Smelly black substance behind wallpaper

[CarolineTheChemist]

Hello everyone!

This is my first post after many months of lurking. We have recently bought our first beautiful old house and starting to investigate and plan the love and care it needs.

Yesterday I found something I've not seen before and would like some help in identifying what and why...

I pulled back some old wallpaper in our hallway to discover that someone has painted some horrible smelly black stuff under the paper. It has visible brush marks in it, seems like it was sticky once and has a tarry smell to it. It's only in one corner of the hall; the other wallpaper in there is polystyrene backed. Not sure if it makes any difference but there's a fairly large crack in that wall too.

Any suggestions of its purpose and how we might remove it?

 

[Craig89]

Hello and welcome.

I have no experience of what it may be however if I was to guess then maybe its some form of old damp proof coating or someones attempt at damp proofing anyway. Removal could be tricky, scraping maybe?

 

[Gothichome]

My thoughts, they had an issue with getting the wall paper to stick to the wall in that one area (for unknown reasons) the fellow had some thing more like a mastic lying about and simply used what was at hand.

 

[TheForge]

Might be some form of bitumen based paint to try to stop damp? Especially given the tar like smell. Although I would have expected that to have dried hard.

The polystyrene backed paper would suggest possible issues with damp or perceived coldness in the room.

 

[Feltwell]

Some sort of anti-damp bodge would be my guess too. Quite possibly not meant to be used inside! People will try all kinds of daft things (*)

Scrape it off as best you can is all you can do.




(*) Many years ago I worked at B&Q's head office. One of my favourite complaints was a customer who rang in to complain that they've painted their lounge floorboards, it's 3 weeks later and the smell is still really bad.

They'd painted the floorboards with creosote!

 

[CarolineTheChemist]

Thanks gang!
My guess is some sort of weird old damp proofing too. I'd never heard of polystyrene backed wallpaper until I found it in the hallway this weekend!
Poor old house....
I really hope I don't find any creosote stained floor boards next weekend! :lol: :lol:

 

[CarolineTheChemist]

@TheForge
It has dried hard so that adds weight to your suggestion.
I've put a couple of photos here if anyone would like to see...
https://imgur.com/gallery/1nM6ZD5?s=sms

 

[Abi Cott]

I've found a polystyrene backed wallpaper with a bitumen coated top layer in most of my top floor rooms.

Your finds could be someone that's heard of the product my guys used and tried to replicate the effect in a more ad hoc way.

Interestingly I've found it on walls that are very unlikely to have ever really been damp or subject to condensation.

 

[88v8]

... how we might remove it?

Hello and welcome.

The funny things one finds in old houses.

You might ask Strippers of Sudbury whether they have any options.
Otherwise, I'd just paper over it again.
https://www.stripperspaintremovers.com/

Question then is, what wallpaper paste to use.
Hmmm.

Ivor

 

[Pennyviz]

Yes probably bitumen, it's all over the place here. On walls, under floor tiles etc.

Penny