Content uploaded by Remo F Pedreschi
Author content
All content in this area was uploaded by Remo F Pedreschi on Apr 15, 2016
Content may be subject to copyright.
Proceedings of the Institution of
Civil Engineers
Construction Materials 163
May 2010 Issue CM2
Pages 109–121
doi: 10.1680/coma.2010.163 .2 .109
Paper 800058
Received 27/11/2008
Accepted 27/01/2009
Keywords:
Buildings structures & design/steel
structures/research & development
R. Mark Lawson
SCI Professor of
Construction Systems,
University of Surrey,
Guildford, UK
Sunday O. Popo-Ola
Department of Civil
and Environmental
Engineering, Imperial
College, London, UK
Andrew G. Way
The Steel Construction
Institute, Ascot, UK
Trevor Heatley
Corus Research,
Development and
Technology,
Rotherham, UK
Remo Pedreschi
Professor of
Architectural
Technology, University
of Edinburgh,
Edinburgh, UK
Durability of light steel framing in residential applications
R. M. Lawson PhD, CEng, MICE, MIStructE, MASCE, ACGI, S. O. Popo-Ola MEng, DIC, PhD, A. Way MEng, CEng, MICE,
T. Heatley
BSc(Eng) and R. Pedreschi PhD
This paper presents a summary and analysis of research
findings on the durability of galvanised cold-formed steel
sections used in housing in order to deduce their design
life. These cold-formed sections are produced from pre-
galvanised strip steel. It reviews reports and publications
from research projects carried out by Corus and the Steel
Construction Institute on zinc-coated, cold-formed steel
products. New data have also been gathered from
measurements on houses and similar buildings that have
used galvanised steel components. The data also extend
to over-cladding applications in building renovation. The
performance of galvanised (zinc-coated) steel compo-
nents within warm-frame applications is very good. The
research leading to this paper shows that the predicted
design life of the standard G275 coating, based on the
measured loss of zinc from the strip steel, is over 200
years, provided that the building envelope is well
insulated and properly maintained. The evidence for this
conclusion is based on measurement of zinc loss on light
steel frames in various applications and locations. A
formula for the loss of zinc over time in areas subject to
low condensation risk is presented.
1. INTRODUCTION
Galvanised steel has been used successfully for over 30 years in
light steel framing and other components in housing and low-
rise residential buildings (Lawson et al., 2003a). In the UK, the
current market for light steel framing is increasing rapidly,
particularly for residential buildings of three to six storeys in
height. Modern light steel framing systems use sections that are
cold formed from rolls of pre-galvanised (zinc-coated) strip
steel. The steel is delivered to BS EN 10326 (BSI, 2004), which
has recently replaced BS EN 10147 (BSI, 1992). The zinc coating
is able to protect the steel much more reliably than paint
coatings because it chemically passivates the steel and is
resistant to local damage.
Historically, many steel housing systems were built in the UK
between 1920 and 1970 (Harrison, 1987) but the house building
systems of the pre- and postwar period used painted, hot-rolled
steel components, and were not insulated to modern standards.
The performance of the earlier steel houses, which are now 30 to
70 years old, has generally been good despite some poor
construction details employed when questions of building
physics were less well understood.
Galvanised steel provides a much higher level of protection and,
in modern building construction, the risk of moisture within the
insulated building envelope is largely eliminated.
Maximum thermal transmission levels (U-values) of 0?15 to
0?25 W/m
2
˚
C are now required for all elements of the building
envelope to meet the Building Regulations Part L (DCLG, 2006)
and the UK Government’s Code for Sustainable Homes (DCLG,
2007). The light steel components within a warm frame are
subject to only minor temperature and humidity fluctuations in
comparison with the external conditions, which leads to
relatively benign conditions from a durability point of view.
The durability of light steel and its coatings in a range of
climatic and exposure conditions is the subject of continuing
research both in the UK (Popo-Ola et al., 2000) and inter-
nationally (ECSC, 2000). Further data are being collected
through exposure trials and monitoring of buildings in the UK,
Finland, Portugal, Japan (Honda and Nomura, 1999), Australia
and the USA, and the present findings support the conclusions
of this report.
1.1. Light steel framing in housing
Cold-formed sections are the primary components of light steel
framing, the sections being produced from pre-galvanised steel
strip by processes known as cold rolling. Smaller components
and other sections of varying shape can be produced by press
braking.
The advantages of light steel framing include speed of on-site
construction, achieved by prefabrication of the wall panels and
their easy assembly on site. This creates a dry working
environment for following trades, allowing the brickwork
cladding and roof tiling to follow off the critical path.
Light steel frames are constructed using light steel components,
typically of C or Z section of 70 to 200 mm depth and 1?2to
2?4 mm thickness. The sections are joined using bolting, self-
drilling, self-tapping screws, riveting, clinching, welding (in the
factory), or new methods such as press joining. Any factory-
produced welds are painted over with zinc-rich paint to
maintain the required level of protection.
Construction Materials 163 Issue CM2 Durability of light steel framing in residential applications Lawson et al. 109
Downloaded by [] on [16/03/16]. Copyright © ICE Publishing, all rights reserved.
There are three basic residential steel framing assembly methods
(a) stick built construction (site assembled)
(b) panelised systems (factory made and site assembled)
(c) mixed light steel panels (infill walls) and structural frames
in steel or concrete.
Most light steel framing systems in residential construction use
wall panel construction, as illustrated in Figure 1. This example
shows the use of bonded expanded polystyrene to create a
monolithic panel to which external insulation and cladding are
attached. C-shaped sections are commonly used for the studs in
walls and frames. Normally, a ‘warm frame’ is created in which
the majority of insulation is placed externally to the frame, as
illustrated in Figure 2. C or Z sections are widely used as floor
joists, and composite decking is used in composite ground floor
and suspended floors (see Case Study 4 in Section 3.4.).
Where U-values less than 0?25 W/m
2
˚
C are required, insulation
may be placed between the wall studs, and it is necessary to
ensure that there is sufficient insulation outside the studs to
minimise cold bridging and therefore to avoid condensation on
the steel studs.
1.2. Roofs in steel-framed houses
Purpose-made light steel trusses and purlins have been widely
used for many years, although less so in housing. Typically,
trusses comprise cold-formed sections as the chords of the truss,
with bent bars or C sections forming the bracing elements. They
can be designed for spans of 8 to 15 m and can also be used for
flat or slightly pitched roofs. Purlins span between cross-walls
or structural frames and are the normal form of construction in
large enclosures, warehouses and supermarkets.
