CHAPTER IFoundations

CARPENTRY

Fig. 1. Transit.

1. 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. A level upon the telescope enables the observer to sight grades or levels; a helper carrying the leveling rod,Fig. 2.

Fig. 2 Leveling Rod

Fig. 3shows 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.

Fig. 3 Y-Level

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.

Fig. 4. Batter Boards

If an instrument is available it will be located over this stake and the front lineA-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 toA-Bby 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 atAalong 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 hypotenuse 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 stakeAgiving 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 diagonalsA-DandB-C. If the building lay-out is square the diagonals should be equal. If they are not equal, shift the cords atCandD, 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.

2. Grade Line.—A properly drawn set of plans will show both the present lay of the ground upon which the building is to be erected and the new grade line which is to be established after the building is completed. The most convenient method of determining old grade lines and of establishing new ones is by means of the transit,Fig. 1, or the Y-level, Figs.3and5, with the rod,Fig. 2.Both instruments operate upon the same principle in grade work. The telescope is set level and sights taken thru it to the target upon the rod. The reading of the target's position upon the rod compared with the height of the telescope above the base, usually the street walk, determines the difference in grade of that particular placing of the target.

Fig. 5. Taking Sights with Y-Level

To locate levels for the masonry, (1) set the instrument at someconvenient place and level the dial. (2) Having determined the height of the instrument above some predetermined base, such as the street walk, swing the telescope about and, making allowance for the difference in level as shown by the drawings, place successively stakes at each corner of the building with the required level marked thereon. As a rule, the mason has his own Y-level and uses it freely as the wall is constructed, especially where levels are to be maintained as the layers of material are placed.

Fig. 6. Leveling with Straight-edge

In a similar manner the earth grade about the building may be located, stakes being driven into the ground at frequent intervals and the amount of "fill" or reduction indicated thereon. Grade levels are established usually only after the builders are thru, except that the mason will have the grade indicated for him where the wall above the grade is to be differently finished from that below.

Where no surveyor's level is at hand, the mason or carpenter will secure the levels by means of a straight-edge of some 14 feet in length. A common level is placed upon this plank as shown inFig. 6.By successive levels with stakes driven to indicate thesuccessive levelings, a grade may be carried quite a distance without very great variations.

Fig. 7. Foundation Detail

3. Excavations.—Excavations should be made enough larger than the proposed foundation that the mason may have room to wield his trowel in pointing the outer joints, and for waterproofing. An extra foot of excavation upon each side will usually be required.

All foundations must be carried well below the frost line. Excavations should be made accordingly.

4. Foundations; Footings.—Because of the tendency of a building to settle unevenly, due to variations in the strength of the supporting ground or the unequal weight placed upon this ground, foundations must be constructed of some non-yielding material such as brick or stone, and of such thickness and so bonded that the weight of the building may be evenly distributed.

The thickness of wall will depend upon the weight to be supported and upon the character of the soil.

Unless rock or gravel is encountered, every foundation should have a footing,Fig. 7.The amount of footing used is usually twice the thickness of the foundation wall. In brick walls this footing draws into the wall by "stepped" courses of brick, each layer being narrower than the one just preceding. For ordinary residence work with ordinary soil conditions a 10- or 12-inch wall resting upon a footing 2 feet wide and 8 or 10 inches deep will suffice.

A safe footing for supporting posts of 66" × 6" yellow pine, for most soils, will be 10 inches deep by 18 inches square. Partition walls carrying no unusual load need not be over 8 inches in thickness.

Fig. 8. American Bond

Fig. 9. English Bond

In many communities the use of concrete is supplanting that of stone or brick, especially below the grade line. Such a wall should be composed of 5 parts of crushed stone or gravel, 3 parts sand, and 1 part cement. The footing may be formed by tamping the mixture in a form made by spading out of the earth a depth and width sufficient for the wall to be supported.

5. Foundation Materials; Construction.—Of the materials commonly used in the construction of foundations monolithic concrete is becoming the most common for that part of the wall which lies below the ground or grade level. Brick and stone are sometimes used.

Where brick or stone is made use of, some device is required to "tie" the material together, due to the fact that the mortar usedin filling the voids or spaces between the members has little strength as compared with that of the stone or brick itself. This bonding is secured by placing the brick or stone so that they shall overlap one another, both along the faces of the wall and across the wall.

Bricks laid with their lengths in the same direction as that of the wall are known as stretchers; those laid with their lengths across the wall are known as headers,Fig. 8.The manner of placing these headers among the stretchers determines the type of bond. The American, English and Flemish are the more common types. Of these the American,Fig. 8, is the most used upon ordinary work. It consists of a course of headers placed every sixth course. The English bond,Fig. 9, is much stronger, having every other course a header course. It is used mainly upon very important work where unusual strength is required. Flemish bond is illustrated inFig. 10.

