Housebuilder October 2018

uild methods
Continued from page 76
Timber, reports that in 2017 the demand for offsite
manufactured buildings, in particular timber frame
housing, outweighed the industry’s ability to
supply, and that this issue in conjunction with the
shortage of light weight blocks caused numerous
programming problems. “The timber frame industry
has addressed this problem by increasing productivity
and working closer with our customers to ensure
they become an integral part of the supply chain
and that they are made aware of delays as soon as
possible to avoid the ‘concertina effect’ that stop-start
productivity inevitably causes,” Whittle explains.
Many national housebuilders have decided to follow
in the footsteps of companies such as Persimmon
and are manufacturing or acquiring their own timber
frame manufacturing plants to service their future
requirements. Whittle believes that this is a positive
step: “As demand for new housing increases this will
certainly take some of the pressure off timber frame
manufacturers and free up capacity for the small to
medium sized property developers.”
Should housebuilders fully embrace modern
methods of construction? It would seem sensible to
deploy a mixture of solutions. Andrew Orriss, sales
director of SIG360 Technical Centre, confirms this.
He says: “The definition of offsite construction or
MMC into pre-manufactured value (PMV) will help
the industry to understand that a blend of new and
traditional will in the short to medium term provide
the most economical solution to housebuilding.”
lintels and thermal bridging
Recent changes in Building Regulations mean that a
building’s fabric performance must now hit a target
for fabric energy efficiency (TFEE) in addition to the
traditional target emission rate (TER) for CO2. These
changes have increased the focus on lintel energy
efficiency. The thermal performance of each individual
building component needs to be carefully considered
in terms of its contribution to heat loss calculations.
Richard Price, technical director at Catnic, says:
“Steel lintels are prone to thermal bridging. Our new
Thermally Broken Lintels feature a unique composite
design to provide a complete thermal break between
the inner and outer leaf of a cavity wall providing an
energy transmittance psi value of 0.02 to 0.05 W/mK –
surpassing the requirements of SAP 2012 Appendix and
reducing heat loss through window head details by as
much as 96%.”
Birtley has also responded to the TFEE and TER by
developing a range of Supatherm Lintels to tackle
thermal bridging. “Increased emphasis on reducing
heat loss – a significant proportion of which can
be attributed to lintels and other non-repeating
thermal bridges – led us to develop the new range of
Supatherm Lintels that offer more than 75% less heat
loss compared to single-piece lintels. This conveys
benefits to both housebuilders and homebuyers
because it means less insulation, less spend on
glazing, and the avoidance of wider cavities,” says
James Matthews, sales director at Birtley Group. “It’s
in the interests of housebuilders to choose thermallybroken
lintels such as our Supatherm to achieve lower
PSI values.”
Target Timber Systems designed, manufactured and erected this scheme
of contemporary three storey town houses on the Kent coast
weather
The weather often has a significant effect on
housebuilding and in early 2018 there was a slow down
in activity with many housebuilders reporting lost days
due to snow and icy conditions. “The poor weather and
the ‘beast from the east’ in February and March affected
progress, however with the recent spell of good weather
builders seem to be making the most of it and catching
up on themselves for their 2018 expectations. I do
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