PVA or oil based barrier?

[imageel]

Am renovating 1930's house, and after stripping wallpaper of bedroom walls have found what appears to be some sort of oil glaze over a distemper base (pic attached). Have tried removing oil glaze but apart from strong caustic soda nothing -even Nitromors won't touch it. Using a scraper and much elbow grease parts of it will come away, but it is all over the walls and ceiling, so would rather seal it and skim over with plaster.
What would you recommend to seal it - PVA/WBA or an oil based primer/paint?
Also -I have some PVA from a local builders merchant but it is quite thick - do you use it neat or watered down?
Cheers
Ed

 

[advancemaintenance1]

remove all the loose and flaking surface water the pva down 10 to 1 and apply everywhere let it dry then apply a 5 to 1 ratio of pva and skim over will be absolutely fine

 

[trowelmonkey1]

you definitely need to remove all the flaky bits, easy with a scraper.

how much suction is there? if there is quite a bit then it needs killing with something, diluted PVA 24hours before plastering will do the trick, a second coat immediately before plastering (while still tacky) to help it adhere to the substrate.

alternatively, you could use WBA, will give a great key so no worries on the adhesion front.

WBA will kill some suction as well, if there is already little suction then applying either PVA or WBA will almost remove it, for this i would suggest using board finish over multi-finish as it prefers low suction backgrounds.

 

[imageel]

Apologies for not replying sooner, BT in their wisdom have stuffed my internet connection.....

Will scrape off the loose stuff and have a go with PVA,
Thanks trowelmonkey1 and advancemaintenance1
Ed