Beginner's Guide to Concrete Forming

a foundation being laid
  • 4-40 hours
  • Beginner
  • 40-8,000
What You'll Need
Tape measure

Concrete forming isn’t difficult. It’s important to know the right way to do things, however, to ensure proper concrete forming. There’s a skill in forming concrete, but it’s a skill set that can be quickly learned. Having the right equipment helps everything go smoothly.

Step 1 - Position

Using stakes and string, mark out the position for the concrete slab. Use the level to determine the grade of the concrete. With the tape measure, keep shifting the parallel sides until the diagonals of the slab are equal. Keep the width at the desired distance.

Step 2 - Form

The form is made from boards, which should be placed about 1/8 inch from the string line, held in place by wooden stakes. If the concrete will be 4 inches thick or less, use a 1-inch board. For thicker concrete, go with a thicker board for the form. The timber should be flat and straight with very few knots.

If the slabs will be 4 inches thick or less, the forms can be 32 inches on center. That will ensure that the concrete is properly supported. If the concrete will be thicker, the concrete should never be less than 24 inches on center. The form boards should be nailed to the stakes and put so they’re level to the string line, almost touching it. Pack soil around the stakes to help hold the form in place.

Step 3 - Concrete

You can buy ready-mixed concrete, having it delivered to your site. With a large job, this is a much better option. For smaller jobs, consider mixing the concrete yourself. The type of concrete you mix and how you mix it will depend on the job you’re undertaking. For paths, for instance, use about 5 ¾ gallons of water for each sack of cement when the sand is damp. If the sand is wet, just use 5 gallons of water.

It’s important to know how much concrete you’ll need for the job. If the path covers 100 square feet and will be 4 inches deep, then the estimate is 1.2 cubic yards of concrete to fill the form.

Step 4 - Pouring

Before pouring concrete, wet the entire area thoroughly. Pour in the concrete and tamp it down thoroughly. Once tamped, take a piece of 2 inches by 4-inch lumber to level the concrete for proper concrete forming. Move the lumber backward and forward, as if sawing, to give a proper level to the concrete.

Step 5 - Expansion Joints

It’s important to put expansion joints into the concrete. Once the concrete has set to the point where it can support a plank that’s 2 inches by 8 inches, use that plank as a guide for the groover. The groover will cut into the concrete to make the joints. On paths, these should be cut every 4 feet to 6 feet. On larger slabs, they should be cut in both directions.