How Far To Span A Patio Roof Supports

If an example roof is 10 feet by 20.

How far to span a patio roof supports.

Rafter and joist span faq. As a general rule roofs that have a high human occupancy rate should be framed with rafters every 16 structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. In general the maximum span for a 4 by 6 beam is 6 feet between 4 by 4 posts.

For example you can span a 1 grade no knots southern yellow pine a greater distance than a 2 grade with knots southern yellow pine. If you move up to 4 by 8 you re usually allowed to span up to 10 feet between posts. How to size a beam to hold a porch roof. The lengths and sizes of joists vary depending on the species and quality of the lumber used.

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. For example in the rafter span table below the highlighted cell in the 40 live load table indicates that 2 x 8 southern yellow pine joists that have a grade of 2 that are spaced 24 apart can have a maximum span of 10 feet 3 inches 10 3 if designing for a live load of 40 lbs ft 2. Multiply the load per square foot by the total area of the roof. 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.

The smallest beams for patio covers are typically 4 by 6. The dead load is. The roof load is composed of a dead load and a live load. 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.