Prep wall for painting

[kpk2000]

Had problems with flaking/cracking paint in small section on one wall in toilet room. Was intending to fill but ended up stripping the whole wall of paint back to plaster. Now unsure about prep for painting due to plaster.

Wall looks like its been tiled upto halfway in past.

Plaster on bottom half, dark pink and smooth.
Middle strip (1/2 foot thick) Yellow plaster smooth - possibly filler.
Top Half - light pink plaster but rough/dusty to the touch.

Was planning to sand rough edges, sugar soap and then 1st mist coat(30% water) followed by second mist coat (10% water). Planning to use matt emulsion.

Any advice would be appreciated especially with dusty top half and possibility of sealing it with PVA/primer or not.

Thanks in advance from novice

 

[NickStone]

Any advice would be appreciated especially with dusty top half and possibility of sealing it with PVA/primer or not.

Thanks in advance from novice

Don't use PVA if you're intending to paint. It will stop the paint soaking into the plaster and lead to flaking.