney breast etc) - and (although they complain about house being too warm in summer!) have a really warm house in winter and no condensation problems...I have asked and looked but cant see any obvious form of ventilation in these homes (other than extractor fans) and presumably they are more insulated than mine..?

How do the new homes 'get rid' of their vapour?

Many thanks!

[Peter Parry]

Condensation is caused when warm humid air falls in temperature to below where it can hold all its water as vapour. Hot air can hold more water vapour than cold so when it strikes a cold surface it cools, cannot hold as much water, and the water condenses out onto the surface.

Insulating the surface will stop condensation there but won't alter the amount of water already in the air.

Its common when the air in the house is sufficiently moist for exposed corners to be the place you first see condensation.

Not really, the air coming in will simply add more water - not less. It's the house you need to ventilate, not the cupboard. With adequate insulation the cupboard temperature will hopefully rise above the dew point and condensation shouldn't occur.

They also act as in insulator :-)

A lot use trickle ventilators above the windows, these are a cheap but not hugely effective method of achieving air exchange. An active or passive stack whole house ventilation system is preferable. Also a lot won't generate anything like the amount of water vapour you are. They probably use a tumble dryer and the bathrooms will have extraction systems. The cooker probably has a hood extracting outside.

[Stuart Noble]

I think maybe you need to spend more on heating and less on clothes.