Hi cooperman, you can paper over gloss paint but you will need to give the walls a good rub down with glass paper first then wash them down to give the size something to adhere to. If you get patches where the size doesn't dry out then you need to wash those bits off and rub them down again before resizing them. Then they should be fine to paper over. Not the best surface to paper over but it can be done with good preparation. Good luck. Shed.