Positive Drainage On A Roof

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.

Positive drainage on a roof.

I am building a new home soon and i do not want water drainage problems of any sort in my yard. Exception 1 of section 1511 1 states existing roofs do not have to meet the requirements of the code if positive drainage is provided. Meaning of positive drainage. 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.

How to pronounce positive drainage. The most established way to ensure constant water evacuation on a low slope roof is via positive drainage. Positive drainage prevents ponding. My existing home is built on a slab and i frequently have standing water around the house after a rainfall.

The minimum slope the code allows is in 12 in. 1515 2 2 1 in new construction the minimum deck slope shall be. 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. 1514 4 all roof systems must be installed to ensure positive drainage.

The rationale for not requiring secondary drainage is that if positive drainage is provided that is adequate to drain the roof. Unless roofs are sloped to drain over roof edges roof drains shall be installed at each low point of the roof.