Patio Roof Structural Beam Spacing

If you move up to 4 by 8 you re usually allowed to span up to 10 feet between posts.

Patio roof structural beam spacing.

In general the maximum span for a 4 by 6 beam is 6 feet between 4 by 4 posts. Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads. Before i began designing the structure of my new patio cover i expanded the existing 10 x 10 patio slab by pouring another 10 x 10 slab next to it making it roughly 10 x 20. Pergola s are thicker mounted on the shorter width and do not move.

Roof cover 1 2 plywood shuttering 1 5 psf roof framing 3 5 psf. Divide the total load according to how many supporting beams the roof will have. 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. Then there are wooden beams that are evenly spaced over the frame to create the roof.

Both have posts or columns that support a frame. The smallest beams for patio covers are typically 4 by 6. The difference comes in with the type and installation of the beams. If one side of the roof is supported by the house and the other side is supported by the beam divide the total load by two as the beam is only supporting half of the roof.

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. A 4 by 10 can usually span up to 12 feet between posts. Since i was planning to attach my patio cover to the existing roof overhang of my home i ensured that it was capable of carrying half of the weight of the new patio cover roof. Strength given in the nds and wood structural panel design properties given in the apa pds.

You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths. Timber beam design seismic forces wind forces floor shearwall diagram lateral loads. 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.