Patio Roof Joist Spacing

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

Patio roof joist spacing.

A 4 by 10 can usually span up to 12 feet between posts. 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. If the size of the roof is not even you will end up installing 2 or more joists closer together than 16 inches. Floor joist span use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size.

In general terms joists spaced 16 inches on center can span 1 5 times in feet their depth in inches. 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. So the space between rafters can be greater without reducing the maximum span. On a two story house you can usually tie the ledger into a band joist also called a rim joist located between the floors as shown below.

If attaching a patio roof to a ledger beneath the eaves does not allow for enough headroom you can set the new patio roof s rafters on the wall s top plate. The smallest beams for patio covers are typically 4 by 6. 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. The same concept holds true for roof trusses.

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. Common spacing for trusses on this type of building is often between 2 and 4 feet but trusses built with advanced designs may allow spacing as great as 8 or 12 feet. There are several variables to consider when determining the proper rafter size. Install a roof joist at each corner of the roof and then from these you measure the distance for the next roof joist and so on until they all are in place.

In general the maximum span for a 4 by 6 beam is 6 feet between 4 by 4 posts. Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter. A 2x8 up to 12 feet.