Roof Joist Thickness

This is the distance between joist centres.

Roof joist thickness.

Depending on loads and spans c joists are typically spaced at 12 16 19 2 or 24 on center spacing. Ceilings directly applied to the bottom edge of the floor members or equivalent 1x or 2x strapping is a. Though there is no standard joist size for the ceilings in all buildings most average homes use ceiling joists in a board size of 2 by 6 inches. The range of joist sizes used in homes varies though between 2 by 4 inches and 2 by 12 inches.

Standard asphalt shingles add very little thickness to the roof because a standard three tab shingle is about 3 16 inch thick. Span calculator for wood joists and rafters also available for the android os. Featuring trus joist tji joists for floor and roof applications. 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.

When installed however the shingles overlap doubling the thickness. Another option are 2 x 8 rafters spaced 24 inches o c. Also available for the android os. That will suffice on a roof with rafters set 16 inches apart with minimal roof loads.

Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter. There are several variables to consider when determining the proper rafter size. Minimum thickness most roofs will be sheathed in plywood at least 3 8 inch thick. Joist to girder attachments are normally supported with joist hangers easyclip e series or s series support clips.

Usually 400 450 or 600mm but any value can be used up to 610mm max 1 2 timber strength class and joist size automatically calculate sizes suitable for supporting the loads below. This sizing guide for roof rafters will help determine what you need for your small project. Thickness generally improves floor.