How to Pour Concrete - Complete Slab & Patio Guide
Master concrete pouring with proper site preparation, mixing ratios, finishing techniques, and curing methods for professional DIY results on walkways, patios, and slabs.
Dr. Snezana Lawrence
Mathematical Historian
15+ years experience
PhD from Yale University. Published mathematical historian ensuring precision in all calculations.
Education
PhD in Mathematical History - Yale University
Bruce Zawalsky
Survival & DIY Expert
28+ years experience
28+ years wilderness survival and hands-on construction experience. Author of "Canadian Wilderness Survival."
Education
Canadian Armed Forces Wilderness Survival Training
Quick Answer
Concrete pouring requires proper site prep (4" gravel base, compacted), correct mixing (6 quarts water per 80-lb bag), pouring within 90 minutes, finishing in stages (screed, float, trowel), cutting control joints every 8-10 feet, and 7-day curing with moisture. Plan on 2-3 helpers - this is NOT a solo project.
Project Overview
Difficulty Level
Intermediate skill level. Very physically demanding - must work fast! Concrete sets in 90 minutes, so timing is critical. Minimum 2-3 helpers needed.
Time Required
10×10 slab (4" thick): Site prep 4-6 hours, forms 2-3 hours, base prep 2-3 hours, pouring 2-4 hours (continuous!), finishing 2-3 hours, curing 7+ days.
Cost Estimate
10×10 slab (1.23 cu yards): Ready-mix delivery $150-200, OR 80-lb bags (42 bags) $210-250, gravel base $40-60, forms $30-40, rebar/mesh $40-60.
Concrete vs Cement: What's the Difference?
Cement
Powder ingredient (limestone + clay). The binder in concrete. Cannot be used alone. Portland cement is most common.
Concrete
Cement + sand + gravel + water. The complete structural material you actually pour. Hardens through chemical reaction (hydration).
Concrete Mix Ratios
| Mix Type | Ratio |
|---|---|
| Standard Mix (1-2-3) | 1 part cement, 2 parts sand, 3 parts gravel, 0.5 parts water |
| 80-lb Pre-Mixed Bag | Makes 0.6 cubic feet. Add 6 quarts (1.5 gallons) water |
| Ready-Mix Delivery | Ordered by cubic yard. Minimum order often 1 yard. Must use within 90 minutes |
Tools & Materials
Tools
Essential Tools
- •Wheelbarrow or mixing tub
- •Square shovel
- •Hoe (for mixing)
- •Screed board (straight 2×4)
- •Bull float (long handle)
- •Mag float or wood float
- •Steel trowel
- •Edger tool
- •Jointer/groover tool
- •Stiff-bristle broom
Site Prep Tools
- •Tamper (hand or power)
- •Level (4')
- •String line
- •Stakes
- •Hammer
- •Saw (cutting forms)
- •Rake
Safety Gear
- •Rubber boots
- •Work gloves (concrete burns!)
- •Safety glasses
- •Long pants and sleeves
Materials
| Material | Specification |
|---|---|
| Concrete | Bags (80-lb) or ready-mix delivery See calculator for amounts |
| Gravel base | 3/4" crushed stone 4" depth over entire area |
| 2×4 lumber | For forms Perimeter + stakes |
| Stakes | Wooden or metal Every 3-4 feet |
| Rebar or mesh | #3 or #4 rebar, or 6×6 welded wire Cover entire area |
| Rebar chairs | Plastic or dobies Every 2-3 feet |
| Plastic sheeting | 6-mil for curing Cover entire slab |
| Form release | Oil or spray Coat all forms |
💡 Pro Tip: Use our Concrete Calculator to calculate exact quantities needed for your project.
Step-by-Step Concrete Pouring Guide
Site Preparation & Forms
Proper site prep is the foundation of a lasting concrete slab. Excavate deep enough for gravel base plus concrete thickness, with room above grade for drainage.
Key Tips:
- ✓Mark corners with stakes, use string lines for straight edges
- ✓Use 3-4-5 method for square corners (3ft + 4ft + 5ft diagonal)
- ✓Excavate 8-10" deep (4" gravel + 4" concrete)
- ✓Slope away from buildings (1/8" per foot minimum)
- ✓Set forms at finished height with stakes every 3-4 feet
- ✓Oil inside of forms for easy removal
Forms must be level and secure. They are your screed guide - any imperfection shows in the finished slab.
