What is on my wall?

johnfás

The spare bedroom in our house has been wallpapered ever since we got the house. We decided we'd like a change and paint the room instead so today I hired the wallpaper stripper and set to work. Removed the wallpaper off the first three walls and everything was normal. Then I got to the final wall (which is also an external wall) to find this . What on earth is it and does anybody know can I paint over it, does it need to be treated or what is the story with it? It looks like some sort of treatment but I have no idea - would be a pain in the ass to have to paper again!



The other walls just look like this when stripped down

PirateShampoo

Its the Lime thats in the Concrete, is the wall damp?

johnfás

We've never had a damp problem in the room, the wallpaper on top of it was completely fine and the room next door (which is the continuation of that wall) is also fine - it has always been unpapered.

Equally there is nothing like it on the perpendicular external wall which the window and radiator is on.

We were planning on painting the room a sort of cream - have the paint and all - just a bit worried how it will turn out on that wall. If it will cause an issue we might have to paper that wall or equally would a darker colour end up OK on it?

PirateShampoo

Well from the photo it looks like Lime, they use it in the concrete. Its nothing to worry about.

I would slab over it with kingspan backed boards fixed with mushroom fixings.

civildefence

Are the other walls plasterboard partitions? If so i'd imagine they're not there as long as the substrate wall. It looks to me simply like wear and tear from years of stripping, papering, painting etc. Hard to tell from a photo though

PirateShampoo

Sorry i was assuming the wall in question had been plaster boarded. Its very odd if they just wall papered a external concrete wall.