Half building width minus 1 2 ridge thickness.
Roof joist angle thickness.
It is measured from the horizontal wall line to the sloped rafter using the rise over run.
Ridge the upper edge where two roof slopes or decks meet.
Let s consider a basic gable wood roof framing design.
Floor beam span tables of residential structural design we will now look at roof rafter and beam design.
Require bolted diagonal bridging section number 001 168 3 28 07 10 52 am page 5.
For low pitch roofs building codes may require larger dimension rafters.
Allow for ridge thickness when determining rafter run to outer wall.
A 14 angle gives a 3 12 slope 4 12 is an 18 2 angle and 6 12 a 26 6 angle.
Standard joist details 6 gen.
For instance if your roof has a steep pitch you may be able to use 2 inch by 4 inch rafters but if your roof has a low pitch building code may require that you used 2 inch by 6 inch or 2 inch by 8 inch rafters.
K series joists range in depth from 10 to 30 and can span up to 60.
Here the wall thickness is 240 57 inches.
See rafter run to outer wall calculator below.
The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.
Once all of these inputs have been entered into the calculator you will see that the appropriate rafter width is 120 33 inches.
Slope the slope of a roof is represented as x 12 where x is the number of inches in rise for every 12 inches of run this is very useful information for many purposes especially for roof framing the slope sometimes called pitch is calibrated on speed squares.
These welded steel products are used to support a building s roof and floors.
Span calculator for wood joists and rafters also available for the android os.
Includes result for hip valley factor slope factor and the roof slope in degrees.
Bridging angle size equal leg angles table 2 6 1b lh series joists maximum joist spacing for horizontal bridging spans over 60 ft.
Here we have a wood framed gable roof.
Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement.
They are custom engineered to suit the design of each building.
About o donnell metal deck.
Angle the angle of a roof is the same as the roof s slope except instead of being.
If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length.
In addition using the rafters diagram you can see the precise dimensions of the roof rafter including length from every possible angle.
Print full scale rafter cut templates and birdsmouth templates fold template over rafter to mark or cut through.