Purlin Spacing For Corrugated Roofing Nz

In the valleys due to the angle typically produced at the valley and the use of transition flashing it is essential that the purlins are doubled in the valleys that is two purlins side by side on each side of the angle of the valley.

Purlin spacing for corrugated roofing nz.

Purlin spacing should suit the end laps required for the size of sheet to be used. They are a breather type material consisting of bitumen saturated heavyweight kraft paper or fire retardant solvent free laminated two layers reinforced heavyweight kraft paper coated with a water based water repellent. For curved structures the maximum pulin spacing should be 750mm and a minimum and 14000mm for 5 rib profile. When a combination of sheets provide a run of in excess of 40 metres and up to 60 metres the roof pitch should be increased by 1 degree.

Patterns should be based on a given wind speed ask them for a roof plan giving purlin spacing and serviceability design loads. For the lighter material such as lightweight aluminum the common spacing length is 4 inches of clear gap. For roofing purlin batten spacings should be no more than those shown in table x maximum purlin spacings. For the greca profile 900mm first and last and 1200mm for the intermediates.

It often depends on the wideness thickness and the types of roofing materials the climate it has to withstand and many other factors. Corrugated sheet roofing material is widely available and easy to use. Unrestricted access roof expect regular foot traffic to access the roof for maintenance work and able to walk anywhere on the roof. Suntuf is supported on the structure via purlins these are the bearers that run left to right along the width of the roof the maximum purlin spacing for the corrugated profile is 800mm centres on the first and last purlins and 1 meter centres for the intermediate purlins.

No congregation of foot traffic expected. For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet. Longer lengths require specific design. For walls nogging spacings shoud be no more that 1200mm.

Minimum recommended purlin size is 4 x 2 50mm x 100mm in timber or z140mm x 1 6mm in steel. All purlin joints must be supported by a rafter. Doubling up in the valleys refer to the installation manual for the proper on center spacing and be sure that the purlin is attached to the roofing truss. The minimum roof pitch for corrugate is 8 degrees approx 1 7 and if end lapped 10 degrees approx 1 6.

Minimum purlin size will vary according to span. The overlaps ends and sides depends upon the sloop of the roof see below. Corrugations should run in a straight line between the highest and lowest points and at a right angle to the purlins the intermediate supports. Self supporting roofing underlays designed to span between purlins where the purlin spacing is not more than 1200 mm.

Restricted access roof expect occasional foot traffic educated to walk only on the purlin lines in the profile pans or carefully across two profile ribs.