Wood Purlins Metal Roof Insulation

They are divided into categories based on the material from which they are made and their shape.

Wood purlins metal roof insulation.

Several kinds of purlins exist. Do all roofing projects require purlins. When made of wood it is usually covered with some sort of weatherproofing and sometimes an insulation material. Metal roofing panels rated for architectural use attached to purlins horizontal pieces of wood or metal fastened to roofing trusses are structurally sound when installed according to your roofing manufacturer s instructions and local building codes.

In metal buildings banding can be used to secure metal roof insulation or in the walls most commonly used in the roof steel bands typically 1 wide are screwed to the underside of the metal purlin or wood truss in a pole barn 30 apart creating a grid system. 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. This type of assembly is designed to dry to the interior so the assembly should never include an interior polyethylene vapor barrier. The spacing of your purlins depends on the expected snow and wind load.

The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to. It is suitable to use for roof sheeting from fiber cement. Install a layer of closed cell spray foam against the underside of the steel roofing or roof sheathing and fill the rest of the purlin cavity with an air permeable insulation. We do recommend it however.