Condensation on external single brick wall

[RodgerTheBodger]

For some reason my 1930's built house has an extra bit built on the side which is only single brick thick. This wall is always cold and gets wet, which I'm fairly sure is due to condensation and the last two winters we've started getting mould. It's Northeast facing, the whole house was rendered a few years ago, there's doble glazing on this wall with no windows and a lack of ventilation.
Whilst I've seen tips on this forum for eradicating the damp and mould I wondered if doing something like adding a layer of drylining on to a studded frame attached to the wall would help by stopping the face of the cold wall coming into contact with the heat of the house? May make no difference and be a waste of time and effort? Any ideas?

 

[JohnD]

start by improving the ventilation. You can hire a 110mm core drill that the duct for an extractor fan will fit neatly, Drill from outside to avoid visible spalling. Without extraction, you will not be able to remove the moisture.

You can line the inside. The rigid foam boards like Kingspan and Velotex are about twice as effective for the same thicknes as mineral wool quilt, though more expensive. You need a vapour barrier on the room side to prevent moist air reaching teh cold wall. Look on the Kingspan webpage, there is a product with a plasterboard face that I think does all you need. You will have to treat the ceiling as well.

 

[gissle]

You may also able able to clad the outside if you need to. You can get insulated external render panels, but this is a lot of work to do.

 

[RodgerTheBodger]

Thanks for the advice, I'll start looking into the vapour barrier and foam boards solution then fitting an extractor fan afterwards. Will update on the success or not next year!

 

[JohnD]

do the extractor first, it will suck the steam out so there is less moisture in the room to cause condensation.

 

[RodgerTheBodger]

If I fit the extractor fan first, would that mean that I'd fit the insulated boards around the extractor leaving it sunk in the wall which wouldn't look very neat? Or would I be able to remove the face of the extractor and refit after fitting the insulated boards? Wouldn't the duct be too short or doesn't that matter? Thanks.

 

[JohnD]

I suppose you could leave the extractor duct a bit long. They will slide tightly through the hole in the wall if they are mortared in (not if you use silicone or expanding foam) so you have the choice of the excess sticking outside or in, whichever looks worse.

 

[RodgerTheBodger]

I guess neither would look good. Might see if I can get through the winter with mould killer, anti damp paint and a humidifier then look at your solution after a dry summer?

 

[jal]

Thanks for the advice, I'll start looking into the vapour barrier and foam boards solution then fitting an extractor fan afterwards. Will update on the success or not next year!

have a look at my thread Insulating internal walls - which i am still in the process of, well its all completed just waiting for it to be skimed off..

//www.diynot.com/forums/general-diy/insulating-internal-walls.337674/#axzz2BlcgjtY4

i will uploading more pictures of my progress - so watch the space in my thread above..