Insulate Metal Roof Over Purlins

Apply double sided tape on the top of purlins helps keep the insulation from blowing in the wind.

Insulate metal roof over purlins.

It gets more complicated when you look at adding the foam into the equation. The system of installing metal roofing over the trusses or over purlins is typical. Your roof purlin spacing can vary but 5 on center and 8 inches in depth is common which is the available insulating area. When fiberglass batts are installed in unvented bays the batts allow moist indoor air to reach the cold steel roofing or sheathing.

A thermal spacer block is typically recommended depending on the stand off distance and the amount of insulation draped over the purlins. This shop will be insulated but mostly unheated except when i m working in there say 10 hours a week. As long as the plywood under the shingle roof is in good condition this way can provide many benefits. I am installing ribbed metal panels over a singlt slope roof on a new workshop.

Roof wall new install over purlins. Both materials make a great physical barrier between the interior building and the metal roof. This is by far the most common way to install a metal roof. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to.

I was planning to install directly over 2x4 purlins which are mostly already installed. Fiberglass batts or glass mineral wool metal roof insulation. The batts are located side to side on the rafter of the roof. Use prodex 48 inch fast action 72 inch 10m white rustic reflective bubble reflective or foil fiberglass vinyl.

Make sure that the insulation you are using is the same thickness so that the metal roof will fit better. In this case simply lay the insulation between the purlins. We do recommend it however. How to insulate a metal building.

One of the more popular methods of placing metal roofing on a home is to lay down purlins across the existing shingles. 3 install 1x4 purlins down over the shingles before installing the metal roof the third way to install a metal roof over shingles is by applying 1x4 purlins over the shingle roof. 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. Do all roofing projects require purlins.

The code restrictions on the use of air permeable insulation between purlins were developed to prevent the purlins or roof sheathing from rotting. Factory pre cut white vinyl faced fiber glass blankets are placed in between the metal roof purlins and held in place by steel strapping called banding screwed to the bottom of the purlin.