Rafter and roof joist spacing is only one part of a complex roof design that works together to form a structure that meets building codes and can hold up the weight of the roof and roof load.
Framin roof layout 2 foot on center.
While this can be true it is not always accurate unless in some high stress situations.
If you re framing a gable roof on a new house or building a shed or even a doghouse with a gable roof you ll need to cut a number of roof rafters.
Structurally in most cases exterior wall framing can easily be 24 in.
From one end of the rafter material using a speed square or framing square mark an x in 12 angle on the rafter and cut it measure down y height from the long point of the rafter cut and make a mark.
Industry standard increments typically either 12 16 or 24 inches apart.
Most older houses have 2 by 4 wall studs spaced 16 inches on center.
This means from the exact center of one stud to the exact center of the adjacent stud is 16 or 24 inches.
These spacing intervals are measured on center meaning that the.
The standard roof truss spacing is 2.
And the line length measurement from the roof peak to the building wall is the hypotenuse.
This will the first point of the rafter measurement line using the results of your rafter length calculation measure from this point along the rafter measurement.
It has a bending strength of from 1105 to 1170 psi pounds per square inch depending upon the species of lumber.
Below is the framing for a gabled roof.
Floor beam span tables of residential structural design we will now look at roof rafter and beam design.
Depending upon the complexity of the roof s design.
The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.
Continuing on from part 3.
Roof framing rafter layout.
Let s consider a basic gable wood roof framing design.
The run or half the building span is the base of the triangle.
Now that you have an idea about the materials you ll need as well as any mistakes you ll need to be wary of making it s time to get to work on the wall layout.
The framing of a basic gable roof is based on a right angle triangle and the various roof framing components fit the triangle.
Many newer houses have 2 by 6 wall studs either 16 or 24 inches on center to make exterior walls stronger and create a larger cavity for wall insulation.
There is a misconception that spacing trusses every 16 on center is better because it will be strong than the average 2.
The rise or height of the roof at its peak is the altitude of the triangle.
The exception according to the 2015 irc is 2 6 walls supporting two full floors plus a roof assembly above or 2 4 walls supporting one floor plus a roof assembly above zip sheathing can typically be installed either vertically or horizontally.
When you go to your local lumberyard to purchase a 2 6 graded as 2 the standard for framing throughout the industry.
Studs wall framing members are placed on either 16 inch or 24 inch centers.
Here we have a wood framed gable roof.