How Much The Roof Thickness

Sheathing should be a minimum of 19 32 inch thick.

How much the roof thickness. The problem with metal roofing gauge is that there is a wide range of tolerances. Better to have 3 or more. The typical thickness range for sheathing is 3 8 to 3 4 inch. 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.

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. So a 45 mil roofing membrane is actually 0 045 inches thick. Each gauge represents a nominal decimal range. When it comes to estimating the weight of an existing roof field verification of the in place construction is necessary.

Any difference is minimal in actual thickness but may have an effect on how sturdy the metal is. 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. Whereas a 60 mil membrane is 0 06 inches thick and so on. A mil is a unit of measure where 1 mil is equal to 0 001 inches.

Recommended roof insulation r value is 38 r but ideal is to have 50 r or more. This strengthens the connection of it to the rest of the roofing system. 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. As for insulation thickness it depends on how much you can afford.

If possible make sure that gutters are installed with hangers. Metal roof panels are measured by gauge and are usually between 22 and 29. 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. Since your attic is insulated i would advise at least 2 of polyiso insulation in the roof for good measure.

Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame. 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.