I've just finished a renovation of my house. In the new half of the house, we have had problems with the paint on our cornices cracking. The cornices were brand new when installed, this was done months before painting and they seemed in good condition. Our first painter painted them at the same time as the ceiling – the cornice paint is now cracking but the ceiling paint is fine. The numerous cracks are fine and short (perhaps 3~5mm long). The only room upstairs that the paint is not cracking on is in the bathroom which was painted with mould resistant paint.
We had the same corninces installed downstairs and had a different painter paint them – they have had no problems.
Do you have any idea what may have gone wrong? Our painter swears he did everything perfectly.
Do you have any idea how to fix this? They are decrative corninces so sanding back is not really an option.
Needless to say, we've been having fights with our painter over this.
The original cornices are 90 years old and they are fine as well.
Best Answer
The cracking would imply a drying problem. I would think that the cornice was primed improperly. If the primer was of cheap quality or the painter used a paint with a built in primer for drywall. The primer may have not effectively sealed the plaster. Then the drying of the paint would be effected, basically the plaster sucking out the moisture to quickly. this could cause the paint shrink and crack as it dried.
Answer to comment.
You have to fill the cracks. either by sanding them out or filling them. If sanding isn't an option try coating an area with a light coat of mud and after it drys lightly wipe it smooth with a damp cloth. Then repaint starting with a good sealer, kiltz would probably do.
A type of self leveling paint might work without all the mud filling, but It depends on the size of the cracks. I would sample a couple areas to see what works best.
There are paints that claim to have this ability. I would still start with a good primer/sealer before anything.
Cashmere
This is not an endorsement of the paint only an example of what to look for. I have never used it.