I'm just repainting my living room and am trying to complete the job around newly fitted UPVC double glazing. As part of the finish, the installers used transparent sealant, through which some of the old paint colour is visible. Paint will not adhere to the area covered by the sealant - I assume it's too smooth and that there's nothing for the paint to key in to.
I don't imagine that this can be roughed up with sandpaper - can anyone advise?