There are two generic forms of roof design
(a) a ‘cold’ roof in which the roof acts only as a weather-tight
barrier and insulation is placed at ceiling level to the floor
beneath
(b) a ‘warm’ roof, in which the roof is insulated, so that the
space under the roof is relatively warm.
In modern construction, ‘warm’ roofs are preferred, as the loft
may be employed for habitable use during the building’s life.
Modern roofs are insulated to achieve a U-value of typically
0?16 W/m
2
˚
C.
1.3. Floors
Steel floor joists of C or Z section or fabricated lattice joists may
be used in place of timber joists. The joists may be built into
walls or supported on continuous Z section hangers placed over
the load-bearing walls. Internal floors are in the warm internal
environment, but there may be cases where this is not the case –
for example, joists built into solid masonry walls. In these
applications, care should be taken to ensure adequate ventila-
tion where the steel can be exposed to moisture over an
extended period. A thicker galvanising layer, or some additional
form of protection, may be required.
1.4. Ground floors
Suspended composite ground floors have been used successfully
in buildings with a sufficient air gap so that risk of exposure to
moisture is small. This form of construction uses galvanised
steel decking acting together with an in situ concrete slab to
achieve spans up to 4?5 m. The degree of exposure is mild, as
long as good ventilation is provided in the void beneath the
floor and an over-site membrane is used so that contact with soil
is avoided. The required level of insulation is provided by rigid
insulation boards placed on top of or suspended below the
decking.
1.5. Infill walls in primary frames
Non-load-bearing walls in steel or concrete frames have become
a common form of construction in recent years due to their
speed on installation, low weight and zero waste on site. A
typical form of construction is shown in Figure 3. Infill walls are
generally placed between the slab and beam on the floor above.
Insulation is placed externally and lightweight cladding may be
attached through the insulation. Brickwork is generally ground
supported or supported on stainless steel angles attached to the
perimeter steelwork.
Figure 1. Light steel framing in housing development, using
bonded expanded polystyrene between the C sections (Fusion
Building Systems)
Two layers of fire-resistant
plasterboard
Mineral wool
Light steel frame
Insulated sheathing
board
Wall ties
Brick cladding
Figure 2. Warm frame construction showing external and
inter-stud insulation
110 Construction Materials 163 Issue CM2 Durability of light steel framing in residential applications Lawson et al.
Downloaded by [] on [16/03/16]. Copyright © ICE Publishing, all rights reserved.
1.6. Modular or hybrid construction
Modular construction comprises light steel floors, walls and
ceilings and often additional corner posts, which are constructed
in factory-controlled conditions often with additional sheathing
boards or protective coverings. The size of the modules is limited
by transportation, and their maximum size is typically 4?2m
wide 6 12 m long. There are three generic forms of modular
construction which are defined in Lawson et al. (2003b)
(a) four-sided modules with load-bearing walls, as illustrated in
Figure 4
(b) open-sided modules with corner posts and edge beams
(c) non-load-bearing modules with a separate support struc-
ture.
Many ‘hybrid’ forms of modular construction exist, such as
modules and panels, or modules and structural frames, which
permit use of more open plan space or higher-rise buildings.
2. GALVANISING AS CORROSION PROTECTION
FOR STEEL
In external environments, the surface of bare carbon steel is
unstable, reacting with air and airborne pollutants to form the
complex series of oxides generically known as rust. In dry, warm
environments this process does not occur and no protection is
required. For example, most hot-rolled steelwork within multi-
storey buildings is unprotected because of the low risk of
corrosion, as evidenced by over 70 years of excellent
performance.
In exposed environments, some form of protection against
corrosion is required, and the main forms of protection are
(a) encapsulation, in which a coherent barrier is used to exclude
corrosive agencies from the surface
(b) sacrificial, in which another metal, which corrodes prefer-
entially to steel, is used in proximity to the surface.
The use of metallic zinc (in galvanising, sprayed metal coatings,
plating, sherardising, zinc-rich paints, and cathodic protection)
as corrosion protection may use one or both of these
mechanisms. Hot-dip galvanising provides both forms of
protection and is the most common form of protection to thin
cold-formed steel sections.
2.1. The hot-dip galvanising process
Hot-dip galvanising involves dipping steel in almost pure
molten zinc. The zinc and steel react to form a series of zinc–
iron alloy layers bonded metallurgically to the steel. When the
steel is lifted from the bath, molten zinc on the surface of the
bonded alloy coating solidifies and becomes part of the coating
itself.
Because of the casual use of the term galvanising within the
building industry, it is not always appreciated that immersion of
steel in molten zinc can create various products. Differing steels,
different zinc alloys and variations in the process may be used to
alter the character of the final coating.
Continuous galvanising onto steel coil tends to produce only a
very thin zinc–iron alloy layer with a (relatively) thick pure zinc
top layer, because of the speed at which the steel coil passes
through the bath. Continuous zinc coating of the steel coil is
controlled carefully to produce a range of coating weights for
different specifications of corrosion protection.
In the UK, the normal standard has been 275 g/m
2
(i.e. a surface
thickness of about 20 mm). This grade was formerly used in BS
EN 10147 (BSI, 1992) and has now been incorporated into BS EN
10326 (BSI, 2004). The technology of coating has improved, and
there are many sources of continuous zinc-coated steel strip.
In the field of continuous metal coatings, various zinc–
aluminium alloys are available as an alternative to pure zinc
coatings. One very well-known product is the original
Bethlehem Steel formulation 55% aluminium–45% zinc, which
is available as coated steel coil from several licensees. Galfan is
the trade name for a coating with 95% zinc and 5% aluminium.
Post-galvanising treatments may be offered to protect the zinc
coating during storage. These treatments include chromate
passivation to suppress the development of white zinc corrosion
products that can form in continuously wet conditions, such as
when water is trapped between the sheets. A thin film of mineral
oil is applied to the surface for the same purpose. This oil must
be removed if the product is to receive further treatment such as
painting or welding.
Figure 3. Light steel infill walls used in a multi-storey
residential building
Figure 4. Example of four-sided load-bearing module
(by Terrapin)
Construction Materials 163 Issue CM2 Durability of light steel framing in residential applications Lawson et al. 111
Downloaded by [] on [16/03/16]. Copyright © ICE Publishing, all rights reserved.
2.2. Performance of galvanised coatings
Zinc coatings provide a barrier that prevents oxygen, moisture
and other atmospheric pollutants from reaching the steel.
