How to fill in these massive gaps??

[a1993h]

So we’re renovating an upstairs bedroom and some of the wall is in dire shape. This corner is especially bad. A big chunk of the plaster came off while removing the the skirting and unsure how to fill it. There are some more loose pieces that are only held in place by the wallpaper (blue line in photo).

We’re painting over the wallpaper and have filled in some other holes with polyfilla. Don’t have the time or resources to tackle the walls properly so just looking for an easy solution that will do the job and provide some integrity so the skirting has somewhere to hang onto!

Would expanding foam and a coat of bonding over the top do the job?

Thanks!!

 

[Wayners]

Cavity walls?
Don't look like it.
You could just use foam to stick skirting but I'd use some limelite restoration plaster first, but not bonding as you shouldn't use gypsum plaster if you don't have a cavity wall.

Then stick skirting on with foam

 

[Justin Passing]

you shouldn't use gypsum plaster if you don't have a cavity wall.

I didn't know that. Ooops!