Bubbling paint & wall staining problems.....PLEASE HELP!

[davehughes]

Hi

I have an end terrace house which is 3 storey and was built in around 1875. All of the external walls on the inside of the house are really bad for paint bubbling up/paper coming off, mildew (black stains) and sometimes a white powder appearing on them. I believe that as the house has no wall cavities it is likely to be condensation, but it is driving us all mad and making the house smell damp. The problem is really bad on the ground and first floors, the second floor is free of it, as is the bathroom (1st floor).

We always have a window in each affected room cracked open (on the security setting) through the winter to try and air the rooms, we also have a dehumidifier in the kitchen.

Can anyone please help and tell me how to stop this and be able to decorate without it coming back?

Many thanks, David

 

[r896neo]

Whilst the black mould is probably as a result of condensation the white deposits may be damp. What sort of condition is the render in?

Or if it's exposed brickwork how is the pointing?

 

[Nige F]

and your end wall- does it face the prevailing wind

 

[davehughes]

Hi.
Thanks for the reply. The render on the outside is fine, no cracks and paint in good condition. The gable wall faces west and the front south (we have a south westerly prevailing wind most times.

In the bedroom where the damp is around the window cill at the bottom I found that the 6 inches below the cill was filled with expanding foam and when I removed it I found that the foam had been used to replace the inner bricks and was soaking wet, like a sponge and when i removed it I also found that the window wasn't sitting on anything.

I have filled the gap between the top bricks and the bottom of the window frame with sand & cement and will put in the inner bricks tomorrow, then plaster it once dry. Whilst this may explain the damp upstairs I could still use some advice on stopping the condensation problem?

 

[r896neo]

The condensation is caused as you probably know by lack of ventilation and lack of insulation, providing cold walls/ areas for the water vapour to condense on.

Basically speaking you need to increase ventilation or often more importantly in a house with solid walls increase insulation.

In a solid wall house this is usually done by lining the walls with insulation and plasterboard, sometimes dot and dabbed as a single product or sometimes via battening out the wall.

Do a search of the forum as the solid wall insulation topic has been covered thoroughly.

As for the condensation problems there is also a lot of info in search old posts.

But don't be afraid to come back/ repost another topic with any specific queries which aren't well answered by your searches

 

[ajrobb]

Have a look at http://www.heritage-house.org/damp.html

I have no personal experience with these products but have seen good comments from owners:

http://www.nuaire.co.uk/Product/Residential_Products/Positive_Input_Ventilation/

As well as increasing ventilation (as you have by opening windows), you need to keep the walls warm to prevent condensation. Outside air is often close to 100% relative humidity. Just letting it in without warming it is not going to dry anything. Air from the loft space is often warmer than outside and at a lower relative humidity.

 

[davehughes]

Thank you all for some great advice. It seems that the roof on my bay windows may be leaking........oh well, just another problem to add to the pile that increases daily!