Gravel Base & Compaction
The gravel base provides drainage, stability, and prevents cracking from settling or frost heave.
Key Tips:
- ✓Spread 4" of 3/4" crushed stone
- ✓Rake level across entire area
- ✓Compact with plate compactor or hand tamper
- ✓Add more gravel to low spots, compact again
- ✓Base should be firm - footprints shouldn't show
- ✓Lightly dampen if very dry (aids compaction)
Skipping proper compaction leads to settling and cracked concrete. Rent a plate compactor for large areas.
Install Reinforcement
Reinforcement (rebar or mesh) prevents cracking and holds concrete together if cracks do form.
Key Tips:
- ✓For rebar: Use #3 or #4 in 12" grid pattern
- ✓Overlap rebar joints by 12", tie with wire
- ✓For mesh: 6×6 welded wire, overlap 6" at edges
- ✓Elevate reinforcement on chairs/dobies
- ✓Position in middle of slab thickness (2" up for 4" slab)
- ✓Keep 2" from edges
Reinforcement lying on the ground does nothing! It MUST be elevated to mid-slab height.
Mix Concrete
Proper concrete consistency is critical. Too wet = weak. Too dry = hard to work. Mix to "peanut butter" consistency.
Key Tips:
- ✓For bag mix: Add 3/4 of water first, then mix, then remaining water
- ✓80-lb bag needs 6 quarts (1.5 gallons) water
- ✓Mix thoroughly for 2-3 minutes
- ✓Should hold shape when squeezed, not crumbly or soupy
- ✓Mix only what you can pour in 20-30 minutes
- ✓Have helper mixing while you pour (continuous operation)
Adding too much water is the #1 DIY mistake. More water = easier to work but MUCH weaker concrete.
Pour & Screed
Pour concrete and level it using the forms as a guide. Work quickly - you have about 90 minutes before concrete sets.
Key Tips:
- ✓Start at far corner from your exit
- ✓Pour close to final position (don't pour from height)
- ✓Spread with shovel, slightly overfill forms
- ✓Tap forms to release air bubbles
- ✓Screed immediately: rest board on forms, saw back and forth while pulling
- ✓Two people for wide pours
Once concrete is poured, you're on the clock. Have all tools ready and helpers in position BEFORE pouring.
Float the Surface
Floating smooths the surface and brings the "cream" (cement paste) to the top for finishing.
Key Tips:
- ✓Bull float immediately after screeding
- ✓Use overlapping arcs, don't overwork
- ✓Wait for bleed water to evaporate (surface goes from shiny to dull)
- ✓This takes 30 minutes to 2 hours depending on conditions
- ✓NEVER finish while water is present on surface
- ✓Use mag or wood float after bleed water gone
Working concrete while bleed water is present creates a weak, dusty surface that will scale and flake.
Edge & Cut Control Joints
Edging rounds corners to prevent chipping. Control joints direct where inevitable cracking will occur.
Key Tips:
- ✓Run edger along forms after floating
- ✓Creates smooth, rounded corners
- ✓Cut control joints every 8-10 feet (max 2.5× slab thickness)
- ✓Joints should be 1/4 to 1/3 of slab depth
- ✓Use groover tool with straight board as guide
- ✓For exterior: drag stiff broom for slip-resistant texture
No control joints = random ugly cracks. Control joints make cracks form in straight, hidden lines.
Cure Properly
Curing is critical! Concrete gains strength over 28 days through a chemical reaction that needs moisture.
Key Tips:
- ✓Keep concrete moist for 7 days minimum
- ✓Option 1: Spray with water 2-3× daily
- ✓Option 2: Cover with wet burlap
- ✓Option 3: Cover with 6-mil plastic sheeting
- ✓Option 4: Apply curing compound spray
- ✓Don't remove forms for 24-48 hours
Poor curing is the leading cause of weak, dusty concrete. The first week of moisture is critical.