Furthermore, zinc is a reactive metal and, on exposure to the
atmosphere, a complex mixture of zinc compounds forms
readily on a galvanised surface. As many of the products formed
are partially soluble in water, the zinc is consumed over a period
of time in any damp location. The loss of zinc is accelerated in
situations where the galvanised surface is exposed to the
atmosphere and to water running over the surface.
Galvanising has the advantage that, when the encapsulation is
breached, for example at cut edges or drilled holes, or when the
zinc has been eroded away locally, significant corrosion of the
steel substrate will not necessarily occur. This is because zinc in
close proximity to the exposed steel will still corrode
preferentially, acting as a consumable anode in an electro-
chemical cell (i.e. it protects the steel cathodically). The use of a
sacrificial metallic layer is known as galvanic action. Only when
the distance between the zinc and steel is too great will the steel
begin to corrode.
The galvanic series of metals is shown in Table 1. The more
anodic (electronegative) metal will corrode preferentially to the
more cathodic metal (in the presence of water and oxygen).
Therefore common coating metals such as zinc and aluminium
will protect the steel substrate against corrosion. Conversely,
stainless steel or more electropositive metals may lead to
preferential corrosion of mild steel, if directly connected and
subject to prolonged moisture.
In more benign exposures, an initial layer of zinc hydroxide
often changes to a hard, stable layer of zinc carbonate by the
absorption of carbon dioxide, and this provides a further barrier
layer to any further loss of zinc from beneath. The loss of zinc,
and hence the life of zinc-coated steels, can be calculated with
reasonable accuracy for specific environments from research
data. This loss of zinc with time is part of its protective
mechanism, and should not be considered as a failure of the
protective system.
2.3. Loss of thickness of zinc with time
The expected product lifetime of the zinc coating in external
atmospheres has almost doubled over the last 20 years in the UK,
which is a consequence of improved air quality, as in most
European countries. This has enabled hot-dip galvanised coat-
ings to protect steel for longer periods, and newly manufactured
components are given a much longer life expectancy than
would have been predicted 20 years ago, and old coatings are
expected to exceed the original predicted life expectancy.
The effective life of galvanised coatings is inversely propor-
tional to the levels of airborne sulphur dioxide; their life
expectancy has increased as the pollution has decreased. Given
that hot-dip galvanising is unaffected by ultraviolet (UV) light,
it is also able to outperform other coating systems in countries
where UV levels are high. In a mathematical model designed to
investigate the relationship between sulphur dioxide levels and
the reduction in thickness of zinc, lowering the sulphur dioxide
concentration in the air by 1 mg/m
3
led to a reduction in loss of
coating thickness of exposed zinc of about 0?2 g zinc/m
2
,or
0?03 mm, per year (John, 1991).
The approximate performance of zinc coatings in different
environments is shown in Table 2. The lifetime of zinc coatings
has improved, and recent work suggests that these figures are
very conservative.
The Galvanizer’s Association in the UK produces a zinc
corrosion ‘map’ which indicates the expected annual loss of zinc
in various geographical locations. The rate of zinc loss is
typically 0?5to1?5 6 10
23
mm depending on location, the
higher rates applying to industrial areas (Table 2).
The zinc-galvanised coating attains its anti-corrosion charac-
teristic because a protective layer forms at its surface. This
protective layer, or patina (see Figure 5), consists of a mixture of
zinc compounds including zinc carbonate, zinc oxide and zinc
hydroxide. Environmental factors dictate which of these
compounds are formed.
In dry air, a film of zinc oxide is initially formed by the
influence of oxygen in the atmosphere, but this is soon
converted to zinc hydroxide, zinc carbonate and other zinc
compounds by water, carbon dioxide and chemical impurities
present in the atmosphere. The patina of zinc carbonate, when
fully formed across the entire surface, has excellent anti-
corrosion qualities that are long-lasting because rainwater
cannot easily dissolve the zinc compound. However, if sulphur
dioxide is present in the atmosphere when the patina is forming,
zinc sulfate will form along with the zinc carbonate. The zinc
sulfate is more soluble and thus significantly more susceptible to
the effects of rainwater. Rainwater gradually reduces the coating
thickness and its protective capabilities.
Falling levels of sulphur dioxide have reduced the rate of build-
up of zinc sulfates in the protective patina. The consequent
improved resistance to corrosion leads to a marked increase in
the lifetime of galvanised coatings. Further reductions in
sulphur dioxide levels are anticipated over the next decade, with
a commensurate increase in life expectancy for galvanised
coatings.
2.4. White rust on galvanised steel sections
White rust is a corrosion product of zinc formed from hydrated zinc
carbonate/zinc hydroxide under specific conditions of exposure.
White rust cannot be seen until the steel is dry, when it appears as a
white film. White rust may occur due to ingress of water between
the adjacent surfaces in a stack of galvanised steel sheets.
White rust does not usually indicate a serious degradation of the
zinc coating or that the product life has reduced, but removal of
white rust may accelerate the loss of zinc. A chromated layer is
Anodic: Magnesium (Electronegative)
Zinc
Aluminium
Cadmium
Iron or steel
Stainless steels
Lead
Tin
Cathodic: Copper (Electropositive)
Table 1. Galvanic series of metals
112 Construction Materials 163 Issue CM2 Durability of light steel framing in residential applications Lawson et al.
Downloaded by [] on [16/03/16]. Copyright © ICE Publishing, all rights reserved.
used as the standard coated product in the UK to inhibit the
formation of white rust.
2.5. Factors affecting durability in the building envelope
When considering the durability of galvanised steel sections, it
is necessary to consider two main criteria: the duration of
wetness and the general atmospheric or exposure condition. The
shorter the time of wetness and the drier the atmosphere, the
better will be the durability. The rate of zinc loss in an internal
environment is less than 10% of that in an external environment
because of the drier indoor conditions. However, if the building
envelope is of poor quality, the time of wetness can be greater,
due to condensation and possible external water ingress.
Transient moist conditions due to condensation are much less
critical than the case of water washing over the zinc surface
because zinc hydroxide, which is produced by contact with
moisture, is soluble and can be washed away.
Good building practice, thermal insulation and proper ventila-
tion ensure that the design of modern houses conforms to a
warm dry environment, even though humidity is created by the
occupants or activities inside. There is long experience of using
galvanised steel in housing, and even within the building
envelope, exposure conditions can vary considerably.
