LT7®

Standard Colours

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

Black
Minimum pitch
Rib type
High
Ribs per sheet
7
Width
635mm cover
725mm sheet
Suitable for
Light Commercial
Commercial
Manufactured in
Wellington
Invercargill
Terms & Conditions

LT7 ® Performance


Designed for applications where protection from severe climatic conditions and maximum structural economy is required, the strong section properties of LT7®allow for wider purlin and girt spacings which add extra economy to building projects. It also has excellent water shedding characteristics as well as being perfect for low pitch roofs.

Cover (mm)
Sheet width (mm)
Minimum Pitch
889
Sheet width (mm)
933 (Wellington)
942 (Invercargill)
Minimum Pitch
3º (approx. 1:20)

All dimensions given are nominal

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

Material options
Steel 0.40mm
Steel 0.55mm
Aluminium 0.7mm
Aluminium 0.9mm
Nominal weight / lineal metre (kg/m) options
Steel 0.40mm
4.12
Steel 0.55mm
5.55
Aluminium 0.7mm
2.31
Aluminium 0.9mm
2.96
Drape curved roof - min. radius (m)
Steel 0.40mm
80
Steel 0.55mm
50
Aluminium 0.7mm
80
Aluminium 0.9mm
50
Purlin spacings for drape curved roof (mm) (1)
Steel 0.40mm
1.4
Steel 0.55mm
2.2
Aluminium 0.7mm
1.24
Aluminium 0.9mm
2.2
Machine crimp curved - roof min. radius (mm)
Steel 0.40mm
900
Steel 0.55mm
400
Aluminium 0.7mm
n/a
Aluminium 0.9mm
400
Unsupported overhang (2)
Steel 0.40mm
250
Steel 0.55mm
350
Aluminium 0.7mm
200
Aluminium 0.9mm
300

1) Recommended maximum purlin spacing’s at minimum radius.

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

n/a not available

Roll-forming facilities at: Wellington and Invercargill

Crimp Curving facility at: Wellington

Sheet lengths: LT7® 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

LT7 ® Limit State Load / Span Capacity

(span in mm, distributed serviceability and ultimate 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
800
Internal Span
1200
Serviceability
2.5
Restricted Access / Roof
End Span
900
1000
1200
Internal Span
1300
1500
1800
Serviceability
2.2
2.1
1.7
Non-Access / Roof or Wall
End Span
1300
1500
1800
Internal Span
1900
2300
2700
Serviceability
1.6
1.1
0.8
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
1300
Internal Span
2000
Serviceability
2.2
Restricted Access / Roof
End Span
1400
1700
1900
Internal Span
2100
2500
2900
Serviceability
2.1
1.8
1.5
Non-Access / Roof or Wall
End Span
2000
2300
2500
Internal Span
3000
3400
3800
Serviceability
1.4
1.2
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
Internal Span
Serviceability
Restricted Access / Roof
End Span
900
Internal Span
1300
Serviceability
1.7
Non-Access / Roof or Wall
End Span
900
1100
1400
Internal Span
1400
1700
2100
Serviceability
1.6
1.3
0.9
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
1100
Internal Span
1600
Serviceability
2.3
Restricted Access / Roof
End Span
1100
1300
1500
Internal Span
1700
2000
2300
Serviceability
2.3
2.1
1.7
Non-Access / Roof or Wall
End Span
1600
1900
2100
Internal Span
2400
2800
3200
Serviceability
1.6
1.2
0.9
Duraclad 1.7mm (Note 4)
Unrestricted Access / Roof
Restricted Access / Roof
Non-Access / Roof or Wall
Unrestricted Access / Roof
End Span
Internal Span
Ultimate
End Span
Internal Span
Ultimate
Restricted Access / Roof
End Span
600
800
Internal Span
900
1200
Ultimate
4.5
4.5
Non-Access / Roof or Wall
End Span
900
1100
1400
Internal Span
1300
1700
2100
Ultimate
4.5
2.7
1.7
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 3.5kPa. If design requirements exceed this limit, Contact Dimond Roofing for specific advice.
  4. Duraclad
    - Serviceability Limit State Load are not applicable to Duraclad material, as it does not experience permanent deformation
    - System must include Safety Mesh it 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 fasteners withdrawal resulting in sheet detachment due to wind up-lift (outward) loads.
  8. System Design
    The span capacity of LT7®/5 is determined from the LT7®/5 Limit State Load/Capacity Chart using the section of the chart appropriate to 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 cyclone 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

    Expected 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 pan. Walkways installed where regular traffic is expected, and “Restricted Access” signs placed at access point.
    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 no-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.

LT7 ® Fastener Design



LT7® should be screw fixed to either timber or steel purlins. The use of the appropriate length of 12g or 14g screw will ensure
failure by screw pull out will not occur under loads within the scope of the Limited State Load/Span Capacity Chart.

Purlin
Roof Base Material - Steel
Roof Base Material - Aluminium
Wall (over vented cavity batten, 18 - 25mm thick) Base Material - Steel
Wall (over vented cavity batten, 18 - 25mm thick) Base Material - Aluminium
Timber
Roof Base Material - Steel
Type 17 14g x 75Timbertite
Roof Base Material - Aluminium
14 x 65mm Alutite
Wall (over vented cavity batten, 18 - 25mm thick) Base Material - Steel
Type 17 12g x 50mmTimbertite
Wall (over vented cavity batten, 18 - 25mm thick) Base Material - Aluminium
14g x 55mm Alutite
Steel
Roof Base Material - Steel
12g x 35mm Steeltite
Roof Base Material - Aluminium
n/a
Wall (over vented cavity batten, 18 - 25mm thick) Base Material - Steel
12g x 35mm Steeltite
Wall (over vented cavity batten, 18 - 25mm thick) Base Material - Aluminium
n/a

*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 to Section 2.2.3.1 of Technical Manual.

The Limited State Load/Span Capacity Chart for LT7® is based on 4 screw fasteners/sheet/purlin without the use of load spreading washers. For LT5 Load /span capacity chart is based on 3 screw fasteners/sheet/purlin without the use of load spreading washers.

Profile metal washers are recommended for use:

  1. On end spans, or large internal spans where Ultimate Limit State distribution load is limiting. Contact Dimond Roofing for specific advice in these 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. Whenever the designer wishes to ensure the risk of fastener over-tightening will not cause dishing in the crest of the profile rib.

Use in serviceability categories (1) and (2) can allow the reduction of fasteners to 3 screw fasteners/sheet/purlin. If this is done, the distributed load capacities given in the chart should be reduced using a multiplying factor of 0.75.

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

Design Examples



Restricted access roof, 0.55mm G550 steel LT7® has a maximum end span of 1900mm and a maximum internal span of 2900mm.

The following distributed load capacities apply.

4 fasteners/sheet
2 fasteners /sheet
End Span
4 fasteners/sheet
1900mm
2 fasteners /sheet
1900mm
Internal Span
4 fasteners/sheet
2900mm
2 fasteners /sheet
2900mm
Serviceability
4 fasteners/sheet
1.5kPa
2 fasteners /sheet
1.1kPa

Fixing Layout Options

Terms & Conditions
Technical Manual
All Dimond Roofing CAD details can be found on EBOSS

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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