Do I absolutely have to buy special outdoor paint or can I use normal emulsion? Not sure if it's just a gimmick to charge twice as much. It's just a little brick wall at end of garden.
Outdoor paint it will last longer.http://upload.wikimedia.org/wikipedia/commons/0/07/Banksy_28_October_installment_from_%22Better_Out_Than_In%22_New_York_City_residency.jpg