This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
A very popular form of truss for use in churches is the hammer beam truss mentioned above. This is shown in Fig. 243. On the left is shown the framework for the truss, while on the right is shown the way in which it may be finished. Its characteristic feature is the hammer beam A. The sizes of the pieces can only be determined by calculation or experience, and depend entirely upon the span of the truss and the loads to be carried, which are different for different locations. It is common practice to insert a tie rod between the points B and C to take up the thrust which would otherwise come on the walls. All parts of the framework must be securely bolted or spiked together so as to give a strong, rigid foundation for the decoration, which should be regarded merely as decoration and should not be considered as strengthening the truss in any way.
Fig. 243. Hammer Beam Truss Used Particularly for Churches.