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.

[Nickfromwales]

You can buy patching plaster etc in the likes of B&Q in much smaller ‘hobby’ sized bags.

 

Get the wallpaper off!!!!! Why do you think this failed  ?

 

Remember if using PVA on any surface you must plaster on to it when it’s still wet. If you let it dry it’ll have the opposite effect.

 

Run a Stanley knife down each corner (a good few times) to stop the plaster breaking away from the side walls too.