Choosing a roofing designer, fabricator and erector may seem as simple as picking up a phone, asking for a few quotes and, in true South African fashion, the buyer

will accept the cheapest quote and a whole host of promises at face value.

The specifier or end user should ask a number of pertinent questions when requesting a design and fabrication of a monoplaner prefabricated roof system. Although to a lesser degree for residential roofs, the following is especially relevant for any ‘public building’, class of occupancy other than H3 or H4, as defined in SANS 10400-A of the National Building Regulations.

• Does the fabricator hold a current Certificate of Competence as issued by the Institute for Timber Construction (ITC-SA) in the appropriate category? There are presently four categories and only fabricators in category A (high risk) may fabricate roof structures for public buildings, laminated timber structures, spans larger than 10m, scissor trusses > 5m, attics, dormers, piggyback trusses, complex industrial and commercial buildings and complex hip systems.

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Caveat lector – let the reader beware

All too often we are presented with the legal term ‘caveat emptor’ – let the buyer beware – but this is more than often too late and the wrong

choice has already been made.By Lyndsay Cotton, General Manager of LCP Roofing and Chairman of the ITC-SA.

NOV / DeC 2013

• Does the erector hold a category A certificate as issued by the ITC-SA if erecting the abovementioned class of buildings? He must be able to produce his certificate of competence.

• Can the fabricator prove that his system (software supplier) has verified and checked his design if it falls into category A?

• Can the fabricator prove, through an approved quality system, i.e. SANS1900, that he has verified the dimensional accuracy of his incoming timber? It is the writer’s experience that more and more timber in South Africa does not conform and the potential of failure cannot be excluded. The fabricator will not be able to hide behind product liability insurance if he cannot prove that he has used material that conforms to standards.

• Does the fabricator belong to and only purchase nail plates through one of the accredited system suppliers in South Africa, i.e. Alpine Systems, Multinail, MiTek Industries or International Truss Systems and as tested and approved by the CSIR? There are other vendors of ‘pirate’ nail plates who have entered the market in South Africa and their fit-for-purpose applications have yet to be conclusively proved through an accredited and pre-defined testing process as recommended by Timber engineering Advisory Committee of the ITC-SA and the CSIR. They are able to produce ‘so-called’ SABS test certificates, but these are not in accordance with the procedures as laid down by the ITC-SA.

• Can the fabricator prove that his bracing design and the application is strictly in accordance with Volume 2 as published by the ITC-SA?

• Can the fabricator prove that all timber used is structurally graded? The use of non-structural timber or XXX (‘black cross’) timber is specifically prohibited.

• Can the fabricator prove that he has used the correct loading for the roof cover envisaged? Generic, ‘one fits all’ loadings on quote templates are not acceptable.

• Do quotations and site documentation comply strictly in accordance with the requirements of the ITC-SA?

• Does the fabricator subscribe to an externally audited quality system such as SANS1900 and is he audited by either SATAS or the SABS?

• Are trusses stored, handled and transported in accordance with SANS 10243? Large and complex timber roof structures should only be transported in a manner so as not to damage or weaken the joints. Any reputable fabricator will transport his product on fit-for-purpose and specially designed truss trailer.

• Does the accredited inspector or engineer inspecting the roof have a complete erection drawing at hand and can he verify through this that the timber structure has been erected according to the design intent? Needless to say, even if it is a registered engineer, is he fully with au fait with the erectors and bracing manual and is he accredited with or an engineer member of the ITC-SA?

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FaIlure to be able to answer posItIvely to all oF the questIons above Could lead to the FollowIng:

• Failure of the roof structure which could lead to serious injury or death which could result in the building owner being held liable to negligent and criminal charges.

• Sagging roofs, eaves or gables which will detract from the aesthetics of the building.

• Non issue of an occupation certificate as the building inspectorate nationally is being educated and briefed on these aspects.

• Possible repudiation of any form of insurance claims regarding roof structures as any competent insurer will, when investigating any claim, confirm if all industry related requirements and norms are being complied with.