How Far Are Purlins Spaced On A Metal Roof Overlay

Correctly measure the spacing of furring strips for a metal roof to further decrease condensation.

How far are purlins spaced on a metal roof overlay.

The typical spacing standards for residential and commercial buildings are about 1 to 2 foot. They give added support to the roof and also provide a nailing surface for the end panels and drip edge. This shop will be insulated but mostly unheated except when i m working in there say 10 hours a week. If the space between posts is greater than 8 feet then brace is needed to avoid buckling.

Purlin spacing is dependent on profile of the metal and gauge plus snow and wind load plus what the rafters are designed to carry. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to. Fyi we run purlins on 3 5 feet on center depending on size of purlin. For 2x6s purlins the posts are spaced in 6 feet distance.

They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top. By the standard the most used placement of purlin span for metal roof is five foot intervals. However sometimes corrugated sheets are 39 wide instead of 37 wide. Edit answer for another 41 minute you need to check the installation instructions from the manufacturer depending on whether the purlins firring strips are 1x or 2x material and how wide thickness metal gage of roofing steel or aluminum type of seams design wind and snow loading whether designed to be walked on or not etc i have seen it vary from as little as 4 inches clear gap between firring strips on lightweight aluminum to as much as 4 feet on very heavy gage.

The diagram above is a typical 37 wide panel and the spacing works out perfectly. For 2x4s purlins the posts are spaced in 4 feet distance. There will be four screws per screw line placed in the high of the corrugated panel. For the lighter material such as lightweight aluminum the common spacing length is 4 inches of clear gap.

Exact requirements will vary but as a rough guide this is a good rule of thumb to follow. For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet. The screws are spaced out so that every third corrugation has a screw. Purlin spacing for metal roofing.

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. Purlins are 2 by 4 feet and are installed much like metal roofing. When positioned roof purlins should be spaced no further than 1 2 metres apart when using sheeting with a thickness of 0 7mm and 1 metre when using 0 5mm sheeting. I am installing ribbed metal panels over a singlt slope roof on a new workshop.

I was planning to install directly over 2x4 purlins which are mostly already installed.