Building or Repairing Concrete Sidewalks Around the Home

Does your home need a new concrete sidewalk or to replace an existing concrete sidewalk? Here is a step by step guide to walk you through it. First things first, you will probably need a permit from you local city or county, they do want their share after all. Also while you are there, ask about width or step requirements (if any) as there is usually a minimum width and thickness allowed on a sidewalk and step treads have requirements as well. After you work your tail off you really don't want the building department telling you to tear it out....

Figure out how much concrete you are going to need, measure the length of the sidewalk you intend to build (covert it to inches) and multiply it by the width (converted to inches) and thickness (three and ½ inches.)

A 15 foot long, 40 inch wide and three and ½ inch thick sidewalk would be figured like the example below.

Example: 15 x 12 = 180 inches length

40 inches wide

X 3.5 inches thick

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25,200 cubic inches, divided by 1,728 = 14.58 cubic feet, divide that by 27 and you get cubic yards = .54. You will need slightly more than ½ yard of concrete.

Knowing how much concrete you need allows you to avoid over ordering and also tells you if the cement company will deliver that much as most suppliers have a minimum yardage they will deliver or a charge for delivering less.

Layout the sidewalk with a string line pulled tightly between stakes, allowing enough room between them for the sidewalk and the 2x4 forms and stakes. These strings are just a guide to work from. Dig up any grass or other vegetation in the path.

When building forms, set the 2x4's end to end and nail a two foot length of 2x4 over them on the outside of your forms. Set stakes about every two feet and nail the forms to them from the outside with double headed duplex nails. (It makes them much easier to pull when the time comes to tear down the forms.) Set a string line at the side of the forms, using a line level to level it out over the length of the run. Level from side to side with a four foot level.

Set the tops of your 2x4 forms at the height of your leveled string line. Tap the stakes with a sledge hammer to adjust or lift it with a pry bar. Dig down to the bottom of the 2x4 forms and no deeper, digging deeper makes an unstable surface and can crack the concrete when the ground sinks as it settles. If you do dig past your mark use washed gravel to fill in to the level of the bottom of your forms. A 2x4 cut just shorter than the width of the inside of your forms can be slide along leveling the inside to keep an even thickness. Fill any holes under the forms from the outside of the forms.

Concrete wire is suitable for re-enforcing the sidewalk's concrete, cut it about an inch short of the inside measure of the forms so it cannot protrude and decay. Support the wire on rocks or bricks at about the center of your slab.

I prefer to order my concrete; having mixed my own I know it is really not much fun. If you need more than ¼ of a yard I highly recommend it since even for that small an amount hand mixing in a wheel barrow will feel like torture, renting a mixer will save your back, but the sheer number of 80 lb bags you will need for even a small project will tell you to order it in a truck if possible. Be sure to tell them what it is for as not all concrete mixes are the same. Bags will be marked for sidewalks if you choose to mix your own.

You will need a few tools to finish your project, a flat trowel 18 to 24 inches long, an edger to finish the edges and keep them from breaking off, and a stiff bristled push broom to add the non-slip final finish. Also, you will need a 2x4 about two feet longer than your forms (a screed) to slide back and forth pulling the concrete along the forms and leveling and filling in voids.

Start at one end of your forms, filling in the end until the corners are full and level using the screed, work the screed back and forth till all the gravel is below the surface and wet concrete is all you see. Continue down the forms, pulling the concrete along and filling and smoothing as you go ( smoothing is perhaps the wrong word here as at this point level with no gravel showing is all that is needed.) A concrete vibrator would come in handy here, but isn't truly necessary in pouring a sidewalk as you can tap the forms with a hammer to settle the cement and fill air pockets as you move down the forms.

Once the concrete is poured, take the flat trowel and smooth the top surface out, submerging any gravel that has surfaced and filling any voids at he forms or where gravel opened holes while being moved around. You may need to add a little concrete here and there to fill or a touch of water to help smooth things out.

Next we use the edger, slide it back and forth along the side of the forms to give the edges a smooth contour and a finished look. It takes some practice to use, but really is not all that difficult.

The final finish here is done with a broom, the only hard part about it is to get the timing right, too soon and you get to re-trowel it, too late and it will not be able to scratch the surface. The concrete has to be soft enough to scratch but dry enough to only scratch. Try this first about 15 to 30 minutes after the pour, carefully checking before going all out. Pull the broom to you across the walk lightly, you shouldn't have to exert a lot of pressure to mark the top surface, it is not necessary to mark it deeply, just enough to make it non slick when wet.

Concrete has a time limit; you cannot stop and eat lunch or run to the store! Once you begin pouring you have to see it through all the way and you will need help if the project is longer than 10 feet. Concrete is very labor intensive, be sure to schedule enough time to do the job and never order more concrete than you and your helpers can handle in a day. The forms can be blocked off to shorten the pour easily enough, try it in small doses to begin with until you get the feel for how much you can do in a day.

You can pull the forms after a few hours after the concrete has set up, depending on the outside temperature and humidity. Also you may need to spray a cure on it, to prevent it from curing to quickly, contact your supplier and ask if it is necessary in your area. If the sides of your walkway are visible, now is the time to touch them up.

Do not walk in concrete without rubber boots on! or allow it to sit on your skin for prolonged periods. People have lost toes due to trying this, concrete is very hard on the skin.

Avoid walking on the cured concrete for a day or so, instead find a nice shady spot to admire your work with a cold drink and a smile on your face.