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A modern cladding well suited to many types of home improvement projects such as room additions, carports and patios. The underside features clean uninterrupted lines, with an attractive gloss finish.

  • Ideal for open sided structures where a high degree of watertightness is not required
  • Perfect for creating a flat, ceiling like finish
  • Nominal cover width: 250mm
  • Minimum roof slope: 2°

Technical Specifications


Sheets are supplied custom cut to length. Minimum and maximum lengths apply. Please contact your nearest LYSAGHT® office for your region for more information.

Material Specification

COLORBOND® steel is prepainted steel for exterior roofing and walling. It is the most widely used. The painting complies with AS/NZS 2728:2013 and the steel base is an aluminium/zinc alloy-coated steel complying with AS 1397:2011. Minimum yield strengths are G550 (550MPa), or G300 (300MPa) depending on profile. Minimum coating mass is AM100 (100g/m2).


Finish Paint Thickness BMT Mass
(mm) kg/m2
COLORBOND® painted both sides 0.42 25um/25um 5.2
COLORBOND® Hi gloss one side 0.42 80um/25um 5.4

Span Table

The maximum recommended support spacings are based on testing in accordance with AS 1562.1:1992, design and installation of sheet roof and wall cladding, and AS 4040.1:1992, resistance to concentrated loads.

Depending on support spacings used, flatdek can be installed as either:

  • light foot traffic roof (one maintenance person walking on roof); or
  • no foot traffic roof (will not support the weight of a person walking on it), see tables below.

The pressure considered is based on a typical flat awning attached to an enclosed structure. The pressure coefficient for this situation is based on 3 sides blocked.

The tables are based on flatdek fixed to supports of 1.0mm BMT minimum. Any FIRMLOK beam can be used. For FLATDEK awning applications, the strength of the receiver channel method of attachment must be considered in the design of any system. An alternative method is to use a rear gutter attachment all round for greater weather-tightness.

Maximum Support Spacings (mm)
Type of Span Wind classification to AS 4055 & BCA
N1 N2 N3 N4
Spans for no foot traffic
Single Span 4500* 4500* 4500* 3800
End Span 4500* 4500* 4500* 3700
Internal Span 4500* 4500* 4500* 4400
Stiffened Eaves Overhang 600 600 450 400
Spans for light foot traffic
Single Span 2100
End Span 2600
No overhang is allowed

Supports must not be less than 1mm BMT. For double spans, use the end span lengths.

* When dead load deflections need to be considered in designs, use the tabulated values. Where the higher deflections can be tolerated, then the spans can be increased to 4800mm for single spans for N1 to N3; 5000 or end & internal spans for N1 to N3.

NOTE: For pitched structures when dead load deflections need consideration, use a maximum span of 3300.

Capacity & Load Tables

Capacity and load tables can be viewed in the LYSAGHT FLATDEK® brochure. Download LYSAGHT FLATDEK® Design & Installation Guide

NCC of Australia Compliance

LYSAGHT® products comply with the National Construction Code of Australia (NCC).


Brochures & Catalogues

LYSAGHT® Build On Inspiration - Design in Steel PDF(36.21 MB). Last updated 16 Oct 2020

User Guides & Manuals

LYSAGHT FLATDEK® Design and Installation Guide PDF(1.22 MB). Last updated 21 May 2020


New South Wales & ACT
Northern Territory
Not Available
Not Available
South Australia
Not Available
Not Available
Not Available
Not Available

Colour Range


  1. Classic Cream™/ Classic Cream™ gloss
  2. Manor Red®/ Classic Cream™ gloss
  3. Paperbark®/ Paperbark® gloss
  4. Woodland Grey®/ Classic Cream™ gloss


Pricing for all our products varies based on availability and quantity.


Phone (Mon-Fri, 9AM-5PM AEST/AEDT):

1800 641 417