Page:Ware - The American Vignola, 1920.djvu/11

 INTRODUCTION

BUILDING is a shelter from rain, sun, and wind. This implies a Roof, and Walls to support it. If the walls entirely enclose the space within, there are Doorways for access, and Windows for light. Roofs and walls, doors and windows are the essential features of buildings.

Roofs may be flat, sloping, or curved. A roof with one slope is called a Lean-to, Fig. 1. When two sloping roofs rest upon parallel walls and lean against one another, they meet in a horizontal Ridge, Fig. 2, at the top. and form a Gable at each end. Roofs that rise from the same wall in opposite directions form a Horizontal Valley, Fig. 3, at the wall. If two walls make a projecting angle, their roofs intersect in an inclined line called a Hip, Fig. 4. If the walls meet in a reentering angle, the inclined line of intersection is called a Valley. Circular walls carry conical, Fig. 5 (a) or domical roofs, Fig. 5 (b).

If there is more than one story, the flat roof of the lower story becomes the Floor of the story above. If the roof extends beyond the wall that supports it, the projection is called the Eaves, Fig. 6. If the wall also projects, to support the extension of the roof, the projection is called a Cornice, Fig. 7. The principal member of a cornice, which projects like a shelf and crowns the wall, is called a Corona, Fig. 8.

Walls are generally made wider just at the bottom, so as to get a better bearing on the ground. This projection is the Base, Fig. 9. A similar projection at the top is called a Cap, or, if it projects much, a Cornice, as has been said. A low wall is called a Parapet. A short piece of wall about as long as it is thick is called a Post, and if it supports something, a Pedestal, Fig. 10, the part between its Cap and Base is then the Die. A tall post is called a Pier, Fig. 11, if it is square, and a Column if it is round. Caps of piers and columns are called Capitals, and the part between the Cap and the Base, the Shaft. The flat upper member of a Capital is called the Abacus. 1