How to Build & Design a Curved Sidewalk

Setting the Forms

• 1

  Plan your layout with a garden hose. A thick hose will maintain a smooth, curved shape to help you visualize what the final product will look like. Pay attention to how the sidewalk meets up with existing structures, such as porches and other sidewalks.

• 2

  Remove any grass and dig down 3 or 4 inches below the finished level of the sidewalk. Design the sidewalk so it has at least a 1/4-inch fall for every foot of length so water will run off. Make the width of your excavation a little wide to allow room for the forms.

• 3

  Cut sheets of 1/4-inch Masonite into 4-inch strips on a table saw. Masonite makes good form material when making curved structures because it bends easily. Position the strips along the length of the hole you excavated. Use 12-inch strips of Masonite as overlapping backing to join the ends of the longer strips. With the ends of two strip butted end to end, run 1/2-inch screws through the face of the strips into the backing to secure the joints. In the end, you should have one continuous strip of Masonite running the length of the sidewalk.

• 4

  Stand the Masonite strip on edge and position it in the curved shape that you want. Drive wooden stakes along the length every 12 inches. Run 1-inch screws through the face of the Masonite and into the stakes to maintain the forms at the desired elevation. Drive stakes behind each of the backing pieces at the joints.

• 5

  Cut a spacer rod out of a piece of scrap wood the same length as the width of the sidewalk. Use the spacer to help maintain a constant width as you set the forms on the opposite side. Use a carpenter's level as you screw the forms to the stakes to keep the same elevation from side to side.

• 6

  Shovel dirt behind the forms to help keep the smooth, curved shape. Concrete exerts quite a bit of outward force on forms, so make sure the forms won't budge.

• 7

  Cut wire mesh with bolt cutters to fit within the forms. If you buy a roll of wire, flip each piece over after cutting to prevent it from curling up again. When it comes time to pour the concrete, remember to lift the mesh as you go so it is in the middle of the sidewalk.

Pouring the Concrete

• 8

  Calculate the volume of concrete you need and order it from a concrete company. For a 4-inch-thick sidewalk, the formula for the number of cubic yards is Volume = (Length x Width)/81. Use feet for the units of length and width. Add 5 percent to your calculation so you don't run short.

• 9

  Cut a straight 2-by-4 a foot longer than the width of the sidewalk. As the concrete fills the forms, use the 2-by-4 to knock down the excess. Each end of the board should ride on the top of the forms on either side. Move the board from side to side as you pull it along the length. The zigzagging motion helps to vibrate the concrete to remove air pockets.

• 10

  Smooth the concrete with a bull float and touch it up with a magnesium float. On the first pass, fill the holes and make it smooth without spending a lot of time on it. The biggest mistake beginners make is overworking the concrete. After the first pass, go over it again two more times with the magnesium float, allowing about 20 minutes between each pass. The float creates suction to pull moisture to the surface, producing "cream" for filling the holes.

• 11

  Round the corners with an edger immediately after each pass with the float and make grooves perpendicular to the sidewalk's length with a grooving tool. Besides looking nice, the grooves help control where the concrete cracks. Divide the length of the sidewalk into equal sections of about 4 to 5 feet for laying out the groove locations. Lay the 2-by-4 across the top of the forms as a straightedge to guide the grooving tool. Use the float to touch up any marks made by the edger, groover or 2-by-4.

• 12

  Broom the concrete with a finisher's broom 10 to 15 minutes after the last pass. For each swath, pull the broom across in the same direction as the grooves in one smooth, continuous stroke. Avoid stopping or having to pass over the same spot a second time. After brooming, apply concrete sealer with a sprayer.