Bathroom paint bubbling. How to fix this ?

Decided to paint bathroom following a refurb. I had no idea if it had been previously painted with oil or water based so decided to use a primer. Walls & ceiling were sanded and damp wiped and left to dry. Primed with leyland acrylic primer & undercoat and left to dry for 2 hrs. Ceiling painted with Dulux bathroom soft sheen & walls painted with valspar standard bathroom soft sheen. I’ve scraped back bubbling paint it’s peeling down to the primer & the primer is chalky(I can scrape with my nail and it turns to powder) For the most part the paint seems to be well adhered and it’s just in 3 spots in having the issue I’m just not too sure where to go from here.

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Answer :-

Here are some steps to fix the bubbling and peeling paint in your bathroom:

1. Remove Loose Paint Start by scraping off any loose, bubbled, or peeling paint all the way down to the primer coat using a putty knife or paint scraper. Feather the edges of the remaining paint so there are no sharp lines.
2. Clean the Surface
   Once all the loose paint is removed, thoroughly clean the area with a degreasing cleaner like TSP substitute to remove any dirt, grease, or chalking primer residue. Rinse with clean water and allow to fully dry.
3. Apply an Acrylic Sealant Since the existing primer seems to be deteriorating, apply an acrylic sealant like ZINSSER’S Bulls Eye 1-2-3 or STIX bonding primer over the areas where the primer is exposed. This will seal the porous surface and provide a good base for repainting.
4. Apply Drywall Joint Compound For any areas with dents or divots after scraping, apply a coat of drywall joint compound to smooth out the surface before repainting.
5. Repaint Once the sealant and any joint compound is fully dried (follow product instructions), you can repaint those problem areas with a good quality 100% acrylic latex paint formulated for bathrooms. Apply in thin coats.

The key is removing all loose material first, sealing the chalky primer areas, and using proper bathroom paint. With a sound surface preparation, the new paint should adhere properly.