Skimming a wall with wallpaper/skim substrate

[jfb]

I need to plaster a wall where the most recent skim wasn’t well bonded.

I've scraped all the skim off the wall now and wondering best way to re plaster it.

The green section you can see in the picture is old wallpaper - very thin and well bonded to the wall (no flaking/weak spots) and would be very tricky to get off.

 

two questions.

1. do we think it should be ok to apply a couple coats 1/3 pva/water and then skim over? Or would I be better off using some blue grit?
2. In taking off the failed skim I have made a couple of small patches that have gone back to the blocks and need filling - what would be the best option for filling them to allow skimming after no more than 24 hours (don’t particularly want to buy a whole bag of bonding for such a small amount)

[Redbeard]

I would not advise skimming over paper, however well-bonded it appears to be. Borrow a steamer and steam it off.

 

24hrs seems a v short time to leave a deeper base-coat before skimming. I'd just say leave it longer. If you can get hold of a small amount of lime putty (which lasts forever when kept under water) you can just mix it as required with plastering sand. There are specialist lime etc. suppliers not so far from Oxford.