Roof Post Spacing

A 2 2x10 can span 10 feet and so on.

Roof post spacing.

The most efficient post spacing is going to depend upon the wind and snow load conditions at any particular given pole building site. In general the maximum span for a 4 by 6 beam is 6 feet between 4 by 4 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. A double 2x12 beam can span 12 feet.

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. Roof trusses were usually produced on site in the past. If you move up to 4 by 8 you re usually allowed to span up to 10 feet between posts. Dimensional lumber deck beam span chart the numbers in gray indicate the distance between the support posts.

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. Beams can be solid lumber or be built from lengths of 2 by lumber nailed together with 1 2 inch pressure treated plywood spacers in between this forms a 3 1 2 inch thick beam that is equal to the width of a 4 by post. 2x4 doubled can span 4 etc. 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.

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. May be attached above the trusses on edge or flat or between the trusses using post frame anchors or joist hangers. 2x12 doubled can span 12 normally. Never place concrete next to wood.

With just rafter load. 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. Use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size. Spacing will vary be design and roof load but usually 24 on center or less.

Rule of thumb a beam can span about one foot for every inch of depth.