Cement Sidewalks:
The method of laying cement sidewalks is as follows: The ground should be leveled off from 12 to 15 inches below the finished grade of the walk, and should be well settled by ramming, care being taken that the excavation is drained to one side. A foundation consisting of about 8 or 10 inches of coarse gravel, stone chips, sand, or cinders, should then be laid and well tamped or rolled with a heavy roller. An attempt often is bade to economize on this kind of foundation by making it only 5 or 6 inches thick. However, foundations of such thickness generally allow the frost to penetrate to the ground and heave up the pavement in spots.

After the foundation has been rolled, the concrete should be prepared in the proportion of 1 part of cement, 3 parts of sand, 5 parts of broken stone, and a sufficient quantity of water to make a stiff mortar. It should be thoroughly mixed and worked while being laid. The top, or finishing, coat should be laid immediately, and only as much concrete should be laid as can be covered with cement on the same day, because if the concrete gets dry on top, the finishing coat will not adhere to it. The top coat should be prepared by mixing 1 part of the best Portland cement with 2 parts of fine sand or 2 parts clean, sharp, crushed granite or flint rock.

A 1/2 inch space should be left between the curb and the pavement and between the building line and the pavement to allow for expansion and contraction. This space should be filled with cinders or ashes. the pavement itself should be laid off into blocks 6 feet square or less. These blocks should be separated from one another by sheets of tar paper, which should extend all the way through the concrete. It is very essential that grooves be made with a trowel in the top coat directly over the tar paper, so that if the concrete cracks while drying out, it will be sure to part in these grooves and not in the body of the pavement.

Hair Cracks are often caused by the mortar in the hot coat being too rich in cement. If the pavement is troweled too much, it has a tendency to make the cement float to the top. This is as liable to cause hair cracks as the use of too much cement. If the top coat is put on too wet, it has the same effect.

In May cities, the law requires that concrete sidewalks be finished with a rough surface. Such a surface is not so slippery in winter as a smooth finish. It also possesses the additional advantages that it is easier to construct and does not show any hair cracks. In laying such a surface, the top coat is leveled with a straightedge running on battens, one set on each side of the walk. The battens are arranged so that the part of the walk at the curb will be lower than the part at the building wall. (this patch is controlled by city ordinances, and is usually 4 inches in 10 feet for all sidewalks.) The sidewalk is then left until it has almost set, before it is troweled. It should be troweled as little as possible, and with a wooden trowel instead of one made of steel. After toweling, it should be covered with straw and kept moist for at least a week. the less the sidewalk is smoothed, with a straightedge or trowel, and the more it is rammed, instead, the better it will be.

Fig 67 shows a section of a concrete sidewalk, the ashes or spalls being shown at a,the first coat of concrete, at b; the finishing coat, at c'; the street paving, at d'; and the joints with tar paper in them, at c.

Layout is much more critical now than was for the footer. The accuracy you achieve in laying out the stem wall will determine the squareness of your structure, which is very important. Start on one corner by measuring in 3-1/4" from each side of the corner and making a mark. This will be the the outside edge of the form work, which will be 3/4" plywood. Now do the same for an adjacent corner that is the farthest away. This will give you a long "baseline" of which to square the rest of the building to.

Squaring your walls can be accomplished by several methods, none of which are too difficult. It will depend greatly on the equipment you have available. If you just happen to have, or know someone who has, a 2 beam laser you could layout your whole foundation in an hour. Set the laser over top one of the points you have made and line one beam with the other mark. Now you should have a perfect 90 degree angle between the two beams. Just mark the laser beam at the opposite corner, measure the distance that you need between points and set up on the mark. You will want to snap chalk lines between these points also.

Another method is the 3-4-5 triangle, which is just some basic geometry. Any triangle with multiples of 3-4-5 respectively will have a 90 degree angle between the 2 shorter legs. Start the same way as before by marking the two corners at 3-1/4" from each side of the corner. Snap a chalk line between them, and double check the length between the two points to match what dimension you require. Now from one point measure towards the other point, along the chalk line. You will want a distance of at least 6', mark it there. Now you will measure a distance of 8' at 90 degrees to the chalk line. This measurement will need to be put down as an arc; with a little practice you should be able to mark the arc by using the end of the tape as a guide. Now measure from your 6' mark toward the 8' arc. You will need a measurement of 10'. Where the 10' mark crosses the arc make a mark. This point and the first point you made creates a line that is a 90 degree angle to the original chalk line.

Continue on around the whole foundation; snapping lines, measuring, creating 90's, measuring, and snapping. After your layout is complete and you feel comfortable with the results you will nail a 2x6 into the 2x8 footing form work with the inside edge lined up with the chalk lines. This is the part where you let it sit for 3 days before nailing the 2x6 down. If you had gotten to it the next day you could drive nails right into the concrete with out too much trouble, but we all know that sometimes it doesn't work out .