The basics of steel roofing in warehouses

To Build is pleased to feature the advice of steel roofing roll-former, Clotal Steel in an article about using steel roofing material optimally.

BDW Sheeting

Modern designs and technologically advanced roofing options has precipitated an increased shift towards metal roofing. The material has gained popularity amongst architects, developers and homeowners, bearing in mind its successful application in overseas markets, including Australia and South East Asia. Metal roofing is seen by designers as economic, durable and enhancing the aesthetics of a project.

Typical scenario An architect has just finished designing a client’s dream project with an aesthetically beautiful metal roof in mind. The client brief for the roof design was simple- a flexible roof design with natural curves. The designer’s initial thought is a metal roof. As steel is readily formable, steel roofing offers the designer a variety of pre-painted colours and material finishes which include gloss, matt and textured options. It also offers freedom of design and creativity, which makes it suitable for a wide variety of roof design features.

However, architects and designers need to be aware of the tips and tricks associated with metal roofs, which are key in executing a project with success.

Important considerations • Soft roof vs hard roof A metal roof is considered a soft roof. Because of the strength of a metal roof, people walking on the roof is no problem. However, this is often abused during construction and maintenance by HVAC and solar heater installers and wet work trades. It is recommended that a site programme as well as roof design places HVAC and other services such as photovoltaic panels near designated walkways are installed in high traffic maintenance areas. This will improve the quality of the roof and its performance over time. • Site conditions Deliver and install roof sheets to the roof in a manner that will not scratch or dent then and cause aesthetic or mechanical damage. • Construction programme Allowing individuals to use a steel roof as a platform to work from will cause significant damage to the roof and problems for the professional team and clients. A programme that allows for the completion of all wet works around and above the roof will mitigate this risk so that metal roof sheeting can be installed in an environment that will lead to a quality finished product. • Location of services Placing services in areas with dedicated access that don’t require people to move about on the steel roof is ideal. If this isn’t possible, the installation of walkways is highly recommended to protect the integrity of the roof over time. • Create a specification for the roof - and police it A specification for a metal roof is the secret to the success of the project. The profile type, material thickness, coating types, yield strengths and paint finishes can often be a confusing combination to get right when it comes to specifying the type of roof to be used on a project.

It is critical to specify each aspect correctly. Ambiguity in specification leads to either honest mistakes, or to

Warehouse project based in Olifantsfontein, Gauteng. Used 7000m 2 for the roof of 0.58mm ISQ300 Chromadek, Craft-Lock ® concealed fixed roofing plus 4600m 2 of IBR cladding.

Typical specification: Concealed roof

A typical example of a Craft-Lock ® concealed fixed roof sheeting specification for a project would be the following: Craft-Lock ® concealed fix roof sheeting manufactured by Clotan Steel with a male/female sideways interlocking mechanism, forming a double capillary action break manufactured from (1) 0.58mm thick (2) ISQ300 steel with (3) Chromadek ® finish, colour (TBD- for example, Fish Eagle White), with a (4) Z275 (5)galvanized coating.

References: (1) Refers to your thickness of choice (2) Refers to the correct material grade (3) Refers to the desired finish (4) Refers to the desired protective coating mass (5) Refers to the desired protective coating

wilful manipulation by contractors or subcontractors on projects, where lesser quality products are used than were intended. By taking the time to write a clear specification and avoiding wording such as “similar or approved” will result in clients and professionals having the roofing materials and profile on their projects that were initially chosen and specified.

In general How to specify a metal roof for your project There are five features to consider when specifying metal roofs for your project: 1. Material thickness: This is the thickness of the material used to manufacture the roof sheets (0.5mm, 0.53mm, 0.55mm, 0.58 mm or 0.8mm) 2. Material type: This refers to the type of material. There are two main categories – pre-painted

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5. (Chromadek ® , Colorbond ® or ColorPlus ® ) and unpainted (ZincAl ® , galvanised, Zincalume ® , Copper, Zinc or Aluminium) Coating thickness: This refers to the protective coating thickness of the steel substrate, like Z200, Z275, AZ100, AZ150, AZ200, where a Z200 grade will mean 200 grams of zinc per square metre or AZ150 will mean 150 grams of Aluminium zinc per square metre. Yield strength: This refers to the material grade (ISQ300, G300,etc). Profile: This refers to the type of profile; pierced fixed (widespan, corrugated, C-tile and IBR) or concealed fixed (Craft-Lock ® and Reehfalz).

Clotan Steel contact@clotansteel.co.za

By ensuring best practice on a metal roof, it is recommended that there is no construction or maintenance traffic on roofs. Hard roofs are recommended with internal access and if traffic is unavoidable, install temporary walkways with marine ply, or design permanent walkways with compatible clips and steel walkways on the roof.

Always choose the correct profile type, taking the roof design into consideration and ensure penetrations through the roof are dealt with in accordance to best practice on manufacturers specifications. Ensure that the correct grade and type of fixings are used. Don’t push construction programmes to such an extent that the roof is used as construction platform, as this will inevitably lead to the complete destruction and replacement of the roof, defeating the purpose of the cost savings. If you want a lasting metal roof to remain aesthetically pleasing, trust the leaders in roofing innovation to provide you with the roofing solutions you need for your project.