Sector Focus: Light GaugLeis tSitnegesl
NSC 11
Feb 20
strip steel in the order of 1.2mm to 3.2mm
thickness.
The most common use for loadbearing
light steel framing is residential
type buildings of two to 14-storeys e.g.
apartments, care homes, hotels and
student accommodation. However, it is
also used in housing, particularly two and
three-storey houses with habitable roof
space, and applications where its light
weight is beneficial, such as mixed-use
buildings, including residential space over
supermarkets.
This enables the designers to reduce lead
in periods for large schemes to acceptable
durations by utilising ‘just in time’
manufacturing methods, typically a lead in
period for a 10-storey hotel could be 10-14
weeks.
Stephen Ginger, Managing Director for
Metsec Framing and Purlins says: “The
general interest in offsite construction
is at an all-time high. Cold rolled steel
systems can deliver significant cost, quality,
performance and reduced on site labour
advantages. Cold rolled manufacturers
must be able to provide evidence that
their products have been designed to the
appropriate BS / EN standards and will
perform in terms of fire, acoustic and
thermal performance.
“Metsec has undertaken significant
testing over the last five years at the
BRE at Watford with various sheathing,
plasterboard and insulation products. The
industry has rightly changed since the
tragic events of the Grenfell tower and
manufacturers must provide full evidence
and supporting documentation of how cold
rolled systems perform.”
How are light gauge steel products
produced?
A very wide range of lightweight structural
sections are produced by cold forming
thin gauge strip material to specific section
profiles. These are often termed light gauge
or cold formed steel sections. In most cases,
galvanized steel strip material is used. The
cold rolling process begins with coils of
galvanized strip steel that are uncoiled, slit
into appropriate widths and then cold rollformed
into the final product form.
Profile shapes and section sizes do vary
but most sections use lips at free edges and
indented profiles to provide stiffness and
avoid premature failure by local buckling.
Thicknesses for load-bearing products
typically vary from 1.2mm to 3.2mm.
Light Gauge Steel products
Infill walling is used across many different
construction sectors; health, education,
commercial, residential and leisure and is
the generic name given to external walls
that are built between the floors of the
primary structural frame of a building, and
which provide support for the cladding
system. Infill walls do not support floor
loads but they do resist wind loads applied
to the façade, and may be used within both
steel and concrete-framed buildings.
Light gauge steel load-bearing walls are
used in light steel-framed buildings and
modular construction, supporting floor
loads, loads from walls above and resisting
lateral wind loads. They generally include
bracing to provide lateral stability to the
building. Light gauge steel load-bearing
walls use vertical C sections of typically
90mm to 120mm depth. Both internal and
external walls may be designed as loadbearing.
Wall panels are typically pre-fabricated as
storey-high units or may be site assembled
from C sections that are delivered cut-tolength,
but this is less common
Composite cladding panels are used for
the external envelope for a wide range of
building structures including industrial,
distribution, retail and residential. They
provide an efficient building envelope
with energy efficiency benefits. Composite
panel cladding systems are produced as
a sandwich construction comprising two
profiled sheets bonded either side of an
insulating core, generally mineral fibre
or similar material. As the panels act
compositely, shallow profiles can be used.
Purlins and side rails are often termed
secondary steelwork and are available in
a variety of shapes and a wide range of
sizes. The depth of the section typically
lies between 120mm and 340mm, with the
profile thickness usually varying between
1.2mm and 3.2mm.
In single storey industrial buildings
where steel commands over 92% of UK
market share, the cladding panels or sheets
are normally supported by a system of light
gauge steel purlins and side rails spanning
between the portal frame rafters and
columns respectively.
Light steel frame construction and
installation
Scaffolding is an important requirement
for the light steel frame installation
process. Two lifts of scaffolding are
generally required around the perimeter
of the slab prior to beginning installation
of the light steel framing. It is common
for scaffolding to be tied to the light steel
frame from level three onwards.
Load-bearing light steel framing uses
storey high wall panels that are delivered
to site appropriate for the build sequence.
These are unloaded from the lorry and
placed on the floors near to where they are
to be installed.
One lorry can deliver 30 to 50 wall
panels which are typically required to
build two houses or four apartments. Wall
panels on the first level are positioned
on the foundation slab, if necessary,
galvanized steel shims are used to level
the panels.
Panels must be fixed to the adjacent
panels. The fixings used are system
specific and should be stated on
construction drawings and comply with
the structural calculations.
Floors in light steel frame buildings are
generally either; light steel joisted floors
with boarding, panelised floor cassettes
or composite slab floors. The installation
process for each of these floor types is
appreciably different, with each having
their own best practice considerations.
Sponsors
Light Gauge Steel
Gold: voestalpine Metsec plc
“The general
interest
in offsite
construction
is at an alltime
high."
Lightweight steel is
versatile and can be
used to form long span
trusses
/Residential_and_mixed-use_buildings#Hotels
/Residential_and_mixed-use_buildings#Student_residences
/Retail_buildings#Supermarkets
/Design_codes_and_standards
/Thermal_performance
/Steel_construction_products#Flat_products_-_strip
/Infill_walling
/Design_codes_and_standards#Wind_actions
/Steel_construction_products#.27Light_steel.27_sections
/Concept_design#Structural_options_for_stability
/Building_envelopes#Insulated_.28composite_or_sandwich.29_panels
/Building_envelopes
/Building_envelopes#Purlin_and_side_rail_options
/Single_storey_industrial_buildings
/Portal_frames
/Fabrication#Handling_and_transportation
/Fabrication#Handling_and_transportation
/Residential_and_mixed-use_buildings
/Construction
/Floor_systems#Composite_slabs