Metal Roof Joist Spacing

Wider panels allow for greater spacing between rafters.

Metal roof joist spacing.

Correctly measure the spacing of furring strips for a metal roof to further decrease condensation. Steel roof panel systems west conshohocken pa. Rafter spacing is based on the width of the metal roofing panels. If the roof is not completely square you can decrease the space between joists but never increase the space.

Astm e1646 95 2011 standard test method for water penetration of. If there are gutters installed on the eaves the eave flashing should be installed to overhang the lip of the gutter by about 1 2 inch. A metal roof must also allow for some overlap on each side of the panels which will reduce the effective width of the panel. In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.

The tables below give maximum spans for rafters and beams. The substructure to which the metal panels are fastened must be properly spaced and sufficiently thick to provide a roof or wall system able to meet required design loads. In other words you would space a roof joist 15 inches apart from another roof joist but never 17 inches apart. Use 1 1 4 inch nails to cover the outline of the roof with strips of metal eave flashing also called edging.

Place corner pieces where panels will meet bends at the edge of the roofing. Astm e1592 05 2017 standard test method for structural performance of sheet metal roof and siding systems by uniform static air pressure difference west conshohocken pa. If purlins are laying flat on top of the truss 5 or 6 feet is the max on 2x4 s edge up can go to 12 feet or more. The figures are based on quality materials.

The same concept holds true for roof trusses. Typically pole barn style buildings in my area have bays distance between trusses of 5 feet to 12 depending on pitch insulation and height. Truss spacing for metal roof. For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.

Common spacing for trusses on this type of building is often between 2 and 4 feet but trusses built with advanced designs may allow spacing as great as 8 or 12 feet. A roof joist is always spaced no more than 16 inches apart from another roof joist. Twenty four inches is a common spacing of furring strips for a metal roof. It all comes down to engineering.