Paint peeling off in large sheets - BUT very good plaster underneath

[dadndaughter247]

Hi there,

I removed the coving in our living room, which seemed to peel off paint. Under the white paint is a yellow colour but it doesn’t seem to be paper?

Either way - the plaster underneath is in good condition so we’ve begun the process of removing the rest of the paint which seems to be coming off in large sheets. What’s the best way to prime the plaster for new paint?

And can anyone shed some light on how come the paint is peeling off at all?

Thanks!

 

[Mottie]

Rough the plaster up with sandpaper and give it a mist coat or two before the main coats.

 

[dadndaughter247]

Rough the plaster up with sandpaper and give it a mist coat or two before the main coats.

Great - that’s what I’ve done with fresh plaster, wasn’t sure if it needed anything else. Thanks

 

[diy_fun_uk]

AI advice:

Common Causes of Peeling Paint on Plaster

• Moisture:
  Trapped moisture from poor ventilation (like in kitchens and bathrooms) or leaks can cause paint to bubble and lift from the plaster.
  
  
• • Poor Surface Preparation:
    If the plaster surface is dirty, oily, or not properly primed, the paint won't adhere correctly.
    
  • Inadequate Mist Coat on New Plaster:
    Plaster is very porous, and applying a thick, undiluted coat of paint directly onto new plaster will cause it to dry too quickly, sucking the water out of the paint and leading to peeling. A mist coat (a highly diluted first coat of paint) is crucial to prevent this.
    
  • Uncured Plaster:
    Painting before the plaster is fully dry and cured can trap moisture, which then comes to the surface and causes the paint to lift.
    
  • Chalking or Hard Plaster:
    Plaster that hasn't been "wetted" enough when applied can become too soft and powdery (chalking), which doesn't allow paint to adhere well. Conversely, a very slick, hard plaster surface can also reduce adhesion.
    
  • High Plaster Alkalinity:
    New plaster has a high pH level, and it needs to be primed with a primer resistant to alkaline conditions before painting.
    

How to Fix Peeling Paint

1. • Scrape and Sand: Remove all loose and peeling paint using a scraper and sand the edges smooth to blend the repair.
   • Clean the Area: Dust the area thoroughly to remove any debris.
   • Prime the Surface: Apply a plaster primer to the bare plaster, especially if the area was heavily scraped or worked.
   • Apply an Undercoat: Once the primer is dry, apply a layer of undercoat to the repaired area.
   • Top Coat: Finish with one or two coats of your chosen wall paint, ensuring each coat is dry before applying the next.