Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal.
Roof rafter size and spacing.
Here we have a wood framed gable roof.
Floor joists ceiling joists rafters snow load rafters roof live load deflection limit.
2x4 2x6 2x8 2x10 2x12.
For standard shed roof rafter spacing see rafter span chart.
1 ft 0 3048 m.
It is always better to have a large rafter rather than be concerned with a sagging roof.
Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches.
Rafters must be strong enough to hold the roof sheathing and the shingles.
For instance 2 grade 2x4s at 16 on center will span just over 9.
Continuing on from part 3.
If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.
If your local building authority has a rafter spacing code you may not space rafters wider than required by code.
2 are indicated below.
If you get premium kiln dried lumber then you could span 10 5 with the same size of lumber and.
3 stud construction standard utility.
Spacing in 12 16 19 2 24.
Structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes.
The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.
There is no standard spacing it depends on what size of rafters you want to use and the span of your shed.
Floor beam span tables of residential structural design we will now look at roof rafter and beam design.
So the space between rafters can be greater without reducing the maximum span.
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.
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.
The same concept holds true for roof trusses.
1 psf lb f ft 2 47 88 n m 2.
L 720 l 600 l 480 l 360 l 240 l 180.
Live load is weight of furniture wind snow and more.
Dead load weight of structure and fixed loads 15 lbs ft 2.
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.
Let s consider a basic gable wood roof framing design.