A slab — a patio, shed floor, or walkway — is one of the most achievable DIY concrete projects, and success comes down to a solid compacted base, the right thickness, and not rushing the pour or the cure. Work through the steps and tap “Add to my materials list” as you go.
IS THIS A GOOD FIT FOR YOU?
Advanced DIY
1Easy DIY
2Some Experience
3Advanced DIY — this project
4Hire a Pro
Why this rating: Concrete is heavy and time-sensitive; mistakes become hard to reverse.
Applies to: A small nonstructural flatwork project with an appropriate plan.
Get help when: Use qualified help for structural slabs, foundations, large pours, reinforcement design, or difficult access.
A planning guide, not a safety certification. Conditions at your home can change the difficulty. Ratings are independent of contractor relationships.
TimeA weekend (plus cure time)
Cost$$ (concrete + base)
PermitsSometimes — check locally
Permits & safety: Many areas require a permit for slabs over a certain size or near structures and setbacks — check first. Call 811 before digging. Wet concrete is caustic, so wear waterproof gloves, boots, and eye protection.
Plan the whole project as you go. Add each calculator result to a named project, then edit quantities and supplier prices, check off purchases and stages, and export CSV, print/PDF, or JSON.
1Excavate and build the forms
Dig out the area and build level form boards (2×4s give a 3½” slab, 2×6s a thicker one), sloping the forms about 1⁄8–1⁄4” per foot away from any structure for drainage. The calculator gives the dirt to dig and haul.
Dirt to remove
22.2 cu yd
Dig area
600 sq ft12" deep
In-ground volume
22.2 cu yd
Loose (haul) volume
27.8 cu yd+25% soil swell once dug
Truckloads
3~12 CY per dump truck
Haul + disposal (est.)
$556~$20/CY (varies by area)
Planning estimate. Adjust allowances and sample prices for your supplier; tax, delivery, and labor are not included.
2Compact a gravel sub-base
Add and compact about 4” of crushed-stone sub-base, keeping it damp as you tamp for a stable, well-drained foundation under the slab. The calculator gives base gravel by the ton or yard.
Gravel needed
10.0 tons
Area
600 sq ftat 4" deep
Gravel needed
10.0 tons7.41 cubic yards
Delivered cost (est.)
$450~$45/ton crushed gravel
Planning estimate. Adjust allowances and sample prices for your supplier; tax, delivery, and labor are not included.
3Lay vapor barrier and reinforcement
Where moisture matters, lay a 6-mil poly vapor barrier, then set 6×6 welded-wire mesh or a #3 rebar grid at mid-depth on chairs (about 2” up in a 4” slab) to control cracking. The calculator sizes the vapor barrier and tape.
Poly rolls
1 roll
Area to cover
600 sq ft
With overlap
690 sq ft+15% for 6" overlaps & waste
6-mil poly rolls
1 rolleach 10'×100' = 1,000 sq ft
Cost (est.)
$70~$70/roll
Planning estimate. Adjust allowances and sample prices for your supplier; tax, delivery, and labor are not included.
4Pour, screed, float, and finish
Place the concrete (3,000–4,000 psi is ideal for home slabs), screed it level with the form tops, float to bring up the paste, run an edger around the perimeter, then broom for a non-slip finish. The calculator gives cubic yards and bags. Never add water to loosen the mix — it weakens the concrete.
Slab-on-grade layers — gravel sub-base, a vapor barrier under the slab, and steel reinforcement held at mid-depth. Control joints crack the slab where you want it to.
Concrete including allowance
8.00 cu yd
Slab area
600 sq ft
Concrete needed
7.41 cubic yards8.00 CY with 8% allowance
80-lb bags
360 bagsor 480 × 60-lb bags
Ready-mix cost (est.)
$1,400$175/CY sample price; delivery and short-load fees extra
How this estimate works
Volume = length × width × (thickness ÷ 12) ÷ 27, in cubic yards. The headline includes your waste allowance (8% by default); do not add it again. Bag counts round up using 0.60 cu ft per 80-lb bag or 0.45 cu ft per 60-lb bag. Confirm the product yield.
The shopping list uses ready-mix plus a sample 4-inch base, mesh, forms, and vapor barrier. These companion materials are starting allowances, not a structural specification. Verify your slab design, reinforcement, strength, and supplier delivery minimums.
Planning estimate. Adjust allowances and sample prices for your supplier; tax, delivery, and labor are not included.
5Cut control joints and cure
Tool or saw control joints ¼ of the slab depth (~1” on a 4” slab), every 8–12 ft, so the slab cracks where you want it to. Then moist-cure for 5–7 days; wait 48 hours before foot traffic and ~28 days for full strength.
