Topspan®

Standard Colours

For Designer, Metallic and Gloss colours, download the ColorCote® special colours brochure.

Black
Minimum pitch
Rib type
High
Ribs per sheet
11.5
Width
900mm cover
970mm sheet
Suitable for
Residential
Light commercial
Commercial
Manufactured in
Christchurch
Terms & Conditions

Topspan ® Profile Performance


Topspan®is a high rib roofing profile that combines wide coverage with long span capabilities. It has a curved rib top and a bold shape. These attributes allow Topspan® to achieve economy, style and ease of installation. Topspan® is ideal for large commercial and industrial applications and the profile is also readily available in Dimond’s range of natural lighting systems.

Cover (mm)
Sheet Width (mm)
Minimum Pitch
Cover (mm)
900
Sheet Width (mm)
970
Minimum Pitch
3º (approx. 1:20)

All dimensions given are nominal

Sheet Tolerances
Sheet width: ±5mm
Sheet width for aluminium +0, -15. If sheet cover widths are critical, advise Dimond® at time of order.
Sheet length: +10mm, –0mm. For horizontal wall cladding where notified at time of order of intended use, tighter tolerances can be achieved +3mm, –0mm.

Material options
Steel 0.40mm
Steel 0.55mm
Steel 0.75mm
Aluminium 0.7mm
Aluminium 0.9mm
Duraclad 1.7mm (total thickness)
Nominal weight / lineal metre (kg/m) options
Steel 0.40mm
4.12
Steel 0.55mm
5.55
Steel 0.75mm
7.47
Aluminium 0.7mm
2.31
Aluminium 0.9mm
2.96
Duraclad 1.7mm (total thickness)
2.70
Drape curved roof - min. radius (m)
Steel 0.40mm
n/r
Steel 0.55mm
120
Steel 0.75mm
12
Aluminium 0.7mm
n/r
Aluminium 0.9mm
120
Duraclad 1.7mm (total thickness)
30
Purlin spacings for drape curved roof (mm) (1)
Steel 0.40mm
n/r
Steel 0.55mm
2.4
Steel 0.75mm
2.4
Aluminium 0.7mm
n/r
Aluminium 0.9mm
2.4
Duraclad 1.7mm (total thickness)
1.5
Machine crimp curved - roof min. radius (mm)
Steel 0.40mm
n/a
Steel 0.55mm
n/a
Steel 0.75mm
n/a
Aluminium 0.7mm
n/a
Aluminium 0.9mm
n/a
Duraclad 1.7mm (total thickness)
n/a
Unsupported overhang (2)
Steel 0.40mm
250
Steel 0.55mm
450
Steel 0.75mm
600
Aluminium 0.7mm
250
Aluminium 0.9mm
350
Duraclad 1.7mm (total thickness)
250

*Available only on request, subject to minimum order quantities. Check availability with Dimond.

(1) 0.4mm BMT not recommended for internal ceiling applications.

(2) Recommended maximum purlin spacing at minimum radius.

(3) Based on 1.1kN point load support, but not intended for roof access.

n/r – not recommended

n/a – not available

Roll-forming facility at: Hamilton

Manufacturing location for Duraclad: Auckland

Sheet lengths: Steelspan 900 is custom run to order.


Where long sheets are used consideration must be given to:

  • Special transportation licences for sheet lengths over 25m
  • Site access for special lifting equipment
  • Fixing techniques to accommodate thermal expansion.

Topspan ® Limit State Load/Span Capacity

(span in mm, distributed serviceability loads in kPa)

