Flat Roof Joist Sizes

Sizes of joists needed for flat roof construction.

Flat roof joist sizes.

1 psf lb f ft 2 47 88 n m 2. Size of joists mm clear span c16 joist m clear span c24 joist m 47 x 95 47 x 120 47 x 145 47 x 170 47 x 195 47 x 220 1 77 2 40 2 89 3 38 3 87 4 36 2 04 2 75 3 47 4 20 4 93 5 66 floor joists flat roof joists assumptions at 400mm centers supporting permanent load excluding self weight of joists up to 50kg m2. 2 are indicated below. K series joists range in depth from 10 to 30 and can span up to 60.

These welded steel products are used to support a building s roof and floors. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. About o donnell metal deck. 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.

So any timber joists that are used need to be strong enough to support this weight. The range of joist sizes used in homes varies though between 2 by 4 inches and 2 by 12 inches. Rafter and joist span faq. 1 ft 0 3048 m.

Live load is weight of furniture wind snow and more. 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. Size of roof joist 400mm 450mm 600mm 47 x 97 1 84 1 81 1 74 47 x 120 2 43 2 39 2 27 47 x 145 3 08 3 02 2 87 47 x 170 3 75 3 67 3 42 47 x 195 4 41 4 31 3 92 47 x 220 5 04 4 85 4 41 75 x 170 4 50. The lengths and sizes of joists vary depending on the species and quality of the lumber used.

Old asbestos roofs are often replaced with flat roofs. Dead load weight of structure and fixed loads 15 lbs ft 2. 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.