Bed Joints. These are the mortar joints between the courses, as EF, Fig. 3. Cross Joints. The short vertical joints at right angles to and connecting the bed joints are known as cross joints or perpends (see GH, Fig. 3). C Transverse Joints.-When the cross joints are continued through the thickness of the wall, they A B FIG. 2. are called transverse joints, as AB, Fig. 2. Wall Joints. - These are D the joints in the thickness of and parallel to the face of the wall CD (Fig. 2). Quoins.-The external angles of a wall are called quoins (see IJ, Fig. 3). Stretcher. This is the 9" face of a brick, K (Fig. 3). Bats.-The half of a brick is known as a 4" bat, while any length above this and below 9" is known as a three-quarter bat. Lap. The horizontal distance between the cross joints in two FIG. 5. successive courses is called the lap. This should never be less than one quarter of the length of the stretcher, X (Fig. 3). Closers (Kings and Queens).-A king closer is a brick made to appear as a header on one end and a closer on the other (Fig. 5). A queen closer is a brick cut, if possible, 9" in length by 21" on the face; most usually the 9" are made up of two 43" lengths (Fig. 2). SETTING OUT A BUILDING. In setting out a building, the line of frontage should first be determined, and a level or datum established by means of a stake driven into the ground; the top of which should coincide with the ground floor or basement level, as the case may be. A centre line at right angles with the front line will then serve as a guide from which to measure and stake out the walls, a similar line being drawn upon the working drawing. This system in many instances will prevent mistakes, though to attempt to give any hard-andfast rules as to mode of procedure would be misleading, different cases demanding different treatment, to be left to the judgment of the experienced foreman. Ax 3'0" Although it may seem a simple matter to note, yet the necessity of occasionally testing the setting - out square for accuracy must be pointed out, especially as it is such an easy matter to prove it. In Fig. 6 let ABC be the square; then, if correct, while AB and BC measure 3′ and 4' respectively, from A to C should measure 5'. These proportions are given, as a 5' rod is usually kept on the works. TRENCHES AND EXCAVATIONS. 4'0" с Having determined the positions of the walls, test for accuracy and proceed to dig trenches. It is impossible to determine by theory how deep the trenches should be taken, although a supposed depth is given on the drawing, and taken in the quantities. It is necessary to sink the trench until a good bottom, if possible, be reached. A good foundation should consist of gravel, sand, rock (if not interspersed with clay-holes), and hard chalk (when not affected by water), etc. When this has been attained, all levels should then be taken and marked by means of stumps. Timbering for Excavations.-In some cases, either through the depth of the trench or the nature of the soil, timbering has to be resorted to, when the methods are as follows: In moderately firm ground, after 3′ or 4' deep, poling boards 9" x 1" are placed at intervals opposite each other, and struts of rough scantling, 4" x 6", wedged downwards in between (see Fig. 7). In looser ground, poling boards are placed close together and supported by 3" planks or walings, which in their turn are strutted. The thickness of the struts will depend upon the width of the trench, the pressure upon them, their distance apart, the strength of the walings, and the nature of the soil (see Fig. 8). FIG. 7. FIG. 8. FIG. 9. In very loose soils, such as running sand and slipping clay, the sides have to be supported at once as the excavation proceeds, and boards are used horizontally as sheeting, being kept in position by poling boards and struts (see Fig. 9). In excavations over 5' in depth, stages every 5' in height, and supported upon the struts, become necessary. FOOTINGS AND FOUNDATIONS. It is not intended in the present elementary work to dwell at any length upon foundations. This important subject is reserved for a more advanced course, and foundations will therefore be dealt with only as far as is necessary. The foundation is that portion of any structure which acts as a base upon which to erect the superstructure; and consists sometimes of brick or stone alone, but, where necessary, of concrete and stone, or concrete and brick. The purpose of the foundation is to spread the weight of the structure over a larger bearing surface than would be covered by the structure itself, thus minimizing or preventing unequal settlement. All structures are expected to settle more or less, according to the weight, quality of the work, thickness of the joints, etc.; but when an unsightly crack appears in a building, it shows clearly that one portion of the structure has settled more than the others, or, in other words, that inequality of settlement has taken place. This may be due to a faulty place in the bottom of the trench; or to a weight being concentrated upon a certain point which has not been properly strengthened to receive it; or, lastly, to the use of two distinct qualities of work, such as gauged brickwork or stone ashlar facings, and ordinary brick-and-mortar backing. A Concrete. It may be possible that, in some situations, where hard gravel, etc., forms the bottom, concrete is unnecessary, but according to the London Building Act, it is required that concrete at least 9" thick, and extending 4" each way beyond the width of the bottom course of footings, should be used. The depth, however, will depend upon the thickness and height of the wall or structure, the weight to be carried, and the nature of the subsoil. A safe guide, however, is exemplified in Fig. 10. Taking the wall in section, and extending the concrete each side of the bottom course of footings, drop perpendicular lines as outside width of concrete, the depth deing determined by an angle of 45° passing from the point A of the neat work, and cutting the outside line of concrete. -6" Angle of 45° FIG. 10. 6" The concrete should consist of one part finely ground Portland cement, or blue Lias lime, two of sand, and five or six of gravel, broken brick, or stone. Broken brick or stone small enough to pass through a 13" mesh is preferable for the aggregate. A cubic yard of concrete would require 27 cub. feet of broken brick, stone, or shingle, 9 cub. feet of sand, 4 cub. feet or 3 bushels of Portland cement, and 25 gallons of water. These quantities should be correctly measured, turned over together three times dry, and again several times while the water, through a rose, is being sprinkled over the mass. It was once considered that concrete should be shot into the trenches from a considerable height, but this has since been proved to be an error, as the heavier particles sinking to the bottom and the lighter floating to the top, prevent the desired formation of one homogeneous mass. The concrete should therefore be gently placed in position to the levels previously taken, and allowed to become thoroughly set before the brickwork is started. FIGS. 11 and 12. FIG. 13. As rule being that the bottom course of footings shall be twice the thickness of the wall intended to be built, each course losing in thickness half a brick successively, stepping off in offsets of 21" on each side until the desired thickness of the wall is attained. an example, a 12-brick wall will have a bottom course of 3 bricks, the next 2, the next 2, and then the neat work. It is also advisable that walls of 18" and over in thickness should have the bottom course of footings doubled. Thus a 2-brick wall will have the two bottom courses of footings 4 bricks thick. Students preparing for the various Building Trades Examinations will find the following an easy, accurate, and quick method of drawing plans, elevations, and sections of footings for all thicknesses of walls. Taking the footings for a 1-brick wall as an illustration, it being immaterial whether plan, elevation, or section be drawn first, it is convenient |