T W E N T Y S E C O N D E D I T I O N
T H E B U I L D I N G C O N S E R VAT I O N D I R E C T O R Y 2 0 1 5
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you include the time it takes to build the
new house it will be around 2050 before
the carbon starts to pay back. The UK has
legally binding targets to reduce its carbon
emissions by 80 per cent by 2050, from a 1990
baseline. Rebuilding the UK housing stock
therefore doesn’t help to meet these targets.
Instead we must look to refurbishment
to help with this challenging target.
This, however, is where our generic
embodied carbon analysis must stop. Each
refurbishment is entirely different and
therefore each case needs to be assessed
individually. The embodied carbon of the
materials for a refurbishment needs to be
compared with the additional operational
carbon saving for the building under study.
Each building also has a different energy use
profile. This should be done on a case-by-case
basis. However, the analysis above still shows
that refurbishment is a promising option and
that refurbished buildingdo not necessarily
need the same level of thermal performance
to compete when considered from a whole-life
carbon perspective.
There are, of course, many products that
do not impact on the operational carbon of a
building. The refurbishment of such materials
and products typically brings with it a carbon
benefit. Retaining existing materials avoids
the need for new materials and products.
When it comes to refurbishment
and repair, some simple measures can
be taken to reduce the embodied carbon
footprint. One of the most effective is to
reuse materials, either on the same project
or elsewhere. Reuse of materials can save
up to 95 per cent of the embodied carbon
emissions of buying a new product.
Beyond this, there are savings to be
made through material selection. One rule
of thumb is ‘timber first’. Timber is a natural
material that has a wide range of uses and,
if responsibly sourced, its production has
a relatively low environmental impact.
Therefore if timber materials and products
are suitable it is usually a lower carbon option.
Timber from sustainably managed sources
also stores carbon, which is a carbon footprint
benefit. Timber is composed of approximately
50 per cent carbon by mass. What’s more,
Traditional details in new development (above)
rarely match the quality of historic architecture, no
matter how good the materials.
Left: Brynmor Terrace, Penmaenmawr, North Wales,
badly damaged by aluminium double glazing and
other home improvements. Double glazed timber
windows have since been installed in some of the
houses with the aid of grants from Conwy County
Borough Council under a townscape heritage
initiative. (Both photos: Jonathan Taylor)