Designing Timber issue 10 for online - Flipbook - Page 41
HOWDEN
HALL ROAD
he house was originally
designed as a singlestorey property. It
had had one owner
occupant until its sale in
2011. Now, its original 91m2
footprint has been increased to
197m2 utilising three di昀昀erent
forms of modern methods of
construction (MMC).
The extension work was
carried out in two phases:
2014-17 and 2022-24, due to
the client needing to raise the
necessary capital.
Overall, the performance
of the property has been
signi昀椀cantly upgraded,
using novel approaches that
improve quality of life whilst
minimising environmental
impact.
The house had previously
only ever undergone minor
remedial measures including:
the addition of a small 7m2
uninsulated sun room to the
rear of the property; new
windows in the form of UPVC
double glazing installed in
1996 (which had since failed);
and cavity wall insulation
(the installation date of which
was unknown, but which was
con昀椀rmed with bore hole
testing).
T
The 昀椀rst phase
The Sun Room - or “sitooterie”,
as it is a昀昀ectionately known in
Scotland - uses a lightweight and
highly insulated timber frame
closed-panel cassette system. This
was installed onto the upgraded
foundations of the previous
dilapidated Sun Room in 2014
- so reducing new foundation
requirements. Timber windows
and doors and cladding were all
speci昀椀ed in Accoya (an acetylated
timber) for durability.
In the same year, a second glazed
extension was installed for the
dining and living area. This was
cantilevered out, negating the need
for foundations: the design was
tailored to be integrated with the
DESIGNING TIMBER
41
NOV/DEC 2025
existing structure. Precisionengineered Accoya glulam
support beams and frame
were installed for dimensional
stability. This approach o昀昀ers
longevity and resistance
to movement, which is
particularly essential for glazing
components.
The 昀氀oor of the existing house
was insulated with 100mm
glasswool insulation, placed
between the suspended 昀氀oor
support joists. This has a
thermal conductivity of 0.030.04 W/mK., forming a new
昀氀oor U-value of 0.35 W/m2K.
The attic of the property was
then converted to add 35m2 of
space, for a further bedroom
INSPIRATION
A 1950s bungalow in Edinburgh has been dramatically recon昀椀gured by a retro昀椀t
and extension which has doubled the useable 昀氀oor space, improving form and
functionality, while the overall energy consumption has dropped due to fabric
improvements in the retro昀椀t works.
