Why Proper Post Setting Matters
Fence posts are the foundation of your entire fence. A poorly set post leads to:
- Leaning fences within 2-3 years
- Gates that won’t close
- Premature fence failure
- Expensive repairs
Take the time to set posts correctly, and your fence can easily last 20+ years.
Post Setting Methods Compared
Method 1: Concrete Setting (Recommended)
Best for:
- Privacy fences
- High-wind areas
- Gate posts
- Security fencing
Pros: Maximum stability, long-lasting
Cons: More work, permanent placement
Method 2: Gravel/Crushed Stone
Best for:
- Low fences
- Areas with good drainage
- Temporary installations
- Frost-heave prone regions
Pros: Easy adjustment, good drainage
Cons: May shift over time
Method 3: Tamped Earth
Best for:
- Agricultural fencing
- Very temporary fences
- Remote locations
Pros: Quick, no materials needed
Cons: Least stable, not recommended for most applications
Tools and Materials
Tools
- Post hole digger or auger
- Level (4-foot and torpedo)
- Tape measure
- String line
- Shovel
- Tamper
- Wheelbarrow
- Safety glasses and gloves
Materials
- Fence posts (wood, metal, or vinyl)
- Fast-setting concrete (or gravel)
- Gravel for drainage (2-4 inches)
- Stakes and string for layout
- 2×4 lumber for bracing
Step 1: Plan Your Post Layout
Determine Post Spacing
| Fence Type | Recommended Spacing |
|---|---|
| Wood privacy | 6-8 feet |
| Wood picket | 6-8 feet |
| Chain link | 10 feet |
| Vinyl | Per manufacturer |
| Metal/ornamental | 6-8 feet |
Mark Post Locations
- Mark corners first - These are most critical
- Mark gate posts - Allow for gate width + hardware (add 3.5”)
- Run string line - Stretch between corner posts
- Mark intermediate posts - Equal spacing along string
- Mark end/terminal posts - Where fence meets structures
Formula for spacing:
Total fence length ÷ desired spacing = number of sections
Round to whole number, then recalculate exact spacing
Example: 64 feet ÷ 8 feet = 8 sections → 64 ÷ 8 = 8 feet exactly
Step 2: Check for Underground Utilities
CRITICAL: Call 811 before digging
- Free service in all US states
- Required by law in most areas
- Utilities marked within 2-3 business days
- Prevents dangerous (and expensive) accidents
Common underground hazards:
- Gas lines
- Electric cables
- Water/sewer pipes
- Telecommunications
- Irrigation systems
Step 3: Dig Post Holes
Hole Depth Rule
General rule: 1/3 of post length below ground
| Post Height (Above Ground) | Post Length | Hole Depth |
|---|---|---|
| 4 feet | 6 feet | 24 inches |
| 5 feet | 7 feet | 28 inches |
| 6 feet | 8 feet | 32 inches |
| 8 feet | 10-12 feet | 36-40 inches |
In cold climates: Dig below frost line (check local codes)
Hole Diameter
- Minimum: 3× post width
- 4×4 post → 12” diameter hole
- 6×6 post → 18” diameter hole
Digging Methods
Manual post hole digger:
- Good for 4-10 posts
- Hard work but inexpensive
- Best in sandy/loamy soil
Power auger (one-person):
- Rent for $50-80/day
- Good for 10-20 posts
- Struggles in rocky soil
Power auger (two-person):
- Rent for $80-120/day
- Best for large projects
- Handles most soil types
Pro tip: Augers work best in slightly moist soil. Very dry or wet soil is harder to dig.
Step 4: Prepare the Hole
Add Drainage Gravel
- Pour 2-4 inches of gravel in bottom
- Tamp firmly
- This prevents water from pooling under post
For Wood Posts
Even pressure-treated wood benefits from:
- Coating end grain with wood preservative
- Copper naphthenate or similar product
- Prevents moisture wicking
Step 5: Set Corner and End Posts First
Corner posts take the most stress. Set them perfectly.
