How to Pour a Concrete Slab

Pouring a concrete slab is achievable as a DIY project for small areas (under 2 cubic yards). For patios, walkways, and shed pads, the process is straightforward with the right preparation.

How much concrete to buy

Slab size	4 in thick	6 in thick	80 lb bags (4 in)
6 × 6 ft	0.44 cu yd	0.67 cu yd	20 bags
8 × 8 ft	0.79 cu yd	1.19 cu yd	36 bags
10 × 10 ft	1.23 cu yd	1.85 cu yd	56 bags
10 × 20 ft	2.47 cu yd	3.70 cu yd	Ready-mix recommended
12 × 12 ft	1.78 cu yd	2.67 cu yd	Ready-mix recommended

Rule of thumb: For slabs over 1.5 cubic yards, order ready-mix concrete. Mixing that many bags by hand is impractical — concrete begins setting in 30–60 minutes and you need the whole slab poured before any section starts to set.

Use the Concrete Calculator for your exact slab dimensions.

DIY vs. ready-mix concrete

Option	When to use	Approximate cost
Bagged (80 lb bags)	Under 1 cubic yard	$5–$8/bag
Bagged (60 lb bags)	Small patches, posts	$4–$6/bag
Ready-mix truck	Over 1–1.5 cubic yards	$150–$200/cubic yard delivered
Volumetric truck	Any size, flexible timing	$180–$250/cubic yard

Ready-mix is delivered in minimum loads of 1 cubic yard at most plants.

What you’ll need

Materials:

Concrete (bagged or ready-mix)
2×4 lumber for forms
Gravel base (4 inches compacted)
Rebar or 6×6 wire mesh
Plastic chairs for reinforcement support
Curing compound or plastic sheeting

Tools:

Excavation: shovel, plate compactor
Formwork: drill, stakes, string line, level
Pouring: concrete mixer (rental) or wheelbarrow, shovel, concrete rake
Finishing: bull float, hand float, edger, groover, stiff broom

Concrete slab thickness guide

Use	Recommended thickness	Reinforcement
Sidewalk / walkway	4 inches	Wire mesh optional
Patio	4 inches	Wire mesh recommended
Shed floor	4 inches	Wire mesh
Garage floor	6 inches	#4 rebar 18” centers
Driveway	6 inches	#4 rebar 18” centers
RV pad	6 inches	#4 or #5 rebar

Frequently Asked Questions

How thick should a concrete slab be?

A 4-inch slab is standard for patios, walkways, and shed floors. A 6-inch slab is used for garage floors and driveways that will support vehicle weight. Footings and structural slabs often require 8–12 inches — check local building codes.

How many bags of concrete do I need for a 10×10 slab?

A 10×10 ft slab at 4 inches thick requires 1.23 cubic yards of concrete. Using 80 lb bags (0.6 cu ft each), you need about 56 bags. Using 60 lb bags (0.45 cu ft each), you need about 74 bags. For slabs over 1 cubic yard, ready-mix is cheaper.

Can I pour concrete myself?

Yes for small slabs (under 1–2 cubic yards). Larger slabs are better done with ready-mix concrete delivered by truck, as hand-mixing is too slow — concrete starts setting in 30–60 minutes and a large slab needs to be poured and finished before the edges set.

How long does concrete take to cure?

Concrete reaches 70% of its strength in 7 days and full design strength at 28 days. You can walk on it after 24–48 hours. Wait 7 days before driving vehicles on a slab. Curing time is longer in cold weather and faster in heat.

Do I need rebar in a concrete slab?

Rebar or wire mesh is recommended for any slab exposed to vehicle loads or frost. For light-duty slabs (walkways, patios with no vehicle traffic in Zone 3+), 6×6 wire mesh is standard. Driveways and garage floors should have #3 or #4 rebar on 18-inch centers.