Old polystyrene wall insulation -- keep it or not?

[veryfluffy]

I am about to start knocking some walls down to create the kitchen/dining room, and so I began peeling off some of the early 1980s textured wallpaper that I was blessed with by the previous owners. I discovered that on the outside wall, underneath the wallpaper is a very thin layer of polystyrene. Question: should it stay or should it go? It's a Victorian building, outside walls are three bricks deep with no other insulation. This stuff is about 2 mm thick only. It seems to me to be a potential fire hazard, for not much insulating value, and means I'd have to paperline before painting. On the other hand, it might provide some insulation, and I don't know how dastardly it would be to get off.

Anyone dealt with this or have suggestions?

 

[misterhelpful]

The polystyrene veneer you have was commonly used in those days and you are right that it does provide some insulation. It was/is used to combat cold external walls that are often subject to condensation and mould and so it may be wise to keep it. You might find that, as you remove the paper, patches of veneer will come off with it and so removal will be necessary. It can usually be removed easily with a scraper.

If you do remove it then it would be worth re-insulating with something like Wallrock insulating lining paper which has a thermal veneer attached to it. You can then hang your finishing paper/lining paper on top.

There is some fire hazard with all polystyrene veneer products but providing they are hung correctly (solidly), it is minimized.