Z purlins are connected to the rafters using cleats.
Purlin spacing for corrugated metal roofing.
These panels can cost more to install that a traditional roof but in the long run are often a better value.
We do recommend it however.
Corrugated sheet roofing material is widely available and easy to use.
The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to.
The typical spacing standards for residential and commercial buildings are about 1 to 2 foot.
When using purlins fabral recommends a maximum spacing of 24 on center note that 5v requires solid decking.
Corrugated metal panels often called tin because in the past such panels were sometimes made of tin are typically steel or aluminum sheets that are used as a roofing material.
The screws are spaced out so that every third corrugation has a screw.
There will be four screws per screw line placed in the high of the corrugated panel.
When framing the roof the spacing for roof trusses should not exceed 24 inches 61 cm and purlins should not exceed 36 inches 91 cm apart.
You can use both types of corrugated roofing together creating panels that will allow light to come through as with a clear or white fiberglass corrugated panel known as a skylight.
Purlins provide horizontal support for the sheets and form part of the framework for the building.
Do all roofing projects require purlins.
Minimum recommended purlin size is 4 x 2 50mm x 100mm in timber or z140mm x 1 6mm in steel.
Pullout values decrease if the fasteners protrude completely through the purlins.
Be sure the larger edge is laid so that the small edge of the next panel will overlap it.
However sometimes corrugated sheets are 39 wide instead of 37 wide.
Purlin spacing should suit the end laps required for the size of sheet to be used.
For the lighter material such as lightweight aluminum the common spacing length is 4 inches of clear gap.
Install the roofing screws vertically along each rib in the panel.
Fyi we run purlins on 3 5 feet on center depending on size of purlin.
Purlins are non pressure treated 1 x 4 x 12 lumber that is installed on to the roof in a specific layout pattern and screw pattern.
All purlin joints must be supported by a rafter.
The diagram above is a typical 37 wide panel and the spacing works out perfectly.
Purlin spacing for metal roofing.
Purlin spacing is dependent on profile of the metal and gauge plus snow and wind load plus what the rafters are designed to carry.
Corrugations should run in a straight line between the highest and lowest points and at a right angle to the purlins the intermediate supports.
Align the first metal roofing panel so that it overlaps the edging by 1 2 to 3 4 of an inch and is square to the roof line.
The overlaps ends and sides depends upon the sloop of the roof see below.
