I currenty have glossed wood panelling on all the walls in my bathroom....(gross, but I don't want to take it off coz I don't know whats behind it and I want to sell soon!!!).......but want to change the colour, but there are very limited colours available in gloss!!
You can do it but you'd need to sand the old gloss down very well in order to get a key for the new emulsion. However, it's not recommended if there's going to be condensation in that room - bathrooms and kitchens - as the new emulsion will soon flake off ! Good decorating shops as well as the big DIY stores have mixing machines that can make up gloss paint to virtually any colour you want. You don't have to have the "high" gloss finish either - satinwood is really nice.
i think you would have to key the surface by sanding it to take the shine off, then i think it would be ok to emulsion it.....not sure. if im wrong someone will correct me.
Both the previous answers are good advice concerning the sanding to obtain a surface on which paint can adhere. I would add that a good DIY store will recommend one of the many primer coats that are now available for such applications. It will be well worth small additional cost and effort, in my experience...
You can emulsion over gloss, but first you'll have to give it a good rub-down, then apply a coat of acrylic primer/undercoat, then apply your emulsion. Have you thought of painting it with eggshell ? You get all the benefits of a semi-gloss finish which is tough & washable.
You can paint it directly on to gloss, 2 coats should do it. You can get most of the colours in the dulux range. You can get these from Dulux Decorators Centre or B&Q. I forgot to mention that you should wash the panels down with 'sugar soap' prior to sanding, due to contamination from shampoo,soap etc.