G550 Steel 0.40mm*
Unrestricted Access / Roof
Restricted Access / Roof
Non-Access / Roof or Wall
Unrestricted Access / Roof
End Span
Internal Span
Serviceability
End Span
1200
1300
Internal Span
1800
2000
Serviceability
3.4
2.7
Restricted Access / Roof
End Span
1500
1800
2000
Internal Span
2200
2700
3000
Serviceability
2.6
2.0
1.6
Non-Access / Roof or Wall
End Span
2200
2300
Internal Span
3300
3500
Serviceability
1.5
1.3
G550 Steel 0.55mm
Unrestricted Access / Roof
Restricted Access / Roof
Non-Access / Roof or Wall
Unrestricted Access / Roof
End Span
Internal Span
Serviceability
End Span
2000
Internal Span
3000
Serviceability
2.3
Restricted Access / Roof
End Span
2300
2400
2900
Internal Span
3500
3600
4300
Serviceability
1.8
1.7
1.3
Non-Access / Roof or Wall
End Span
3300
3400
Internal Span
5000
5100
Serviceability
1.0
0.9
G550 Steel 0.75mm*
Unrestricted Access / Roof
Restricted Access / Roof
Non-Access / Roof or Wall
Unrestricted Access / Roof
End Span
Internal Span
Serviceability
End Span
2800
Internal Span
4200
Serviceability
2.3
Restricted Access / Roof
End Span
2900
3400
4000
Internal Span
4400
5200
6000
Serviceability
2.2
1.8
1.5
Non-Access / Roof or Wall
End Span
4100
4300
Internal Span
6200
6600
Serviceability
1.3
1.1
5052, H36* Aluminium 0.70mm
Unrestricted Access / Roof
Restricted Access / Roof
Non-Access / Roof or Wall
Unrestricted Access / Roof
End Span
Internal Span
Serviceability
End Span
1100
Internal Span
1700
Serviceability
2.6
Restricted Access / Roof
End Span
1200
1400
1600
Internal Span
1800
2100
2500
Serviceability
2.4
2.0
1.6
Non-Access / Roof or Wall
End Span
1700
Internal Span
2600
Serviceability
1.4
5052,H36 Aluminium 0.90mm
Unrestricted Access / Roof
Restricted Access / Roof
Non-Access / Roof or Wall
Unrestricted Access / Roof
End Span
Internal Span
Serviceability
End Span
1700
Internal Span
2600
Serviceability
2.2
Restricted Access / Roof
End Span
1800
2100
2500
Internal Span
2700
3200
3800
Serviceability
2.0
1.5
1.2
Non-Access / Roof or Wall
End Span
2600
Internal Span
3900
Serviceability
1.0
Duraclad 1.7mm (note 4)
Unrestricted Access / Roof
Restricted Access / Roof
Non-Access / Roof or Wall
Unrestricted Access / Roof
End Span
Internal Span
Serviceability
Ultimate
End Span
Internal Span
Serviceability
Ultimate
Restricted Access / Roof
End Span
900
1000
Internal Span
1500
Serviceability
-
Ultimate
4.4
Non-Access / Roof or Wall
End Span
1100
1300
Internal Span
1600
1900
Serviceability
-
-
Ultimate
3.6
2.4

*Available only on request, subject to minimum order quantities. Check availability with Dimond.

Notes
  1. In any category, spans above the maximum shown should not be used. Category 1 and 2 maximum spans are based on static point load testing as a guide, and further limited by practical experience of roof performance under dynamic foot traffic loads. Category 3 maximum spans are limited as a guide to achieving satisfactory appearance for wall cladding.
  2. Loads given are based on 4 screw fasteners/sheet/purlin.
  3. Loads given are limited to a maximum of 4.5 kPa. If design requirements exceed this limit, contact Dimond for specific advice.
  4. Duraclad
    – Serviceability Limit State loads are not applicable to the Duraclad material, as it does not experience permanent deformation.
    – System must include Safety Mesh if intended for use as a Restricted-Access roof. Refer Section 2.2.1.8.
  5. N/R = not recommended.
  6. End span capacities given in this table are based on the end span being 2/3 of the internal span.
  7. Design Criteria for Limit State Capacities
    1. Serviceability Limit State
      No deflection or permanent distortion that would cause unacceptable appearance, side lap leakage or water ponding, due to foot traffic point loads, inward or outward wind loads or snow loads.
    2. Ultimate Limit State
      No pull through of fixings or fastener withdrawal resulting in sheet detachment due to wind up-lift (outward) loads.
  8. System Design
    The span capacity of Steelspan 900 and Topspan® are determined from the Steelspan 900 and Topspan® Limit State Load/Span Capacity Chart using the section of the chart appropriate to the grade and type of material, and to the category of serviceability selected from the three categories below. Serviceability loads have been derived by test to the NZMRM testing procedures. To obtain an ultimate limit state load we recommend factoring the serviceability load up by 1.4 in-line with NZMRM guidelines. The capacities given do not apply for cyclonic wind conditions.

