A sloped property changes how a chain link fence should be measured, laid out, and installed. Grade changes affect post layout, bottom clearance, footing requirements, fabric alignment, and gate operation.

Before ordering materials or digging post holes, measure the fence line and identify every significant change in elevation.

Measure the Grade

For each fence run, record:

  • Total horizontal length
  • Elevation at each end
  • High and low points
  • Sharp grade changes
  • Corners and gate locations
  • Driveways and retaining walls
  • Drainage paths

For a consistent slope:

Grade (%) = Vertical Rise ÷ Horizontal Run × 100

A 3-foot rise over a 30-foot horizontal run equals:

3 ÷ 30 × 100 = 10% grade

Quick Grade Reference

Rise Over 20 ft. Approximate Grade
6 in. 2.5%
1 ft. 5%
2 ft. 10%
3 ft. 15%
4 ft. 20%

Measure individual sections when the property contains dips or multiple slopes. One measurement between the first and last post can miss significant changes between them.

Establish Posts and Fence Alignment

Identify terminal points before laying out line posts:

  • End posts
  • Corner posts
  • Gate posts
  • Major direction changes
  • Changes in fence configuration

Posts must remain plumb even when the ground slopes.

CLFMI commercial/industrial chain link specifications call for line posts at intervals not exceeding 10 feet (3.05 m) on centre. Actual spacing can be reduced to divide a run evenly.

For example, a 36-foot run can use four equal 9-foot spaces rather than three 10-foot spaces followed by one 6-foot space.

Chain link fabric can generally follow gradual contours while the posts remain vertical. Sharp transitions should be identified during layout so fabric tension and terminal points can be planned before installation.

SafeFence can assess these conditions when planning a professional chain link fence installation.

Check Bottom Clearance at Low Points

Uneven terrain can create excessive openings beneath the fabric, particularly where the fence crosses a depression.

Measure clearance at:

  • Low points between posts
  • Drainage swales
  • Sharp slope transitions
  • Driveways
  • Areas used for pet containment or perimeter security

There is no universal bottom-gap dimension for every chain link fence. The acceptable opening depends on the fence's purpose, terrain, security requirements, and project specifications.

If a maximum bottom clearance is required, define it before post elevations and fabric placement are finalized.

Account for Footing Depth

CLFMI's commercial/industrial specification, referencing ASTM F567, gives a minimum footing depth of 24 inches (610 mm) for a 4-foot fence, plus 3 inches (76 mm) for each additional foot of fence height above 4 feet.

Fence Height Reference Minimum Footing Depth*
4 ft. 24 in.
5 ft. 27 in.
6 ft. 30 in.
7 ft. 33 in.
8 ft. 36 in.

*These are reference minimums, not universal requirements. Soil conditions, local frost depth, wind loading, fence height, gate loads, and project specifications can require different footing dimensions.

CLFMI guidance also calls for the top of concrete footings to be crowned so water drains away from the post.

Check Gate Clearance Through the Entire Swing

A fence may follow a slope correctly while its gate cannot operate.

If the ground rises through a swing gate's travel path, the frame can contact the surface before reaching its fully open position.

Check clearance at several positions:

Gate Position Check
Closed Clearance beneath frame and latch
25% open Beginning of grade change
50% open Mid-swing clearance
75% open Highest ground in swing path
Fully open Final clearance and stopping position

Where the grade interferes with a swing gate, options may include changing the gate location, swing direction, bottom clearance, or gate configuration. A cantilever sliding gate may be considered on some commercial properties because it moves laterally instead of sweeping across the driveway.

Account for Drainage and Finished Grade

Before setting posts, identify:

  • Drainage swales
  • Pavement runoff
  • Downspout discharge
  • Erosion
  • Areas that remain wet
  • Planned paving or landscaping

If paving, grading, or landscaping is scheduled, establish the finished grade first. Raising or lowering the surrounding surface after installation can change fence clearance and gate operation.

This is particularly important when coordinating larger commercial fencing projects.

Pre-Installation Checklist

Before approving the layout, confirm:

  • Fence runs and elevations measured
  • High and low points marked
  • Terminal, corner, and gate posts located
  • Line-post spacing calculated
  • Required fence height confirmed
  • Bottom-clearance requirements established
  • Gate swing checked against grade
  • Driveway slopes measured
  • Finished grade confirmed
  • Drainage paths identified
  • Footing requirements reviewed for site conditions
  • Underground utilities located before excavation

Plan the Grade Before Installation

A chain link fence can work effectively on sloped or uneven terrain when the elevation changes are accounted for before installation. Posts must remain plumb, fabric must follow the intended grade, footings must suit site conditions, and gates need sufficient operating clearance.

If your property includes slopes, depressions, driveway transitions, or retaining walls, SafeFence can help determine the appropriate fence and gate layout.

Contact SafeFence for a quote or consultation, or email info@safefence.ca with your project measurements.