Roof Post Spacing

Dimensional lumber deck beam span chart the numbers in gray indicate the distance between the support posts.

Roof post spacing.

With just rafter load. As a general rule the best bang for your buck is most typically spaced every 12 feet although 10 foot and 14 foot spacings are often a close second. If you move up to 4 by 8 you re usually allowed to span up to 10 feet between posts. A 4 by 10 can usually span up to 12 feet between posts.

Roof rafter span use this table to determine the maximum lengths of roof rafters based on species and grade of lumber spacing dimensions load and slope. When supporting joists that span 12 feet with no overhang beyond the beam a double ply beam can span in feet a value equal to its depth in inches. Spacing will vary be design and roof load but usually 24 on center or less. A 2 2x10 can span 10 feet and so on.

Roof purlins are 2x4 2x6 or 2x8 lumber that spans between the trusses to provide framing for metal roofing or roof sheathing. Roof trusses were usually produced on site in the past. In general the maximum span for a 4 by 6 beam is 6 feet between 4 by 4 posts. May be attached above the trusses on edge or flat or between the trusses using post frame anchors or joist hangers.

A double 2x12 beam can span 12 feet. Never place concrete next to wood. Doesn t mater what size the posts are the spacing is governed by beam size and roof load roof slope plays a part in the loading of the beam. The most efficient post spacing is going to depend upon the wind and snow load conditions at any particular given pole building site.

Use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size. Engineers have since determined however that the physical design of a post frame building will allow for standard spacing as great as 12 feet from the center when using high quality metal connector plates and lumber. 2x12 doubled can span 12 normally. Maximum rafter spans for a patio roof in areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.

An essential part of planning a patio roof or gazebo project is determining the number size and spacing of rafters beams and posts according to the loads they will carry.