FAQ’S on Aluminium-Zinc Coated Metal Roofing
Benefits of installing a metal roof
There are many benefits of installing a metal roof: it is available in a wide variety of profiles and colours. It is largely intruder proof, and it is highly thermally effective when well -insulated, making the building more comfortable and more affordable to occupy.
- For architects, it is a versatile material allowing for both creative and functional flexibility.
- For engineers, it is light but very strong, and delivers exceptional structural and weather performance.
- For the planet: Metal roofing is energy efficient and sustainable: it contains significant recycled content and is 100% recyclable at the end of its useful life.
- It has a long life expectancy, and is the ideal substrate for many green technologies such as solar PV and solar water systems, water harvesting, and more.
- Metal roofing can also be effectively insulated to create air spaces which provide optimal ‘R’ values (thermal efficiency and internal comfort, plus energy savings!)
Q-Are all metal-coated or pre-painted steel sheets of the same quality?
A-The world’s most modern and widely used steel coating incorporates a mix of zinc and aluminium which work in harmony to provide optimal coating protection for the steel core. Global research has established that the performance of aluminium-zinc coated steel offers a service life at least 4 times longer than that of an equivalent Zinc galvanised sheet of the same coating thickness in the same application.
As part of its commitment to world class roofing and materials, Safintra recommends that it supplies you with aluminium zinc coated steel, the world’s leading metal coating technology for enhanced service life.
(See pdf on this website entitled "Benefits of Aluminium Zinc coating technology”)
Q-Are different materials recommended for different environmental conditions.
A-For inland and rural conditions, an aluminium-zinc coating of 150 g/m2 (known as AZ 150) will offer a durable service life of 15 years and more. For extremely corrosive environments, and within 1-2 kms of the coast or similar, we recommend steel with a minimum coating of AZ 200 (a thicker aluminium-zinc coating depth) to endure these harsh environments.
Safintra also supplies Aluminium and Rheinzink material for specialist applications.
- An alternative to AZ 200 coated steel is Aluminium. Aluminium is both lighter and softer than mild coated steel so is generally used in thicker gauges than steel.
- Rheinzink is a titanium-zinc material which is maintenance-free and offers a service life of 75 years or more in all environments. The material is available in three finishes: bright rolled, "preweathered blue-grey" and "preweathered graphite-grey". Visit www.rheinzink.co.za
Q-How does a metal roof compare in cost with other roofing materials?
A-Because aluminium-zinc coated metal roofing (Zincal, Zincalume) is a top quality product, you can expect a new residential roof to cost about the same as a clay tile roof. In the longer term, homeowners see a significant financial benefit from a metal roof that, unlike tiled roofs, will not have to be substantially repaired for at least 30 years. A metal roof will also save you money on energy bills if properly insulated.
Q-What is the lifespan of a metal roof?
A-The life expectancy of metal roofs will depend upon a number of different factors including climatic conditions and the type of material initially specified. Generally a metal roof has an aesthetic and cosmetic life approaching 30 years. This can be linked to a functional life approaching 60 years. The best possible performance from any roof will be secured by undertaking regular (probably annual) inspections and completing any required maintenance timeously.
A pre-painted metal roof has the same life expectancy as a metallic coated (unpainted) roof. The life expectancy comes from the metal coating, not the paint coating. Paint coating is largely aesthetic.
Q-Can I get a warranty on my Safintra Metal Roof?
A-Safintra Metal Roofing Systems carry meaningful long-term warranties (of up to 20 years) against perforation of the roofing material. In addition, we will get you a warranty on the fasteners which will at minimum match the warranty on the roofing material. And you can get an installation warranty from our recommended installers.
Q-What type of fastener (screw) should be used?
A-For optimal performance, the service life warranty of your fasteners must match the service life warranty of the sheeting being used. All fasteners recommended by Safintra carry a Manufacturer’s Warranty and have a coating system that complies with SANS1273 – 2009 (AS3566.2-2002) standards.
- Saflok Concealed Fix Systems will only be warranted if installed with Safintra approved fasteners.
- Only Class 3 & 4 fasteners are suitable for use with ZincAl / Zincalume/ AZ coated sheeting & Colourplus / Colorbond / pre-painted sheeting.
- Class 4 fasteners must be used within 5km of coast, river and corrosive environments.
- Aluminium roof sheeting: use ONLY stainless steel fasteners.
Q-Must metal flashings be used or would waterproofing be sufficient?
A-Despite the advances in modern day external waterproofing products the harmful rays of the sun will eventually play havoc with their efficacy. These types of products, albeit very effective, should ideally be protected from prolonged exposure to the sun, so a metal flashing becomes the obvious solution.
Q-Is metal roofing noisier than other roofing?
