Purlins can be fixed to rafters and all joins and laps should be supported by a rafter.
Roof purlin support.
With rafters it runs in perpendicular from the walls to the ridge while with purlins it runs to the ridge in parallel.
In architecture structural engineering or building a purlin or historically purline purloyne purling perling is a horizontal beam or bar used for structural support in buildings most commonly in a roof.
A common arrangement is a rafter and purlin system which combines purlins and rafters.
Purlins support the loads from the roof deck or sheathing and are supported by the principal rafters and or the building walls steel beams etc.
Using a combination of rafters and purlins is common.
Once your purlins have been fitted and a supporting framework has been created you should look to carry out an inspection before you continue work.
Purlins are supported either by rafters or the walls of the building.
How to support roof purlins.