Placement
- Set post in hole on gravel base
- Check height - top should be at finish height
- Check plumb with level on two adjacent sides
- Brace temporarily with 2×4s staked to ground
Plumb Checking Tips
- Check two adjacent sides, not opposite sides
- Use torpedo level for tight spaces
- Post must be plumb in ALL directions
Step 6: Fill the Holes
Concrete Method (Recommended)
Mixing:
- Use fast-setting concrete (sets in 20-40 minutes)
- Follow package directions for water ratio
- Mix in wheelbarrow - don’t pour dry into hole
Pouring:
- Fill hole to within 4 inches of top
- Re-check plumb as you pour
- Tamp/vibrate to remove air pockets
- Slope top away from post for water runoff
- Keep bracing in place until set (minimum 4 hours)
Amount needed per post:
| Hole Size | Bags (80 lb) |
|---|---|
| 8” × 24” | 1 bag |
| 10” × 30” | 2 bags |
| 12” × 36” | 3-4 bags |
Gravel Method
- Add gravel in 4-inch lifts
- Tamp each layer firmly
- Check plumb after each layer
- Crown top to shed water
- Fence can be built immediately
Step 7: Set Line Posts
Using String Lines
- Stretch string between corner posts at top
- Stretch second string at bottom (above concrete level)
- Align each post to both strings
- This ensures straight, uniform fence
Setting Sequence
- Place post in hole
- Adjust height to string line
- Check plumb on two sides
- Fill with concrete/gravel
- Move to next post
Step 8: Brace Gate Posts Extra
Gate posts take significant stress. Reinforce them with:
Option 1: Larger Posts
- Use 6×6 instead of 4×4
- Deeper hole (add 6 inches)
- More concrete
Option 2: Steel Post Reinforcement
- Drive metal T-post alongside wood post
- Lag bolt together
- Cover with trim if desired
Option 3: Concrete Collar
- Pour concrete above ground level
- Slope away from post
- Provides extra lateral support
Common Mistakes to Avoid
| Mistake | Problem | Solution |
|---|---|---|
| Posts too shallow | Leaning, heaving | 1/3 post length minimum |
| No drainage gravel | Post rot, frost heave | 2-4” gravel base always |
| Posts not plumb | Crooked fence | Check two sides, brace until set |
| Inconsistent spacing | Panels don’t fit | Measure twice, dig once |
| Skipping utility check | Dangerous, expensive | Call 811 - it’s free |
| Rushing concrete cure | Post shifts | Wait 24-48 hours before building |
Post Material Guide
Pressure-Treated Wood
- Life expectancy: 15-20+ years
- Cost: $8-15 per 8-foot post
- Pros: Economical, easy to work with
- Cons: Can warp, requires treatment at cuts
Cedar/Redwood
- Life expectancy: 15-25 years
- Cost: $20-40 per 8-foot post
- Pros: Natural rot resistance, beautiful
- Cons: Expensive, softer wood
Metal Posts
- Life expectancy: 25+ years
- Cost: $15-30 per post
- Pros: No rot, straight
- Cons: Rust potential, harder to attach panels
Vinyl Post Sleeves
- Life expectancy: 25+ years
- Cost: $30-60 per post assembly
- Pros: No maintenance, uniform appearance
- Cons: Requires internal support, expensive
Special Situations
Rocky Soil
- Use power auger with rock-cutting head
- May need jackhammer for large rocks
- Consider surface-mounted post brackets
High Water Table
- Use all-gravel method
- Extend gravel below water line
- Consider composite or metal posts
Sloped Terrain
- Step fence sections (posts vertical, panels level)
- Or rack fence panels (parallel to slope)
- Adjust post heights accordingly
Timeline for Complete Installation
| Task | Time (per post) |
|---|---|
| Layout and marking | 5-10 min |
| Digging (manual) | 20-30 min |
| Digging (auger) | 5-10 min |
| Setting and bracing | 10-15 min |
| Concrete setting | 10-15 min |
Example: 20-post fence with power auger
- Layout: 1 hour
- Digging: 3-4 hours
- Setting: 4-5 hours
- Total: 1 full day
Calculate Your Fence Materials
Ready to plan your fencing project? Use our free Fencing Calculator to determine:
- Number of posts needed
- Concrete requirements
- Material costs
- Labor estimates
Pro Tip: Set posts on a dry day when rain isn’t expected for 24 hours. Rain can wash out fresh concrete and make working in the holes miserable. Also, work in the morning during summer - you’ll be done before the heat peaks.