Mould and wallpapering

Mutton_Geoff

I agree DG. Always amused by those "my OH has one hour long showers and I put my wet laundry on the radiators. It's too cold to open the windows but I don't understand why my house is damp with mould growing everywhere".

FreeBear

Chloe_G said:

FreeBear said:

Doozergirl said:

If you have the money, a layer of insulted plasterboard on each wall. 

It will make her room warmer and should solve the mould too as you will be increasing the dew point of the wall.  

The moisture is trapped behind the vinyl layer of the wallpaper.   It may not appear if you were to use a breathable matt paint instead of paper as you'd hopefully get air circulating.  No guarantee though, if the wall is cold, it's susceptible to condensation.

A cold wall is a damp wall. It attracts condensation, which just increases the level of damp which in turns, makes the wall even colder. Having dealt with a cold, damp box room, I can thoroughly recommend insulating the walls. This can either be with insulated plasterboard, or multiple layers of Celotex/Kingspan topped of with plasterboard (look up "warm batten method").

The room I did was a nominal 2.4m by 2.4m. Fixing 75mm of insulation to the two external walls has made a huge difference, and one does not notice the loss of floor space. With a 600x600mm Type 21 radiator (2700BTU or 800W) in there, the room is nice and toasty.

Slapping a bit of thermal wallpaper on will reduce the risk of condensation slightly, but it will do little to improve the insulation levels. There is also a very good chance that any thermal wallpaper will trap moisture in the plaster and cause it to turn to mush eventually.

Insulating the walls properly will boost your EPC rating, reduce the heating bills slightly, and should improve the saleability of the house when the time comes to move.

Wouldn't the insulated plasterboard also trap moisture in the wall? Or does it allow the wall to breathe through it??

Yes. But moisture should still be able to evaporate through the outside surface as long as it hasn't had modern plastic paints or a waterproofing agent slapped on. If there is a question mark over allowing the wall to "breath", one can either leave a small air gap vented to the loft space, or use woodwool/cork boards.

stuart45

BRE have looked at how internal insulation can affect the external masonry because the walls don't dry out as well. In certain cases it can cause damage in a freeze/thaw situation.

Mimi_Arc_en_ciel

Sorry for the delay and thank you so much for all the info. 

I have a plasterer coming to look and quote at the end of this week 

I think i am going to buy some mould remover to treat it, then get plasterer to work his magic then paint the walls rather than wallpaper 

Thanks again

M x

baser999

Doozergirl said:

baser999 said:

We had a similar issue with a couple of small sections of the wall in our lounge to the extent that some plaster had actually started to crack and fall away. We had a builder in who broke it out and replastered and suggested it was down to damp permeating the old brickwork, best remedied by masonry painting the outside and treating with Thomson’s water seal. Managed to get a couple days of dry weather last week, got the job done and inside wall definitely seems a lot less damp. Reckon another week and it will take wallpaper 🤞

I hope it works for you, but that is not a professional solution at all. ☹️

May not be, but it seems to have worked here. Damp has certainly started to die away

kriswouldnt

Mimi_Arc_en_ciel said:

Hi, 

I would like to redecorate my daughter's bedroom but I have noticed there is mould behind the wallpaper. Her room is the coldest (2 external walls) 

What's the best way to proceed? I can treat the mould but there won't be any protection for future. 

Thanks in advance 

Really need to resolve the issue before cleaning and re-papering. While it is still a sticking plaster fix, but cheaper than dampproofing, I had something similar and ended up buying a cube dehumidifier for the house. use it in various rooms now and no longer have the problem. Only paid £250 (after asking for a discount online) and best £250 Ive spend on the house! 

badger09

I’m calling spam on kriswouldnt 
who joined to today & is resurrecting old threads apparently to mention his dehumidifier

Though no brand mentioned on this one 

baser999

Doozergirl said:

baser999 said:

We had a similar issue with a couple of small sections of the wall in our lounge to the extent that some plaster had actually started to crack and fall away. We had a builder in who broke it out and replastered and suggested it was down to damp permeating the old brickwork, best remedied by masonry painting the outside and treating with Thomson’s water seal. Managed to get a couple days of dry weather last week, got the job done and inside wall definitely seems a lot less damp. Reckon another week and it will take wallpaper 🤞

I hope it works for you, but that is not a professional solution at all. ☹️

Whether it was the professional solution I don’t know but it’s worked a treat, rain runs off the external walls, the inside walls are no longer damp and the wallpapers okay