Specifying metal roofs – it’s in the detail

by Darren
Specifying metal roofs its in the detail SAFINTRA

The design of a roof system demands detailed and fastidious focus on every system component.

A roofing system is the hardest working part of the building envelope, and therefore the design demands detailed and fastidious focus on every system component in order to make the most of its potential.

From selecting the appropriate roofing material and roofing profile, to considering roof ventilation, as well as rooftop fitments such as solar arrays, satellite dishes or heavy HVAC units, all these factors should be considered at the design stage. In fact, the performance of the total roof system should be seen as a single investment by property owners, investors and occupants.

Specify the right material
Whether selecting a material for roofing or cladding, metal is a good choice for architects on the cutting edge of green. Not only is it cost-effective, but steel roofing also contributes to sustainability since it is 100% recyclable at the end of its useful life.

However, not all metal roofing materials are the same. When it comes to coated steel, aluminium-zinc coated metal has huge benefits over a traditional galvanised material in terms of a longer service life and superior thermal efficiency, which delivers cost savings when heating and cooling buildings.

For extremely corrosive environments or specialised applications, aluminium (painted or unpainted) and Rheinzink (titanium zinc) provide uniquely extended lifespans.

Specify the correct profile
Metal expands at approximately 1mm per metre, so when installing long lengths, natural thermal expansion and contraction can be a serious concern, particularly where there are significant differences in daytime and evening temperatures.

This is where concealed fix systems such as Saflok™ or a standing seam system such as Newlok™ is ideal. These systems have hidden clips, anchors and other attachments, allowing for thermal movement, and can withstand challenging wind conditions. They are also aesthetically pleasing.

Specify appropriate fasteners
Equally important as selecting the correct sheeting materials and suitable profiles, is the quality of fasteners selected. For pierced-fix applications, Safintra recommends nothing less than Fixtite® or Safintra-approved Class 4 fasteners.

For the attachment of anchoring or clamping systems with concealed or standing seam, where the fasteners are not exposed to external weather conditions, Safintra indicates that a Class 3 fastener is more than adequate.

Specify flashings and ventilators
Flashings are the components of a roof primarily intended to ensure water-tightness, but they can also contribute to the overall aesthetics.

If penetration of the roof is necessary for the installation of rooftop cooling systems or HVAC installations, designers and contractors must ensure that suitable materials are used in order not to void material warranties. These should also have a service life which reduces frequent maintenance.

Safintra makes flashings for all their profiles, using material matching the roof sheeting, which extends the service life of the entire roof system. The company also makes bespoke ventilators and louvres unique to each project, with warranties that match the sheeting lifespan.

Ensure the roof is serviceable
Finally, roofs need to be able to withstand foot traffic, as well as the loads imposed by the installation of rooftop utilities.

Safintra recommends that all professionals request technical support to ensure that the roof is serviceable and practical for rooftop installations and routine maintenance. Having a strong technical focus, Safintra offers this service free of charge to its customers, from its seven branches countrywide.

Safintra South Africa
Tel: 011 323 6300
Email: info@safintra.co.za
Website: www.safintra.co.za and www.safintra.com

Branches in South Africa: Johannesburg, Durban, Cape Town, Nelspruit, Polokwane, Port Elizabeth and Bloemfontein.
Further operations: Namibia, Botswana, Zambia, Mozambique, Malawi, Tanzania and East Africa.

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Detailed specification matters when it comes to metal roofing.

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