Conservation & Heritage Issue 49 October 2025 - Flipbook - Page 104
Here we look at some recent projects by Clement Windows
Group where the installation of new steel windows has
meant a real difference to the energy performance of the
heritage project involved.
Kew Studios, Surrey
Kew Studios and Works is a former manor house which has
been completely refurbished with an eye to incorporating
the original period charm into the new modern design.
Sustainability was a key objective and solar panels, a
living green roof and electric vehicle charging points
have been included. The development has achieved a “B”
Energy Performance Certificate and a BREEAM Very
Good certification.
There is no doubt that the new steel windows and doors
contributed to the overall energy efficiency of the project.
For the exterior, Clement manufactured double glazed, steel
frames from their W40 range. These double glazed, argon
filled, low emissivity warm edge insulating glass units are
ideal for heritage refurbishment projects where the pattern
of the original fenestration is to be maintained. Instead
of being painted, the frames were left with a contemporary
Clement Naked Steel galvanised finish. The internal
doors and screens were manufactured by Clement from
slim Jansen Janisol 2 and C4 profiles which are thermally
broken. They also meet the highest requirements for
security and fire protection, while ensuring natural light
flows throughout the space.
impact on the property, which is located in the East
Marylebone Conservation Area and abutted by a Grade II
listed building.
The original single glazed windows would have prevented
achievement of the required improvements in energy
performance. Refurbishment was not an option as the
frames were too badly corroded, not thermally broken and
provided practically no insulation value, acting as a cold
bridge and a source of condensation.
Architect Peter Warren explained: “Approval was sought
from Westminster Council to replace the existing windows
with thermally broken, double glazed, steel framed units
to improve thermal and air tightness whilst replicating the
existing appearance as closely as possible.” Steel was chosen
to allow the slimmest profile without compromising on the
required performance improvements.
Clement manufactured bespoke steel windows and doors
from the Jansen Janisol Arte 2 and Jansen Janisol HI ranges
for the project. The new windows and doors contributed to
the achievement of the project objectives.
Above, the Jansen windows and doors by Clement at Little Portland
Street ‘improve thermal and air tightness whilst replicating the existing
appearance as closely as possible’ according to architect Peter Warren
Above, the internal doors are manufactured by Clement from
thermally broken Jansen profiles
22-23 Little Portland Street, London
The original commercial premises at 22-23 Little Portland
Street encompassed a vacant basement, ground floor and
four upper floors. Robson Warren Architects were briefed to
design a scheme to improve the office facilities and services,
to enable the building to attract further tenants.
It was important that any proposals took account of
the environmental sustainability of the works and their
I
Little Theatre, Gateshead
Believed to be the only playhouse built in Great Britain
during the Second World War and home to The Progressive
Players since 1939, The Little Theatre remains Gateshead’s
only theatre to this day.
Closed during the pandemic, funding was completed on
an extension to the theatre creating a new rehearsal room
above the auditorium.
The new rehearsal room has the same dimensions as the
main auditorium stage allowing a smooth transfer from
rehearsals to final production. It is acoustically isolated
allowing rehearsals to proceed even during a performance
and was designed to be in keeping with the look and feel of
Conservation & Heritage Journal
102
I
