Stramit® Top Hats and Battens

Specifications

Features

• High tensile steel – for high strength and low weight
• Quality products – with Stramit’s proven record for manufacture and supply
• Limit-state design data – for fully conforming designs
• Fully tested – for technical confidence
• Rolled safety edges on roof and ceiling battens – to enhance user confidence
• Knurled anti-slip surfaces on roof and ceiling battens – for easier fastening

Applications

The range of Stramit® Top Hats is ideal for small to medium sized sheds and similar structures. Stramit® Roof Battens have been developed specifically for domestic applications but may be used in small commercial structures as well, with Stramit® Cyclonic Roof Battens having enhanced performance to endure the repeated loadings that can be experienced in tropical cyclones. Stramit® Ceiling Battensare intended for use with plasterboard sheeting in both domestic and commercial situations.

Materials

Stramit® Top Hats & Battensare manufactured from high-tensile (G550/G500) steel with either AZ150 zinc-aluminium alloy or Z350 galvanised coating in full conformance with AS1397. 

Specification

Maintaining the structural integrity of a building structure is important.  Even an apparently small change in product material or dimensions can lead to a considerable reduction in performance.  One of the best ways to ensure structural adequacy is to prepare and enforce an appropriate specification for structural components. 

A suggested specification is:
“All top hats/roof battens/ceiling battens shall be Stramit sections or approved equivalent supported by submission of section properties and capacity calculations/data in accordance with AS4600,AS3623 and AS1562.  All sections shall be produced from high-tensile G500/G550 steel with a galvanised/zinc-aluminium alloy coating conforming to AS1397.  All sections must be installed in accordance with the manufacturers recommendations with particular reference to the number, size, grade and positioning of fasteners.” 

Adverse Conditions 

Stramit® Top Hats and Battens will give excellent durability in most applications. In exposed conditions, unwashed areas subject to salt-laden air or other corrosive matter may need additional protection. Stramit® Top Hats and Battensare not recommended for use in enclosed areas within 450mm of moist soil.   

Compatibility

Contact between galvanised steel and copper (e.g. pipework) must be avoided as premature corrosion will occur.

Design

General

Stramit recommends that all designs conform to relevant Australian Standards such as AS1170 series (Loading Codes), AS4600 (Cold-formed steel structures) and AS3623 (Domestic metal framing).

Sizes

Information on Sizes for Stramit® Top Hats & Battens, please refer to page 3 of the Stramit® Top Hats & Battens & Capacity TablesProduct Technical Manual.

Section Properties

Information on Section Properties for Stramit® Top Hats & Battens, please refer to page 3 of the Stramit® Top Hats & Battens & Capacity TablesProduct Technical Manual.

Loadings

All loadings used in deriving the design data are assumed to either act uniformly along the top central flange of the sections or, for connections to support members, evenly between each of the lower flanges (feet).  Foot traffic loadings, where used, are based on AS1562. 

Spacings

Member, fastener or roof sheeting capacity influences top hat spacing. It is often economical to reduce top hat spacing at the building edge and ends to account for the higher wind pressures encountered on these parts of the building. Additional runs may be required adjacent to roof penetrations or in areas of additional loading. Roof batten spacings are influenced by support (truss) spacing, sheeting capacity or roof tile spacing.  Ceiling batten spacing is invariably chosen to suit plasterboard manufacturer’s requirements.

Performance

Stramit® Top Hats
Single Spans – comprise of a single section simply supported and attached to a support member at each end.  They may form part of a series of spans in which sections have a short (non-structural) overlap at each support.  

For further information on Single Spans, please refer to Table 1a on page 4  and Table 1b on page 5 of the Stramit® Top Hats & Battens Capacity Tables Product Technical Manual.

Laps/Ends

Lapped Stramit® Top Hat configurations require a minimum 10% lap length (i.e. 5% at each end). Section properties within the lap have been assumed to be twice that of a single section rather than the properties of a double thickness section. 

End fastenings of top hats or battens are recommended to be at least 25 mm from the section end irrespective of whether this occurs at the structure end or at an internal support. The absolute minimum required by AS4600 is 1.5 df (where df is the nominal screw diameter).  Remember to allow for this additional material over and above the span length/s when specifying, ordering or cutting sections. 

Stramit® Top Hats
TH96 and TH64 have one end partially crimped to facilitate lapping. 

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.

Double Spans – are simply supported and attached at each end and in the middle (unlapped) or have a structural (10%) lap at that central support (lapped).  

For further information on Double Spans, please refer to Tables 2a, 2b, 3a and 3b on pages 6 & 7 of the Stramit® Top Hats & Battens Capacity Tables Product Technical Manual.

Triple Spans – are also simply supported and attached at each end and at two equally spaced intermediate supports (unlapped) or have a structural (10%) lap at those intermediate support (lapped).  

For further information on Triple Spans, please refer to Tables 4a, 4b, 5a and 5b on pages 8 & 9 of the Stramit® Top Hats & Battens Capacity TablesProduct Technical Manual.

Roof Battens

Stramit® Roof Battens may be used with either metal sheeting or with concrete/terracotta tiles.The relevant performance can be obtained from the following sections.

For information on Stramit® 0.75 Cyclonic Roof Battens, please refer to page 7 of the Stramit ® Cylonic Areas Roof & Wall Cladding(now includes LHL data) Product Technical Design Supplement.

Tiles

Based on the foot traffic requirements of AS3623 the maximum span for Stramit® 0.48 Roof Batten is 900mm and Stramit® 0.55 Roof Batten is 1200mm.  

