How Far Apart Are Bar Joist Roofs

Came home opened up my 75 year joist manual and found the chord angles listed in the size chart at the beginning an exact match.

How far apart are bar joist roofs.

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. Went to the table for the corresponding. If the roof is not completely square you can decrease the space between joists but never increase the space. So the space between rafters can be greater without reducing the maximum span.

Given that 2x8s are actually 1 inches wide it works out to be 14 inches between each joist. This wide spacing creates several dangers to a firefighter cutting an. If that seems like a lot in st louis in the mid 80 s we once got 24 of snow overnight. For heavy roofs or in.

You probably should allow for 30 40 lb sq ft snow load the local codes will tell you exactly what. I measured up the joist using my handy micrometer. Open web steel bar joists can be spaced up to eight feet apart depending on the size of the steel used and the roof load. Bar joists meaning roof trusses with z welded between two angles top and bottom.

I investigated an existing bar joist roof for a client just the other day. To determine how far apart to set rafters measure the width of the metal panel and then the width of the first hill and valley of the panel. In other words you would space a roof joist 15 inches apart from another roof joist but never 17 inches apart. To find the actual distance between the inside edges of each adjacent floor joist subtract 1 inches from either 12 or 24 inches.

The same concept holds true for roof trusses. If purlins are laying flat on top of the truss 5 or 6 feet is the max on 2x4 s edge up can go to 12 feet or more. With some structures floor joists are required to be 12 or 24 inches apart on center. Maximum rafter spans for a patio roof.

Proper distance a roof joist is always spaced no more than 16 inches apart from another roof joist. Asked the client when the building was built. Double the hill and valley width since this is the amount that the panel will overlap the one next to it on each side. 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.