Every fence installation starts with layout — and layout errors are permanent. A string line that's 2 inches off at one end creates a fence that's visibly crooked for its entire life. Per the AFA's Fence Installation School, site preparation and layout are dedicated modules because they're the foundation everything else is built on.
Here's the professional layout process that ensures your fence goes up straight the first time.
Before Layout: Site Preparation
Per the AFA's site preparation module, three things must happen before you touch a string line:
1. Verify Utilities (811)
Call 811 a minimum of 2 business days before digging. Utility markings last 10 days. Our 811 guide covers the full process.
2. Verify Property Lines
Compare your site plan or property survey with the actual site. Know exactly where your property boundaries are. A property survey ($300–$600) eliminates any guesswork.
3. Check the Permit
Verify setback requirements, height limits, and any placement restrictions from your fence permit.
Step 1: Set Corner and End Stakes
Mark the starting point and ending point of each fence run with wooden stakes driven firmly into the ground. Mark every corner, end point, and gate opening.
Materials needed:
- Wooden stakes (1×2 or 2×2, 18–24 inches long)
- Hammer or mallet
- Tape measure (at least 100 feet)
- Spray paint for ground marking
Step 2: Run String Lines
Stretch mason's line (nylon or polyester — not cotton, which stretches) between stakes, pulled taut. This string represents the exact center line of your fence posts.
Tips for straight lines:
- Pull the string as tight as possible — any slack creates a curve
- Use intermediate stakes every 50 feet on long runs to prevent wind deflection
- Check that the string is the same height above ground at both ends
Step 3: Square Your Corners (3-4-5 Method)
The most important layout step. If your corners aren't square, your fence will look wrong where sections meet.
The 3-4-5 triangle method (Pythagorean theorem):
- From the corner stake, measure 3 feet along one string line and mark
- From the same corner, measure 4 feet along the other string line and mark
- The diagonal between the two marks should be exactly 5 feet
- If it's not 5 feet, adjust the string lines until it is
For greater accuracy on long runs: Scale up to 6-8-10 or 9-12-15 (same ratio, larger triangle = less measurement error).
The AFA's tools module covers measuring and squaring tools specifically because accurate layout requires proper equipment.
Step 4: Mark Post Locations
With string lines set and corners squared, mark each post location along the string.
Post Spacing by Fence Type
| Fence Type | Standard Post Spacing | Notes |
|---|---|---|
| Chain link | 10 feet on center | Per ASTM F567-07 for residential |
| Wood privacy | 8 feet on center | Standard for 16-foot rail spans (2 × 8 ft) |
| Wood privacy | 6 feet on center | For horizontal fences or heavy panel loads |
| Vinyl | 6–8 feet | Per manufacturer specs |
| Ornamental | 6–8 feet | Per manufacturer panel width |
| Split rail | 8–10 feet | Standard rail lengths |
The AFA's site preparation module includes line post spacing charts that account for fence height and wind load zone. In high-wind areas (Oklahoma City, Tampa), closer post spacing may be required.
Terminal Posts First
Mark terminal posts (ends, corners, gate openings) first. Then divide the remaining distance equally for line posts.
Example: You have 72 feet between two terminal posts and want 8-foot spacing. 72 ÷ 8 = 9 spaces = 8 line posts. Mark every 8 feet.
When it doesn't divide evenly: If you have 70 feet and want 8-foot spacing, you get 8.75 feet per space (70 ÷ 8 = 8.75). This is fine — slight variations in post spacing are invisible. What's NOT fine is making 7 equal spaces and one short space. Distribute evenly.
Gate Post Marking
Gate posts need specific spacing:
- Measure the actual gate width (not the advertised size)
- Add ½" to ¾" clearance on each side for hardware and swing clearance
- Mark both gate post positions precisely — gates are unforgiving of spacing errors
See our gate installation guide for gate post specifications.
Step 5: Mark Post Holes
At each marked post location, spray paint a circle on the ground indicating the hole diameter:
- Wood posts (4×4): 10–12 inch diameter hole
- Steel posts (2⅜"): 8–10 inch diameter hole
- Gate posts: 14–16 inch diameter hole (larger footing per AFA recommendations)
Remove the string lines before digging — they'll get in the way. But keep the stakes in place so you can re-run strings to check post alignment after setting.
Step 6: Final Verification
Before digging a single hole, walk the entire layout and verify:
- [ ] All corners are square (re-check with 3-4-5)
- [ ] Post spacing is consistent
- [ ] Gate openings are the correct width
- [ ] The fence line is inside your property boundary
- [ ] No post locations conflict with utility markings
- [ ] Setback requirements are met
This 15-minute walk-through prevents thousands of dollars in mistakes.
Common Layout Mistakes
Not Checking for Square
Eyeballing corners creates angles that are 2–5 degrees off square. Over a 50-foot run, that's 2–4 inches of visible deviation. Always use the 3-4-5 method.
String Line Sag
A sagging string creates a curved fence line. Pull tight, use intermediate stakes on long runs, and don't use stretchy cotton string.
Unequal Post Spacing
One 10-foot gap in a row of 8-foot gaps is visible. Distribute spacing evenly — the AFA's layout materials specifically address consistent line post spacing.
Ignoring Grade Changes
On sloped ground, measure post spacing horizontally (with a level tape), not along the slope surface. Measuring along the ground on a slope makes posts closer together than intended. See our slope installation guide.
Forgetting Gate Clearance
The gate needs room to swing, clear the ground, and accommodate hardware. Mark gate posts with extra precision. Our gate guide covers the clearances needed.
Frequently Asked Questions
How accurate does layout need to be?
Posts should be within ½ inch of their intended position. Corner squareness should be within ¼ inch over a 5-foot measurement. These tolerances produce a fence that looks straight and professional.
Can I lay out a fence by myself?
Yes, but a helper makes it much easier — especially for long string line runs and holding tape measures at both ends. Solo layout is doable with intermediate stakes and patience.
What if my property line isn't straight?
If your boundary follows a curve or irregular shape, you'll need to break the fence into straight segments with angle posts at each direction change. Few fences need to follow exact property boundaries — building 2–6 inches inside gives you a straight line. See our property line guide.
Do I need a laser level?
For most residential fences, a string line and tape measure are sufficient. A laser level helps on long runs (100+ feet) or when setting post heights on slopes. Professional crews use them regularly. Our installation guide covers the full tool list.
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*Layout and site preparation procedures per American Fence Association Fence Installation School Core Training modules 2 (tools) and 5 (site preparation).*