Concrete Slab & Patio Calculator

Pouring a slab is the most common DIY concrete project. For small patios (10x10 or smaller), one or two people can handle it. For driveways or large slabs, you need a crew of 3-4 friends. Concrete sets fast—you can't pause halfway through.

Expect a physically demanding day. You will be moving heavy wheelbarrows, raking wet mud (which is heavier than dirt), and working on your knees. The critical window is the first 45 minutes after the truck arrives.

Don't start without these: 1) A straight 2x4 for screeding. 2) A Bull Float (rent this) to smooth the wet concrete. 3) A Magnesium Hand Float. 4) An Edger tool. 5) A Finishing Broom. 6) Rubber boots.

A good rule of thumb for DIYers: have one helper for every 1.5 cubic yards of concrete. If you are pouring 3 yards, you want at least 2 people total. If you can't find a crew, find a pro at LocalConcreteContractor.com.

Your slab is only as strong as the ground under it. Remove all grass and soft topsoil. Add 4 inches of gravel (crushed stone) and run a plate compactor over it until it's rock hard. If you leave footprints, it's too soft.

Use straight 2x4s held by wooden stakes. CRITICAL: Slope the forms away from your house (1/4 inch drop per foot) so rain doesn't pool against your foundation.

Dump the concrete inside the forms. Use a rake (not a shovel) to pull it roughly level. Then, take your straight 2x4 board, rest it on the forms, and saw it back and forth while pulling it down the slab to create a flat surface.

Right after screeding, push the bull float across the surface. This pushes down rocks and brings up the smooth 'cream'. Do this before the bleed water appears.

Wait until the surface water (bleed water) has disappeared and the concrete stiffens slightly. Then run your edger around the perimeter and use a broom to lightly drag across the surface for traction.

Concrete doesn't 'dry', it cures. Keep it damp for 3-7 days by misting it with a hose or covering it with plastic. This prevents cracking and makes the surface 50% stronger.