Laying Out Foundations. In most communities it is customary for the carpenter to be present and to assist the mason in the laying out of the foundations. Where buildings are large and important, this work is done by an engineer with a steel tape and a surveyor's instrument, Fig. 1. This instrument is known as a builder's transit, and consists of a tripod upon which rests a small telescope with crossed hair wires within, by means of which the observer may fix the line of sight very accurately. A circular dial contains a magnetic needle which enables the fixed dial to be set with reference to the true north and south line of the observer. After the fixed dial has been adjusted, the telescope may be swung to the right or the left until the circular graduations indicate that it points in the direction wanted, after which stakes may be set.
Fig. 1. Transit.
A level upon the telescope enables the observer to sight grades or levels; a helper carrying the leveling rod, Fig. 2.
Fig. 3 shows a more common instrument. This is an architect's Y- level and differs from the other in that it is less complete. It has no attachment for measuring vertical angles. This is not serious, however, since the builder seldom needs such an attachment, the level being the most essential part. Y- levels are made both with and without compass attachments.
Upon ordinary residence work a surveyor is employed to locate lot lines. Once these lines are located the builder is able to locate the building lines by measurement. Suppose it is desired to locate a building by means of the side lot line: (1) Measure from the side lot line, along the front and along the back lot lines, a distance equal to that which it is desired the house shall hold relative to the lot side line. Drive stakes here. (2) While sighting from one of these stakes to the other, have an assistant locate two other stakes in the line of sight, a distance apart sufficient to guarantee the placing of the cross-lines for the back and front of the house without restaking these, A-B, Fig. 4. The process of laying out lines for a house is almost identical with that used in laying out a rectangle on a drawing board. (3) Having located a line of indefinite length for one side of the house, a second line of indefinite length, preferably for the front of the building, may next be located. To do this, first locate a front corner stake upon the first line just located. This is done by measurement from the street line. Having located and driven in this stake, A, Fig. 4, drive a nail in the top of the stake to more accurately locate this corner. If an instrument is available it will be located over this stake and the front line A-C, Fig. 4, located by laying it off at 90 degrees from the side line already located. If no instrument is available, the front line may be laid off at right angles to A-B by holding a framing square at their intersection. This angle should be verified by the 6-8-10 method. This consists in measuring from the intersection at A along one line a distance of 6 feet and sticking a pin in the line at that point; a pencil mark may be used when the cord is white. In a similar manner, measure off 8 feet along the other line and then measure the hypothenuse of the triangle so formed. It should measure 10 feet. If it does not, the front building line must be shifted until it does. (4) With these two lines located, the remaining two lines may be located by measurement from them, the nail of stake A giving the starting point. Before this is attempted, however, the batter boards should be placed. Batter boards are variously constructed. Those shown are common types. They should be placed free of the foundation proposed by at least 3 or 4 feet. (5) Test the squareness of the whole lay-out by measuring the diagonals A-D and B-C. If the building lay-out is square the diagonals should be equal. If they are not equal, shift the cords at C and D, retaining their parallelism, until the diagonals become equal. (6) Once the lay-out is correct, saw kerfs should be made in the batter boards where the cords are placed. These kerfs will permit the cords being removed and replaced without further measuring.
Fig. 2 Leveling Rod.
Fig. 3. Y-Level.
Fig. 4. Batter Boards.