prepare old wall for new plaster/wallpaper

[mthdiy]

Hi all,

As my first bigger DIY project for my new home I want to give the walls of the second bedroom a new finish. The building is a 1930 purpose build flat and you could tell that there are several old layers of wallpaper, paint and whatnot.

After I removed the wallpaper with a steam remover, patches of the underlying layers came partially off in small patches as well. I try now to identify, what exactly these layers are and how I need to replace them to prepare the wall for a new finish.

I have attached two pictures that show two different walls of the same room. It seems that used materials are slightly different.
I believe they are:

View media item 84976- white top layer: paint (thin, smooth, comes off in flakes)
- orange: finishing plaster(?) (thin, smooth, comes off in flakes, but is rather sandy)
- grey: the thick base plaster

View media item 84977- grey top layer: finishing plaster
- orange: base plaster (seems thick and sturdy, covers most of the wall)
- white, uneven patch: I guess that was some repairing work? it covers a smaller bit of the wall at the same layer as the orange bit

My plan is now to remove any paint and finishing plaster, scrub the base plaster smooth, wash it and the use lining paper to mask the slightly uneven wall and prepare it for a paint.

My worries are now if I need to apply a finishing plaster or if it is good enough to put the lining paper directly on the base plaster. Also I do not exactly know how to deal with the white "repairing" areas (picture 2).

Any hints and tips are highly appreciated!

 

[ree]

Any chance of a pic of the whole walls?

Dissimilar base coats or skim are no problem just so long as they are firm.

Its usually best to remove any loose plaster, and then to prep, and then give the prepped patches a local skim.

If the surfaces are also pretty uneven then its best practice to prep, and skim the whole wall(s).

But many people live quite happily with double layers of lining paper below the decorated surfaces.

 

[mthdiy]

Hi Ree,

many thanks for your answer. I made pictures that show more:

View media item 85054
View media item 85055

 

[ree]

Its still difficult to see - the light or focus for the pics is bad.

Do as advised above but for any extensive patching then skim the whole wall(s) instead of bits here and there.

 

[mthdiy]

I tried to take better pictures, but the light in the room is not very good, so here is another take:

View media item 85195View media item 85196
So if I understand you right, you advise to skim the whole wall, but do not see a reason to scrape the paint off.
One of my biggest question marks is to figure out what the faster/better approach is: scraping off the paint (takes a lot of time!) and sanding the wall, then painting/ lining paper. Or skim over it (which I haven't done before)

 

[NickB_99]

One of my biggest question marks is to figure out what the faster/better approach is: scraping off the paint (takes a lot of time!) and sanding the wall, then painting/ lining paper. Or skim over it (which I haven't done before)

No need to scrape off the paint, so long as it sound. All wallpaper remnants must be removed though!
An over skim is the best way to get a decent finish. It would be advisable to use a decent bonding agent before skim.
However - if you've never skimmed before, chances are it won't end well without some practice first!
I hate the stuff, but I'd be inclined to go with the lining paper if you don't want to pay a plasterer to just skim for you and want to do something yourself.
Use a surface filler first to get any holes filled where plaster came off.