2.6. Design life of galvanised steel
The design life of a galvanised steel component comprises the
life of the protection system plus that of the substrate. The
design life of the protection system may be defined as the time
period to the first major maintenance of the coating, when
recoating or some other treatment is required to restore the total
effectiveness of the protection. If there is no maintenance at this
time, the coating would continue to deteriorate and the
underlying steel may start to corrode, eventually leading to
serviceability problems. The design life does not represent
structural failure of the component, and there will be a
considerable margin between the design life and potential
failure.
Two categories of use may be defined that influence the
requirements for design life.
(a) Category A: concealment of structure components so that
they cannot be inspected during their service life.
(b) Category B: location of components so that they can be
inspected readily, such as by removal of inspection panels
or trapdoors, etc.
Examples of category A are wall frames, window lintels, wall
ties and possibly suspended ground floors. Examples of
category B are roof trusses, purlins, internal floors and external
elements.
The required design life depends on the conditions of use, as
there should be a greater reserve of life for components that
cannot be inspected and therefore cannot be assured for
recoating, repair or replacement. Typically for residential
buildings, the required design life is 60 years, representing a
sensible time to major maintenance of the primary components.
For infill walling, a design life of 30 to 60 years may be specified
depending on the importance of the infill walling to the support
of the cladding elements.
In the context of galvanised steel, the definition of the actual
design life depends on the degree of loss of zinc from the
surface. The rate of zinc loss is likely to be uneven, and
experience shows that some surface rusting may appear when
an average of 50% of the original weight of zinc coating has
been lost. To cater for this variability, a general basis of
evaluation must be conservative, and the design life may be
defined as a function of the conditions of use.
(a) Category A: when 50% of the weight of zinc has been lost
from the exposed surface (which for G275 coating is 137 g/
m
2
).
(b) Category B: when 80% of the weight of zinc has been lost
Figure 5. Typical micrograph of hot-dip galvanised coating
Environment
Corrosivity
of environment
Average
reduction in
coating thickness:
mm/year
C1 Interior: Dry Very low 0?1
C2 Interior: Occasional condensation Low 0?1–0?7
Exterior: Inland and rural
C3 Interior: High humidity, some air pollution Medium 0?7–2?0
Exterior: Industrial and urban inland or mild coastal
C4 Interior: Swimming pools, chemical plants, etc. High 2?0–4?0
Exterior: Industrial inland or urban coastal (chloride-rich environment)
C5 Interior: Industrial with high humidity or high salinity coastal Very high 4?0–8?0
Exterior:
Table 2. Performance of zinc coatings in different environments
Construction Materials 163 Issue CM2 Durability of light steel framing in residential applications Lawson et al. 113
Downloaded by [] on [16/03/16]. Copyright © ICE Publishing, all rights reserved.
from the exposed surface (which for G275 coating is 220 g/
m
2
).
This is then consistent with other coated light steel products,
such as roof sheeting, where the design life is related to the
performance of the coating rather than the steel substrate.
3. CASE STUDIES
The following case studies present information on the long-term
performance of galvanised steel sections in various examples in
which measurements of zinc loss have been made.
3.1. Case 1: Environmental and performance monitoring
of modern steel-framed housing
The former Department of the Environment sponsored a 3-year
corrosion and environmental monitoring exercise in 15 houses
in Manchester, London and South Wales (John, 1991).
Galvanised steel test panels were left uncovered at opposite ends
of each (unheated) house loft and were exposed to the
atmosphere. The zinc corrosion rate was measured together with
relative humidity, temperature and the time-of-wetness of any
condensation. In addition, some laboratory experiments tested
galvanised steel that was freely exposed to mortar and gypsum
plaster in accelerated corrosion test environments.
The results showed that there was no significant difference in
relative humidity or temperature values at the three geogra-
phical locations. Data-logging indicated that conditions that
may lead to condensation can exist in roof spaces up to 21% of
the time averaged over a year. Only one cavity wall was
monitored, but it showed that conditions that may lead to
condensation can exist for up to 16% of an average year.
3.1.1. Exposure conditions. The average weight loss measured
over a 3-year period (John, 1991) in a loft environment is given
in Table 3. The average rate of zinc loss per year may be
expressed as the total weight loss divided by the time period.
From these data, the average rate of zinc loss was approximately
0?3 g/m
2
per year. Chromated galvanised steel was found to
have a lower rate of zinc loss than non-chromated galvanised
steel. The data are subject to some variability because the
specimens were removed and measured but were not replaced.
There could therefore be some variation in exposure conditions
and surface characteristics among the specimens.
No significant difference was found between the corrosion rate
of galvanised steel panels exposed at the north or south sides of
each loft, and no significant difference was found in the
corrosion rate of the panels in the three geographical areas.
For comparison, the equivalent uncoated mild steel specimens
stored in the same locations lost weight at a rate of
approximately 2?5 g/m
2
per year (or 30 mm thickness of steel per
year).
3.1.2. Interpretation of zinc loss. From the results of these
studies, the zinc weight loss (g/m
2
) for galvanised steel exposed
over a 3-year period was found by linear regression analysis to
follow a relationship of the form
1 Weight loss ~ a timeðÞ
b
where time is measured in years.
A difference in performance was observed between chromated
and non-chromated zinc specimens (a chromate layer is the
standard product in the UK).
The value of b was found to be 0?64, indicating that the rate of
zinc loss decreased with time. This occurred because the
protective oxide film that formed on the zinc surface in dry
conditions reduced the exposure of the zinc. Figure 6 shows the
individual test results over time (marked as x), and also the
mean line and the mean plus 2 standard deviations of the data
(both drawn as solid lines). The best fit for the mean of the test
data was for a 5 0?4. The characteristic value of weight loss
corresponds to 95% probability that all results lie below the line
given by the mean plus 2 6 standard deviations of the data
(Figure 6). This line is obtained for a 5 1?0 and the expression
becomes
2 Weight loss ~ 1
:
0 timeðÞ
0
:
64
3.2. Case 2: Environmental and performance monitoring
of the light steel-framed building at Ullenwood
This building is situated at the National Star Centre for disabled
persons at Ullenwood near Cheltenham, and was one of the first
light steel framing systems constructed by PMF (now Corus
Panels and Profiles) in 1982. The residential building, illustrated
in Figure 7, was monitored to gain more data on in-service
performance. Areas investigated were the environmental con-
ditions in the wall cavity, the loft and below the suspended
ground floor. The loft was monitored in the south corner, north
corner, near the water tank and at the centre near the flue. The
exercise included the measurement of the weight of zinc-plated
coupons, which were removed annually over the 5-year period
(John, 1991).
