One & Two Southbank
Squire and Partners,
Kohn Pederson Fox
Steel tonnage: 6,300t
basements were completed, along with the
Building One has two cores, a main core
that reaches the full height of the structure,
and a secondary satellite core that only
serves the lowest five levels. Building Two
has just the one centrally-positioned core.
“Building One is a fairly straightforward
building, based around a repetitive 9m ×
12m grid pattern,” explains WSP Associate
Director Andrew Martin. “Two on the
other hand is much more complicated as its
design is partially dictated by the Bakerloo
underground line that passes beneath its
The tube line actually passes under
the structure’s south eastern corner and
series of steps for
Steel model of
Building One (foreground)
and Building Two viewed
from York Road
consequently no piles could be installed in
this area. In order to not position columns
over this important transport link, this
corner, that houses the main entrance of the
building, slopes inwards from the sixth floor
down with the aid of two raking columns.
These raking columns make the building
structurally pull itself towards this corner.
To counterbalance this temporary bracing
has been installed, which has to remain
in position until the structure’s floors are
Both buildings have used cellular beams
throughout for efficient service integration.
However, unlike Building One, which
has some internal columns, Building Two
has none, with clear uninterrupted spans
reaching a maximum length of 17m.
“With such long spans, some of our
connections are very big, as the finished
main member is up to 30t in weight in
places,” says Severfield Senior Project
Manager Paul Walmsley. “We’ve also had
to use a number of plated sections to
achieve these spans and for the supporting
The north and west elevation of Building
Two features a series of outdoor spaces
accommodated on 2m-wide cantilevers.
These spaces extend upwards from level 6,
and they are formed by two further raking
columns positioned at fourth floor level that
extend up to the underside of the sixth floor.
The uppermost floor of Building Two is
known as the entertainment area. Formed
with 12m-high elliptical members, it is
a glazed pavilion that is set back from
the floors below and offers access to a
rooftop terrace. Adjacent to this feature the
structure also has a rooftop two-storey plant
Meanwhile, Building One’s standout
features are the five further outdoor terraces,
formed as the structure steps in at levels five,
eight and nine, and Level 11 is a plant space.
Both blocks will have different cladding
systems, with Building Two finished with
curtain walling, and One predominantly
clad with large precast panels weighing up
to 12 tonnes each.
Both buildings are aiming to achieve a
BREEAM “Excellent’ rating, and are due to
complete towards the end of 2018.
The project is one of the first to be
operating as an Ultra Site under the
Considerate Constructors Scheme.