    Serviceability Requirements
    While these categories are given for design guidance to meet the serviceability limit state criteria, foot traffic point load damage may still occur if there is careless placement of these point loads.

    Unrestricted-access roof

    Expect regular foot traffic to access the roof for maintenance work and able to walk anywhere on the roof. No congregation of foot traffic expected.
    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.
    Walkways installed where regular traffic is expected, and “Restricted Access” signs placed at access points.
    Non-access roof or wall

    Walls or roofs where no foot traffic access is possible or permitted. If necessary, “No Roof Access” signs used.

  9. Wind Pressure Guide
    As a guide for non-specific design the following S.L.S. design loads in accordance with the MRM Roofing Code of Practice can be used for buildings less than 10m high, otherwise AS/NZS 1170.2 should be used
    Low wind zone = 0.68kPa, Medium wind zone = 0.93kPa, High wind zone = 1.32kPa, Very high wind zone = 1.72kPa and Extra high wind zone = 2.09kPa.

Topspan ® Fastener Design


Topspan® should be screw fixed to either timber or steel purlins. The use of the appropriate length of 14g roofing screw will ensure failure by screw pull out will not occur under loads within the scope of the Limit State Load / Roofing Span Capacity Chart.

Purlin Type
Roofing Rib Screw Length* (mm)
Roofing Rib Designation
Wall Cladding Pan Screw Length* (mm)
Wall Cladding Pan Designation
Timber
Roofing Rib Screw Length* (mm)
100
Roofing Rib Designation
T17 - 14 - 10 x 100
Wall Cladding Pan Screw Length* (mm)
50
Wall Cladding Pan Designation
RoofzipM6 x 50 HG-Z4
Steel
Roofing Rib Screw Length* (mm)
95
Roofing Rib Designation
Tek - 14 - 10 x 95
Wall Cladding Pan Screw Length* (mm)
20
Wall Cladding Pan Designation
Tek - 12 - 14 x 20

*If sarking or insulation is used over the purlins or for wall cladding fixing onto a cavity batten, into the stud, the screw length will need to be increased.

For screw size range and fastener / washer assembly refer Section 2.2.3.1 in Technical Manual.

The Limit State Load / Span Capacity Chart is based on 4 screw fasteners/sheet/purlin without the use of load spreading washers (except for 0.4mm steel, 0.7mm aluminium and Duraclad material, which must be fitted with profiled metal washers and 36mm EPDM seals).

Profiled metal washers are recommended for use:

  1. On end spans, or large internal spans where the Ultimate Limit State distributed load is limiting. Contact Dimond for specific advice in these design cases.
  2. When required to enable the fixing system to accommodate the thermal movement of long sheets – see Section 2.1.3.4 Thermal Movement in Technical Manual.
  3. Wherever the designer wishes to ensure the risk of fastener over-tightening will not cause dishing of the crest of the profile rib.

Use in serviceability categories (1) or (2) can allow the reduction of fasteners to 2 screw fasteners/sheet/purlin by using 2 fasteners/sheet/purlin. If this is done, the distributed load capacities given in the chart should be reduced using a multiplying factor of 0.5.

Long spans may require the specification and use of side lap stitching screws – see Section 2.3.2C Installation Information: Layout and Fastening Technical Manual.


Design Example

Restricted access roof, 0.55mm G550 steel Steelspan 900 has a maximum end span of 2900mm and a maximum internal span of 4300mm. The following distributed load capacities apply.

4 fasteners/sheet
2 fasteners /sheet
End Span
4 fasteners/sheet
2900mm
2 fasteners /sheet
2900mm
Internal Span
4 fasteners/sheet
4300mm
2 fasteners /sheet
4300mm
Serviceability
4 fasteners/sheet
1.3 kPa
2 fasteners /sheet
0.6kPa

Fastener Layout Options

Terms & Conditions
Technical Manual
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Product Technical Statement



To help you get through the building consent process as quickly as possible, we have developed the Product Technical Statement (PTS) downloads to make it quick and easy for both Architects and Home Owners to access the documentation required.

The PTS downloads hold all of the information that the council requires for a building consent where Dimond product is specified.

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