Shed Roof Support Beams

Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.

Shed roof support beams.

This means the example porch would need a 6 inch by 8 inch beam. It has been my experience to never use a beam smaller than a two ply 2 x 8. The same is true for beams like structural ridge beams and center girders. In other words the maximum distance it can cover without support from posts.

The determining factor of post spacing is the allowable span of your beams. This calculator matches up with 90 of the applications in the 2012 international residential code book. Come to think of it the only style shed i can see that would be easy to use a ridge beam is the gable style shed. The term pitch refers to the slope of the roof.

Too often builders gang together 2 inch dimension lumber to support roof and floor loads without considering other options. However our instructions include making shed rafters with a ridge beam. You can t beat sawn lumber for most small window headers but as spans and loads increase stronger materials are a better choice. Gable shed roof with ridge beam framing a ridge beam is thicker than a ridge board so nailing through it into the rafter end isn t an option.

Toenailing from both faces of the rafter into the beam is one option but makes keeping the rafter lined up difficult. This tells you the size of the beam needed to support the porch s roof. A ridge beam runs the length of the shed roof connecting every pair of rafters. 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.

In order to adhere to standardized building codes and ensure adequate runoff your shed s roof must have a pitch of at least 3 12 read as three in twelve. Most interior beams need to include the roof load. You can repeat the same process using a different breadth if you want a beam that is wider or thinner than 6 inches. In the example d calculates to 7 75.

If there is are any questions about anything else then you should contact your supplier or an engineer. However if the spacing is too wide the patio cover s beams will bow under the weight of the joists and roof covering materials. For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements. Some shed rafters do not incorporate ridge beams either due to small size or lack of technical know how.

I can t ever recall seeing a saltbox shed built with a ridge beam or even a gambrel roof shed for that matter.