Roof Rafter Size And Spacing

Spacing in 12 16 19 2 24.

Roof rafter size and spacing.

If you get premium kiln dried lumber then you could span 10 5 with the same size of lumber and. 1 psf lb f ft 2 47 88 n m 2. Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches. 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.

1 ft 0 3048 m. Structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes. If your local building authority has a rafter spacing code you may not space rafters wider than required by code. 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.

Floor joists ceiling joists rafters snow load rafters roof live load deflection limit. Maximum rafter spans for a patio roof in areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot. For instance 2 grade 2x4s at 16 on center will span just over 9. Let s consider a basic gable wood roof framing design.

Rafters must be strong enough to hold the roof sheathing and the shingles. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. For standard shed roof rafter spacing see rafter span chart. There is no standard spacing it depends on what size of rafters you want to use and the span of your shed.

So the space between rafters can be greater without reducing the maximum span. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. Dead load weight of structure and fixed loads 15 lbs ft 2. The same concept holds true for roof trusses.

3 stud construction standard utility. Floor beam span tables of residential structural design we will now look at roof rafter and beam design. Here we have a wood framed gable roof. Live load is weight of furniture wind snow and more.

L 720 l 600 l 480 l 360 l 240 l 180. 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. 2 are indicated below. It is always better to have a large rafter rather than be concerned with a sagging roof.

The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial. An essential part of planning a patio roof or gazebo project is determining the number size and spacing of rafters beams and posts according to the loads they will carry.