Roof Deck Slope Ratio

Determine the minimum slope of the roof based on the roofing material.

Roof deck slope ratio. Gradation of the bedding sand for pedestrian applications should conform to astm c 33 7 or csa a23 1 fa 1 8. The minimum pitch for. The risk of saturated bedding sand is reduced by adequate slope of the roof structure and correct sand gradation. Roof slope created a simple and great fix to a project were crickets were missed and ponding water became an issue for an owner.

Sand requires at least a minimum deck slope of 2 to drain. Flat roofs which aren t perfectly flat require a small slope to allow for water runoff. A deck that projects 9 feet out. Then we were able to correct the owner s ponding water concerns.

If the deck extends 9 feet out from the house the divided measurement is 1 8. 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. Generally such roofs have a pitch ranging from 1 2 12 to 2 12. A minimum slope of 1 50 1 4 in 12 is strongly recommended.

Often you express roof pitch as the ratio between the rise and the run in the form of x 12. Match roof material and use appropriate slope match the roofing on the covered porch with the main roof. A ratio of 1 1 62 is known as the golden ratio and therefore the vast majority of roof pitch in degrees charts you see will be working to this ratio at the very least.