warming up a north facing outside wall?

[benpost]

where i only own the ground floor...

so cavity wall insulation isn't really an option as upstairs dont seem to have the problem as bad.

a plasterer suggested insulating plasterboard on top of the walls which takes about an inch of room space? but then there are radiators, wall sockets, heating pipes etc to think about?

are there any other options to try and stop this cold wall attracting the water vapour and turning to mould? i have heard of anti mould paint or wallpaper but i'm guessing these aren't a real solution?

[Doctor Drivel]

Cavity wall insulation. Get upstairs to do it and share the cost. Even if you have to foot the lot, it is still the best way.

[The Natural Philosopher]

A very thin layer of insulant - like polystyrene sheet or cork tiles - will generally be enough to lift the surface temperature above the dew point and stop condensation.

But an inch of celotex is a lot better, and yes, it does mean moving EVERYTHING attached to that wall.

[Roger Mills]

Well then just fill the cavity up to your ceiling level - if the people above don't want their bit doing then sobeit.

[Dave Liquorice]

I wouldn't expect a cavity wall, insulated or not, to present a condensation problem on the wall.

Remove the water vapour by ventilation. Where is the water coming from? Do the kitchen(s) and bathroom(s) have extractor fans the vent to the outside? If they do are they used... Beware of cooker hoods that only recirculate the air rather than extract it.

Is this an older property that has had double glazing added? This can often lead to condensation problems as the previous ventilation has been removed.

Correct.

[Doctor Drivel]

They will not partially fill and water can move across the top of the insulation.

[TPMcCann]

I'm a bit late to this thread so forgive me if I repeat other advice. Simple if expensive solutions are (1) De-humidifier and/or (2) Incease the tempurature in the room. The de-humidifier will do the job on its own but will work a bit better with a bit of heat. Increasing the temperature in the room should heat up the cold surfaces on which the humid air is condensing. I don't believe all the insulation in the world will help unless you have some heat in the room first. We had a bungalow once where the kitchen and living room faced south and the bedrooms faced north. All the humid air migrated to the north of the house, which it will tend to do naturally I believe. We tried a de- humidifier in one of the rooms and boy did it collect water. Would have needed one on each room so eventually scrooge (me) agreed to run the radiators on this sided of the house for longer periods. Cured the problem.

While ventilation will help it can make the rooms very cold. It is best to vent at the source of the humid air, usually the kitchen and bathrooms though you may have an indoor pool I suppose, which can give real problems with condensations.

Paul Mc Cann

[no spam here, thanks]

Yup. We have a north facing kitchen wall which used to drip water (kitchens are a humid place!!). The polystyrene insulation roll from B&Q stopped it totally. But it's a crappy, soft, easily dented surface

- it's not a 'finish' but something you need to do something over ... tile? I don't know, might work. It's very fragile until bonded to the wall, then it's just soft, but doesn't tear. I used PVA to fix to wall.

[The Natural Philosopher]

Thats why I reckon cork is a shade better.

Youu can always paper/tile over it.