This assumes a maximum batten spacing of 300mm and a maximum tile weight of 0.67 kPa.

Metal Roofing

For information relating to batten and sheeting spans, please refer to page 10 of the Stramit® Top Hats & Battens Capacity TablesProduct Technical Manual.

Darwin Deemed-To-Comply

Information on the use of the Stramit® Cyclonic Roof Batten in the Darwin area can be found in the deemed to comply sheets in the Darwin Area Manual.  These sheets can also be obtained from the local Stramit Building Products office.  Each application must conform to the specific details outlined in Design Data Sheets. 

STRAMIT® CEILING BATTEN –
MAXIMUM BATTEN SPANS (mm)
  materiallayersbatten centres (mm)
450600
12mm plasterboard115001400
12mm plasterboard212501100

 

STRAMIT® WA CEILING BATTEN –
MAXIMUM BATTEN SPANS (mm)
  materiallayersbatten centres (mm)
450600
12mm plasterboard115501400
12mm plasterboard212501150

Spans are only suitable for fully internal applications and apply to three or more continuous spans.

Additional Fasteners

Two pairs of screws (or even a single pair positioned obliquely) fixed to a relatively flexible support member, such as a purlin flange, cannot be assumed to share load.  

For example in the diagram below the proportion of total load taken by screws at position A will be substantially less than at position B. In Tables 1a to 5a the capacity increase through using four screws rather than two is just 30%.

Fastener Sizes

For fixing sheeting to Stramit® Top Hats & Roof Battens
- No.12 self-drilling and threading screws*
(see relevant sheeting manual for length and other requirements) in non-cyclonic areas
- No.14 self-drilling and threading screws*
with cyclone washer assemblies for through fixed sheeting in cyclonic areas
* Use Type 17 screws or proprietary batten screws for battens of 0.75mm thickness or less.

 

For fixing Stramit® Top Hats to supporting structure. (At least two fasteners are required at each connection - size to be as determined for design capacity)
- No.12 x 20mm self-drilling and threading screws
- No.14 x 22mm self-drilling and threading screws

 

For fixing Stramit® Roof Battens to truss or rafter. (At least two fasteners are required at each connection)
- No.1 0 x 16mm self-drilling and threading screws for G450 steel of at least 1.9mm thickness or for G550 steel of at least 1.0mm thickness
 - No.12 x 20mm self-drilling and threading screws for G450 steel of at least 1.5mm thickness
- No. 10 x 35mm type 17 screws into softwood
- No. 10 x 25mm type 17 screws into hardwood (F11 or better)

 

For fixing Stramit® Ceiling Battens to truss or rafter. (At least two fasteners are required at each connection)
- No.10 x 16mm self-drilling and threading screws for G450 steel of at least 1.9mm thickness or for G550 steel of at least 1.0mm thickness
- No. 10 x 20mm type 17 screws into softwood in non-cyclonic areas
- No.12 x 25mm type 17 screws into softwood in cyclonic areas
For fixing plasterboard to Stramit® Ceiling Battens
– No.6 x 25 bugle-head self-drilling screws

Installation

Good Practice

Stramit recommends that good trade practice be followed when using these products, such as found in AISC/Australian Standards HB62 part 1 and HB39.

Walking

Stramit® Top Hatsare not designed for walking on. Residual oil may be present on these components from manufacturing. The use of appropriate cradles or cherry pickers is recommended. As a minimum follow these rules: 

 

  • Never walk on purlins without safety mesh in place
  • Always use a safety harness if walking on girts 

Stramit® Roof Battens have a lightly knurled upper surface that assists in maintaining a foothold.  Stramit® Roof Battens are designed to withstand foot traffic load during installation and service.

Stramit® Ceiling Battensare not able to sustain foot traffic loads and must therefore not be walked on. 

Fixing/Connections

Always use the correct size and quantity of fasteners as specified by the design engineer. Pairs of screws at connections must be directly in line (parallel with the supporting member).

 

Laps

Structural laps for Stramit® Top Hats 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 cutting sections.



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.

Welding

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.

 

Procurement

Prices

Prices of Stramit® Top Hats, Stramit® Roof Battens and Stramit® Ceiling Battens can be obtained from your nearest Stramit location or distributor of Stramit products.

Orders

Stramit® Top Hats & Battenscan be ordered directly through distributors or from steel merchants.

Related Products

Purlins. girts and bridging - a comprehensive range of purlin sections and high-performance bridging. 

Roof and wall sheeting - a wide choice of roof & wall sheeting, decking profiles and walling.

Delivery/Unloading

Delivery can normally be made within 48 hours, subject to the delivery location, quantity and material availability, or can be at a pre-arranged date and time.  Please ensure that suitable arrangements have been made for truck unloading, as this is the responsibility of the receiver.  Pack mass may be up to one tonne. Packs must never be placed onto unclad purlins except directly above portal frames.

 

Extra

Further Information

Our standard range of Technical Manuals, Installation Leaflets, Case Studies and other promotional literature Stramit has a series of Guides to aid design. 
These include:  

  • Concealed Fixed Decking
  • Roof Slope Guide
  • Foot Traffic 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.

References

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) 

Other Products

Stramit offers a wide range of building products, including:  

  • Formwork decking
  • Roof and wall sheeting
  • Purlins, girts and bridging
  • Truss components
  • Gutters and downpipes
  • Fascias
  • Custom flashings
  • Insulating products
  • Fasteners

Availability

Availability

Most Stramit locations offer the full range of Stramit® Top Hats & Battensin stock lengths and some offer a cut-to-length service for larger sections. Check with your nearest Stramit office for availability.

 

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