Designing Timber issue 10 for online - Flipbook - Page 14
———— IN BRIEF ————
CLT WEARS THE CROWN AT ROYALTY STUDIOS
This central London rooftop extension
project, recently completed by TDUK
members ConstruktCLT, demonstrates
the potential of using cross laminated
timber (CLT) to modernise and extend
existing buildings.
Royalty Studios, in Ladbroke Grove, is
undergoing a full refurbishment and
redevelopment, involving the addition
of two new CLT storeys on top of the
existing four-storey Post Moderniststyle o昀케ce building. The lightweight
timber frame element – 300m3 of
timber, which increases the building’s
昀氀oor area by 40% – was designed and
installed by specialist CLT contractor
ConstruktCLT. The scheme will o昀昀er
up to 23,000 square feet of 昀氀exible
commercial space.
IN BRIEF
"It brings together principles of
Optoppen – adding storeys to an
existing building with timber – with
innovative solutions, such as our use
of Rothoblaas’ Spider connections and
improved waterproo昀椀ng," explains Jim
Johnstone, Director of ConstruktCLT.
"It's a beautiful, resilient building with
large, open spaces.”
Turning the design timber
The aim of the client, UCG, was to
update and transform the existing
building into a landmark contemporary
workspace – and they were keen to do so
using low-carbon timber construction.
ConstruktCLT were brought onto the
project in the early design stages to
help develop the design in timber,
and model it for costing. “We worked
collaboratively back-and-forth with the
Engineer, Architect and client to rework
the design to suit timber construction."
As it was the client’s 昀椀rst time working
with mass timber, the predictability of
cost and construction timelines were
reassuring factors; with ConstruktCLT
able to provide a 昀椀xed price based on
detailed modelling of known material
quantities.
Balancing old and new
Externally, the building’s postmodernist
character has been preserved,
with most heritage considerations
focused on the façade, including the
brickwork and round window details.
The interior however allowed for
more design freedom, with the new
昀氀oors characterised by exposed CLT
providing a warm and contemporary
feel to the workspaces.
“The client wanted to future-proof the
building, to make it into something
notable, and they were keen to see
timber.”
Tolerances for interfacing the CLT
structure with existing brickwork and
structural elements were managed
carefully. “For some details, we built
in tolerance, and in some places,
small adjustments were made during
installation – but this is part of the
beauty of CLT construction, that it can
be easily manipulated.”
A very clever spider
Internally, the structure features large
open-plan spaces, made possible by the
innovative use of Rothoblaas’ Spider
connectors. These enabled the design to
remove internal columns and structural
partitions, resulting in a clean and
昀氀exible layout, with just two internal
glulam columns (each measuring
240x240mm) on each 昀氀oor.
The load from the timber extension is
transferred directly through the two
glulam columns down to the existing
building’s load-bearing points. Two Spider
connectors are used at the top 昀氀oor,
where they distribute loads and prevent
the columns from punching through the
CLT panels. This allows the columns to
go straight to the ceiling, which works as
a monolithic slab, without the need for
internal beams or down stand beams.
Rothoblaas’ engineers provided handson support throughout the engineering
process collaborating with ConstruktCLT
and their engineering partner Studio
Allen.
From forest to structure
The client had been inspired by high
pro昀椀le commercial spruce CLT o昀케ces
like the Black & White Building, but they
DESIGNING TIMBER
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NOV/DEC 2025
ultimately decided to opt for pine
instead, as a visual preference. The CLT
was manufactured by Xilonor using
Radiata Pine grown in Galicia, Spain.
The timber was transported by boat
to Birkenhead and then by lorry to
London, resulting in a signi昀椀cantly lower
environmental footprint than traditional
transport routes for CLT. The installation
of the CLT took a crew of 昀椀ve people
and a 60T Telescopic Crawler crane
just seven weeks and involved seven
articulated lorry deliveries.
Access and logistics were a challenge
due to the site’s location. “Building
something like this in the middle of
Ladbroke Grove had its di昀케culties for
delivery access and getting the crawler
crane on site. We were building through
winter with visual grade timber, so it
was crucial to maintain the integrity of
the 昀椀nish on the internal face and be
very careful with water management.”
