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How to Pour a Concrete Slab — Complete DIY Guide

Pouring your own concrete slab saves $2,000–$4,000 on a contractor, but only if you get the material quantity right. Order too little and you'll have a cold joint (a permanent weak line where fresh concrete meets partially set concrete). Order too much and you're paying $150/yard for material that goes to waste.

This guide walks you through every step — planning, form building, mixing, pouring, finishing, and curing — with a built-in calculator that tells you exactly how many yards to order.

Step 1: Plan Your Slab

Start with three numbers: length, width, and depth. A standard patio slab is 4 inches thick. Driveways need 5–6 inches. For a 10×10 patio at 4 inches, you're looking at about 1.25 cubic yards of concrete.

💡 Pro tip: Always add 5–10% to your calculation for waste, spillage, and uneven ground. Concrete trucks charge a short-load fee if you order less than their minimum (usually 3–5 yards).

Step 2: Build the Form

Use 2×4 or 2×6 lumber for the form boards. Set them at the right height using stakes every 3–4 feet. The top of the form is your finished concrete level — get this right and the rest is easy. Check for square by measuring diagonally: both measurements must be identical.

💡 Pro tip: Coat the inside of your forms with release agent (or vegetable oil in a pinch). This prevents the concrete from bonding to the wood and makes form removal clean.

Step 3: Prepare the Base

Excavate 6–8 inches below your finished grade. Add 4 inches of compacted gravel for drainage. Compact it with a hand tamper or plate compactor. A solid base prevents cracking from freeze-thaw cycles.

Step 4: Reinforce

Wire mesh or rebar grid on 2-inch chairs keeps your slab strong. For a patio, 6×6 welded wire mesh is sufficient. For driveways, use #4 rebar on 18-inch centers.

Step 5: Calculate Your Materials

Use the calculator below. Enter your slab dimensions and local concrete cost per yard. The calculator accounts for the 5% waste factor automatically.

Length (ft)

Width (ft)

Depth (in)

Cost per Cubic Yard ($) US average: $150/yd³. Adjust for your region.

📊 Concrete Estimate

Volume — Cubic Feet—

Volume — Cubic Yards—

80 lb Bags Needed—

60 lb Bags Needed—

Estimated Cost—

Surface Area—

Includes a 5% waste factor. Order 5–10% extra for safety.

Step 6: Pour and Screed

Pour the concrete starting from one corner. Work it into the form with a shovel or rake. Use a straight 2×4 as a screed board — pull it across the top of the forms in a sawing motion. This levels the concrete flush with your forms.

Step 7: Float and Edge

Wait until the bleed water evaporates (the surface loses its wet shine). Run a bull float across the surface to embed aggregate and bring cream to the top. Then run an edger along the perimeter — this rounds the edges so they don't chip.

💡 Pro tip: Don't overwork the surface. Too much troweling traps water beneath the surface, which causes blistering and scaling later.

Step 8: Cure — The Most Important Step

Concrete doesn't dry — it cures through a chemical reaction with water. Keep the slab moist for at least 7 days. Cover it with plastic sheeting, burlap, or spray it with water 2–3 times daily. Concrete that cures properly is 50% stronger than concrete left to air-dry.

⚠️ Critical: Never pour concrete when temperatures will drop below 40°F within 24 hours. Cold concrete doesn't hydrate properly and loses strength permanently.

Cost Breakdown

For a 10×10 slab at 4 inches thick at $150/yard:

Concrete: ~$195 (1.3 yards × $150)
Gravel base: ~$50 (1 ton)
Form lumber: ~$40 (reusable)
Wire mesh: ~$30
Total DIY: ~$315
Contractor price: $2,000–$4,000

Ready to calculate your slab? Use the calculator above, or explore our other concrete calculators for footings, walls, and rebar.