MMC 52pp M10 WEB

External Building Envelope
This is MMC… but not as we know it
Advances in construction techniques over the past decade have given rise to some genuine commercial, sustainable and health and
safety benefits – all while improving efficiency and performance.
However, as building regulations are
updated over time and standards
become increasingly stringent, these
modern methods of construction risk failing to
keep pace, particularly where thermal
insulation is concerned. Chris Lea, Technical
Sales Manager, SIG Performance Technology,
explores why the construction sector needs to
rethink its approach to reducing heat loss in a
building and why the aerospace industry
appears to hold the answer.
Some of the major specification drivers for
building design in modern times are the need to
keep building footprint to a minimum, maximise
internal rentable space and achieve the highest
energy efficiency performance possible.
Working within the confines of these design
objectives, developers must also achieve
accelerated build programmes in a bid to
complete within budget and realise the return
on investment as promptly as possible.
Fast track construction which uses steel or
timber frame has become a tried and tested
build method in the UK, particularly in high rise
developments. As the exterior of these buildings
is commonly a cladding finish, the challenge of
reducing heat loss while maximising internal
floor space and minimising building footprint
comes to the fore. Crucially, the insulation has
to be installed within the through-wall build up,
but this construction suffers from cold bridging
as soon as the rainscreen carrier system is
installed. This is where innovative new
insulation techniques are helping modern
construction techniques to stay at the forefront.
Helping hands
The availability of 3D thermal modelling has
proven a valuable technology in assisting the
development of new solutions which address
current construction challenges. After reviewing
thermal models of buildings using rainscreen
systems, the innovation team at SIG
Performance Technology identified high levels of
heat loss being caused by the helping hand
bracketry in the support systems. Realising that
a reduction in the cold bridging through the
bracketry would significantly improve the overall
performance of the building envelope, research
began into developing an insulated clip-on
solution.
After a programme of development, aerogel –
most commonly used in aerospace and
industrial applications – emerged as the most
suitable insulant owing to its exceptional
thermal performance and proven flexible
properties. This led to the launch of CHI-
GASKET, a patented insulated component which
is simply clipped on to standard helping hand
bracketry on-site. In doing so, the cold bridging
is significantly reduced and means the
insulation within the
through-wall buildup
does not have to
compensate for this
and consequently
does not have to
achieve such low U-
Values. It is because
of this that the CHI-
GASKET is now
considered from
initial design stage.
Aerogel in
action
The use of Aerogel
as an insulant in
helping hand
bracketry is a unique application but one where
a change in design process has enabled major
developments to achieve core design objectives.
This principle is also now being applied in
modular buildings and offsite construction,
where linear areas of heat loss at construction
junctions prove a common challenge.
As the modular buildings typically have much
tighter junctions than those constructed onsite,
these developments present several
challenges. Firstly, lower density insulation is
more flexible and easier to install into tight
frames, but these materials are generally
lower performing from a thermal perspective.
Secondly, rigid materials offer good thermal
insulation, but require cutting to size, either
on or off-site, which adds a layer of
complexity to the construction process.
Finally, both of these methods leave room for
installation error, as the materials are being
cut to size or pushed into place manually.
Offering a solution to this challenge is
Aerogel. The material can be precision cut to
size and fabricated to any bespoke shape to
meet the exact needs of modular building
specifications. Thermally excellent yet
flexible, precision manufactured aerogel
linings would deliver a much greater level of
quality control and reduce labour time in
construction – all of which align with modern
methods of construction.
While the name Aerogel is probably more
synonymous with NASA than with MMC, as the
construction market continues to innovate
with insulation, this could be set to change in
the not so distant future.
www.sigpt.co.uk/chigasket
36 MMC
Nov 2018 M10