Installing concrete sidewalks is by no means an easy project. The serious do-it-yourselfer can manage it with a little guidance and proper preparation.
Excavating – The hardest work is usually digging the ground because you probably have to use a shovel and wheelbarrow unless you want to tear up the yard with a tractor. Dig approximately 6 inches below the intended top of the sidewalk. This will allow 4 inches of concrete and a few inches of granular fill underneath. Use sand, pea gravel, or crushed stone for the subgrade. The granular fill is used to fill in low areas and allows water to flow under the sidewalk.
Forming – Use 2x4s for the formwork. Set a string line to get desired height and straightness. The strings should be set so that the side closest to the house is slightly higher. The sidewalk should slope away from the house approximately ¼ inch per foot. So a 4 foot wide sidewalk should have about 1 inch slope.
Drive stakes every 4 feet, raise the board to the string and nail or screw in place. For curved sidewalks, use a flexible material such as masonite for forms. Since the forms for curved walks are flexible, you must drive more stakes to keep the concrete from pushing out the forms. Once the forms are set, rake down the fill so that it’s 4 inches below the top of the forms.
Pouring – Have plenty of help with you when pouring concrete. It’s hard work and you only have so much time before the concrete gets too hard. It’s highly recommended that you use concrete from a ready mix company instead of mixing your own. A ready mix company will suggest the best mix and slump for the job. Slump is basically a measure of the wetness of the mix. They can also slow down or speed up the set time.
Start at the end furthest from the mixer. If you use a wheelbarrow, don’t fill more than half way. Concrete is very heavy and you don’t want to spill or hurt yourself. Use a piece of 2×4 the same length as the sidewalk width to strike off or level the concrete as you pour. Someone should be gently floating behind the pour to bring the cement paste to the top. Place expansion joint between new and existing concrete. Most ready mix companies can supply the expansion material.
Finishing – Finish concrete using a wood or magnesium hand float. Magnesium is used for air entrained concrete. If you live in a climate subject to freeze and thaw cycles, the concrete should be air entrained. The ready mix company will know this. The most common type of finish for sidewalks is a broom finish. After the concrete is hand floated again and the surface is smooth, drag a broom across the surface perpendicular to the length. If it appears to rough, let it dry a little longer and try it again. Use an edging tool to dress up the edges.
Control joints can be placed during finishing with a hand groover or the next day with a saw and diamond blade. Joints should be spaced evenly. If the sidewalk is 4 feet wide, then cut a joint every 4 feet. Joints should also be placed at stress points such as corners or across a turn in the walk. Apply concrete sealer immediately following finishing with a sprayer. Adjust the tip and pump the sprayer for misting so you don’t mark up the surface.
Pouring and finishing concrete is a skilled trade not usually recommended as a do-it-yourself project. But if you’re feeling up to it, then installing concrete sidewalks is the easiest place to start.