Tophat Purlins

Rollforming Services' Tophat Purlins are a versatile, lightweight, economical and an easy-to-use product for roof purlins, wall girts, floor joists, and many other applications such as carports, fencing and racking.

Ideally for spans from 3m to 7m, Tophat Purlins will provide an economical alternative to standard timber beams or steel C purlins.

Tophat Purlins are easy to work with – they are fastened directly to their supports which results in a saving on cleats. The symmetrical section means no braces or nogs are needed to prevent twisting, and the profile is easily lapped for optimal performance.

Tophat Purlins are available in long run lengths up to 14 metres, depending on the available transport and handling facilities.

Check out the technical documents below for span and load capabilities.

Enquire now to order or for further information.


Jamb Flashings

Available in two variations they are used where a door or window is cut into the side of a building to flash off the cladding and Tophat girt. Made from G250 Z275 Galvanised steel.

THF Flashing Plates

Used where Tophats pass through internal or external wall linings and fire-rated wall linings. They provide fixing for the sheets and a neat tidy hole which would otherwise be hard to achieve. Lapped Tophats will also pass through the plate. They are made with AZ150 steel. When required you can colour them with spray paint to match your cladding.

Batten Hanger Brackets

Designed to work in with 100mm and 120mm Tophats, where a shed is to be lined and you require a 150mm ceiling cavity.


Tophat Purlins are manufactured from hot dipped galvanised steel with a coating weight of 275g/m2, in line with other common lightweight steel structural building products. Z450 Galvanised steel is available upon request with up to a 12-week lead time.

This gives good protection in most exposed internal environments, and for external use in moderate marine environments. Where used in a lined interior dwelling, a thermal break should be installed between the Tophat and the cladding to avoid thermal bridging.

Handling and Storage

Tophat Purlins must be kept dry during storage as water present between close stacked sections will cause premature corrosion. If they become wet, they should be separated and stacked openly to allow for ventilation to dry the surface.

Where sections are exposed to salt spray but not rain washing, maintenance is required to remove any build-up of salt deposits on the surface.

Run-off from, or contact with, materials which are incompatible with zinc should be avoided.

Please refer to the NZ Steel Durability Statement for further information.


Cutting is preferably done by shear or hacksaw. When using abrasive disc blades care must be taken to ensure the swarf produced does not affect other materials and the burred edge should be cleaned off at the completion of cutting.

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