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LYSAGHT CUSTOM ORB® 990 is a corrugated profile, equally
at home with traditional and contemporary design. It is long,
wide, strong, lightweight and economical. It can be aligned
quickly and easily. Add up these features and you have a steel
roof or wall cladding that simply offers outstanding value.
CUSTOM ORB® 990 is made of high strength steel and despite
its lightness provides excellent spanning capacity and remarkable recovery after deformation.
Simple, low-cost fixing
CUSTOM ORB® 990 can be fixed with hex head screws, which
is fast and simple. T
he standard overlap is one and a half corrugations.



CUSTOM ORB® 990 can be curved for stylish architectural
designs. For bull nosing, use 0.60 mm BMT, G300 MPa.


Minimum roof pitch
A special anti-capillary forming in the side lap allows you to use CUSTOM ORB® 990 on roof pitches as low as 5 degrees (1 in 12).
Sheet lengths of up to 24 m can be used before an
expansion joint is required.




LYSAGHT CUSTOM ORB® 990 is 990 mm wide coverage
profile with nominal 19 mm deep ribs. (Please refer fig. 1)
Material specifications
LYSAGHT CUSTOM ORB® 990 is manufactured out of high
strength steel grade with minimum yield strength of
550 MPa. The coated steel is zinc-aluminium alloy coated
ZINCALUME® steel complying with AS 1397, G550, AZ150
(550 MPa minimum yield stress, 150 g/m2 minimum coating
mass); or pre-painted COLORBOND® steel conforming to
AS/NZS 2728 Type 3-4.
(Please refer to ZINCALUME® steel and COLORBOND® steel brochure for details)
Sheets are supplied custom cut.Tolerances
Length: + 10 mm, – 10 mm
Width: + 4 mm, – 4 mm



Maximum support spacings
The maximum recommended support spacings are based on
testing in accordance with AS1562.1-1992, AS4040.1-1992 and
Roof spans consider both resistance to wind pressure and light
roof traffic (traffic arising from incidental maintenance). Wall
spans consider resistance to wind pressure only.
The pressure considered (in accordance with IS 875.3) is based
on buildings up to 10 m high, Zone 3 (Basic wind speed Vb =
47m/s), Class A, Terrain category 3, K1 = 1.0, K2 = 0.91, K3 = 1.0,
with the following assumptions made;
Cpe = – 1.20 (internal cladding spans)
Cpe = – 2.0 (single and end cladding spans)
Cpi = + 0.2
Cpe = – 0.80 (internal cladding spans)
Cpe = – 1.20 (single and end cladding spans)
Cpi = + 0.2
These spacings may vary for particular projects, depending on
specific structure characteristics.
Maximum roof lengths for drainage measured from ridge
to gutter (m)

Penetrations will alter the flow of water on a roof. For assistance
in design of roofs with penetrations, please seek advice from
your nearest Tata BlueScope Building Products office.
roofing_product-5Limit states wind pressures
CUSTOM ORB® 990 offers the full benefits of the latest methods for modeling wind pressures. The Wind pressure capacity table
is determined by full-scale tests conducted at
BlueScope Steel’s NATA- registered testing laboratory, using the  direct pressuretesting
rig.Testing was conducted in accordance with AS 1562.1-1992 Design and Installation of Sheet Roof and Wall  Cladding-Metal,and AS 4040.2-1992 Resistance to Wind Pressure for Noncyclonic Regions.The pressure capacities for serviceability are based on a deflection limit of (span/120) + (maximum fastener pitch/30).The pressure capacities for strength have been determined by testing the cladding to failure (ultimate
capacity). These pressures are applicable when the cladding is fixed to a minimum of 1.0 mm, G550 steel.





roofing_product-8Storage and handling
Keep the product dry and clear of the ground. If stacked or
bundled product becomes wet, separate, and wipe it with
a clean cloth to dry thoroughly.
Handle materials carefully to avoid damage: don’t drag
materials over rough surfaces or each other; don’t drag
tools over material; protect from swarf.
Sealed joints
For sealed joints use screws or rivets and neutral-cure
silicone sealant branded as suitable for use with
galvanised or ZINCALUME® steel.





For cutting thin metal on site, we recommend a circular

saw with a metal cutting blade because it produces fewer
damaging hot metal particles and leaves less resultant
burr than does a carborundum disc.
Cut materials over the ground and not over other
Sweep all metallic swarf and other debris from roof areas
and gutters at the end of each day and at the completion
of the installation. Failure to do so can lead to surface
staining when the metal particles rust.
Non- Cyclonic Areas
The information in this brochure is suitable for use only in
areas where a tropical cyclone is unlikely to occur.
Ask for advice from your nearest Tata BlueScope Building
Products office on designs to be used in cyclonic areas.





Fastening sheets to supports
CUSTOM ORB® 990 is pierce-fixed to steel or timber supports.
This means that fastener screws pass through the
sheeting. To maximize water tightness, always place roof
screws through the crests. For walling, you may use either
crest- or valley fixing. (Please refer fig. 2)
roofing_product-9Always drive the screws perpendicular to the sheeting,
and in the center of the corrugation or rib. Don’t place
fasteners less than 25 mm from the ends of sheets.
CUSTOM ORB® 990 standard lap is 1.5 corrugations. It is
generally considered good practice to use fasteners along
side-laps however, when cladding is supported as
indicated in maximum support spacings; side-lap fasteners
are not usually needed.


End lapping

End-laps are not usually necessary because
CUSTOM ORB® 990 is available in long lengths. If endlaps
are used, complete each run of sheets from gutter to
Seal end lap at both ends with a 3 mm bead of
neutal cure silicone sealant.
For roofs, allow a minimum end-lap of 200 mm for pitches
of 5 to 15 degrees, and 150 mm for pitches above 15
degrees. For walls, allow minimum endlaps of 100 mm.
Where you intend to end-lap CUSTOM ORB® 990
sheeting with curved sections of CUSTOM ORB® 990,
order them at the same time to ensure a good fit.
Ends of sheets
It is usual to allow roof sheets to overlap into gutters by
about 50 mm. The valleys of sheets should be turneddown
at lower ends, and turned-up at upper ends. Use five
fastenings at the ends of sheets.
Laying procedure
For maximum weather-tightness, start laying sheets from
the end of the building that will be in the lee of the worst
anticipated or prevailing weather.
Lay sheets toward prevailing weather. It is much easier
and safer to turn sheets on the ground than up on the roof.



Before lifting sheets on to the roof, check that they are the
correct way up and the overlapping side is towards the
edge of the roof from which installation will start.
Place bundles of sheets over or near firm supports, not at
mid span of roof members.


1. All screws are self drilling, self tapping with EPDM sealing washer unless otherwise noted 2. The number of screws per support are per sq.m and are only for guidance, based on support spaced at 1 m and wall 0.6 m 3. HG refers to Hi-Grips 4. * – the screw quantity is based on an average number of screws 5. Please refer to the above data for guidance purpose only. You may contact Tata BlueScope Building Products office for further information

For more information, please contact: SHADOWRIB 900_12(A Division of Tata BlueScope Steel Limited)