Positive Drainage On A Roof

Exception 1 of section 1511 1 states existing roofs do not have to meet the requirements of the code if positive drainage is provided.

Positive drainage on a roof.

The drainage condition in which consideration has been made for all loading deflections of the roof deck and additional slope has been provided to ensure drainage of the roof within 48 hours of precipitation. Condition in which consideration has been made during design for all loading deflections of the deck and additional roof slope has been provided to ensure drainage within 48 hours following rainfall during conditions conducive to drying. The most established way to ensure constant water evacuation on a low slope roof is via positive drainage. 1514 4 all roof systems must be installed to ensure positive drainage.

Positive drainage in commercial building design is considered to be sufficient slope to facilitate drainage that removes water from the roof surface within 48 hours after rain during ambient drying. Positive drainage prevents ponding. A material having a low emittance surface of 0 1 or less installed in building assemblies. My existing home is built on a slab and i frequently have standing water around the house after a rainfall.

Positive drainage keeps a house dry. 1515 2 2 1 in new construction the minimum deck slope shall be. Positive drainage the drainage condition in which consideration has been made during design for all loading deflections of the deck and additional roof slope has been provided to ensure drainage of the roof area within 48 hours of rain during conditions conducive to drying. Meaning of positive drainage.

The rationale for not requiring secondary drainage is that if positive drainage is provided that is adequate to drain the roof. I am building a new home soon and i do not want water drainage problems of any sort in my yard.