How Much The Flat Roof Thickness
Low slope or flat roofs are another story.
How much the flat roof thickness. Sheathing should be a minimum of 19 32 inch thick. Well known midcentury real estate developer joseph eichler built many low slope or flat roofed homes in marin and the bay area. A low slope roof is anything under 2 inches of fall per foot. A built up roof for example will typically include the built up membrane itself with or without gravel as well as some kind of insulation and cover board which will vary in thickness from roof to roof.
The typical thickness range for sheathing is 3 8 to 3 4 inch. In general a roof truss manufactured from 2 by 4 lumber will support as much roof load as a 2 by 6 or 2 by 8 rafter. Flat roofs come in many shapes and sizes which include parapet roofs roof decks and green roofs to name just a few of the options available. A classic flat roof is either almost completely level or has a very slight pitch of 3 in 12 inches or less.
For example one company might sell a product as being 24 gauge but in reality the thickness of the metal could vary from 0 018 to 0 0335 based upon exactly how that company looks at things and how big of a tolerance they allow for. Tpo is a type of roofing membrane that can come in a variety of thicknesses. Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame. So why have all the companies i ve asked so far just wanted to put a random and insufficient thickness on.
Ultimately a flat roof should play a part in a total architectural composition and has the ability to enhance the aesthetic and practical outcomes of a home. Most flat roofs are typically not as long lasting or durable as sloped ones because the latter shed snow and rain a lot quicker. Built up roofs or burs also called a tar and gravel roof is a well established and popular style of flat roof that is made up of alternating layers of roofing felt or fiberglass and asphalt that is applied with heat which combine to make a long lasting sturdy roofing system. When it comes to estimating the weight of an existing roof field verification of the in place construction is necessary.
Modern for their time they do present a bit of a challenge when they need to be re roofed. I think it has to be 140mm but the quotes so far have been for 90 70 or 50 mm. Roof sheathing standard roof sheathing which consists of 4 by 8 sheets of plywood or oriented strand board or osb is 1 2 inch thick and attaches directly to the roof rafters or the roof trusses. Whereas a 60 mil membrane is 0 06 inches thick and so on.
The most common thickness is probably 60 mils. A mil is a unit of measure where 1 mil is equal to 0 001 inches.