Roof - Truss count

Not Reviewed
Equation / Last modified by AndrewBudd on 2019/03/01 15:58
KurtHeckman.Roof - Truss count

The Truss Count calculator computes the number of trusses needed for aRoofTrusscount-illustration.png  roof based on the dimension of the area covered. 

INSTRUCTIONS: Choose your preferred units and enter the following:

  • (W) The width of the roof (see diagram).  This is the same as the measurement of the ridge line.
  • (oC) The onCenter spacing of the trusses.

Truss Count: The calculator computes how many roof trusses are needed.

See Also:
  • To compute the number of 4x8s needed for a roof, CLICK HERE.
  • To compute the number of bundles of shingles needed for a roof, CLICK HERE.
  • To compute the pitch of a roof, CLICK HERE.

General Information

The user can enter the on-center figure for the spacing of the truss, but the system has put 24" as the default. An adder of one (1) is added to the truss count if the onCenter spacing does not come out close to even. This means that the spacing with the last truss may be less than the onCenter value, because engineering allows for trusses to be closer together without weakening the roof. Whereas, it is not permissible to space the trusses out further to make up the overage.