Special Report: Functional facades
Discussing façade design in Qatar
Qatar is embracing new construction technologies at an accelerating pace in an endeavour to deliver the new buildings and infrastructure required to achieve the Qatar 2030 National Vision. The increasing variety and complexity of façades adorning Qatar’s new buildings is a highly visible manifestation of this trend.
Changes taking place to achieve the Qatar National Vision have given rise to significant legislative and technological changes which have had a major impact on building construction and façade design. Key drivers in this change have been the requirement for sustainable buildings and the adoption of BIM.
The Qatar Construction Specification (QCS) 2014 now requires that designers and contractors give far greater consideration to building envelope performance. Section 15: Insulation of Buildings (formerly Thermal Insulation of Buildings) Part 02 Building Insulation is significantly enhanced. It now includes Section 2.2.1 Minimum Performance Requirements for building envelope façades, providing comprehensive target ranges for glazing in respect of thermal transmittance, shading coefficient and light transmittance, and for ratios of glazed to solid areas, ranging from below 40% to 60% plus. The QCS also makes reference to GSAS in respect of heritage and culture and an increasing emphasis has been given due consideration to Qatari regional identity and heritage.
In the ten years since 2006, façade technology and design has developed rapidly from rendered façades – simple stick curtain walling and simple GRP clad structures – to encompass ventilated façades, double curving envelopes and sophisticated layered façades. Quality control is much improved and earlier problems experienced in respect to vertical fireproofing and poor quality glazing, resulting in pronounced distortions in glazing, appear to have been solved. Qatar can now boast buildings which are both award winning and unique to the country, each of these employing modern techniques in façade design and construction.
Notable amongst these is the Doha Tower which employs externally mounted sun screens in a striking and unashamedly modern interpretation of the traditional Islamic mashrabiya, to shade the building from high temperatures and, while winning awards along the way, has quickly become a symbol for Qatar.
Rain screen cladding, common in northern climates has been adapted for the Qatar climate in the form of ventilated facades in which the interspace between the external cladding and the inner wall is designed to allow the natural flow of air displacement, thus helping to keep the building cool.
This approach has been employed at the Museum of Islamic Art. Also, a combination of ventilated facades and externally insulated rendering systems are used to great effect at the M’Sheireb development in Downtown Doha in which façade materials and proportions are cultural and are integrated to a homogenous predetermined set of architectural and urban design guidelines.
Major government and non-government clients are also now demanding that project teams develop designs using BIM to ensure a greater level of design quality control. This has implications and opportunities for the whole supply chain, including façades.
Glass-reinforced concrete (GRC) has been common in Qatar for some time, most notably on many of the towers on the Pearl development, while the new National Museum of Qatar, which is rapidly moving toward completion, is elevating this technique to an art form. The exterior sand-colored skin comprises several thousand interlocking GRC panels to evoke the sculptural qualities of the desert rose.
To build this has required the design and construction teams to work to new levels of accuracy in virtual space, made possible by BIM technology and fabrication.Further developments supported by BIM include the Lusail Multipurpose Sports Arena in which a diagrid clad skin flows seamlessly over a series of double curving volumes, becoming both façade and roof at the same time.
These projects set the benchmark for others to follow and there is still room for improvement. In the wake of the highly publicised flooding last year and with FIFA 2022 now scheduled to take place in the winter months, is heightened awareness of the disruption that water ingress can cause.
Clients are demanding increasingly higher levels of envelope performance to protect their assets and reduce maintenance and operational costs.
Going forward, there will be challenges as budgets are tightened in the wake of oil revenue cuts. This, coupled with an increasing trend towards design and build contracting to help deliver projects on time, will place further pressure on designers and façade engineers. Quality control and client representation will be essential to ensure that façades are not easy targets for misplaced value engineering to reduce cost.
In this context, the team has to think value management rather than value engineering, as life cycle is becoming increasingly important.
Ashghal has adopted the slogan ‘Qatar Deserves the Best’ and is making sure that this message is understood Qatar-wide. As Qatar’s major projects are being designed with legacy in mind, it is clear that giving due consideration to sustainable façade solutions will be a major determinant in the success of this legacy.
Martin Hay, principal at Kasian.