Fencing Guides

Building a Gate That Lasts: Design, Construction, and Hardware Guide

Learn how to build a fence gate that won't sag. Covers gate frame construction, bracing, hardware selection, and installation for years of trouble-free operation.

8 min read Updated: 2025-11-30

Why Gates Fail

Gates are the weak point of any fence. They:

  • Move constantly (stress on hinges)
  • Carry their own weight unsupported
  • Face weather exposure on all sides
  • Receive more abuse than fixed fence sections

Understanding why gates fail helps you build one that doesn’t.

Gate Anatomy

Essential Components

Frame members:

  • Two stiles (vertical sides)
  • Two rails (horizontal top and bottom)
  • Diagonal brace (corner to corner)

Support elements:

  • Hinge-side post (must be extra sturdy)
  • Latch-side post
  • Hardware (hinges, latch, stops)

Gate Frame Design

The Critical Diagonal Brace

This is the secret to a sag-free gate.

Direction matters: The brace runs from the bottom of the hinge side to the top of the latch side. Think of it as a compression member pushing the latch side up.

Latch Side    Hinge Side
    |            |
    |    ╲       |
    |      ╲     |
    |        ╲   |
    |          ╲ |
    |____________|

Wrong direction = sagging gate

Frame Dimensions

Gate WidthRecommended Lumber
Up to 4 ft2×4 frame
4-6 ft2×4 or 2×6 frame
Over 6 ft2×6 frame or steel

Frame Construction

Materials:

  • 2×4 or 2×6 lumber (same as fence rails)
  • Pressure-treated or cedar
  • Exterior screws (3” minimum)
  • Construction adhesive (optional but recommended)

Steps:

  1. Cut frame pieces:

    • Stiles: Gate height minus 2-3 inches (ground clearance)
    • Rails: Gate width minus 3 inches (stile widths)

  2. Assemble frame:

    • Lay out on flat surface
    • Check for square (measure diagonals)
    • Join with two screws per corner

  3. Add diagonal brace:

    • Measure corner to corner
    • Cut with appropriate angles
    • Fit snugly
    • Attach with screws through both ends

  4. Check for square again before adding pickets

Alternative: Steel Frame

For heavy or wide gates, consider a steel frame kit:

  • Adjustable for various sizes
  • Stronger than wood
  • Won’t warp
  • More expensive but bulletproof

Building a Standard Walk Gate (3-4 ft)

Step-by-Step Construction

1. Measure the opening:

  • Measure top, middle, and bottom
  • Use the smallest measurement
  • Subtract 3/4” for each side clearance
  • Example: 42” opening = 40.5” gate width

2. Cut frame pieces:

  • Two stiles: Gate height (minus ground clearance)
  • Two rails: Gate width minus 3” (for stile overlap)

3. Assemble on flat surface:

  • Position stiles on edges
  • Fit rails between stiles
  • Predrill all holes
  • Drive two 3” screws per joint

4. Square the frame:

  • Measure both diagonals
  • Adjust until equal
  • Clamp or tack to hold

5. Cut and install diagonal brace:

  • Measure corner to corner
  • Mark angles at each end
  • Cut with circular saw
  • Attach with screws (through each rail and into ends)

6. Attach pickets:

  • Same spacing as fence
  • Use same fasteners as fence
  • Keep tops even with frame or matching fence style

7. Install hardware:

  • Hinges at top and bottom
  • Latch at comfortable height
  • Test operation before final tightening

Building a Double Gate (8-12 ft)

Special Considerations

Double gates need:

  • Extra-strong hinge posts
  • Cane bolt on one side
  • Center stop
  • Possible gate wheel support

Construction

Each gate half:

  • Build as single gates
  • Width: Opening width ÷ 2, minus 1” total clearance

Cane bolt:

  • Install on first gate to close
  • Drops into ground receiver
  • Prevents movement when double gate closed

Drop rod/center stop:

  • Wood or metal post in center when closed
  • Receiver embedded in concrete
  • Provides latch point

