plasterboard fixings showing in paint

about 2 years ago i renovated a 1950's cottage. it has a cavity wall with a 60mm cavity. I put 38mm insulated slabs on the inside and the same on the ceiling and skimmed them. i also pumped the cavity with the bonded beads. Lately a problem has arisen that i can see where each fixing is (there is a dark patch on the paint) it has shown up in every room and also on the ceiling. Has anyone any advice about what caused this problem and how it can be rectified? thanks.

I'll guess the fixings are metal mushroom fixings.
Depends on the paint you have used. You can get similair spots and marks on angle beads around windows.
Paint all the spots with stains block and then repaint the areas.

Did you use the pegs on the ceiling?

Ya your right i used the metal mushroom fixings on the walls but drywall screws on the ceilings and the spots are now showing up on the ceilings. have you any ideas what the cause is? Surely it can't be the paint cause there is different types of paint used throughout the house?

It is usually a reaction between the metal and paint.
You used maybe different brands of paint but they were all emulsion based.
Emulsion paint is not designed to cover or act in a non reactive manner towards the metal pegs.

If the skim on the boards is really thin, the paint will leech into the skim and react with the pegs.

Grab some white gloss paint and paint one of the spots.
then give it a very light sand and paint it twice with the same paint you used orignally on the ceiling.
See how it looks.

I would be inclined towards using undercoat or primer rather than gloss as the gloss might not adhere to the metal longterm

thanks for the advice guys i'll let ye know how i get on if i ever get round to it!

hi Neilltim im having the same problem as your self with the fixings showing through. can you tell me if the stain block / undercoat worked or did you have to do anything else. ? Cheers..

metal fixings

I haven't done anything about my problem since but my friend has the same problem and his painter put oil based paint on the spots and then the ordinary emultion on the whole wall so I'll wait and see how that works. That seems to be the general advice I've received so far anyway. Best of luck.