When the ceiling is in the shape of a barrel vault, the system of longitudinal trussing will often be the only one that can be used. Fig. 180 shows a transverse section through a church roof and ceiling, where this system is the only one that could have been employed. The section is approximately that of the roof and ceiling of the Emanuel Baptist Church, Brooklyn, N. Y., Francis H. Kimball, architect, which has a very handsome vaulted ceiling, with groined vaults over the side windows, the shape of the ceiling giving the appearance of nave and aisles, although there are no posts except one under each longitudinal truss near the front.
This arrangement could also be adapted to a vaulted ceiling,with-out the outer portions shown, the side walls taking the place of the Howe trusses, while the latter are placed at each side of the central vault.
Fig. 181 shows a section through the roof and ceiling of the Temple Emanuel, Denver, which are supported on the same principle as the roof shown in Fig. 180, the principal difference between the two being in the form of the ceiling and of the trusses between the longitudinal trusses. In Fig. 181 the blackened sections C, C, are the chords of two Howe trusses, each having a clear span of 64 ft., a total height of 11 ft. 6 ins. The distance between the trusses, centre to centre, is 35 ft. 6 ins. The central portion of the roof and ceiling is supported by scissors trusses, four feet on centres, which rest on the top chords of the Howe trusses.
The scissors trusses support the cradeling for the barrel vault which extends the full length of the audience room.