Pest Control Business Park

A long two-storey face-brick building with mono-pitch roofs and deep eaves. The roof structure is exposed black steel — rafters, purlins and cantilever cleats running out past the brickwork to carry the overhangs. There is no roof void and there is no ceiling behind the steel. Whatever went on top of those purlins was going to be the finished surface underneath as well, seen from inside and seen from the ground at every eave.

Technopol supplied LiteSpan 990 IBR insulated roof panels. The panel is factory-laminated: a profiled Chromadek steel weatherskin on top, an FRCel fire-retardant EPS core, and a white Chromadek ceiling pan underneath, bonded into one composite element. Cover width is 990 mm with ribs at 330 mm centres. It is laid in a single pass across the purlins — sheet, insulation and finished soffit in one lay, with no brandering, no ceiling board and no skim to follow.

That is what the building asked of it. On a roof this exposed, the product has nowhere to hide: the underside of the panel is the architecture. The panels were craned up in slung bundles on a spreader beam under a truck crane — three panels nested one on the next in the lift photographed here, ribbed top skin over flat pan. The core does not show in that frame, or in any frame published here; the three layers above are the datasheet's account of the panel, not something read off a photograph. Once landed, the panels were fixed down through the pans and not through the rib crowns, with self-drilling screws under sealing washers, and that line of screw heads sitting in the valleys is the one thing you read across the finished roof plane. The LiteSpan fixing schedule for 990 IBR calls for three Class-4 sealed-washer screws per panel at every support — a count and a coating class that no photograph of this roof records.

The rest is junctions. Side flashings lap over the pans where the roof runs into the brick parapets, turn up against the brickwork and are screwed down along both edges. At the eaves the panel simply runs out over the steel and stops, and its own underside becomes the soffit — that is the photograph a specifier should look at twice, because it is the whole argument for the product. Internally the same white pan spans between the purlins and is the ceiling. What crosses it is the black steel — purlins, rafters and a bay of cross-bracing — and the panel laps; in the one interior frame a bay at the head is still open to the sky.

Two things a designer should carry away. 990 IBR is a lapped metal roof with a 5° minimum pitch, not a membrane. And panel depth and purlin centres are one decision, taken together off the LiteSpan load/span tables for the actual loads on the building — the panel is a self-supporting deck between supports, and nothing else. What the photographs do not settle is which depth was used here, at what purlin centres, or at what pitch.