FOUNDATION. This term may be applied either to the surface or bed on which a building rests, or to the lower part of the building which rests on the natural bed. 1. F. as the bed.—The best that can had is solid rock, or any -.kind of resisting incompressible stratum, Tree from water, there is no chance of water, sand forms a solid foundation. When the soil is soft, loose, and shifting a solid bearing can be obtained only by driving piles or long beams of wood, sharpened at the end, through the soft soil, till they reach a hard bottom. This is then planked or laid with cross beams, on which the superstructure is built. The piers of many bridges are formed in this manner. Where the soil is soft, but not shifting, as in the case of made or deposited earth, the method of concreting (q.v.) is adopted—i.e., a large surface is laid with broken metal or gravel, and run together with hot lime, so as to form a broad solid artificial rock, on which the building may rest. .2. F. as the base of the building.—The broader and larger the lower courses of the mason-work, the stronger the wall. The stones should, if possible, extend through and through, and project on each side of the wall.
In the best periods of art, the foundations have always been most attentively con sidered. The Romans formed solid bearings of concrete as above described, and
paid great attention to secure the stability of their buildings. In the dark ages, when there was want of knowledge combined with want of materials and means, many build ings fell from the yielding of the foundations. Some of the earlier Gothic buildings also suffered from the same cause. But knowledge came with experience, and the founda tions of the later Gothic buildings, during the 14th and Rith centuries, were built with extreme care, and on the virgin soil—the stones being as finely dressed as those above ground, where necessary to resist a strong thrust. And where the weight is thrown unequally on piers and walls, these detached points are all carefully united below the floor with a net-work of solid walls.
Bad foundations have been the cause of the ruin of many modern buildings. This has arisen from the costly nature of making a good foundation, when the soil is not naturally suitable. But it is clear that no expense should be spared to make the F. good, as the value and stability of the superstructure depend entirely on the security of the foundation.