Roof Truss Layout Measurements

These will include wood a hammer a saw roof truss.

Roof truss layout measurements.

A 12 in 12 pitch is a steep 45 degree angle roof. Your top chords can protrude beyond the bottom chord anywhere from 1 3 feet 0 30 0 91 m. The truss is a framework consisting of rafters posts and struts which supports your roof. A roof s pitch is determined by how much it rises vertically for every foot it runs horizontally.

Pitch slope the pitch or slope is the incline of the roof expressed as a fraction describing the rise over the run. Standard truss boards are spaced 24 inches apart from one end of the roof to the other. The important point to keep in mind when you use your truss calculator is that every truss calculation is completely unique and is based on the size of your roof and its specific dimensions. These measurements are for a common roof trusses.

This conforms to the 4 by 8 foot dimensions of plywood or oriented strand board osb sheets used to deck or cover the roof in preparation for shingles. Improperly spaced trusses will not provide correct nailing points to secure decking. If you think you d prefer an overhang style truss adjust the measurements for your top chords accordingly. There are other types of roof trusses that require different measurements.

Trusses can be constructed with smaller sized lumber than rafters and often their cost is not significantly higher than normal rafters. Thus a moderate 6 in 12 roof pitch means that the roof rises 6 inches vertically for every 12 horizontal inches it runs. The run or the base number is 12 inches. To obtain the actual height of the truss deduct the height of the wall from the total number calculated on the roof truss calculator see resources.

The second step in building a roof truss is to prepare the materials needed. The rise will be the elevation change over the 12 inches. Roof pitch is the rise over the run of the roof meaning a 7 12. On some roof trusses the 2 top chords extend down over the edges of the bottom chord creating a built in overhang.

For example a slope of 6 12 means for every 12 inches of horizontal distance the slope of the roof will rise 6 inches vertically.