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Painting & Decorating Question
Why is my newly plastered wall so patchy?
I have recently had my basement bathroom replastered. The plaster on one of the walls took much longer to dry than the rest and needed a dehumidifier then heater but did eventually dry out. I then primed all of the walls with half water / emulsion and applied two coats of anti-mould emulsion. After a few days however the paint on 2 of the walls has become very patchy in colour, with random areas much lighter than others. It is generally not peeling other than a very small area which has blistered. It looks awful which is such a shame after all the hard work thats gone into it.
Any advice where I should go from here for both problems?
Newly plastered walls can take months to dry. Basements are notorious for damp walls due to being underground, you were right to mist coat before top coating but your wall may haver retained more water in some places more than others. Was a damp membrane put in place before plastering? Zinsser have a product that stops damp from coming through and can be bought at most reputable decorating centres like Brewers or Johnstone/Leyland paint centres.,
Answered 10th Oct 2014
Your issue may also be Efflorescence coming from the new plaster, you can google the symptoms to compare to your own in more detail, an Alkali Resisting Primer might be called for if this is the case.
Answered 8th May 2017