16 NSC
Feb 20
What to do with outdated
and inefficient city centre
commercial buildings is
a conundrum developers
have been battling with for many years.
Demolish the structure and start again with
a new scheme is one option, but nowadays
refurbishment is more commonly seen as a
cost-effective and environmentally-friendly
solution.
Each building has to be looked at
individually and each option will have its
own particular merits, although demolishing
a high-rise building in a crowded city centre
can be highly challenging.
To reuse an existing structure’s fabric
and foundations, reconfigure the building’s
internal layout, and in some cases, add extra
floors, is a design solution many developers
are opting for in order to create costeffective,
modern, efficient and high-quality
work spaces.
This is the design option taken at 60
London Wall, where a 1990s steel-framed
office building in the heart of the square
mile is being extensively refurbished and
reconfigured.
EPR Architects Project Director Jason
Balls says: “We sought to reinvent the
existing, outdated building, by repositioning
the main core whilst adding large flexible
floorplates and external terraces.
“Re-using and adapting the existing
steel frame reduced the carbon footprint of
the building, effectively saving the energy
embodied in the existing fabric.”
The building’s fabric has been stripped
back to its original steel frame, the cores have
been removed, perimeter steelwork and slab
around two elevations replaced for a new
façade, and new floors added to the top of
the structure, all of which has increased the
overall floor space by more than 50%.
“The original building was a seven-storey
office block with ground floor retail and a
basement. We have removed the uppermost
floor, as it didn’t fit our new design, and then
added five new levels increasing the structure
to 11-storeys,” explains Skanska Project
Director Tony Boorer.
Main contractor Skanska began on-site
during August 2017 and although much of
the original building has been retained, the
initial works included a large-scale reworking
of the structure, which required a year-long
demolition and enabling works programme.
Large amounts of temporary supports
had to be installed to allow the removal of
the four original concrete cores – one in each
corner of the building. These areas were then
subsequently infilled with new steelwork and
metal deck flooring. Another central area of
the building was then demolished in order
to create space for a new stability-giving
concrete core.
A 3m-wide section of the perimeter slab
was also removed along the London Wall
and Copthall Avenue elevations, to facilitate
the installation of a new façade.
The design for the new scheme has
maintained the original 7.5m × 7.5m column
spacings, but along these elevations a much
smaller 3m perimeter column spacing was
originally in place to match the cladding
system.
Perimeter columns that were on grid were
retained and strengthened, while those that
were deemed to be off grid, and would have
Commercial
Retain and enlarge
A complex project that has included a partial demolition
programme, strengthening of existing steelwork and the addition
of new upper floors has extensively refurbished and reinvented
an outdated steel-framed office block in the City of London.
Terraces have been
added to the building
FACT FILE
60 London Wall, London
Main client:
LaSalle Investment
Management
Architect:
EPR Architects
Main contractor:
Skanska
Structural engineer:
Heyne Tillett Steel
Steelwork contractor:
Severfield
Steel tonnage: 2,100t
/Multi-storey_office_buildings
/Design
/Braced_frames
/Life_cycle_assessment_and_embodied_carbon#What_is_embodied_carbon.3F
/Concept_design#Concrete_or_steel_cores
/Construction#Temporary_works
/Steel_construction_products#Decking_for_floors
/Concept_design#Structural_options_for_stability
/Facades_and_interfaces
/Concept_design#Floor_grids