Fig. 10. Flemish Bond

Of the various types of stone work, rubble work and ashlar predominate,Fig. 11.Rubble work is most frequently used for that part of the wall below the grade line, and ashlar for the remainder of the wall. In either case, thru stones are placed every 4 or 5 feet in the length of the wall and every 18 inches in the height, to provide bonds.

Fig. 11. Types of Stone Work

In rubble work the stones are rough and unhewn. They must be laid upon a good bed of stiff mortar with their stratifications in a horizontal position. Otherwise, the face of the wall might "peel" from the effects of frost and moisture, making an unsightly as well as a weaker wall. The term "ashlar" refers to a wall builded of stones having finished faces. When either rubble work or ashlar is laid up in courses it is known as coursed rubble or coursed ashlar. When the horizontal joints are not continuous the wall is known as random rubble or broken ashlar.

Not infrequently a wall will be constructed with an ashlar facing attached to a brick backing by means of metal bonds. In such a wall, the faced ashlar, unless more than 8 inches in thickness and well bonded into the wall, should not be considered in estimating the strength of the wall.

Fig. 12. "Form" for Concrete

In the construction of both brick and stone walls the workshould be carried up as nearly as possible at the same levels. In both brick and stone walls the corners are run up with stepped courses, the corners being plumbed as the wall is carried upward. A line is then stretched between the corners and, layer by layer, the rest of the wall filled in. No corner should, ordinarily, be carried more than 3 feet above the rest of the wall. In the case of uncoursed stone work the wall is leveled every 15 to 18 inches in its height.

6. Forms for Concrete Walls.—The economical building of forms for concrete walls is a matter of importance in building construction.Fig. 12shows a type of form suitable for foundation work. Such forms should be made of semi-seasoned stock. Thoroughly seasoned stock will warp badly when the wet concrete is placed. Spruce, Norway pine, etc., are better woods to use than hard or Georgia pine.

For ordinary foundation work 1-inch boards may be used, the studs being placed not over 2 feet apart. These studs may be assisted materially in holding the forms in position, by wires placed as inFig. 12, and by props placed against the dirt wall of the excavation.

In placing the concrete a 4-inch layer is laid and then "spaded" or "worked" well into place, a "wet mix" being used. The smoothness of the resulting faces is increased by an additional spading of the mixture away from the form. A good spading tool is made by straightening out an ordinary garden hoe. This allows the cement and mortar to flow next to the form and hold this place while the filling proceeds.

Where forms are placed to give finished walls, that is, walls to which no plaster is to be applied, they should be aligned with no greater variation than ⅜" from the lines specified.

Forms should be allowed to remain until the concrete will resist indentation with the thumb, upon ordinary walls.

There is no limit to the ingenuity one may make use of in form building. The illustration given is merely suggestive.

7. Waterproofing.—The extent to which a wall should be waterproofed will depend upon the location of the building. Foundations near running water must naturally be better protected than those in well drained locations.Fig. 7illustrates a treatment which will prove quite safe for almost all localities. The exterior face of the wall is covered with several layers of asphaltum or tar. By coating the top of the footing and the top of the concrete floor just before the finish floor of cement is placed, little water will enter. A drain tile carried about the house as shown inFig. 7, especially if gravel is placed against the wall above it, will meet every emergency.

There are other ways of waterproofing basement walls, but this is typical of the external wall treatments. In monolithic construction waterproofing may be secured by appropriate additions to the mixture of waterproofing materials such as slacked lime, just before the mixture is placed, no external applications being required.

Fig. 13. Cellar Frame with Sash

8. Basement Frames.—Fig. 13illustrates one successful form of basement window frame construction, with sash. In this type the sash is hinged to the top of the frame, and a catch or button at the bottom of the frame secures the sash when closed. The construction is such as to best shut out wind and water when the sash is closed.

Fig. 14. Basement Door Frame

Fig. 14illustrates a basement door frame. Frames such as this, and the window frame ofFig. 13, are made of heavy stock and are known as plank frames.

Basement frames are held in place by means of wooden blocks nailed to the sides of the frame, as well as by the projecting "lugs" of the frame itself. The frame is set and plumbed by the carpenter as soon as the mason has prepared the sill.Fig. 14shows a frame plumbed and stayed, ready for the mason to lay the adjacentwall.Fig. 15indicates the position of plumb and level in the setting of a frame. The edges of a door frame are "sighted" for wind.

Where it is necessary to attach frames or other woodwork to brick walls, it is customary to have the mason insert wooden "bricks" as the wall is constructed. Wooden bricks are of the same size as other bricks, and should be constructed with the edge which is to be laid back in the wall thicker than the front edge, so that a dovetailed effect is secured.

Fig. 15. Plumbing and Leveling Cellar Frame

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