This is the distance between rafter centres.
Roof purlin wood purlin size and spacing.
For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet.
Ft psf in purlin weight based on 43 g nds total purlin dead load 1 638 psf.
The typical spacing standards for residential and commercial buildings are about 1 to 2 foot.
15 3 12 in.
Roof steel dead load 63 psf steel american building components catalogue.
Spacing for purlins on a standard load most designs call for purlin placement at five foot intervals.
Ft 15 23 75 12 in.
For the lighter material such as lightweight aluminum the common spacing length is 4 inches of clear gap.
Usually 400 450 or 600mm but any value can be used up to 610mm max.
The heavier the expected load is the shorter the distance between the purlins.
Net variation for combned dimension.
7 25 12 in.
3 1 43 lbs ft.
For 2x4s purlins the posts are spaced in 4 feet distance.
Purlin spacing 23 75 in.
The standard of purlin length will vary anywhere between 100 to 300 mm while the thickness will vary anywhere between 1 to 3 mm.
If you want to know how to support roof purlins they are usually supported by 2 4 or 2 6 struts or posts.
Roof lumber dead load 62 4 pcf 43 lbs ft.