Glass is the new norm for Nairobi’s highrise offers, but is the cost more than just the extra shillings?

At 105 metres tall, Kenyatta International Convention Centre dominated Nairobi’s skyline for years.

The building towered over the rest of Nairobi’s architectural offerings, dwarfing such other highrise structures of the time like Teleposta Towers and Nyayo House.

But today, with more than 50 highrise structures jostling for space, Nairobi is rapidly transforming into a proper concrete jungle, in the words of the great reggae musician, Bob Marley.

That growth is angling for a piece of the city’s aesthetic pie, meaning that, even though KICC still remains the most iconic building here, it is surrounded by structures that are more than just concrete edifices. The race for beauty and elegance is attracting all sorts of architectural designs, and the craze now is for all-glass finishes.

In other global capitals, shiny complexes have all but swallowed the gothic and other styles from the early 1900s.

In Dubai, the world’s tallest building, the Burj Khalifa, kisses the skies with astounding beauty, and at night it is lit by hundreds of lights that reflect its glassy modishness over the Emirati skyline.

In London, The Shard, described by Jonathan Jones of The Guardian as a “transparently misconceived and prodigiously cocksure colossus”, towers 87 stories over Southwark. Standing proudly at 309.6 metres, it became the tallest building in the European Union in December 2011, surpassing Germany’s Commerzbank Tower, which pierces the skies at 259 metres.

FUTURE IN GLASS

So, what is the connection between Burj Khalifa and The Shard? The answer is simple; glass, and Nairobi is following suit, although not as extravagantly as these two other capitals.

The city, whose real estate sector has been on a rapid upward trend, has over 10 buildings standing higher than 80 metres. But the skyscraper boom is not all that city residents have to contend with as a myriad of glass façade buildings are also taking over the skies.

From the imposing I&M Building, which glitters in the warm Nairobi sun like a lone star on the width and breadth of Kenyatta Avenue, to the ocean-green panes of the newly constructed Sifa Towers which pour life to the surrounding buildings on the junction of Lenana and Ring roads, Nairobi clearly sees a future in glass.

For architects, just like developers, the outward appearance of a building matters a lot; so much so that it is said to set the tone for the rest of the structure.

For this reason, developers, architects and contractors will strive to put up aesthetically appealing buildings that pass across a muted yet strong statement about their creativity.

Sifa Towers, an all-glass-façade, 12-storey structure that has adopted the architectural concept of a “hyperbolic-parabolic curve”, took three years to build. And when it was finally finished, it attracted rave reviews from the industry.

The developers, King’s Properties, call it “a 21st century commercial complex that goes beyond the conventional building”, and which anticipates “the growing needs in Kenya for a modern business environment that delivers growth and prosperity”.

In Upper Hill, construction is ongoing for Britam Tower, a 31-storey building inspired by the shape of a prism, and whose developers say will be a game changer in the battle for Nairobi’s skies.

So developers are no longer just competing for the few additional feet at the top, but also for the most aesthetic construction in town. As Nairobi-based architect Gad Opiyo explains, a building’s aesthetic appeal matters as much to a developer as its structural rigidity.

However, that appeal comes at a price as glass frames are more expensive than other finishes, like paint. “The use of glass as a finishing tool is costing developers up to three times the amount they would spend on concrete walls,” says Mr Opiyo.

As if borrowing a leaf from the glistening capitals of the developed world, foreign and local investors are using an architectural language that is giving more importance to the “transparency” and “lightness” of building spaces, and hence driving Nairobi towards a flattering, glazed environment.

BUILDING CODE

Interestingly, Mr Jeffrey Gitau, a structural engineer, says that most of the developers are local investors who are interested in bringing “the London feel” to Nairobi.

“Glass is a good material and local developers are now going for it since it gives a sense of modernity,” says Mr Gitau, adding that developers are also interested in having much natural light within the building to cut down on the cost of power.

Also, adds Mr Opiyo, it is faster to construct using glass than concrete.

“Technology has evolved from the traditional wall-to-wall brick-and-mortar variety to today’s screen walls and glass facades which are fixed after major constructions are completed. These facades are mounted on aluminium frames, the latest technology in construction,” he says.

A glass wall not only brings light to offices, but also gives developers the leeway to adjust their office space and feel to suit their preferences. For instance, one may decide to have the whole wall as a window, thereby altering the design of the building and creating the illusion of a wide, open space.

“Masonry, compared to glass, is heavier. A developer will go for glass because, although it is costly, it will only use up small-size structural beams and columns, making it a bit cheaper,” says Mr Opiyo.

So, how high can these glassy edifices rise? Should we expect one to dwarf the postcard-dominating KICC?

Mr Opiyo explains that even though there are no skyline bylaws in the country, there is a building code which acts as a guideline on how tall a construction can be. The code guides the contractor based on the plot size and ratio, he adds.

“The building code dictates a construction’s height coverage. For the CBD and Upper Hill areas, it allows for 100 per cent coverage, while in most residential areas, one can only use up to half of the plot’s coverage to control the density of the area,” explains Mr Opiyo.

Mr Jerry Ndong’, an architect and former chair of the Architectural Asssociation of Kenya, advises that during construction, it is crucial for the developer to get the right advice on the type of glass to use.

“For small frames, one should use thinner glass that is up to 3mm thick, while for wide frames one should use glass of up to 20mm thickness to prevent it from easily breaking.”

GREENHOUSE EFFECT

Those who go the glass way say they are saving the planet by ensuring their buildings have natural lighting. The Glass for Europe website (www.glassforeurope.com), for instance, says growth in building products is fuelled by that of construction projects, both of which are magnified by an architectural and engineering trend towards greater use of glass in building facades.

“The environmental protection in this case is exploiting the ability of glass to capture natural heat and light, and thus reducing the carbon output associated with heating and electrical power,” an excerpt from the site reads.

But the United Nations Environmental Programme differs with this explanation, saying that some global architectural trends “such as the use of glass envelopes in high-rise office buildings, may not be appropriate for their climatic conditions, particularly in hot climates”.

Mr Opiyo agrees, saying glazed buildings “reflect sun rays as they absorb heat”, meaning that if one doesn’t open the windows for aeration, one will need an air conditioner.

“During the cold season, the room will be so cold that  you will need a heater, therefore it is not energy-efficient,” he says, adding that glass façade constructions are also not suitable for tropical areas where there is long duration of sunshine since they will retain a lot of heat.

However, the experts agree that if the structure of the building is done to the required standards, giving it a nice touch by cladding it (covering the skeleton of the structure) with glass should not be a daunting task if the developer is using professionals.

However, there are basic things to bear in mind while going for glass. First, since glass has a greenhouse effect, it is important to use screens on windows. These can be curtains or sun-shading glass.

UV rays from the sun penetrate the glass walls and become infrared rays which are retained in the room. This feature tends to make glass buildings hotter and in need of air conditioners.

To ensure there is free flow of air to maintain the temperatures of the room, use cross ventilation, which reduces the effects of direct sunlight.

Secondly, the movement of the sun determines how the structure will be constructed, and it is important to avoid direct sunlight.

“Each frame and fixing depends on the designs of the desired end product and therefore it is imperative that it be done meticulously to counter any negative aspects,” says Mr Gitau.

Finally, the structural engineer advises that a good glass façade building should be positioned relative to the movement of the sun around the year.

“A general rule is to build the unit in the East-West direction. Also, remember that the higher you construct the unit, the stronger the glass frames should be since at that point, wind becomes a real danger.”