It is better, however, that the under side or "soffit" of the lintel should be left flush throughout, a wood lintel with relieving arch, concrete beam, or fiat arch, supporting the wall behind it, being kept higher than that of the stone lintel, so that room is afforded for the head of the wood frame (see Figs. 543, 545).
It is often advisable to relieve the stone lintel of the weight of the wall above it. This may be done by a relieving or discharging3 arch, which either forms a feature in the elevation, as in Fig. 143, or if that be objectionable, the walling above may be formed in a sort of flat arch without being conspicuous (see Fig. 542).
Stone Lintel with Relieving Arch.
When a discharging arch is used, it is sometimes made of the same span as the opening, so that it rests upon the ends of the lintel instead of being just clear of them as shown in the figure.
2 An Architrave is an ornamental border formed round an opening such as that for a door or window. 3 Sc. Saving arch.
The "core" or portion between the soffit of the relieving arch and the top of the lintel, should be left out until the whole work has taken its bearing, or the settlement of the arch may cause the core to bear upon and to break the lintel.
They should, if of sufficient projection, be weathered and throated.
Corbels are stones projecting from a wall, generally in order to form a support, as in Fig. 287.
When the weight to be borne is very great, and in other cases (see p. 9), several courses may be corbelled or gathered over, as already described.