Cladco have been manufacturing and supplying cladding and a range of building components since 2000, gaining a wealth of experience for the requirements for the industrial and commercial sector of the construction industry.

Investment in machinery and processes, have allowed Cladco to become a major supplier to the Scottish market, and further afield, with their range of profiled metal cladding, standing seam, flashings, purlins, fixings & accessories. Cladco are a one-stop-shop for all building needs

Cladco’s range of purlins are available as Sigma section, in 7 depths – 145mm,175mm, 205mm, 225mm, 235mm, 265mm and 300mm – to suit most building requirements. The sections are available in a range of thicknesses, for use in single span, double span or sleeved systems.

Testing has been carried out at Oxford Brookes University, with the load/span tables developed from those tests. This gives the specifier confidence in knowing that Cladco’s range of purlins & cladding rails have been fully tested and accredited.

Developed for purlins and cladding rails, the Cladco Sigma sections may be used as a lightweight flooring support system, as single or compound sections. Cladco’s technical department should be contacted, to discuss any such application.

Overview of Purlin Systems

Single span purlins are the simplest arrangement, with single bay length sections, jointed at each rafter.

Double span purlins span across three supports (rafters), giving an economical design and speed of erection. Care must be taken when specifying a double span purlin system, to ensure that the loads on each rafter are evenly distributed by staggering the system joints. This will necessitate single span purlins at alternate purlin lines, in end bays.

Heavy end bay purlins may be introduced to cater for high wind uplifts at verges.

Sleeved purlins are a variation on the single span system, with sleeve sections at each joint. This system involves more components, but increases the load carrying capacity of the single span system, by adding stiffness over each joint.

When specifying a purlin system, all loads, including local and variable loads, must be checked. In particular, local wind coefficients at verges, eaves and apexes, and drifting snow loads, may affect the system chosen.

In certain circumstances, anti-sag bars and apex ties are required. The load/span tables show where sag rods are needed, and are generally required on large bay widths, under wind reversal conditions. On roof slopes greater than 15 degrees, we would recommend that sag bars and apex ties are always installed. On large bays (>6m), we recommend that apex ties are installed, to give stability to the purlin system during the roof cladding operation.

The load/span tables show where sag rods are required for normal profiled metal roof cladding. However, other roofing systems, which do not provide lateral support to the top flange of the purlin, may necessitate the use of sag bars. Please consult our technical department for guidance, should there be any doubt.

Cladco’s range of purlins are complemented by cleats, which may be bolted or welded to the rafter, and by sleeves, which increase the load carrying capacity of the purlin section.

Simple bolted connections, make site assembly easy, and the choice of systems allows the specifier to choose the right arrangement for loadings, site restrictions, and erection processes.

The material used for the manufacture of Cladco’s range of purlins is Hot Dipped Galvanised Steel to BSEN 10326:2004 & BS 10143:1993. The minimum grade of steel used is S450GD, with Z275 zinc coating.

Steel is a re-usable product, and Cladco’s system, with simple bolted connections, makes dismantling straightforward. The sections may then be re-used on another building, either as they are, or cut and re-drilled to suit. Steel is one of the planet’s most recycled material, with a large percentage of new steel, being manufactured from recycled steel.

Cladco’s range of purlins & cladding rails are available in almost any length – please consult our technical department for details, should long lengths be needed. Transport restrictions may be the limiting factor to the length supplied, so all aspects of the supply process need to be checked.

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