Weather Considerations
| Condition | Challenges | Solutions |
|---|---|---|
| Hot/Dry (>85°F) | Fast setting, surface cracking | Pour early morning, mist frequently, use shade |
| Cold (<50°F) | Slow curing, freeze damage | Use accelerator, insulate, provide heat |
| Rain Expected | Washout, weak surface | Cover immediately, reschedule if heavy |
| High Humidity | Slow bleed evaporation | Extended wait before finishing |
| Windy | Rapid drying, surface cracks | Windbreaks, frequent misting |
| Freezing (<32°F) | Ice crystals, total failure | Don't pour - wait for warmth |
✓ Ideal Pouring Conditions
- • Temperature: 60-80°F
- • Low humidity
- • No rain forecast for 24 hours
- • Calm wind
- • Early morning start (beat afternoon heat)
Common Mistakes to Avoid
| Mistake | Consequence | How to Avoid |
|---|---|---|
| Too much water in mix | Weak, crumbly concrete that dusts | Follow package directions exactly (6 qts per 80-lb bag) |
| Finishing while bleed water present | Weak surface, scaling, flaking | Wait until surface is dull (30 min - 2 hours) |
| Not compacting gravel base | Settling, cracking | Use plate compactor or hand tamper thoroughly |
| Skipping reinforcement | Cracking, pieces breaking apart | Always use rebar or mesh, elevated to mid-slab |
| No control joints | Random ugly cracks | Cut joints every 8-10 feet, 1/4-1/3 slab depth |
| Removing forms too soon | Edge damage, crumbling corners | Wait minimum 24-48 hours |
| Poor curing | Weak, dusty surface | Keep moist for 7 days minimum |
| Working alone | Concrete sets before you can finish | Minimum 2-3 helpers required |
When to Hire a Professional
✓ Good DIY Projects
- • Small walkways (4×20 or less)
- • Small pads (10×10 or less)
- • Simple rectangular shapes
- • You have 2-3 helpers
- • Good weather forecast
✗ Hire a Pro For
- • Driveways: Heavy traffic requires 4" thick, proper reinforcement, and professional finishing
- • Large patios (>200 sq ft): Too much concrete to finish before it sets - requires crew
- • Garage floors: Requires specific slope to drain, thickened edges, and perfect finish
- • Basement floors: Moisture barriers, drainage, and structural considerations
- • Decorative finishes: Stamped, colored, or exposed aggregate requires specialized skills
- • No helpers available: Impossible to mix, pour, and finish alone before concrete sets
💵 Cost Comparison (per sq ft)
DIY
$3-5 per sq ft
Professional (basic)
$6-12 per sq ft
Decorative
$10-20+ per sq ft
10×10 slab: DIY $300-500 vs Pro $600-1,200 = $300-700 savings (if successful!)
Frequently Asked Questions
How much concrete do I need?
Calculate: Length (ft) × Width (ft) × Depth (inches ÷ 12) ÷ 27 = cubic yards. Example: 10×10×4" slab = 10 × 10 × 0.33 ÷ 27 = 1.23 cubic yards. Order 10% extra for waste. Use our Concrete Calculator for exact amounts.
How long does concrete take to dry?
Concrete doesn't "dry" - it cures through chemical reaction. Initial set: 24-48 hours (can walk on). Full cure: 28 days (full strength). Can drive on after 7 days for light vehicles. Keep moist during first 7 days for proper curing.
Can I pour concrete over existing concrete?
Yes, if existing concrete is sound, clean, and properly prepared. Minimum 2" thickness for overlay. Use bonding agent. Better to remove old concrete if badly cracked or settling. New concrete won't bond well to smooth, deteriorated surfaces.
What PSI concrete should I use?
Residential walkways/patios: 3000-3500 PSI. Driveways: 4000 PSI. Garage floors: 4000 PSI. Higher PSI = stronger but more expensive. Most ready-mix is 3000-4000 PSI. Bag mix is typically 4000 PSI when properly mixed.
Why did my concrete crack?
Common causes: no control joints, too much water in mix, poor curing, inadequate base preparation, no reinforcement, froze before curing, or settling. Some hairline cracks are normal. Control joints direct where cracks form (making them invisible).
Related Resources
This guide has been reviewed by multiple experts to ensure both technical accuracy and practical application.
Dr. Snezana Lawrence
Mathematical Historian | PhD from Yale
Dr. Lawrence is a published mathematical historian with a PhD from Yale University. She ensures mathematical precision and accuracy in all our calculations, conversions, and academic score calculators. Her expertise spans computational mathematics and educational assessment.
LinkedIn ProfileBruce Zawalsky
Survival & DIY Expert | 28+ Years Experience
Bruce is a wilderness survival expert with 28+ years of experience and author of "Canadian Wilderness Survival." His extensive hands-on experience in building wilderness shelters, construction projects, and practical DIY work, combined with his military training, ensures all our construction guides and survival content are field-tested and practical.
LinkedIn Profile