Qatar: Picking correct façade material is priority
There is more to façades than meets the eye in the heat of the Middle Eastern desert
Architecture in Qatar is as limited as the imagination. Looking around the growing capital city, Doha, the multitude of building styles is astounding. However, what creates the grest impact amongst the plethora of structures, it is the variety of façades. While aesthetics are obviously important, given the extreme climate of the region, selecting the correct façade material is a priority.
Shaukat Ali, director of structural engineering, Design Division KEO International Consultants, says, “In façade design, both thermal and visual comfort is required during the selection of material, which needs to comply with sustainable design as well as perform well in heat resistance – while offering better resistance to heat flow from air space.”
Lindsay Mellum, principal consultant, Façade Engineering in WSP I Parsons Brinckerhoff, draws attention to local considerations when choosing a façade: “The façade is effectively a filter. In the Middle East, we aim to keep out the sun’s heat, but let in the right amount of visible light for us to comfortably work / live / play.
“We may also want to allow fresh air in during the cooler months, or even give us access to balconies where we can extend our living environment outside. We also need it to be durable enough to withstand high UV, salts, heat, humidity and pollution.
“Façade design and selection is a balance between meeting the client and architect’s design intent, delivering the needed performance, and complying with local regulations. After all that is done, we must be sure the system can be delivered by the local contractors. Procurement times, local fabrication limitations and installation conditions all influence the selection of the façade. Buildability and practical design are key issues associated with a successful outcome of this balance.”
Indeed, there are multitudinous considerations when it comes to selecting a façade, for example, the impact and abrasion resistance of the material, what the U-value is, the weight of the material on the building and its effects on the main structure, its fire safety qualities and sound resistance, to name a few.
With the bombardment of design influences and cultural clashing, Doha is truly becoming a testing ground for construction distinctiveness and technological advancements.
“There is always a push for new materials and systems never before seen in the city, but the reality is new materials take time to test and certify, as well as the risk of long lead times. There is a benefit to working with local materials approved by the municipality, but exploring innovative ways to use the material and adapt the system,” Mellum says.
Ali expands on current façade trends in the region: “In the building design industry especially in Qatar, the glass exterior is still considered most popular. Aesthetic appearance remains a driving factor for this. Floor to ceiling height glass windows provide market value and a sense of openness in a space utilisation strategy,” he explains.
New technologies have included high performance glass types such as one that offers more heat and light resistance, with the U-value determining the performance of the material’s heat resistance, while double glass panels serve for both noise and heat insulation.
In Tornado Tower, one Doha’s landmark buildings, special solar control glazing was used to protect the building from the intensive solar radiation. This special type of glazing is slightly bluish and gives the tower its characteristic colour. The distinctive glazing features an extremely low solar factor and effective thermal insulation at a light transmittance of 38%.
“For the entrance façade, neutral 70/39 was used, which features high light transmittance, low total energy transmittance and high colour neutrality. The floor-to-ceiling glazing allows plenty of daylight to enter into the building. The glass parapet, the tower’s ‘crown’, is made of laminated sheet glass,” Ali elaborates.
Double skin façade technology is also one of the preferred options in Qatar. In this system, two façade layers, one an insulated wall and the second, a shading layer, is used. “The inner panel basically works as a weather shield. The visual appearance of the building dictates the type of the outer layer.
“This is advantageous when the aim is to achieve a high standard of thermal insulation and sound protection, maximum transparency, reduce cleaning cost, low maintenance solar protection and an expedited construction phase,” he explains.
Other than use of glass on the exterior, light weight glass fibre reinforced concrete (GFRC) is another popular material available to architects and engineers. GFRC is 75% lighter than normal concrete and precast concrete, with the added bonus that complex shapes and texture can also be achieved, so architects do not have to compromise on the visualised aesthetic appearance of the finished product.
“Qatar has always focused on integrating façade design with the region’s heritage,” Mellum contests, adding, “The architecture is trending towards more contemporary interpretations of the cultural influence, through use of natural materials, geometry and patterns.
“It is great to see the transformation from a more literal application of traditional design elements to the type of design we are seeing now – truly inspired by the region.”
Alongside traditional materials like reinforced concrete and the precast curtain wall system with insulation, commonly used in the building industry, increasing in popularity, is glass fibre reinforced plastic (GFRP).
This is desirable for use in places where fire rating, impact resistance and weight considerations are important factors. Made of fibre reinforced composite, GFRP façade panels provide a visually impactful façade system in an extensive range of colours. “Its modern appearance is combined with excellent light fastness, heat resistance and reliable protection against driving rain. GFRP façade panels are highly suitable for rear-ventilated curtain wall façades, an increasingly popular construction element, owing to the increase in thermal insulation requirements,” Ali enthuses.
Façades rest on more than materials however, as he points out: “The solar shading strategy of the building elevations play a vital role in the façade design. Multiple shading and thermal comfort studies are required. In the Middle East, the design strategy is to protect the building from absorbing excessive outside heat, which results in an increase in cooling energy.”
Mellum sees a move towards natural ventilation solutions and expands on her thinking: “We are going to see innovative solutions for natural ventilation, to comply with the region’s focus on sustainability and municipalities’ operable window requirements. The clever solution will be a system that provides occupant control over the internal environment, while addressing the air infiltration, acoustic and safety issues with traditional operable windows.”
Sustainability is increasing in focus in the façade side of construction, along with environmental friendly green building which in turn, impacts on the selection of material.
“Sustainable buildings will require special attention to study the orientation of the building in an effort to minimise summer heat from directly entering the inside of the building and, to achieve optimised shading,” Ali explains.
Mellum muses: “When cities become more developed, the effort shifts to how the building integrates into the landscape of the city – or stands out from it. The challenge lies in creating something new in a city that’s already done it all. We are seeing that in Dubai right now, and we will start seeing it in Qatar as well.”
She believes that the stadia and developments leading up to the FIFA World Cup “are heavily influencing the future look of Doha, just as the new developments planned for the Expo 2020 will dictate the trends in design in Dubai.
“World-class architects are being brought in to both Qatar and the UAE to design these projects, and combined with the expertise of the local architects and consultants, we are going to see great things from it,” she maintains.