Patchy paint on newly plastered walls

[jamesn6]

We have just applied a watered down undercoat onto walls that were plastered a few weeks ago.

The paint does not seem to have been absorbed in places and I have painted two coats of a colour over a patch to see what happens. You can still see a dark patch underneath.

We filled any holes etc. before painting, sanded the rough bits, wiped the walls down and then applied the watered down coat.

Can anyone offer advice as to how we can get the paint to 'stick' to the patches.

Thanks.

 

[Welstead]

If you wiped down the walls with greasy dish water, you will have left grease on the wall and the paint will never cover!

 

[confidentincompetent]

We have just applied a watered down undercoat onto walls that were plastered a few weeks ago.

The paint does not seem to have been absorbed in places and I have painted two coats of a colour over a patch to see what happens. You can still see a dark patch underneath.

We filled any holes etc. before painting, sanded the rough bits, wiped the walls down and then applied the watered down coat.

Can anyone offer advice as to how we can get the paint to 'stick' to the patches.

Thanks.

Sounds like overtroweled/polished plaster.. If its bad thin some solvent based undercoat with white spirit and apply to polished areas. Dont apply too heavy and feather it out so edges wont show.
good luck ..

 

[jamesn6]

I have managed to cover most of the patches by applying another coat of undiluted paint but there are two patches that are visible in the plaster when I have taken the paint off. I have tried to sand them a bit and skim over the top but there is still a mark showing thru. Must be grease I guess. Will the thinned solvent paint work here do you think? Thanks.

 

[confidentincompetent]

I have managed to cover most of the patches by applying another coat of undiluted paint but there are two patches that are visible in the plaster when I have taken the paint off. I have tried to sand them a bit and skim over the top but there is still a mark showing thru. Must be grease I guess. Will the thinned solvent paint work here do you think? Thanks.

Yes touch prime with thinned undercoat. when dry, touch in with emulsion,then coat over the whole wall.The dark patches, usually because of overtrowling are quite common, this can bring the binders what they call 'fats' (thats what they called it when i was a nipper~~~~sigh) to the surface producing greasy like shiny surface...
good luck ..