In the wall space and loft, the galvanised steel suffered very little
weight loss, as shown in Table 4. The annual weight loss on the
galvanised steel specimens was extremely low (0?2 g/m
2
)
Materials
Number of years
12 3
Non-chromated galvanised steel 0?44 0?75 0?71
Chromated galvanised steel 0?28 0?69 0?47
Electro-galvanised steel 0?75 1?26 1?24
Mild steel (unprotected) 2?60 5?70 7?00
Table 3. Average weight loss (g/m
2
) for exposed specimens in loft environment (after 1, 2 and 3 years) in the BRE investigations
114 Construction Materials 163 Issue CM2 Durability of light steel framing in residential applications Lawson et al.
Downloaded by [] on [16/03/16]. Copyright © ICE Publishing, all rights reserved.
compared with the mild steel specimens (1?26 and 1?62 g/m
2
in
wall space and loft, respectively) despite the wide fluctuations in
temperature and relative humidity in these locations.
Over the 5-year study period, the annual rate of zinc loss was
approximately uniform. In February 1996 (after 14 years), the
building was inspected and internal plasterboard panels were
removed. Only slight tarnishing (i.e. loss of normal bright
appearance as in Figure 8) was observed. In situ measurements
were taken of the standard galvanising on the wall studs, and
could not detect any significant loss of the zinc coating. The rate
of zinc loss is therefore negligible and is considered to
correspond to a long-term rate of zinc loss of no more than
0?2 g/m
2
per year.
The measurements taken of the specimens under the ground
floor were affected by their proximity to an air brick in the
external cladding. The rate of zinc loss after 5 years was 1?22 g/
m
2
per year. The conditions under the ground floor are not as
severe as external conditions, but clearly the galvanised steel is
exposed to moisture over a longer period than in warm frame
applications. The exposure can be reduced by additional
insulation or a membrane placed below the floor.
3.3. Case 3: Monitoring of over-cladding panels at
Edinburgh University
This study concerns the environmental monitoring of two types
of steel over-cladding panels constructed on the eighth floor of
the James Clerk Maxwell building on the Edinburgh University
campus, where the wind and rainfall regime is severe (Figure 9).
Two panel types were monitored.
(a) Composite (sandwich) panels 50 mm thick fixed to
horizontal rails (C section) at 2?4 m spacing vertically
(Figure 10). These panels were installed in August 1994.
(b) Steel cassette panels (flat panels with rigidised backing)
fixed to vertical rails (Figure 10). These panels were
installed in October 1996.
In both cases, the external face of the panel is in colour-coated
steel suitable for at least 30-year design life in cladding
applications. In over-cladding applications, the environmental
conditions behind the new cladding are potentially more severe
than in internal conditions, as although the cavity space is
ventilated, the galvanised steel is subject to periodic wetness due
to condensation and possibly to direct rain ingress.
Over 200 galvanised steel coupons were positioned behind both
over-cladding panels. For the composite panels, L-shaped
coupons were used in order to trap any moisture that might
enter the cavity space. Chromated and non-chromated zinc
coupons were installed behind the composite panels in order to
assess the effect of the passivation through the chromate finish.
The original zinc coating in both cases was 275 g/m
2
or
approximately 20 mm per face.
For the cassette panels, flat coupons were installed behind the
panels, as shown in Figure 11. Zinc (non-chromated) and zinc–
aluminium coupons were installed in this case. Zinc–aluminium
is an alternative coating system that is used in some countries
and the product Galfan that was tested has about 95% zinc. Its
original coating was 250 g/m
2
.
The location of the coupons was chosen to be easily accessible.
The coupons were removed initially over 4- to 12-month periods
and then over a gap of 5 years. The final measurements were
taken in mid-2007 after 13 and 11 years, respectively, in order
4
.
00
3
.
50
3
.
00
2
.
50
2
.
00
1
.
50
Weight loss: g/m
2
1
.
00
0
.
50
0
.
00
0
.
00 6
.
00 12
.
00 18
.
00 24
.
00
Time: months
30
.
00 36
.
00
98%
probabilit
y
line
95%
probabilit
y
line
Mean line
Figure 6. Zinc weight loss with time for exposed hot-dip
galvanised steel specimens (upper line corresponds to the
characteristic value of weight loss)
Figure 7. Steel-framed building for disabled persons at
Ullenwood, Gloucestershire, UK
Location
Time:
months
Measured zinc
loss: g/m
2
Annual zinc loss:
g/m
2
per year
Wall
space
60?09 0?18
12 0?27 0?27
18 0?30 0?20
24 0?41 0?20
60 1?20 0?24
Loft
space
60?09 0?18
12 0?19 0?19
18 0?32 0?22
24 0?29 0?15
48 0?55 0?14
60 0?59 0?12
Rate of weight of zinc loss is averaged over the exposure time.
Table 4. Results of measurements on galvanised steel coupons
installed in the wall space and loft of the Ullenwood building
Construction Materials 163 Issue CM2 Durability of light steel framing in residential applications Lawson et al. 115
Downloaded by [] on [16/03/16]. Copyright © ICE Publishing, all rights reserved.
to determine the loss in weight of the samples and to observe
signs of possible corrosion (Figure 12).
The results of the samples removed at various stages are given in
Table 5. The total weight loss was measured from samples that
were removed from behind the composite panels and weighed at
the stated exposure time. The rate of zinc loss was the equivalent
annual rate of loss averaged over the exposure time.
For chromated zinc samples, the average rate of zinc loss after
13 years was 0?30 g/m
2
per year, although the rate of loss in the
early months was much higher. For non-chromated zinc
samples, the average rate of zinc loss was 0?43 g/m
2
per year
after 13 years and, in this case, the rate of zinc loss tends to be
linear with time. As noted earlier, chromated zinc is currently
the standard finishing later used for production of cold-formed
steel sections.
The results for the zinc and zinc–aluminium (Galfan) coupons
installed behind the cassette panels are presented in Table 6. In
this case, the average rate of zinc loss is 0?30 g/m
2
per year,
which is consistent with the other over-cladding results.
However, the results for Galfan are higher at 0?55 g/m
2
per year.
These results are lower than for the L-shaped coupons in the
adjacent composite panel tests, and suggest that the long-term
coating loss is about 0?3 g/m
2
for zinc and 0?6 g/m
2
for zinc–
aluminium.
Despite the more severe conditions present in the cavity behind
the over-cladding panels, the rate of zinc loss is not significantly
higher than in the loft measurements of case study 1.
