Roof Deck Slope Ratio

Generally such roofs have a pitch ranging from 1 2 12 to 2 12.

Roof deck slope ratio.

The minimum pitch for. The risk of saturated bedding sand is reduced by adequate slope of the roof structure and correct sand gradation. Often you express roof pitch as the ratio between the rise and the run in the form of x 12. Then we were able to correct the owner s ponding water concerns.

We were able to make new crickets to the existing roof membrane providing positive water flow to the drains. If the deck extends 9 feet out from the house the divided measurement is 1 8. 3 use the divided measurement as the total amount of slope for the deck in inches. A minimum slope of 1 50 1 4 in 12 is strongly recommended.

Tapered slope insulation products can only be used to provide slope if any differences from level in the roof deck are less than the percentage of slope provided by the insulation. Flat roofs which aren t perfectly flat require a small slope to allow for water runoff. Sand requires at least a minimum deck slope of 2 to drain. You can divide roofs into these categories.

A deck that projects 9 feet out. Gradation of the bedding sand for pedestrian applications should conform to astm c 33 7 or csa a23 1 fa 1 8. Match roof material and use appropriate slope match the roofing on the covered porch with the main roof.