Minimum Flat Roof Thickness

The typical thickness range for sheathing is 3 8 to 3 4 inch.

Minimum flat roof thickness.

Loads will vary with the. Most projects that i work on are decent size with roofs of 20 000 sq ft. That will suffice on a roof with rafters set 16 inches apart with minimal roof loads. The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures.

8d ring shank nails should be used instead. There are two types of flat roof. The trend over the last 15 years in california has been towards pvc for the multitude of reasons stated in the article above. As opposed to old built up felt roofing with joins new single ply waterproof membranes are now most commonly used.

Minimum thickness most roofs will be sheathed in plywood at least 3 8 inch thick. Minimum and almost all are flat roofs. As the single ply roofing association spra points out this type of flat roofing is strong durable completely sealed and usually lasts at least 25 30 years. Sheathing should be a minimum of 19 32 inch thick.

The building types include multifamily and institutional. Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame. You can read our article about calculating slope for information on the various roof slope notations. The minimum slope for a flat roof is 1 4 per foot or 1 4 12 but some owners or insurance companies require a minimum slope of 1 2 per foot.