Continuing on from part 3.
Gable roof span of 20 feet with nop bracing.
Maximum rafter spans for a patio roof.
The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.
1 psf lb f ft 2 47 88 n m 2.
Minimum roof loading is 20 lb sq.
Live load is weight of furniture wind snow and more.
B on center inches between trusses c width of bottom cord in feet.
Multiply the load per square foot by the total area of the roof.
Roof length in feet.
1 ft 0 3048 m.
After they re up you can snap a line to mark and trim the tails in a nice straight line to make up for any ridge warp or marking cutting and fixing errors.
2 are indicated below.
I have a span of 26 feet.
I want to know if i take 2x4 s and routed 2 1 2 in channels the length of the 2x4 and used 1 2 inch x 5 inch plywood sandwiched between will support the 26 foot span of roof read more.
If an example roof is 10 feet by 20 feet the total area is 200 square feet.
This number represents the total load that your roof must carry.
Here we have a wood framed gable roof.
Live load 20 lbs ft 2 956.
Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.
1 in 25 4 mm.
Better design with truss 2 feet deep or more depending on snow load.
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.
For a 20 foot span wood beam needs to be minimum 18 inches deep.
For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.
Gable roof framing calculator plan diagram with full dimensions for a good straight fascia add an extra inch or 2 to the tails of all your rafters total length.
Dead load weight of structure and fixed loads 15 lbs ft 2.
A standard triangular roof known as a gable roof is framed using rafters which are diagonal members that support the roofing materials.
Use of manufactured roof trusses can dramatically cut labor costs when framing a gable roof compared to building rafters.
Let s consider a basic gable wood roof framing design.
How to frame a gable roof without ceiling joists.
In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.
If smaller beam will sag ugly.
Almost any wood will do the same geometry of beam or truss is the important thing.
Floor beam span tables of residential structural design we will now look at roof rafter and beam design.
