Decorating over damp but wall to be as breathable as possible

[Steve773]

Hi guys,

(Skip to the end if you want a TLDR)

I moved into a home last month, it was built in 1920s so quite old. A current issue is that the outside rendering has cracks and therefore there's some damp across some areas of the house. I'm looking to get this render looked at and fixed or replaced some time next year when I can afford to pay for the work.

My question is: as I cannot currently fix the root cause, how do decorate the internal walls in a way that doesn't make the damp issue much worse? Currently certain areas are decorated with wallpaper and paint ontop the wallpaper. There's also some type of paint under the wallpaper but I'm not sure what this is I've attached a picture in case anyone can advise?

My plan is to remove the wallpaper and paint to allow the wall to "breathe". We still wish to decorate however I'm wondering what would the best type of paint be? I've seen 'damp proof' paint that apparently allows moisture to escape etc: https://www.amazon.co.uk/dp/B008VQ6RDY/ref=cm_sw_r_cp_apa_glt_fabc_YKS9QTZ1BMVJRNHAMVP7

Would you guys advise something like the above? I've never had experience with this type of paint so don't know if it actually works well or if it can make the issue worse than other paints?

TLDR: what is the best paint to use on damp internal walls caused by external rendering cracks, that will still allow the wall to be "breathable" and minimise making the issue much worse.

Bonus: what have the previous owners used on the picture I have attached? Is this protective damp paint under the wallpaper?

Thanks.

 

[RandomGrinch]

Hi,

I'm just a DIY'er, but have had some damp issues myself.

Personally, I would strip back the wallpaper, the paint, and leave the walls to dry out. Any attempt to decorate now is likely to fail.
Even if you do use a 'breathable' paint, as the walls dry, salt deposits may form from the evaporation and destroy the decoration.

The other problem with old houses, is they don't like being retrofitted with modern materials!

I have a stonewalled 1890's house. It had damp walls; concrete rendered on the exterior and gypsum plastered on the interior.
Both these materials allowed damp to build in the walls and not escape.
Some might advise to remove all the concrete render, all the plaster and go back to lime.
In my case I left the external render, but removed the gypsum. The wall could evaporate water away from the inside and the render protected it from the outside.

I'm not saying this will work for you, but if you have gypsum plaster and concrete render, your damp issues may not be as simple to fix as repairing the cracks and redecorating! Sorry!