5 bays or more.

The heavy end bay sleeved purlin system provides the most economic solution by utilising the benefits of the sleeved system but further maximising these by the use of lighter gauge purlins on internal bays.

This system caters for spans of up to 15m depending on the load to be applied and where the cladding or liner tray offers adequate lateral support by virtue of its screw fixings at 600mm maximum spacings to the purlins. To enable purlin and sleeve to nest together the sleeve is inverted.

Computer controlled production techniques apply the client’s individual mark numbers to all purlins automatically during the manufacturing process.

Purlin and sleeve arrangement

The arrangements shown indicate how the end bay purlins (P1 and P1X) and penultimate rafter sleeves are of the same heavier gauge material, whereas the inner bay purlins (P2, P3, P5, P5X, P6 and P6X) and sleeves are of the same lighter gauge material.

In the arrangements shown, the correct layout is given for both single span and double span applications.

Note: a sleeve must always occur at a purlin joint position.

Typical single span arrangement indicating purlin and sleeve positions

Heavy End Bay Single Span

Typical double span arrangement indicating purlin and sleeve positions

Heavy End Bay Double Span


Heavy end bay system (mm)

142 42 56 240 44 50 614 308 750
172 42 86 290 44 50 714 390 914
202 42 116 350 44 50 834 470 1074
232 42 146 410 44 50 954 583 1300
262 42 176 460 44 50 1054 683 1500
302 52 195 610 55 60 1354 783 1700
342 52 235 760 55 60 1654 933 2000

Unless otherwise stated, all required holes are 18mm diameter for M16 bolts and are normally pierced in pairs on standard gauge lines.

For ‘General detailing’ notes see General Detailing Information.