The trapezoidal flute design still offers the optimum strength, mass and load-span characteristics compared to alternative profiles.

The Inverted Box Rib or better known as IBR has a square fluted profile used for Roofing or Cladding.

Available in transportable lengths and fixed by securing a screw through the narrow flute when used as roofing. Typically when used as side cladding the profile is fixed with broad flutes outwards.


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The profile shall have five trapezoidal ribs at 171.5mm centres giving a nett cover of 686mm with each pan incorporating one stiffener rib. 

The rib height shall be 37mm.

Roof Pitch

IBR may be used at a minimum roof pitch of 5° for rafter lengths up to 30m. A minimum of 7.5° is required for rafter lengths greater than 30m.


IBR 686 can be cranked from a minimum radius of 409mm for material thicknesses of 0.5mm, 0.53mm and 0.58mm.


IBR 686 can be cranked curved to any radius greater than 800mm subject to transportation limits.

IBR 686