How Close Do You Install Perlins Under A Metal Roof

The topic we want to discuss today is the purlin installation.

How close do you install perlins under a metal roof. Metal roof purlins are installed horizontally under metal roofs. The purlins not only give you something other than the existing roof to accept the roof panel fasteners they also create an airspace between the roof panels and the existing roof. Tin roofing also known as metal roofing is considered more durable than composition or wood shingles. If you are placing metal panels over an existing roof you still use purlins.

The roofing is manufactured in panels that. 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. They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top. Purlins are 2 by 4 feet and are installed much like metal roofing.

If you choose to omit the plywood from a residential construction install a vapor barrier between the purlins and the metal roof or plan to spray closed cell foam insulation between the rafters to eliminate the temperature differential between the air in the building and the metal. The washer under the screw head should seal to the surface of the. Installing wood stripping under a tin roof. Secure the screws but do not overtighten.

When installing a metal roof you want to make sure you are starting square. Installing non structural metal roofing on purlins will allow the panels to flex bend crimp and otherwise become damaged in some. 3 remove old roofing and repair any damage start from the top of the roof and remove the old shingles along with the flashing underlayment and vents. The purlins support the panels.

They give added support to the roof and also provide a nailing surface for the end panels and drip edge.