Abstract: A triangular carton is made from biodegradable paperboard or cardboard material and is particularly suitable for flowable building materials. It has a rectangular rear panel and a pair of rectangular front panels as well as a triangular top panel and a triangular bottom. The carton can be folded from a one-piece blank provided with suitable flaps and tabs which serve to releasably interlock the various panels in the assembled state of the carton. The triangular carton lends itself to efficient stacking on shelves as well as to creative displays and unique advertising graphics. Its shape also allows the direct utilization of a roller for the application of material therefrom without requiring that the material be poured into an intermediate trough or tray. If an impervious liner is used the carton can be kept clean and disposed of in normal landfill.