How to Build a Concrete Patio

Building a concrete patio is hard work, but with a lot of planning, a bit of sweat, and the know-how below, it's definitely a job that you can tackle yourself.

1) Like most home improvement projects, a little planning goes a long, long way. You should not only plan your concrete patio itself but be sure to have all the materials you'll need.

Anything other than a tiny concrete patio will require renting a cement mixer. If you're building a typical six inch thick patio, you'll need one bag of pre-mixed concrete for every two square feet of patio.

2) Dig out the patio shape with a shovel, digging down at least six inches if you live in an area that freezes in the winter. If you're building next to your house, establish a grade so that water will run off the patio.

The easiest way to establish a grade is to drive stakes into the ground at the high end as well as the low end, and then hang a string and line level between them.

Try to dig out the patio so that you have a grade of 1 inch for every 3-4 feet.

3) Build a form from 2x6 lumber that will hold gravel and concrete. This is the basic frame for the outer edge of the patio and once inserted into the area you've excavated, it should be level with the ground, assuming you want your patio to be flush.

4) Once the form is in place, put down a two inch base of gravel. This will provide some flexibility so that the concrete won't crack during the winter when it freezes.

5) Insert rebar as reinforcement into the hole, making a grid by placing sections of rebar either one foot or two feet apart, moving from front to back and then from left to right.

6) Mix the concrete in the automatic mixer. Pour the concrete as quickly as possible, mixing in filler rocks as you go and using a straight board (called a screed) to keep it level. Drag the screed down the length of the form, with it resting on both sides.

Use a float to smooth out any lumps, sweeping it in a long arc and taking care not to gouge it into the concrete.

7) For larger patios, you'll need to cut control joints with a trowel to prevent the slab from cracking. These are grooves cut every 3 feet or so in the concrete. For the first pass, use the trowel to etch them in place, with the edge of a board as a guide to keep them straight. Once in place, extend the grooves deeper to about one inch deep with the jointer.

8) Cover the patio with plastic sheeting so that it can cure properly. The sheeting traps moisture in and prevents the concrete from drying to quickly. Try to keep the patio covered for at least a week with the sheeting and avoid putting too much stress on the new patio for at least a month, as concrete takes 3-4 weeks to completely cure.