Our deck is about 20 years old and has been painted a few times during this period. We have it power washed recently and to make it ready for painted or stained. We have heard two opinions, one saying that as the deck has been painted, the old paint has to be totally removed before staining and the other opinion says that we could put stain on the existing paint. We need help to determine whether we should paint on top of the existing paint or should we put stain on the existing paint or should we remove the old paint before applying the stain. Thank you for your help.