Concrete Construction for the Home and the Farm

Specifications

Drainage Foundation

Stake out the lines of the walk, or dimensions of the floor. Excavate to a depth of 16 inches, ram and tamp the ground thoroughly and evenly and fill in 12 inches with clean large cinders, broken stone, pebbles, brick bats, broken tile or other material selected. Place in position wooden forms made of 2 by 4’s, these 2 by 4’s to be set on edge and held in position by stakes firmly driven in the ground, the top edge to be located so as to accurately outline the established grade or slope of the walk or floor.

A walk should be higher in the center, or at one edge, to insure the water running off. This slope should be ¼ of an inch to the foot.

Selection of Materials

Particular attention must be paid to the selection of the materials and their mixing.

The concrete should be composed of gravel or crushed stone all of which will pass through a ¾-inch mesh screen, and be collected on a ¼-inch mesh; sand, free from loam and preferably coarse, and a grade of Portland cement guaranteed to meet all the requirements of the Standard Specifications as adopted by the American Society for Testing Materials and the American Society of Civil Engineers.

Proportions

The strength of the slab is not always governed by its thickness. The greater strength is obtained by properly proportioning the gravel or crushed stone, sand and Portland cement, so that all the spaces between the stone are filled with sand and cement.

The Portland cement, sand and gravel or crushed stone should be mixed in proportions, if the sand is not very coarse, of 1: 2: 4—which means, 1 part Portland cement, 2 parts sand, 4 parts gravel or crushed stone, all passing a ¾-inch mesh and all collected on a ¼-inch mesh. If the sand is coarse and the crushed stone or gravel well graded in size of particles, it may be mixed in proportions of 1 part Portland cement, 2½ parts sand, 5 parts gravel or broken stone. All proportions are measured by volume.

Bank run gravel is often used for sidewalk work, particularly where a good bank can be found on the farm. It is safer, if this material be used, to screen out the pebbles, using them as stone, measuring the quantities of stone and sand as described above. Concrete should not be laid in freezing weather.

Consistency of Concrete

Mix the concrete as described on page 15 to a consistency that when tamped, it will not quake, but it should be sufficiently wet so that some moisture will rise to the surface under tamping.

Placing

Divide the walk by setting forms at right angles to the side forms. The cross forms can be made of 2 by 4’s. These provide for expansion and contraction joints. Hold these forms in place by driving stakes through the foundation into the ground on the opposite side from where the concrete is to be placed. Spread the concrete over the drainage foundation to the thickness of the walk or floor, and in slabs not over 6 feet square. The thickness of a walk should be 4 inches, a driveway 6 inches, a floor over which a wagon may be driven 6 inches, and all other floors 4 inches.

Fill in every other slab, placing enough forms to use up all the concrete mixed in one batch. No batch should stand longer than one half hour before being placed.

Tamp the concrete thoroughly. Use a template, with ends resting on the side forms, and cut to a curve to give the walk the necessary crown. The concrete should be tamped so as to conform to the curve of the template. If one edge of the walk is made higher than the other, use a straight edge resting on the side forms. Tamp the concrete to conform to the straight edge.

Mix another batch of concrete, remove the cross forms and place the concrete between each slab, forming a continuous walk. Use the template or straight edge and tamp as before. Immediately after placing the closing slab, work a straight trowel or knife down through the entire depth of the concrete between each slab, thus insuring a perfect contraction joint. Smooth the surface with a wooden float.

A neat appearance may be given the contraction joints by running a jointer along the top, thus smoothing the edges. Do this before the concrete gets too hard. The sides of the walk may be smoothed in the same way by use of an edger.

When the concrete is nearly hard go over the surface with a piece of oakum or a stiff brush, removing the marks of the float and giving a good even wearing surface which will not be slippery. In using oakum or a brush be careful not to remove the larger pieces of stone. If surfacing in this manner disturbs the particles of stone and roughens the walk to too great an extent, allow the walk to harden a little more before finishing in this way. At the end of each day’s work see that the last slab is entirely filled and finished.

All interior floors, such as floors of cellar, barns and stables require no contraction joints. They are made by laying a solid continuous sheet of concrete. All outside floors should have contraction joints forming slabs not over 6 feet square. These are provided the same as in sidewalks. A feeding floor is formed merely by sidewalk pavements set side by side. Instead of using a template for crowning the surface, use a straight edge, each end resting on the extreme outside forms to give a slope to the feeding floor. Contraction joints for exterior floors are formed in the same way as for sidewalks. The concrete is also placed in alternate slabs and finished in the same way as sidewalks. When completed the walk or floor must be continuously protected from the rays of the sun and from the wind for at least three days, so that it will not dry out at any time. This can be easily done by covering the concrete when it is hard with hay, straw, or old carpet. This covering should be thoroughly soaked with water, and kept wet for three or four days or longer if economy will permit.

While the walk or floor is hardening it should be so protected as to prevent persons or animals from disfiguring the surface by walking on it.

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