How Much The Roof Thickness

A mil is a unit of measure where 1 mil is equal to 0 001 inches.

How much the roof thickness.

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 most common thickness is probably 60 mils. As for insulation thickness it depends on how much you can afford. 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.

Each gauge represents a nominal decimal range. In metal roofing it is common for us to use a gauge 27 0 4mm thickness on roofing panels and a gauge 24 0 6mm on roof gutters. Metal roof panels are measured by gauge and are usually between 22 and 29. The min thickness of the roof slab should be 6 inches and maximum it can go up to 13 14 inches for span up to 7 m long.

Since your attic is insulated i would advise at least 2 of polyiso insulation in the roof for good measure. When it comes to estimating the weight of an existing roof field verification of the in place construction is necessary. 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. Any difference is minimal in actual thickness but may have an effect on how sturdy the metal is.

Recommended roof insulation r value is 38 r but ideal is to have 50 r or more. The problem with metal roofing gauge is that there is a wide range of tolerances. This strengthens the connection of it to the rest of the roofing system. Each number represents a range of inches 0 0179 to 0 0217 for example so two roofs may have the same gauge but slightly different thicknesses.

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. Sheathing should be a minimum of 19 32 inch thick. Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame. Whereas a 60 mil membrane is 0 06 inches thick and so on.

Better to have 3 or more. Manufacturers express the thickness of metal panels as their gauge with 22 gauge being the thickest and 29 gauge the thinnest of traditionally sold metal roof and wall panels.