Garage Roof Joist Spacing

This is the distance between joist centres.

Garage roof joist spacing.

The same concept holds true for roof trusses. Usually 400 450 or 600mm but any value can be used up to 610mm max. Not more than 0 5 more than 0 5 but not more than 0 75 more than 0 75 but not more than 1. Another option are 2 x 8 rafters spaced 24 inches o c.

A roof joist is always spaced no more than 16 inches apart from another roof joist. Centre to centre spacing of joists in mm joist size width depth mm 400 450 600 400 450 600 400 450 600. If this is the case with your structure use the floor joist table to determine maximum joist length load. Permissible clear span metres.

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. 2 8 s come standard at 1 inch thick. Joist spacing of 24 inches is allowed for spans between 16 to 20 feet using 2 inch by 10 inch lumber of these three grades. Pole barn roof truss spacing generally tens to operate according to similar spacing principles though there are some proponents of having higher pole barn roof truss spacing.

Dead load per square metre in kn m supported by joists. 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. In other words you would space a roof joist 15 inches apart from another roof joist but never 17 inches apart.

Variations in ceiling construction nonparallel ceiling joist designs require additional support construction in the ceiling. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. For example the highlighted cell below shows that a 2 x 6 southern yellow pine joist with a grade of 2 and spaced 24 apart can have a maximum span of 10 feet 0 inches 10 0 if you are designing your structure to support a plaster ceiling. The table states that 2 x 6 rafters spaced 16 inches on center o c can span a maximum distance of 13 feet 5 inches.

In making your choice consider how you will insulate your insulate your roof. 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. 2x8s are used frequently for these projects.