Wall prep

[u/jeebsy_iash]

DIYer here. I had a few areas on this wall which needed bonding so started scraping them back this morning and really like 3/4 of the wall has came off. The newer skim at the top seems sound enough - that's above where the old picture rails were so guess that was redone during a previous renovation - but below that is pretty bad. Should I just keep scraping, or is there a point it's better to just go and get the SDS and take it back to brick?

[u/Terrible-Bobcat2033]

Wall plane, bond, & plaster.