Metal Roofing Framing Spacing

Once the purlin spacing is determined then the metal roofing panels are typically attached to every line of purlins.

Metal roofing framing spacing.

The typical spacing standards for residential and commercial buildings are about 1 to 2 foot. For the lighter material such as lightweight aluminum the common spacing length is 4 inches of clear gap. Screw line spacing for metal roofing over metal purlins this will depend upon the type of panel that is used and the thickness of the steel. All purlin joints must be supported by a rafter.

Minimum recommended purlin size is 4 x 2 50mm x 100mm in timber or z140mm x 1 6mm in steel. An engineer will use a load chart in order to determine the spacing between metal purlins. Z purlins are connected to the rafters using cleats. For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet.

Refer to the rain carrying table in this booklet for the maximum allowable panel length per. Purlins provide horizontal support for the sheets and form part of the framework for the building. When placing rafters for a tin roof also frequently referred to as corrugated metal or steel it is common to set the distance between rafters based on the size of the roofing panels. The same concept holds true for roof trusses.

Rafter spacing depends on the roofing panel size. Roof pitch the metal roofing panels shown in this manual require a mini mum slope of 2 per foot to ensure proper drainage. If care is taken metal roofing application can be aided by pre drilling panels allowing screws to go quickly and accurately into the desired spacing. The trim and roofing sheet should be fastened every 12 to 24 inches along the gable edge.