Yellow wash

[Redders]

Hello, I’m trying to understand & fix some damp patches in my 1906 brick cottage. Whilst stripping it back I’ve found some yellow wash applied around the bottom of some walls. Does anyone know what this is please? Thank you!

 

[Stevers]

We had something like that here under a polysterene veneer so could have been the adhesive for that, but it could also be a form of sealer intended to mask symptoms of damp.

 

[Redders]

Thanks @Stevers - do you think I should try & remove it?

 

[Stevers]

I did remove the polystyrene veneer - or what was left of it. I didn't remove the 'glue' which is still under the wallpaper that I put up twenty years ago. Given that it's gone yellow I wonder if it's organic perhaps a glue size which should to some extent respond to warm water.

The 'damp sealant' that my father used on his chimney breast stain over fifty years ago wasn't yellow - other ideas appreciated!