Structural laps for
require a minimum
10% lap length (i.e. 5% at each end).
End fastenings of top hats or battens should be at least
25mm from the section end irrespective of whether this
occurs at the structure end or at an internal support.
Remember to allow for this additional material over and
above the span length/s when specifying, ordering or
Top hat/batten overlaps (or non-structural laps) are
recommended to be 100 mm in length. In these cases
structural continuity must not be assumed.
When connecting overlapping top hats or roof battens
place foot onto upper section to nest sections prior to
and during fixing. Laps must be fastened through both
webs near both ends of the lap as shown below.
Stramit does not recommend the welding of top hats
or battens.The heat produced in welding will affect the
material properties of the high-tensile cold-formed steel
used by Stramit in all its top hats and battens. In many
instances considerable stress concentrations are likely to
arise, even with good quality welding. In addition, welding
will locally remove the galvanized coating leading to a
potential reduction in durability.
A complimentary manual
Purlins, Girts &
– Detailing & Installation Guide is also available.
As well as our standard range of Technical Manuals,
Installation Leaflets, Case Studies and other promotional
literature Stramit has a series of Guides to aid design.
• Concealed Fixed Decking
• Roof Slope Guide
• Foot Traffic Guide
• Roof System Selection Guide
• Bullnosing, Curving and Crimping
• Acoustic Panels
• Cyclonic Areas
• Spring Curving Guide
Please contact your nearest Stramit location for any of
these guides, or other literature.
In preparing this document reference has been made to:
• Standards Australia Handbook – HB39 (Installation
code for metal roof and wall cladding)
• AISC/Standards Australia Handbook – HB62.1 (Code
of practice for safe erection of building steelwork)
Stramit offers a wide range of building products, including:
• Formwork decking
• Roof and wall sheeting
• Purlins, girts and bridging
• Truss components
• Gutters and downpipes
• Custom flashings
• Insulating products