Attempting to paint over a darker colour of paint

painting

trying to paint a bedroom, that has been papered and previously painted , but the paint won't stick to the wall , its all patchy I let it dry for a few days, tried again but the roller is just removing paint, or its just not taking any paint

Best Answer

The walls need to be prepared first.

Light sand and then TSP cleaner over all the walls. If the old paint is oil based, you then need a coat of primer before you paint.