3.4. Case 4: Monitoring the Oxford Brookes
demonstration building
In 1996, a student residence was constructed at Oxford Brookes
University as part of a European demonstration project. It used
Corus’s Surebuild light steel framing system. The building
comprised a four-bedroom house and an adjacent six-room
apartment building (Figure 13). The house and apartments are
occupied by postgraduate students.
The innovative feature of the building was the use of two
alternative habitable roof systems, and a composite suspended
ground-floor system using a perimeter G-shaped galvanised
steel edge beam with Corus’ CF70 decking and an in-situ
concrete slab spanning between these edge beams. The light
steel framing and roof are also highly insulated to a U-value of
0?2 W/m
2
˚
C. The open habitable roof system is illustrated in
Figure 14 and the suspended ground floor is illustrated in
Figure 15.
The building was monitored in the first 2 years to assess its
energy performance and the local temperature and humidity
conditions that may exist in the building fabric. Crawl access
was provided beneath the suspended ground floor to permit
assessment of the performance of the galvanised steel sub-
structure and composite floor. Data for the first 3 years indicated
that no wetness had occurred in the light steel frame, even
adjacent to bathrooms, kitchens and in the roof space.
A series of zinc coupons was suspended in the wall cavity and in
the ventilated void below the suspended ground floor. These
coupons were removed at various intervals to assess the weight
loss. The results are presented after 30 months and 10 years for
four locations in the loft, wall and below the composite deck
floor. The 30-month data are the average of three coupons,
whereas the actual results for the two coupons removed from
each location after 10 years are given. The final case represents a
more severe condition, which although not wet, is subject to
higher humidity conditions and more condensation risk than
internally.
From the results in Table 7, it is apparent that the rate of zinc
loss averaged over 10 years was only about half of the 2?5-year
results. The rate of zinc loss in internal conditions was 0?1to0?2
Figure 8. Wall panel removed, showing no trace of corrosion
on the members after 15 years (the connections are coated in
zinc-rich paint)
Figure 9. Two types of over-cladding panels in exposure tests
at Edinburgh University
116 Construction Materials 163 Issue CM2 Durability of light steel framing in residential applications Lawson et al.
Downloaded by [] on [16/03/16]. Copyright © ICE Publishing, all rights reserved.
g/m
2
, and even in the below ground floor application was only
0?3 g/m
2
. The predicted design life is over 200 years.
3.5. Case 5: Monitoring of the Britspace house, York
In 1998, a pair of two-storey houses were constructed using
light steel modules on the site of the modular company
Britspace, Gilbertdyke near York. The modules are 8 m long 6
2?4 m wide and four modules make one house. The building is
illustrated in Figure 16. The opportunity was taken to install
zinc coupons in the following locations
(a) six coupons on the suspended ground floor of the modules
(b) three coupons at first-floor level
(c) three coupons below the rear windows
(d) twelve coupons at various locations in the unoccupied (cold)
roof spaces of the two buildings.
The coupons were installed in May 2001; the selected coupons
were removed in January 2008. Other coupons were left in place
in order to give a measure of the longer-term performance of the
modular components. The results from the 7-year data are
presented in Table 8.
At the same time, a statistical survey was made of the actual zinc
coating of the galvanised steel members in comparison with
Gasket
Cavity closer
and damp-proof layer
Composite panel
Hanger bracket
Internal flashing
Plastic spacing
Clip
Horizontal
sub-frame member
Self-drilling
self-tapping screw
Steel brackets
(100 mm wide)
Fixings every metre
Additional insulation
behind the C section
to avoid cold bridging
Cover flashing
Plastic spacer
Figure 10. Details of support to composite panels
Figure 11. Zinc coupons being installed behind the
cassette panels
Figure 12. Galvanised steel coupons removed from behind the
over-cladding panel after 13 years (non-chromated zinc on
the right)
Construction Materials 163 Issue CM2 Durability of light steel framing in residential applications Lawson et al. 117
Downloaded by [] on [16/03/16]. Copyright © ICE Publishing, all rights reserved.
similar data recorded when the building was constructed.
Although not as meaningful as the measurements from the
coupons, these results, as presented in Table 9, give some
general correlation of the likely variation that may be
experienced.
The results from Table 8 confirm that the zinc loss within the
building was generally small (less than 0?3 g/m
2
per year).
However, relatively high zinc losses were measured for the
coupons located in the floor of the ground-floor module, which
was not protected other than by insulation. The zinc loss was in
the range 0?5–2?1 g/m
2
per year, which indicates a shorter
design life. The below window result was 0?9 g/m
2
per year
indicating some evidence of condensation.
When the building was constructed, the U-value of the fac¸ade
roof and ground floor was specified as 0?35 W/m
2
˚
C, which is
much higher than the level stipulated by the current regulations.
Exposure time:
months
Chromated zinc Non-chromated zinc
Total loss: g/m
2
Rate of loss: g/m
2
per year Total loss: g/m
2
Rate of loss: g/m
2
per year
60?98 1?96 1?78 3?56
15 0?97 0?78 2?10 1?68
24 0?76 0?38 3?30 1?65
57 1?83 0?38 4?05 0?85
156 3?87 0?30 5?60 0?43
G275 coating thickness. Data averaged over three specimens for each exposure time.
Table 5. Results of measurements on galvanised steel coupons installed behind the composite over-cladding panel at
Edinburgh University
Exposure time:
months
Non-chromated zinc Zinc aluminium (Galfan)
Total loss: g/m
2
Rate of loss: g/m
2
per year Total loss: g/m
2
Rate of loss; g/m
2
per year
12 0?20 0?50
36 0?15 0?20
60 0?47/0?57 0?10 1?13/1?14 0?23
128 0?98/1?09 0?10 1?79/2?13 0?18
G250 original coating thickness for Galfan. Data averaged over three specimens for each exposure time.
Table 6. Results of measurements on the zinc and Galfan coupons behind the cassette panels at Edinburgh University
Figure 13. Oxford Brookes demonstration building con-
structed using light steel framing
Figure 14. Open-roof system in the OBU house (kept open for
demonstration purposes)
Figure 15. Ground-floor system in the OBU house (using
composite decking and perimeter C sections)
118 Construction Materials 163 Issue CM2 Durability of light steel framing in residential applications Lawson et al.
Downloaded by [] on [16/03/16]. Copyright © ICE Publishing, all rights reserved.
It is expected that the long-term performance of light steel
frames and modules will be much better.
