Why is is red?

[Irisheyes]

Hi, I’m pealing wall paper off now as the plastered couldn’t manage a straight line for me!!

Why is it pink/red/orange under the paper??

Thanks!

 

[Blister]

Did you spray water on the paper ? If so it may be where it has soaked through into the plaster.

 

[Irisheyes]

Did you spray water on the paper ? If so it may be where it has soaked through into the plaster.

Nope:
Just peeling it off directly.

 

[Jake]

Pink skim coat plaster

 

[Irisheyes]

Interesting! Thank you!

 

[paulrbarnard]

British Gypsum Thistle is pink. A pretty popular plaster.

 

[Daniel2]

As above, Pink plaster... It does exist

 

[Jake]

To be fair it could be dried seepage from the bodies in the wall.

 

[Bingy man]

It could also be a previous paint that reacted over the years especially with certain pastes..

 

[isaac3d2]

If the paper is peeling off easily, the red colouration could be mould growing on the wall paper glue (basically starch).

 

[Irisheyes]

How do I know if this is mould under the wallpaper, or damp
Proof paint. Talk about regretting buying this house!!

 

[Jake]

Keep taking the paper off. It looks a bit like that might be a straight line where it goes from black to the pink plaster - some kind of bitumen damp-proofing treatment is my first guess. Chip into the black area a bit - is that a cement render (grey) underneath it?

 

[isaac3d2]

Even if it is mould (and it may well not be), that is not the end of the world. Checking with a moisture meter will tell you if there is a systemic damp issue, which may mean some damp-proofing work needs to be done. If it is not damp now, that does not exclude the possibility of periodic dampness. Most people, these days, are blissfully unaware of the moisture they put in to the air through breathing, cooking, washing etc. In the past houses were quite well ventilated (usually unintentionally so), but these days people want to save energy by insulating and often end up making their homes hermetically sealed. Bad idea!
So, even if the red colour is due to mould from occasional condensation problems, you can sort that out by ensuring adequate ventilation is in place and/or using a dehumidifier system.

 

[Jake]

even if the red colour is due to mould

The pink very clearly isn't mould. It is exactly the same hue as pink plaster. Also, the long gouge and chipped bits are all evenly pink (even at the bottom of them).

The black, dunno. I doubt it but maybe.

 

[nigelbuilds]

It probably Distemper. A blast from the past but not that long ago, the mid fifties it was still in use. To check, wet a finger and rub in a circular motion if it wets to a paste is the lime based paint that probably will come back into fashion very soon.
The black is more than likely to be ‘blackjack’ Synthaproof, does it smell a bit like tar? It was spread everywhere as a damp proofing treatment that never worked very well. You’re going to need a proprietary stabalising solution to seal the walls. Go to good professional paint merchants locally and seek their advice not one of the sheds. How are you intending to finish the walls? Paint/paper?