Roof Rafter Size And Spacing

2 are indicated below.

Roof rafter size and spacing.

Rafters must be strong enough to hold the roof sheathing and the shingles. Here we have a wood framed gable roof. Floor beam span tables of residential structural design we will now look at roof rafter and beam design. For example in the rafter span table below the highlighted cell in the 40 live load table indicates that 2 x 8 southern yellow pine joists that have a grade of 2 that are spaced 24 apart can have a maximum span of 10 feet 3 inches 10 3 if designing for a live load of 40 lbs ft 2.

Our roof rafter calculator tools are handy for calculating the number of rafters needed rafter length calculator lineal feet of rafter board feed in ridge and sub facia and the total board feet in the roof. Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches. Let s consider a basic gable wood roof framing design. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal.

If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. So the space between rafters can be greater without reducing the maximum span. Live load is weight of furniture wind snow and more. The same concept holds true for roof trusses.

Structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes. It is always better to have a large rafter rather than be concerned with a sagging roof. Dead load weight of structure and fixed loads 15 lbs ft 2. 3 stud construction standard utility.

For standard shed roof rafter spacing see rafter span chart. For instance 2 grade 2x4s at 16 on center will span just over 9. L 720 l 600 l 480 l 360 l 240 l 180. 1 psf lb f ft 2 47 88 n m 2.

The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial. If your local building authority has a rafter spacing code you may not space rafters wider than required by code. Continuing on from part 3. If you get premium kiln dried lumber then you could span 10 5 with the same size of lumber and.

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. Floor joists ceiling joists rafters snow load rafters roof live load deflection limit. 2x4 2x6 2x8 2x10 2x12. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.

Spacing in 12 16 19 2 24. 1 ft 0 3048 m.