Use this guide to plan a concrete slab for a walkway at 4 inches thick, with a narrow width and regular control joints. For a different walkway size, use the Concrete Slab Calculator as the tool for custom sizes.
Recommended walkway slab setup
Choose a 4-inch walkway slab, usually 3 to 4 feet wide, on compacted ground. Cut control joints at regular intervals so the narrow slab can move without random cracking, and give it a light broom finish for grip in wet weather.
How much concrete for a walkway slab at 4 inches thick
Volume in cubic yards = length (ft) × width (ft) × 1/3 ÷ 27. The “order” column adds a 10% allowance for formwork variation and spillage.
| Walkway slab size | Area | Base volume | Order with 10% allowance |
|---|---|---|---|
| 3 × 20 ft | 60 sq ft | 0.74 cubic yards | 0.81 cubic yards |
| 3 × 30 ft | 90 sq ft | 1.11 cubic yards | 1.22 cubic yards |
| 4 × 40 ft | 160 sq ft | 1.98 cubic yards | 2.17 cubic yards |
Worked example: a 3 × 36 ft walkway slab
Area = 3 × 36 = 108 sq ft. Volume = 108 × 1/3 = 36.00 cubic feet = 1.33 cubic yards. With a 10% allowance: 1.33 × 1.10 = 1.47 cubic yards. At 0.60 cubic feet per 80-pound bag, the allowed volume is 39.60 cubic feet, or 66 bags, although ready-mix is usually simpler for a walkway this long.
Method note
Measure the walkway along its centre line, including bends, and use its average width. A walkway is a long, narrow slab, so joint spacing matters more than it does for a square patio slab.
Walkway slab questions
How wide should a walkway slab be?
Three feet is a common minimum for one person, and 4 feet is more comfortable. Wider walkways need more concrete but are easier to use with wheelbarrows and strollers.
How far apart should walkway control joints be?
For a narrow walkway, cut joints about every 3 to 4 feet, so each panel is roughly as long as the walkway is wide. This is closer than the spacing used for a large patio slab.
Does a walkway need a gravel base?
A compacted gravel base helps drainage and gives a level surface for the slab, especially on soft or clay soil.
Can I pour a walkway in sections?
Yes. Pouring in sections with joints between them is practical for a long walkway, and it matches the control-joint layout.
For custom walkway sizes, use the Concrete Slab Calculator.