Roof Joist Sizes And Spans

These spans were calculated using our flat roof joist calculation engine.

Roof joist sizes and spans.

Rafter and joist span faq. For pitched roofs flat roofs and ceiling joists. It covers 2 common lumber species and sizes at 20 pounds per square foot load. For floor and ceiling construction surveyors can calculate the size strength and centres spacing of joists with reference to the data in these tables.

Click on a span to generate a full calculation you can adjust the exact span. 2 x 12 s are not listed because you can span pretty much whatever you want. Click here for structural design. While most residential construction uses 2x8 joists with 16 inch spacing there are many other factors you need to consider when determining the proper joist span length.

The lengths and sizes of joists vary depending on the species and quality of the lumber used. Select the appropriate table in span tables for joists and rafters. The range of joist sizes used in homes varies though between 2 by 4 inches and 2 by 12 inches. Spans of timber joists in suspended timber ground floors span tables.

Although 2 x 4 s are included in the official table they are not listed because it is never advised to use them. This span table is to the format and methodology given in bs 5268 7 2. These span tables are the equivalent of other industry standard span tables and are calculated to the same standards. For example you can span a 1 grade no knots southern yellow pine a greater distance than a 2 grade with knots southern yellow pine.

Surveyors and structural engineers utilise data from tables below to help calculate the correct size strength and centres of roof timbers for the required spans and loadings. The table of contents indicates that table f 2 watches these loading conditions. View joist rafter tables. Strength class timber c16 sc3 and c24 sc4 span tables.

Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters. Standard size of joists 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. Joist span and spacing is set by your local building code. This ceiling joist span table is based on the 2012 irc for uninhabitable attics with limited storage.

Using table f 2 figure 3 check each lumber size to see if a 16 inch spacing will permit a span of 15 feet 1 inch. Joists rafters simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12.