A-The “clicking” of a metal roof is mostly due to thermal expansion and contraction, and is difficult to silence without insulation. When installed with a quality insulation, you can also silence the noise from rain, hail and bad weather as well - if not better - than that of any other roofing material.
Q-Is a metal roof heavy?
A-A metal roof is, on average, 75% lighter than concrete tile and slate. This, coupled with the format of a sheet, and its high strength to weight ratio, means that even the substructure can be much lighter, using far less purlins / battens than a clay tile roof.
Q-How will a metal roof stand up to extreme weather?
A-A metal roof can withstand decades of abuse from extreme weather like high winds, heavy snow, hailstorms, and even fires. Under high wind conditions, a well installed metal roofing system will have high wind resistance well in excess of SANS requirements.
Q-What will happen to a Metal Roof in a lightning storm?
A-Lightning occurs from the highest object in an area, regardless of the material from which it is made. Metal roofing does not create nor attract lightning and if struck, is non-combustible.
Q-What about fire?
A-A metal roof is completely non-combustible and provides great protection from external fires. Additionally, the low weight of our products minimizes any cave-in threat which might occur with an interior house fire.
Q-What about hail?
A-Metal does not lose impact resistance with age – unlike most other products which become more susceptible to damage with each passing year. In the event of an especially severe storm, even if an indentation does occur, a metal roof will be as watertight as before.
Can one walk on a metal roof?
Yes. And metal roofs don’t lose their strength over time, making them as safe when as when they are new. For heavy foot traffic we recommend walkways are installed over the roof – ask us for advice in advance of installation
Q-Metal roofing seems to have a lot of options; how can I sort my way through everything?
A-Safintra will work closely with you to choose the best roof for the purpose. One of the great things about metal roofing is the wide variety of products available. Our team is here to assist you!
Q-In case of renovation does an existing roof need to be removed to install a new metal roof?
A-Not necessarily. In most situations, a new metal roof can be installed directly over an old metal roof. Ask Safintra about the Ash-Grid over roofing solution which is both cost effective and highly efficient for insulation purposes, in line with new building legislation governing thermal efficiencies of buildings. It is a huge plus that a well-insulated roof on a well-designed building will dramatically reduce your energy bills!
Q-Is metal roofing energy efficient?
A-Pre-painted metal roofing in the light colour range together with low thermal mass, means that it cools down quickly after a long hot summer day, providing cooler interiors. Conversely during the winter a highly insulated roof system responds quickly to retain heat within the structure and provide immediate comfort.
Q-Is a Metal Roof environmentally-friendly?
A-A Metal Roofing System is a Green Roof – it is made from material with a recycled content of up to 60% and its long service life guarantees sustainability. Add in energy efficiency and the ability to be installed over most existing roofs (avoiding landfill disposal of old materials) and you have what is likely the most environmentally-friendly roof available to homeowners!
Q-Is water run-off from a metal roof potable?
A-Yes, the water run-off from our products meets the World Health Organization Standards testing. However, rainwater is variable across regions; atmospheric conditions should be considered in actual use. Water collected during the first or second rain fall after extended dry periods can be contaminated by dirt accumulation.
Q-What maintenance does a metal roof require?
A-Although metal roofing in itself is well protected from the elements, preventative maintenance is required to ensure optimal performance. This includes periodic inspections of the roof as well as regular washing down of pre-painted roofing with a hose pipe and plain water. Do not use hard brushes that will scratch the surface.
Q-What can I do to protect cut edges of metal sheets?
A-Cut edges and other areas where the base metal are exposed are protected by the coating. Due to a phenomenon called Galvanic Action, which is triggered when moisture is present, the coating sacrifices itself by offering itself for corrosion instead of the steel base.
The use of clean paraffin may be applied carefully to the cut edge to further hinder corrosion.
Q-Why use factory-pre-painted metal roofing?
A-Factory pre-painted metal roofing retains its good looks and durability for decades, because it is manufactured under factory controlled conditions providing high quality finishes which are self-cleaning in the rain, anti-bacterial and anti-fungal, and have high thermal reflectance for better interior comfort. Colorplus and Colorbond are both premium quality colour coated products on an aluminium zinc coated metal base.
Q-What should be done if the paint gets scratched?
A-Touching up of Colorplus and Colorbond material is not recommended. Should the scratch or scuff marking be superficial it would be best left untouched. With deep scratches where the protective Aluminium Zinc metal coating has been penetrated, replacement of the affected roof sheets should be considered.
Q-Where do I find a reputable contractor/ could I install the product myself?
A-Safintra SA has a panel of approved installers that specialize in sheet metal roofing installations. Many will also offer you an installation warranty which gives you peace of mind.
Smaller jobs can be certainly be taken on by the DIY handyman, but prior to commencing please feel free to call us and get advice and product information from our qualified staff.