The tallest trees catch the most wind. It’s the same with buildings, which is why a plan for Cape Town’s tallest skyscraper has raised concerns about its “domino” shape and how to stop rooftop furniture being blown away by the city’s gales.
A wind study found it would be difficult to have an outdoor facility on top of the proposed 145m building opposite the Cape Town International Convention Centre.
The summer southeaster — the Cape Doctor — has been known to flatten pedestrians at the blustery end of town, and architects of the Foreshore project have been advised to change their design to counter the wind on the roof and at pavement level.
The erf 204 Roggebaai project has raised eyebrows in Cape Town property circles, not least because of its dimensions: a rectangular shape towering above others and marginally higher than the next highest Cape Town building a short distance away, Portside Tower.
The building would include a 200-bed hotel and 111 apartments on a 1,294m² site, with 180 underground parking bays.
The plan has the thumbs-up from the city planning tribunal but now awaits an appeal process. Planning officials suggested architects go back to the drawing board.
“The building does not have a distinctive shape, and looks like a domino standing up, which is not conducive to creating a varied and attractive CBD skyline,” said a report to the tribunal.
Studies submitted to planners included an analysis of the building’s impact on ground-level shadow, mountain views and wind tunnelling. The impact of wind on the building’s structures was also considered.
“There is evidence that winds in Cape Town can considerably affect pedestrians,” said a wind study by Mackenzie Hoy Consulting Acoustic Engineers. “At the start of the 2009 Argus Cycle Tour, tents and cyclists were blown over in Hertzog Boulevard due to 60km/h (17m/sec) winds.
“It will not be possible to have any form of outdoor facility on the roof of the building without localised protection.”
One objection was that the developer had not made provision for affordable housing. But planning officials said this was not a deal-breaker. “The imposition of a large affordable housing percentage could negatively impact on the financial viability of the project, which is not considered appropriate given the other benefits that the proposal will provide for the CBD and city,” they said.
Consulting town planner PJ Lerm of Urban Dynamics Western Cape declined to answer questions about the project until the window for an appeal had closed.
Sapphyr Properties, which bought the property for R120m in March last year, could not be reached for comment.
Planning tribunal chair Dave Daniels said its decision would be communicated soon. “The appeal period will commence once all interested parties have been notified of the said decision,” he said.
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