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