Soaring glass tower for Cape Town’s skyline

by Ofentse Sefolo
Soaring glass tower for Cape Town’s skyline

An elegant 86m glass-clad office tower, based at 35 Lower Long Street and completed at an estimated cost of R500 million, is the latest edition to Cape Town’s skyline.

The building was developed by Abland Property Developers and designed by dhk Architects. It is characterised by a singular sculpted massing, which is transformed via dynamic glazed planes that extend seamlessly over the office and parking levels.

The two main corners of the building are chamfered towards the roofline and soar upwards, forming a striking wing-like effect – resulting in a distinctive, non-orthogonal addition to Cape Town’s skyline.

Designed for longevity

The building is in Roggebaai, which is Cape Town’s growing financial and hospitality precinct. It was previously occupied by an eight-storey 1980s office building, which prior to that was part of the now-demolished Long Street Power Station site.

Derick Henstra, dhk executive chairman, says: “A fundamental component of the new design concept, as briefed by the co-owners, Ellerine Bros and Abland, was to offer a more positive medium- to long-term viability, as well as to enhance Cape Town’s skyline with a decidedly taller, inspirational tower building. However, the challenge was to maximise the high-quality, multi-tenant commercial space while accommodating core components such as lifts and stairs along with structured basement parking – all within a relatively small floor plate.”

Space maximisation

To maximise the floor plates, dhk proposed a simple singular orthogonal massing bar to the articulation of the south-eastern and southwestern corners. While fundamentally a solid building mass, the appearance of a dynamic, non-orthogonal sculpted mass was created via the tapering or cranked facade planes which extend seamlessly over the office and parking levels.

This was achieved by chamfering both the south-eastern and southwestern corners of the building at the top of the orthogonal parking base and widening them towards the roof. The technique articulates the facade and defragments the solidity of the corners of the building, as the wings shape the elevations and extend past the top office floor. By extending the wing-shaped facade screens beyond the roof level with parapet sloping, the appearance of soaring shards is created opposed to an abrupt utilitarian termination.

Shard-like facade

In terms of materiality, a glazed facade was selected due to its flush and sculpted reflective form, which conceals both the parking levels and solid spandrels. Not only does glass facilitate an exciting play of light, but it also allows for an expressive articulation of the building mass in the screen and shard-like elements. The introduction of pixilation on the portions fronting the parking levels, ceiling voids, structure and internal desk height upstands allows the building to conceal both the parking levels and avoid overbearing horizontal bands.

Mixed-use development

The entire length of the street frontage along Lower Long Street and Jetty Street is enlivened with new ground-floor retail and multiple entry points into the office building. At street level, a double-volume entrance connects to shuttle lifts connecting all parking levels and the ground floor to a spectacular arrival experience within the 10th-floor sky lobby.

Thereafter, individuals are transported via a double-volume area and terrace to the office lifts, which connect to all the floors above. This ensures mid-building activation and an experience for all users to enjoy as part of the arrival journey into the workspaces – encouraging interaction between different tenants.

Oblique views

Internally, the building offers expansive 360-degree views over the city, ocean and mountains. The glazed facade allows for floor-to-ceiling unencumbered vistas, enhanced by glazing with mullions at 2,4m wide centres. The chamfered corners also offer oblique views which facilitate the appreciation of the architectural form both externally and internally – a desirable design aspect often not apparent in tall buildings.

Furthermore, the multi-purpose roof area with terraces above both chamfered corners offers a spectacular city entertainment space and signifies high-level activation. From an external viewpoint, the perimeter desk height upstands provide ease of furnishing right against the perimeter, with fire separation between the floors. Therefore the office furniture is concealed when viewed externally.

Championing sustainability

As part of achieving the building’s four-star Green Building Council of South Africa design rating, a detailed environmental performance modelling study was undertaken. This required a high-performance, double-glazed specification with increased internal sill height raised to desk height – to reduce both solar gain and radiant heat, which significantly lowered HVAC requirements.

Other environmental considerations included building efficiency, choice of materials, energy-efficient lighting and services, lower parking ratio encouraging the use of public transport, as well as showers and bicycle parking facilities.

Overall, 35 Lower Long Street is a much-needed contemporary addition to Cape Town’s skyline which positively contributes to its surrounding cityscape. Swanepoel says: “With its sleek, sculpted form and soaring-shaped facade, 35 Lower Long Street is an example of how client requirements can be met without comprising on design standards. dhk is extremely proud of this building and views it as a catalyst for future developments to come in Cape Town’s central business district.”

Key facts:
Owner/developer: Ellerine Bros and Abland Property Developers
Architects: dhk Architects
Quantity surveyor: Du Toit Pienaar Quantity Surveyors
Structural engineers: Aurecon
MEP engineers: Eckon + Converge Consulting
Development managers: Abland Property Developers
Project manager: Abland Property Developers
Main contractor: Stabilid Cape Construction
Interior designers: Entrance & Office Lobby Areas – dhk

For more information, visit www.dhk.co.za.

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