The on-site measurements may be compared to an original zinc
coating of 20–21 mm (or 275 g/m
2
). The percentage zinc loss is
equivalent to a weight loss of 0?15 g/m
2
per year, which is
consistent with previous results.
4. CONCLUSIONS FROM CASE STUDIES: DESIGN
LIFE OF GALVANISED LIGHT STEEL FRAMING
4.1. Warm frame applications
The monitoring studies have shown that the environmental
conditions present in ‘warm frame’ construction are such that
moisture levels are very low and that the galvanised steel
components are not subject to a risk of significant corrosion
within the expected life of well-maintained modern buildings.
The rates of zinc loss on chromated galvanised steel coupons
were very low at less than 0?3 g/m
2
per year and, taking into
account statistical accuracy, it has been observed that the rate of
zinc loss reduces with time in dry environments. This is because
the zinc oxide layer that forms on the surface also protects the
zinc beneath. However, it was observed that a linear rate of zinc
loss with time was more appropriate for non-chromated zinc
and for conditions with a potentially greater time of wetness.
Chromated zinc is the coating normally used for the production
of cold-formed steel sections.
The following approach may be used to evaluate the design life
of components that are concealed and cannot be inspected or
repaired easily (Category A in Section 2.6).
(a) Assume a linear rate of zinc loss with time (which is a more
conservative extrapolation of the data given by Equation 2).
(b) Assume that a loss of 50% of the total zinc coating may lead
to some rusting of the surface (see design life definition in
Section 2.6).
As the measurements were taken only from the average of three
specimens, assume that the 95% probability level is double the
average rate of loss. In principle, the use of the 95% probability
level means that the design life corresponds to the characteristic
value, namely that only 5% of the structure may suffer a more
severe rate of zinc loss.
Therefore, the design life (in years) may be estimated from
3 Design life~0
:
25|
Total weight of zinc coating
Average rate of the zinc loss=year
The weight of zinc coating is expressed as the total weight (i.e.
275 g/m
2
for G275 specification); the rate of zinc loss is the
weight loss summed over both faces. From the data in case
studies 1, 2 and 4, the average rate of zinc loss of the frame
components does not exceed 0?3 g/m
2
per year. For G275
galvanising, it follows that the design life is at least 230 years.
In comparison, Equation 2 would lead to a design life (calculated
for 50% loss of zinc) given by
137 ~ 1
:
0 timeðÞ
0:64
or time ~ 2150 years
This is almost 10 times longer than the linear estimate in
Equation 3, because in Equation 2 the long-term rate of zinc loss
is assumed to reduce in warm frame applications.
4.2. Roof space of houses
The roof space of houses may represent a more severe
environment than a ‘warm frame’ application; however, from
the data in case studies 1 and 2, the rate of zinc loss was not
significantly higher. In the Oxford Brookes building, the roof
space was insulated and the rate of zinc loss was very low. The
data in case study 1 also include uninsulated lofts and the
average rate of zinc loss was approximately 0?3 g/m
2
per year.
Equation 3 predicts a design life of over 200 years but, given the
potentially more variable conditions in lofts, it is considered that
Location of coupons
Total zinc loss: g/m
2
after: Rate of zinc loss: g/m
2
per year over:
30 months 60 months 124 months 30 months 60 months 124 months
Cold loft space 0?53 0?57 0?63 0?21 0?13 0?08
Suspended in cavity wall:
high level 0?30 0?47 0?45 0?12 0?10 0?09
low level 0?48 1?25 1?31 0?19 0?25 0?16
Below suspended ground floor 1?25 2?13 2?04 0?50 0?43 0?25
All data are for chromated zinc specimens.
Table 7. Measured weight loss of the galvanised steel coupons installed in the demonstration building at Oxford Brookes University
Figure 16. Britspace demonstration house using fully
modular construction
Construction Materials 163 Issue CM2 Durability of light steel framing in residential applications Lawson et al. 119
Downloaded by [] on [16/03/16]. Copyright © ICE Publishing, all rights reserved.
Location of coupons Total zinc loss after 85 months: g/m
2
Rate of zinc loss: g/m
2
per year
Roof space (cold) 0?59, 0?90, 0?91, 0?92, 1?69 0?08 to 0?24
Wall (below window) 1?18, 7?05 0?17 to 10?01
First floor (between modules) 0?79 0?11
Ground floor (between modules) 3?37, 10?4, 14?83 0?48 to 2?12
Table 8. Measured weight loss of the galvanised steel coupons installed in the Britspace building, near Hull
Member type and location
Average zinc
coating: mm
Standard
deviation
Coefficient
of variance: %
Change over
6?8 years: %
House A: unfurnished
Vertical studs: back of house A 10?47 1?53 7?5 20?03
Vertical studs: front of house A 19?96 1?32 6?5 20?77
Floor joists: back of house A 21?25 1?99 9?4 20?10
Floor joists: front of house A 20?83 1?32 6?3 20?09
Floor joists: side of house A 20?58 1?48 7?3 20?83
Roof joists in house A 20?33 2?17 10?6 20?09
Roof rafters – 1: back of house A 20?75 2?16 10?4 20?10
Roof rafters – 2: front of house A 19?38 1?28 6?6 20?75
House B: fully furnished
Vertical studs: back of house B 19?11 2?05 10?7 20?06
Horizontal joists: back of house B 20?75 1?13 5?4 20?30
Roof rafters in house B 20?47 1?51 7?4 20?74
Average values 19?60 1?80 9?2 20?35
Table 9. Measured zinc coating thickness at Britspace Demonstration house
Applications Environmental conditions Special measures
External walls Warm: Properly insulated and
ventilated
No special measures required
Cold: Uninsulated, some risk of
condensation
Provide proper ventilation and reduce exposure
Over-cladding to an existing wall improves the insulation
and life of the existing wall
Suspended ground floors Cold: Moisture from the ground
and from the atmosphere
Provide good ventilation and avoid contact with ground
Use damp-proof course at supports. See note 1 for
further protection
Roofs Warm: Properly insulated and ventilated No special precautions needed
Cold: Uninsulated, some risk of
condensation
Provide proper ventilation. Over-roofing improves the life
of an existing flat roof
Steel lintels Wet: Potential water ingress from
cracks in brickwork
Use thicker grade of zinc coating. See note 1 for further
protection. Also see BSI (1983)
Dry: No water ingress, properly
drained
No special measures required
Over-cladding Drained and back-ventilated Generally, no special precautions for weathertightness
Pressure equalisation
Over-roofing Cold environment, some risk of condensation Generally, good ventilation is provided
Detail carefully at eaves level to prevent water ingress
Infill walls for
multi-storey buildings
Warm: Properly insulated and ventilated No special precautions needed
Contact with other
materials
Contact with other metals See notes 2 and 3 below
Contact with plaster, etc.
