Designing Timber issue 10 for online - Flipbook - Page 13
———— IN BRIEF ————
INCREASE TIMBER USE TO DECARBONISE,
SAYS DEFRA REPORT
A study from Defra (the Department
for Environment, Food and Rural
A昀昀airs), makes a compelling case
for increasing the use of timber in
construction.
“Using timber in
the superstructure
signi昀椀cantly
reduces both
upfront and
embodied
carbon emissions
compared to the
baseline steel and
concrete designs”
And then it looks at the big-picture
impacts: it estimates the UK consumptionbased emissions savings for 2024-2050
across nine di昀昀erent scenarios, which
varied by timber uptake and material
decarbonisation rates. It estimates that
increasing timber use could:
• reduce lifecycle embodied carbon of a
new-build by up to 9%
• save up to 37MtCO2e nationally
between 2024-2050
The report's method
The UK building stock is categorised
into 11 ‘archetypes’: Residential Terrace,
Semi-detached, Detached, Bungalow,
Low/Mid-rise 昀氀at, High rise 昀氀at,
Commercial Low-rise, Mid-rise, High-rise,
Hospital, and Warehouse.
A baseline build (including typical
timber elements such as upper 昀氀oors
and roof for low-rise housing) for these
is then compared to two options which
substitute in:
appropriate in the superstructure frame and
façade. Savings may also be achieved using
timber rather than steel studded partitions,
but this should be considered on a case-bycase basis to prevent more material- and
carbon-intensive partition buildups being
adopted.”
“Timber studded internal partitions in this
study have lower embodied and upfront
carbon compared to steel stud partitions with
comparable performance characteristics.
However, it should be noted that, as
plasterboard accounts for the majority of the
embodied carbon of partitions, switching to a
partition type with fewer plasterboard layers
that achieves the desired performance criteria
(e.g. acoustic rating) would be expected to
reduce embodied carbon, regardless of the
materiality of the studs.”
• a timber structure (Option 1)
• a timber structure plus a timber façade
and partition structure (Option 2).
Embodied carbon savings
“Using timber in the superstructure
signi昀椀cantly reduces both upfront and
embodied carbon emissions compared
to the baseline steel and concrete
designs,” the report found.
“Where timber facades are permitted
within current 昀椀re regulations, they
achieve a reduction in both upfront and
embodied carbon emissions compared
to the conventional facades assumed in
the baseline.”
“The optimum use of timber to reduce
both upfront and embodied carbon
emissions would be to use timber where
DESIGNING TIMBER
13
NOV/DEC 2025
Timber and carbon sequestration
“Biogenic carbon storage over the lifetime of
the timber products used in each archetype
is signi昀椀cant,” the report says, “and therefore
action should be taken to prevent the rerelease of biogenic carbon to the atmosphere
at end-of-life for as long as possible through
reuse, recycling into long-lived products,
and bioenergy (i.e. incineration) with carbon
capture and storage (BECCS).”
“The former – i.e. waste prevention, reuse,
and recycling – should be prioritised before
BECCS, as per DEFRA’s waste hierarchy and
other similar circular economy hierarchies.
Alternative methods to better account for this
biogenic carbon storage should also be sought.”
Improving Whole Life Carbon Estimates
for Buildings Constructed out of Timber
can be read in full via:
sciencesearch.defra.gov.uk
IN BRIEF
Improving Whole Life Carbon Estimates
for Buildings Constructed out of Timber
is the report's catchy title. It analyses
typical new-build designs of 11 di昀昀erent
UK building types. Then it drills down
into the carbon impacts of increasing
timber use in their structure, façade,
and internal partitions.
