180 



WALLS, ESPALIER-RAILS, AND TRELLIS-WORK. 



Fig. 118. Plan of a hollow brick wall 14 inches wide 

 and 12 feet high. 



472. In the construction of walls they are generally built solid ; but 

 when the wall is formed entirely of brick, a saving of material is obtained, 

 as well as a warmer wall produced, by building them hollow. There are 

 various modes of effecting this, but one of the simplest is that shown by the 

 plan fig. 118, in which a wall fourteen inches wide, with a vacuity of five 



~ inches and a half, may be built 

 ten or twelve feet high with 

 little more than the materials 

 requisite for a solid wall nine 

 inches wide. Such walls may 

 be carried to the height of ten 

 or twelve feet without any piers, 

 and one advantage attending them is that they can be built with a smooth face 

 on both sides, whereas a solid nine-inch wall can only be worked fair on one 

 side. A still more economical wall may be formed by placing the bricks on 

 edge, which will give a width of twelve inches that may be carried to the 

 height of ten feet without piers. Walls of both kinds have been employed 

 in the construction of cottage buildings, as well as in gardens. (See Encyc. 

 of Cottage Architecture, p. 168 .to 172, where several kinds of hollow walls 

 are described.) A very strong wall, only seven and a half inches in thick- 

 ness, ma}' be formed of bricks of the common size, and of bricks of the 

 same length and thickness, but of only half the width of the common 

 bricks, by which means the wall can be worked fair on both sides. The 

 bricks are laid side by side, as in fig. 119, in which a represents the first 

 course, and b the second course. 

 The bond, or tying together of 

 both sides of the wall, is not 

 obtained by laying bricks 

 across (technically, headers), Fi - 119 - Plan f a brick wal1 inches thick - 

 but by the full breadth bricks covering half the breadth of the broad bricks, 

 when laid over the narrow ones, as shown in the dissected horizontal section, 

 fig. 119, at &, and in the vertical section, fig. 120. Besides the advantage of 



j p-j being built fair on both sides, there being no headers, or through 



[ t I and through bricks, in these walls, when they are used as out- 

 side walls the rain is never conducted through the wall, and 

 the inside of the wall is consequently drier than the inside of a 

 wall nine inches in thickness. These walls are adapted for a 

 variety of purposes in house-building and gardening, in the 

 latter art more especially. The only drawback that we know 

 against them is, that the narrower half- breadth bricks must be 

 made on purpose. For the division walls of a large garden, or 

 for the boundary wall of a small one, such walls with piers 

 projecting eighteen inches or two feet, to enable the walls to 

 be carried to the height of ten or twelve feet, might be econo- 



^view of a 7J- mically adopted : the space between the piers ought not to be 

 in. thick brick greater than can be covered by a single tree. It must be 

 acknowledged, however, that piers are not desirable iii fruit- 

 walls, because when the wall is newly built it cannot so soon be covered 

 with trees, the piers standing in the places where temporary trees 

 would be planted. Piers, however, on conservatory walls may be turned 

 to good account, both as assisting in supporting the temporary copings or 



