Architect and Builder Dec 2017 / Jan 2018 | Page 79

The roof space is treated as a ‘fifth elevation’
and a usable space. It is landscaped and utilised
as breakaway space for the office users.
Challenges
One of the challenges was achieving the fire
escape capacities required. An unusual feature
is that the public ‘street’ is actually a pressurised
fire escape. All the wood is treated with a fire
retardant and there is fire separation between the
‘street’ and the office and retail spaces. All glass
shop and office fronts are protected by drenchers
aimed directly onto the glass, thus separating them
from the ‘street’ in case of fire. The main staircase
within the ‘street’ also acts as a fire escape. The
huge extraction fans form part of the industrial
design as well as the fire management system.
The building is unusual in terms of its footprint
and it was a challenge to work within the geometry
of the site. Building on top of an existing parking
basement and within the overall design plan of
the Silo precinct resulted in what is essentially
a triangular design. Stipulated pedestrian routes
and public spaces as well as the relationship to
the historical core of the district, the Grain Silo
complex, further defined the building design.
Façade
The façade, engineered by Arup’s façade
engineering team, plays an important role in the
No 5 Silo
successful performance of the building. It is a
practical design when it comes to the window
to wall ratio and the balance between glass and
opaque surfaces. The façade responds very directly
to orientation. For instance the north façade, where
sun control is relatively easy, is entirely glazed with
the addition of fritted glass fins that control the
amount of sunlight coming into the building.
The East and West façades, which are harder
to control in terms of light entering the building,
consist of a high ratio of opaque to glass areas.
Angled towards Table Mountain, the south
façade, with the least sun exposure, is entirely
glazed, bringing a high level of daylight into the
building and playing a large role in supported the
sustainability aspirations.
The façades respond intimately to their
surroundings and make the most of the expan-
sive views of the harbour, mountains and sur-
rounding buildings.
High performance double glazing reduces
solar gain in to the building and ensures excellent
acoustics, removing the majority of noise produced
by a busy working harbour environment. Solar
and thermal performance requirements were
set at a high level to meet the stringent energy
requirements from within the building.
The tile chosen to clad the façade gives the
impression of oxidised steel, supporting the
industrial architectural aesthetic.
79