The heavy end bay system offers an economic solution to the larger and multispan type building, with the inner bays being of a lighter gauge material.

All end bay purlins single span.
Inner bay purlins single or double span.
All joints to be fully sleeved.

The heavy end bay system offers an economic solution to the larger and multispan type building, with the inner bays being of a lighter gauge material.

The system caters for spans up to 15m dependant on loading criteria, and is a fully continuous purlin system, with sleeves at every joint. The penultimate rafter is sleeved with a longer sleeve of a heavier gauge equal to the end bay purlins to cater for the higher moments in the end bay. 

 
The inner bay sleeves are slightly longer than standard sleeves with double hole punchings for sleeve connection, and are of the same lighter gauge as intermediate purlins.

For the system to perform economically only buildings with a minimum of five bays should be considered. The heavy end bay system can also be supplied with the inner bay purlins double spanning with single span purlins introduced to stagger the rigid joints; as shown in the diagram.

Note: Rigid joint of double span purlins can be in line but rafters need to be checked for extra stress.