72 24 24 2x4 2.
Gable roof span of 20 feet with no bracing.
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.
This number represents the total load that your roof must carry.
Represents 12 feet 7 inches and 10 12 of an inch.
Maximum rafter spans for a patio roof.
The rafter length is 16 11 6 or 16 feet 11 6 12 inches.
Multiplied by 40 pounds per square foot equals 8 000 pounds.
Feet more in presence of snow.
Roof length in feet.
Minimum roof loading is 20 lb sq.
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.
A roof with a run of more than 23 feet.
If smaller beam will sag ugly.
Floor beam span tables of residential structural design we will now look at roof rafter and beam design.
Continuing on from part 3.
Here we have a wood framed gable roof.
Use of manufactured roof trusses can dramatically cut labor costs when framing a gable roof compared to building rafters.
They are written as follows.
In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.
For example if the run is 27 feet find the.
The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.
In this design the tops of the rafters attach to a load bearing ridge beam that runs along the length of the roof.
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.
If an example roof is 10 feet by 20 feet the total area is 200 square feet.
Better design with truss 2 feet deep or more depending on snow load.
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.
Let s consider a basic gable wood roof framing design.
12 feet 7 10 12 inches.
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.
For a 20 foot span wood beam needs to be minimum 18 inches deep.
A roof with a 1 2 pitch or a rise of 1 2 the width of the building and a run of 12 feet.
For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.
