Slab Thickness by Use Case
| Application | Min Thickness | Recommended | Reinforcement |
|---|---|---|---|
| Sidewalk / Walkway | 3.5" | 4" | Optional fiber |
| Patio | 4" | 4" | Mesh recommended |
| Residential Driveway | 4" | 5" | Mesh or rebar grid |
| Garage Floor | 4" | 5–6" | Rebar grid required |
| RV/Truck Pad | 6" | 6–8" | Heavy rebar grid |
| Shed Foundation (small) | 4" | 4" | Mesh |
| Pool Deck | 4" | 4–5" | Mesh + control joints |
| Hot Tub Pad | 4" | 6" | Rebar grid |
For freeze-thaw climates (Northeast, Midwest, Mountain West), add 1 inch to the recommended thickness. Always check your local building code — some jurisdictions require 6" minimum for driveways regardless of use.
Slab Pour Checklist
- Excavate to depth. Slab thickness + base depth + 2" for forms = total dig depth. For a 4" slab on 4" base, dig 10" below final grade.
- Compact subgrade. Native soil should be compacted to 95% before adding base. Don't skip this on clay or recently disturbed soil.
- Lay 4" of crushed stone or roadbase. Compact in 2" lifts. 95% compaction is the target.
- Set forms. 2x4 lumber for 3.5" slabs, 2x6 for 5" slabs. Stake every 4 feet. Check for level and proper slope (¼" per foot away from buildings).
- Place vapor barrier and reinforcement. 6 mil poly under interior slabs. Wire mesh or rebar grid raised 1.5–2" off the base on chairs.
- Pour and screed. Pour from far end working back. Screed level with the forms using a 2x4. Don't over-work the surface.
- Float, edge, and joint. Bull float once water sheen disappears. Edge the perimeter with an edging tool. Cut control joints every 8–10 feet.
- Final finish and cure. Broom finish for traction or trowel for smooth. Cover with plastic for 7 days minimum, lightly mist daily.
- Wait before loading. Foot traffic 24–48 hours. Vehicles 7 days. Heavy equipment 28 days.
Common Concrete Pad Sizes and Costs
| Pad Type | Typical Size | Thickness | Yards | 80lb Bags | Est. Installed Cost |
|---|---|---|---|---|---|
| AC / HVAC Unit Pad | 3 × 3 ft | 4" | 0.12 | 4 bags | $75–$200 |
| Generator Pad | 4 × 6 ft | 4" | 0.33 | 10 bags | $150–$400 |
| Hot Tub / Spa Pad | 8 × 8 ft | 6" | 1.32 | 40 bags | $400–$900 |
| Shed Foundation (small) | 10 × 12 ft | 4" | 1.63 | 49 bags | $500–$1,200 |
| Shed Foundation (large) | 12 × 20 ft | 4" | 3.30 | ready-mix | $900–$2,200 |
| RV Pad (single) | 12 × 40 ft | 6" | 10.97 | ready-mix | $2,500–$5,500 |
| Basketball / Sports Pad | 30 × 60 ft | 4" | 24.44 | ready-mix | $6,000–$15,000 |
Concrete Pad Reinforcement Guide
Small pads under 25 sq ft with light loads: AC unit pads, generator pads on stable soil. These are small enough that the concrete mass itself provides adequate strength.
Pads 25–100 sq ft with light to moderate loads: small shed floors, patio sections, equipment pads. Elevate mesh 1.5" off the base using wire chairs so it sits at mid-depth in the slab.
Hot tubs, large sheds, RV pads, anything over 100 sq ft or carrying concentrated loads. Use #4 rebar on 18-inch centers in both directions, elevated 2 inches off base. All corner bars must overlap 12 inches minimum.
Reinforcement does not prevent cracking — it keeps cracks tight when they occur. Proper subgrade preparation (compacted base + gravel) and control joints do more to prevent cracking than reinforcement does. Think of rebar and mesh as insurance, not a substitute for good prep work.
🚛 Truck Payload Reality Check
| 2026 Truck | Max Payload | Concrete Capacity | Bag Capacity (80lb) |
|---|---|---|---|
| Toyota Tacoma (standard) | 1,521 lbs | ~0.38 cu yd | ~18 bags |
| Toyota Tacoma (i-FORCE MAX) | 1,705 lbs | ~0.42 cu yd | ~21 bags |
| Ford F-150 (PowerBoost Hybrid) | 1,740 lbs | ~0.43 cu yd | ~21 bags |
| Ford F-150 (5.0L V8) | 2,235 lbs | ~0.55 cu yd | ~27 bags |
| Ford F-150 (3.5L EcoBoost) | 2,440 lbs | ~0.61 cu yd | ~30 bags |
| 3/4-ton (F-250, Silverado 2500) | 3,500+ lbs | ~0.87 cu yd | ~43 bags |
*Payload values from 2026 manufacturer specs. Your actual payload is on the door-jamb sticker. Add accessories (toolbox, bedliner) and that number drops 100-300 lbs. A driver and passenger count against payload too.
If your project needs more than 1 cubic yard (4,000 lbs), pickup-truck delivery requires multiple trips. For 2+ cubic yards, ready-mix delivery is almost always cheaper than the gas, time, and suspension wear of multiple bag runs. Most ready-mix trucks deliver 8-10 yards in one trip.