IBT Bill Wolmuth
IBT Independent Buildin Technology
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Profiled metal roofing:
built-up systems; composite systems and standing seam systems

Over the years, IBT has undertaken a number of investigations and advised upon remedial works in connection with problems and defects on large, new low slope roofs comprising built-up profiled metal roofing (with through fix, secret clip or standing seam top sheets) or composite systems.   A few examples are given below.


A composite panel roof installation of more than 10,000 sq.m.   Extensive leakage was identified through end laps due to end lap tapes being stretched upon installation at rib positions.  Remedial works undertaken and problem resolved.


A built-up profiled metal roof approximately twenty years old with isolated leakage problems due to details modified since construction and due to poor maintenance.  Advice on remedial works provided.

Checking the airtightness and hence watertightness of fixings with an air suction device.

A built-up profiled metal roof of more than 5,000 sq.m.  Investigations post-construction revealed that a significant proportion of brackets securing the top sheeting through the liner sheets to the purlins only had one fixing per bracket instead of two.  Load tests confirmed a potential problem in the event of wind suction.  Other serious shortcomings were also identified.  As a result, the top sheet was removed progressively across the entire roof, the shortcomings corrected and a new top sheet installed.  The building remained in occupation throughout.  

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Example of bracket fixed through liner sheet with only one fixing instead of two, reducing capacity to resist wind suction.