Extreme zinc: sea, zinc and sand!

 

 

Extreme zinc: sea, zinc and sand!

Punctual but intensive rainfall, sand storms, salt spray and excessive heat: the roofers who worked on the roof of The Gate shopping mall - associated with the lobby of the Al-Bustan Hotel in Doha, Qatar – were confronted with intensive climatic conditions. A challenge they met successfully, as almost ten years after it was installed, this roof continues to provide its owner with full satisfaction, confirming that zinc can be a pertinent solution in these regions!

As we can imagine, the context for installing a roof in this type of subtropical climate is highly specific. The solutions provided must take into account high levels of expansion in the metal due to huge differences in temperature, corrosion of surfaces generated by the high salinity of sea water, erosion that is accentuated by regular friction caused by sand and evacuation of large quantities of water due to sporadic rainfall.

In Qatar, it rains seldom but intensely (around September-October) and the temperature rises well above 35° C, with peaks of up to 50° C and higher in July. However these two climatic extremes are not the biggest constraint for the materials used in the buildings’ envelope. The biggest constraint was the sand storms that make site work extremely difficult and project small silica crystals into even the tiniest of grooves in roofs and gutters. The icing on the cake is that these same storms carry salt spray from the nearby sea.

Technical assistance was decisive

For all these reasons, we decided to complement the sale of our material (in this case QUARTZ-ZINC) with solid technical assistance during forming and installation of standing seam elements in long sheets (the largest of which measure approximately 16 metres). The low pitch roof resembles a large round lens at its centre. The gutter along its edges is concealed by flashing reminiscent of the leading edge of an aircraft wing. Standing seam also features on the underside.

Sammy, our technician, was able to count on an attentive team that was eager to learn zinc techniques. Special care was taken when installing the fixing clips (fixed on the ridge and mobile on the slopes to facilitate expansion at the bottom of the slopes), with an increase in density at the lower edges where wind speed is highest. In the end, the project did not pose any major technical problems, even if it was necessary to manage transport of the long zinc strips by hand during huge gusts of wind and sand!

In this “extreme zinc” series we previously spoke about VMZINC in Patagonia, at the foot of Mont Blanc and at the summit of a tower in Taiwan. Now we have recounted an application in the Arabian Peninsula. Next time, I will tell you about a top end hotel at a very high altitude in Lhasa, Tibet!

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Roger Baltus
Engineer - Architect
VMZINC Communication Director

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