Notes:
1. Where further protection is required, the surface may be painted or powder-coated. If aesthetic effects are unimportant, a well-
proven form of protection is to use a brush coat of zinc-rich paint or bituminous paint.
2 Bimetallic corrosion of dissimilar metals should be avoided by using inert separators, especially between the fixings and cladding.
3. Zinc can be affected by contact with various building materials in damp conditions, for instance fresh concrete (highly alkaline),
mortars, certain natural materials (which may contain inorganic salts, organic acids, or may just act as a source of moisture) woods
(oak and WRC are acidic), timber treatments (CCA is well known but also phosphate fire retardants), and some insulation.
Table 10. Good construction practice to ensure durability in new and existing construction
120 Construction Materials 163 Issue CM2 Durability of light steel framing in residential applications Lawson et al.
Downloaded by [] on [16/03/16]. Copyright © ICE Publishing, all rights reserved.
the design life of galvanised steel in these applications should be
taken as over
(a) 100 years for insulated roof space
(b) 60 years for uninsulated roof space.
These predictions assume that the integrity of the roof is not
impaired and that leaks are prevented.
4.3. Suspended ground floors
Suspended ground floors can incorporate light steel sections or
decking. They are not exposed directly to moisture but may be
subject to periodic condensation from humid air flow; however,
the risk of condensation is much reduced if the floor is insulated
from below.
Case studies 1, 2 and 4 provided data on the performance of
uninsulated composite ground floors using light gauge decking.
Case study 5 provided comparative data for floors in modular
construction. In case study 1, the rate of zinc loss was 1?22 g/m
2
per year after 5 years, and in case study 4, the rate was 0?5 g/m
2
per year. In case study 5, the rate was much higher at 2?14 g/m
2
per year. Equation 3 predicts a design life of 50 to 100 years in
these conditions. However, the exposure severity can be reduced
by using an external insulation layer beneath the floor, leading
potentially to a design life of over 100 years. This type of ground
floor is being further developed.
Any extrapolation from these data assumes that leaks from
outside or inside the building envelope are prevented, that steel
is not in direct contact with soil and is properly protected from
other potential sources of moisture. Further data are being
collected on all types of suspended ground floors.
4.4. Over-cladding applications
The light steel sub-frames to over-cladding systems are subject
to variable conditions, depending on the exposure and type of
cladding that is used. The Edinburgh University tests showed a
rate of zinc loss of 0?38 g/m
2
per year, which is relatively low
for these exposure conditions. For these data, Equation 3 would
lead to a design life of 180 years.
It is difficult to estimate the exposure conditions for all types of
over-cladding system. With good detailing to avoid ingress of
wind-driven rain, and to allow for some air movement in the
cavity, a design life of at least 60 years may be expected for the
sub-frame members; that is, the rate of zinc loss would be less
than 1?1 g/m
2
per year. The more exposed members at the joints
in the cladding should be additionally protected where they are
subject to prolonged moisture.
Other design guidance on the use of galvanised steel in exposed
or external environments is given in BS EN 14713 (British
Standards Institution, 1999).
REFERENCES
BSI (British Standards Institution) (1983) BS 5977–2:1983:
Lintels. Specification for prefabricated lintels. BSI, London.
BSI (British Standards Institution) (1992) BS EN 10147: 1992
Specification for Continuously Hot-dipped Zinc Coated
Structural Steel Strip and Sheet: Technical Delivery
Conditions. BSI, London.
BSI (British Standards Institution) (1999) BS EN ISO 14713:
1999 Protection against Corrosion of Iron and Steel in
Structures – Zinc and Aluminium Coatings – Guidelines.
BSI, London.
BSI (British Standards Institution) (2004) BS EN 10326:
Continuously Hot Dip Coated Strip and Sheet for Structural
Steels: Technical Delivery Conditions. BSI, London.
DCLG (Department for Communities and Local Government)
(2006) Building Regulations (England and Wales) Approved
Document LA1. Department for Communities and Local
Government, London.
DCLG (Department for Communities and Local Government)
(2007) Code for Sustainable Homes: Technical Guide.
Department for Communities and Local Government,
London.
ECSC (European Coal and Steel Community) (2000) European
Commission Steel Research: Elevated and Low
Temperature Performance of Coated Strip Steel Products.
European Coal and Steel Community, ECSC report
FR–W486–7–992.
Harrison HW (1987) Steel-framed and Steel-clad Houses:
Inspection and Assessment. Building Research Establishment
(BRE), Watford.
Honda K and Nomura H (1999) Corrosion Environment and
Availability of Steel-framed Houses. Nippon Steel Technical
Report No. 79, Nippon Steel Corporation, Japan.
John V (1991) Durability of Galvanized Steel Building
Components in Domestic Housing – Fourth Progress Report.
British Steel Welsh Technology Centre (now Corus RDT),
London, Technical Note No. WL/SMP/R/1106E/10/91/D.
Lawson RM, Gorgolewski M and Grubb PJ (2003a) Building
Design Using Cold-formed Steel Sections: Light Steel Framing
in Residential Construction. The Steel Construction Institute,
p. 301.
Lawson RM, Gorgolewski M and Grubb PJ (2003b) Modular
Construction Using Light Steel Framing. The Steel
Construction Institute (SCI), Ascot, p. 302.
Popo-Ola SO, Biddle AR and Lawson RM (2000) Building Design
Using Cold-formed Steel Sections: Durability of Light Steel
Framing in Residential Buildings. The Steel Construction
Institute (SCI), Ascot, p. 262.
What do you think?
To discuss this paper, please email up to 500 words to the editor at journals@ice.org.uk. Your contribution will be forwarded to the
author(s) for a reply and, if considered appropriate by the editorial panel, will be published as discussion in a future issue of the
journal.
Proceedings journals rely entirely on contributions sent in by civil engineering professionals, academics and students. Papers should be
2000–5000 words long (briefing papers should be 1000–2000 words long), with adequate illustrations and references. You can submit
your paper online via www.icevirtuallibrary.com/content/journals, where you will also find detailed author guidelines.
Construction Materials 163 Issue CM2 Durability of light steel framing in residential applications Lawson et al. 121
Downloaded by [] on [16/03/16]. Copyright © ICE Publishing, all rights reserved.
