Purlin spacing for metal roofing.
Purlin spacing for corrugated metal roofing.
Be sure the larger edge is laid so that the small edge of the next panel will overlap it.
Purlins provide horizontal support for the sheets and form part of the framework for the building.
Purlin spacing is dependent on profile of the metal and gauge plus snow and wind load plus what the rafters are designed to carry.
Purlin spacing should suit the end laps required for the size of sheet to be used.
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.
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.
Corrugated sheet roofing material is widely available and easy to use.
Do all roofing projects require purlins.
There will be four screws per screw line placed in the high of the corrugated panel.
All purlin joints must be supported by a rafter.
Corrugations should run in a straight line between the highest and lowest points and at a right angle to the purlins the intermediate supports.
Z purlins are connected to the rafters using cleats.
When using purlins fabral recommends a maximum spacing of 24 on center note that 5v requires solid decking.
We do recommend it however.
However sometimes corrugated sheets are 39 wide instead of 37 wide.
For the lighter material such as lightweight aluminum the common spacing length is 4 inches of clear gap.
The diagram above is a typical 37 wide panel and the spacing works out perfectly.
Pullout values decrease if the fasteners protrude completely through the purlins.
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.
Kiln dried softwood is recommended for purlins or decking pine fir hemlock and spruce.
The screws are spaced out so that every third corrugation has a screw.
For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet.
Without a set of blueprints with a pe s seal you have no option but to follow the inspectors gig.
The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to.
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.
Fyi we run purlins on 3 5 feet on center depending on size of purlin.
Install the roofing screws vertically along each rib in the panel.
Minimum recommended purlin size is 4 x 2 50mm x 100mm in timber or z140mm x 1 6mm in steel.
