Rooftop Drainage

Inspect the roof at least twice yearly, in the spring and fall.  Inspect all roofs after severe weather or storms. Make frequent inspections on buildings that are known to accumulate debris on the roof top or house manufacturing facilities that evacuate or exhaust debris on to the roof. Clean roof drains of debris. Remove leaves, twigs, cans, children's balls, etc., which could plug roof drains. Bag and remove all debris from the roof because debris on the roof surface will be quickly swept into drains by heavy rains, and drainage problems and ponding water may occur.

When installing a replacement roof on a facility that is known to pond water, the building owner should consider the use/addition of a tapered insulation system combined with tapered saddles and drainage crickets to achieve thorough drainage. Tapered saddles should be designed between drains, and crickets should be designed on the upslope side of mechanical, skylight, and other curbs to promote drainage of these areas. The tapered insulation will not only improve drainage, but will provide increased thermal efficiency, which will reduce heating and cooling costs.

In some cases the building owner should consider the installation of additional roof drains, scuppers, or gutter edges to eliminate ponding water on the roof top.

In all new construction, owners should request that the building designer provide a roof design which provides proper slope to prevent ponded water and allows for ease of access for cleaning and maintenance of the roof.

Click on the following for a downloadable pdf version of:

Suggested Design Improvements & Requirements
for Existing & New Construction

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