Still Water Runs Deep - Proper roof slope and drainage are important to prevent excessive water accumulation
ponding; membrane; slope
Ponding water sometimes occurs on membrane roof systems as a result of snow, rainfall or runoff from equipment. Although you may be held responsible for ponding on new or recovered roof systems, many elements that determine how well a roof assembly will drain are outside your responsibility or control. Coordination with the building owner, roof system designer or general contractor often is necessary to address potential drainage deficiencies. Ponding water for short durations is unavoidable and considered acceptable by NRCA and membrane roof system manufacturers, but ponding water in excess of 48 hours can be detrimental to the roof assembly.