Rafters may be spaced up to twelve feet, dependent on purlin size, when purlins are turned edgewise. The same column is used for the roof members in the same direction. all right, PROBLEM BRIEF:A light-grade channel is used as a purlin of a truss whose top chord is sloped at 15 degrees from the horizontal.
#RAFTER SPACING FOR METAL ROOF INSTALL#
Run a tape measure from end to end along the rafters of the roof to determine how many purlins will be needed for installation.Snap a chalk line horizontally across the roof two feet down from the top.Set the second purlin horizontally right next to the first and install it the same way. This assembly video shows a DIY approach to assembling the Centra Series metal building.
In general, metal roof purlins come in two varieties: C-purlins and Z-purlins. Roof sheathing (typically OSB oriented strand board, plywood, or steel roofing) is then attached to the top of the purlins. tolerance is critical for both a good roof line and effective bracing. Pole barn construction spaces the trusses 8 feet apart - or even up to 12 feet apart depending on the building design. roofing membrane, metal tiles, slate) Jun 2, 2017. The spacing of rafters can be determined from the design requirements, type of roof sheeting to employed, type and spacing of purlins, availability of materials, etc. Working backwards, with a 1,2 m spacing, you should be using either 50 x 152 mm, 50 x 228 mm, or 76 x 228 mm purlins. C3 Fix side laps and miss 2, hit 1, miss 3, hit 1, miss 2 etc with approved fasteners alone.