Walls Foundations
stone, wall, cement, soil, piles and class
FOUNDATIONS, WALLS, WINDOWS,FRAMING, JOINTS, AND GIRDERS In olden times, it required the services of only a few men to build a house. The stone mason put up the foundations, fireplace, and chimney, and the carpenter did the rest. Nowa days, however, almost all the details are divided among a multitude' of special trades. It is nevertheless true to-day, more than it ever was before, that while the carpenter is, and will continue to be, of prime importance, yet his functions are more intimately bound up than they used to be with those of his fellow-work men. The carpenter nowadays must know something of masonry, concrete, electric wiring, etc.; and so must the plumber, the plasterer, etc.
Foundations..
The object of a foundation is to form a solid base arranged to distribute the weight of the superstructure over a large area of ground, and so reduce the inevitable "settle ment" to a minimum, and to provide for a uniform settling, so that the framework will not be strained and the plaster cracked.
We are therefore dwelling briefly upon the subject of foundations.
The method of constructing such foundations is largely determined by the nature of the soil and may be classed as follows : Class I.—Foundations where the soil is firm enough to bear the weight of the building.
Class IL—Foundations on marshy grounds.
In Class I the foundation may be formed— Firstly, by brick footings formed by spreading the wall by means of off-sets as shown in Figs. 1, 2 and 3.
Secondly, by laying down rough thick stones of width equal to twice the thickness of the wall, and then forming brick off-sets to distribute the weight of the wall on the stones, as in Fig. 4.
Thirdly, by concrete footings composed of Portland cement, broken stones and sand mixed together with water; a good proportion being, one part of cement, two of sand, and four or five of broken stone. The material thus produced be comes a solid mass as hard as stone. This method as shown in Fig. 5, is preferable to the preceding ones and is being generally adopted. The success
of it depends upon the proportion of cement, sand and stone, as above given, being strictly adhered to, and care should be taken that the mixing is inspected, as the tendency is to economize on the cement to the detriment of the concrete.
In Class II, a solid bed is formed for the founda tion by driving wooden piles into the marshy soil as shown in Fig. 6. Oak, yellow pine, spruce and hemlock are the woods commonly used. The piles are driven through the soft soil to the firm bed beneath. The heads are then cut off at a certain level and a timber capping put on them. This capping is commonly of yellow pine and serves as a support for the foundation above and at the same time ties the piles together.
It frequently happens that the piles do not reach the firm soil owing to its great depth. In this case the load is wholly supported by the friction of the earth on the sides of the piles; which, however, is generally found ample except in the case of large building and engineering operations.
The materials commonly used in the walls of buildings are brick and stone, and within the last few years cement blocks have been used to a great extent and with very satisfactory results. The locality in which the building is being erected and the purposes for which it is intended deter mine largely the material which is to be used. Thus in a district where stone is easily obtained this material is naturally used; while in places where clay is abundant, bricks are largely em ployed. Bricks are to be preferred to the stone in that they lend themselves more readily to regu lar arrangement and to a system of bonding.