Topping the building envelope

by Tania Wannenburg
Topping the building envelope SAFINTRA

A well designed roofing system is a critical part of the total building’s durability and service life, and steel roofs go a long way in terms of sustainability.

A roof is a building’s primary defence from the elements and, as Safintra’s Nicci Solomons points out, the hardest working part of the building envelope. A well designed roofing system is therefore a critical part of the total building’s durability and service life.

Considering that the built environment is responsible for 40% of the world’s greenhouse gas emissions and utilises one third of the world’s resources, embracing sustainability in buildings is no longer an option – it is a necessity.

Thermally effective
Steel does not only have a negligible thermal resistance with an R-value of 0,000,001W/m2K, but it also has a low thermal mass with a propensity to radiate heat away from a building rather than store it.

“The simple addition of an insulation material creates a highly efficient roof cavity with reduced air leakage and reduced dust intake, making both the roof and the insulation more efficient than an insulated clay tiled roof of the same design,” says Solomons.

“A building with metal roofing then also becomes more comfortable to occupy in all weather extremes, and reduces the use and in turn the costs of heating and cooling systems.”

Above-roof attachments
The structural nature of a steel sheet is an excellent substrate for most above-roof attachments and superstructures.

Facts about steel roofing:
–    In steel roofing materials, sustainability is defined as:
o    Being ultimately recyclable – using less material, but also delivering better performance by being thermally efficient or heat-reflective.
o    Helping to reduce energy consumption during its useful occupied life.
–    Steel is 100% recyclable.
–    Steel is the most recycled material in the world with over 40% of global ferrous resources being recycled.
–    Steel roofing is excellent for water harvesting.

Optimal service life
Sustainability also entails using the least material to achieve the best performance. “The aluminium-zinc coating on ZincAL® and ColorPlus® coil is proven to provide optimal service life from the roof – up to four times longer than a galvanised product of the same coated thickness,” Solomons points out.

Safintra is also a systems partner of Rheinzink®, which is coil-manufactured from high-quality titanium zinc material. Rheinzink is available in the Classicorr® corrugated profile and in the Saflok® 410 concealed fix profile.

Cool metal roofs
According to Solomons, the performance of a cool metal roof depends on solar reflectance and infrared emittance. “Metal roofing can reflect up to 70% of sunrays, resulting in less heat transfer to the interior of the building. Modern coating technologies enhance steel’s low emissivity, allowing buildings to cool down significantly at night and to experience less temperature differential during the day,” she explains.

Safintra is part of the Safal Group, the largest steel roofing manufacturer in Africa. Safintra operates from 36 operations in 12 countries on the continent, and is committed to making, “A world of difference” in the lives of people in all walks of life.

Tel: 011 323 6300
Website: www.safintra.co.za

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