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sustainable construction world
Newcastle
Climatic
N,S,E & W 54 137
51 236
60 457
11,67%
18,00%
Zone
Melbourne
Climatic
N,S,E & W 73 050
63 641
72 570
-0,66%
14,03%
Zone
Brisbane
Climatic
N,S,E & W 64 924
65 010
72 554
11,75%
11,60%
Zone
Average GHG
N,S,E & W 64 037
59 962
68 527
7,01%
14,28%
Thermal modelling of verdant and sirocco house plans:
average HVAC green house gas (kg co
2
-e) emissions over 50 years,
extracted from Energetics Full Life Cycle Assessment
Uninsulated Insulated double Insulated
Insulated timber Insulated timber
Location Orientations double brick brick (R1.3)
timber frame more/(less) GHG more/(less) GHG
than double brick than double brick
insulated R1.3
• The most efficient South African walling system for
residential buildings is a 280 mm insulated cavity
brick masonry wall.
• The most efficient South African walling system for
a commercial or institutional building is a 220 mm
solid clay brick masonry wall (or for Climate Zone 4:
a 270 mm clay brick cavity wall, as is the norm for
the Southern Cape condensation problem areas)
• Light steel frame wall construction specified SANS
517 is not as thermally efficient and use more
heating and cooling energy compared to clay brick
masonry cavity walls in all climate regions.
• That there is a significant energy cost premium
associated with the use of lightweight partitioning
systems in all three building typologies modelled.
When all is said and done, clay brick in construction
has so much more to offer than lightweight
IBTs for achieving sustainable, energy efficient
buildings. This sustainability extends to clay bricks
having mineral properties that meet all necessary
requirements for healthy living and to clay brick
being one of a few building material that is both
reusable and recyclable. On top of that of course,
are the enduring maintenance free attributes as
a face brick that help mitigate future carbon debt
associated with replacement, refurbishment and
painting associated with less durable lightweight
walling materials.
As was highlighted in Energetics full Life Cycle
Assessment, today’s environmental paradigm
requires we build buildings able to endure with
little maintenance, and definitely no materials’
replacement, way beyond the 50 year life cycle.
Clay brick buildings in all their forms have proven
themselves over the centuries to be more than up to
this task.
In retrospect, it may be considered most
fortunate that South African building has been
founded on a masonry tradition that endures to this
day; a simple building methodology that science now
proves so relevant for achieving a more sustainable
future and keeping our world a better place.
∞
longer. Should heaters be required the clay bricks
continue to function, absorbing and storing this heat
that is then released to counter the inroads of the
cold, extending the thermal comfort conditions
for longer.
Research further shows that clay brick partition
walls, used in lieu of lightweight, further enhances
a buildings thermal performance no matter the
external wall construction type. It was a conclusion
of the University of Pretoria study that “there is a
significant cost premium associated with the use
of lightweight partitioning systems in all three
building typologies modelled”. The University of
Newcastle, Australia, empirical study found that clay
brick internal partition walls improved the energy
efficiency of the insulated lightweight external
walled building by 20%.
With regard to facilitating a low lifecycle carbon
footprint the substantive thermal modelling done
as part of a Full Life Cycle Assessment (LCA) by
Energetics in Australia highlighted the contribution
of thermal mass to greater thermal efficiency, lowest
operational energy usage that in turn translated into
low to lowest total (embodied energy and operational
energy) Greenhouse Gas emissions over a 50 year
cycle. Cavity brick walls (R0.65) provided lowest
total GHG emissions in most situations modelled
while insulated cavity brick walls (R1.30) provided
lowest total emissions in all situations.
As shown in the table above, the energy savings
provided by double skin cavity walled house
translated into 7% less GHG (kg CO
2
-e) emissions
and the cavity brick with insulation into 14% less
GHG emissions
In South Africa, the University of Pretoria study
modelling of a 130 m² house produced similar
findings. Notably, cavity brick walls outperformed
SANS 517 compliant lightweight in most situations
while cavity brick with insulation R1 applied
in the cavity, to give a wall R-value of 1.3, well
outperformed insulated lightweight R1.9 and R2.2.
The University of Pretoria study reported the
following key findings:
Summary of operational energy greenhouse gas emissions over 50 years.