Gate wheels:

  • Support bottom of heavy gates
  • Reduce hinge stress
  • Install on latch side

Hinge Selection

Types of Hinges

Strap hinges:

  • Long decorative straps
  • Mount to face of gate and post
  • Easy to install
  • Good for lighter gates

T-hinges:

  • T-shaped mounting plate
  • Better weight distribution
  • Standard choice for most gates

Heavy-duty barrel hinges:

  • Commercial grade
  • Maximum weight capacity
  • Adjustable after installation
  • Best for large/heavy gates

Self-closing hinges:

  • Spring-loaded
  • Required for pool gates
  • Ensures gate doesn’t stay open

Hinge Placement

Two hinges:

  • Position 6-12 inches from top and bottom
  • Standard for gates under 5 feet

Three hinges:

  • Add middle hinge for gates over 5 feet
  • Distributes weight better
  • Reduces hinge stress

Hardware Material

EnvironmentRecommended Material
Inland, dryGalvanized steel
Coastal/saltStainless steel or hot-dipped galvanized
Pool areaStainless steel
High-useHeavy-duty rated

Latch Selection

Common Latch Types

Gravity latch:

  • Falls into catch by gravity
  • Reliable operation
  • May lift in wind

Thumb latch:

  • Thumb press releases latch
  • Traditional appearance
  • Easy one-handed operation

Ring latch:

  • Pull ring lifts latch
  • Historic/decorative look
  • Simple mechanism

Lever latch:

  • Push down to release
  • Modern appearance
  • Easy to operate

Keyed lock:

  • Security applications
  • Pool code compliance
  • May add to other latches

Latch Height

  • Standard gates: 36-42 inches (comfortable reach)
  • Child-resistant (pools): 54 inches minimum
  • ADA accessible: 34-48 inches

Hinge Post Reinforcement

The hinge post carries all gate weight. Reinforce it:

Option 1: Larger Post

  • Use 6×6 instead of 4×4
  • Deeper hole (add 6 inches)
  • More concrete

Option 2: Steel Core

  • Drive steel T-post alongside wood post
  • Lag bolt together
  • Cover with trim if desired

Option 3: Concrete Collar

  • Extend concrete above ground
  • Provides lateral support
  • Slope away from post

Option 4: Diagonal Brace

  • Wood brace from post to ground
  • Stake at base
  • Resists gate pull

Gate Installation

Hanging the Gate

  1. Support gate in opening:

    • Use blocks underneath
    • Shim sides for even gaps
    • Check for level top rail

  2. Attach hinges to post:

    • Position gate where it will hang
    • Mark hinge locations
    • Predrill holes
    • Attach top hinge first
    • Test swing
    • Attach bottom hinge

  3. Install latch:

    • Mark strike plate position
    • Attach to latch post
    • Test operation

  4. Final adjustments:

    • Check swing clearance
    • Tighten all hardware
    • Test full operation

Clearances

  • Bottom: 2-3 inches (more for uneven ground)
  • Sides: 3/8 to 1/2 inch each side
  • Top: Level with fence (or as designed)

Troubleshooting Sagging Gates

Gate is Already Sagging

Causes:

  1. Diagonal brace in wrong direction
  2. Missing diagonal brace
  3. Weak hinge post
  4. Failed hinges

Fixes:

  1. Add/replace diagonal brace (correct direction)
  2. Install anti-sag kit (cable from top hinge to bottom latch corner)
  3. Reinforce hinge post
  4. Replace with stronger hinges

Anti-Sag Hardware Kits

Available at hardware stores:

  • Cable with turnbuckle
  • Runs opposite to brace direction
  • Adjustable tension
  • Can save a sagging gate

Maintenance

Regular Checks

  • Tighten loose hardware (twice yearly)
  • Oil hinges (annually)
  • Check post for rot at base
  • Verify diagonal brace is tight
  • Test latch operation

Common Repairs

Loose hinges: Larger screws or fill holes and re-drill

Sticking latch: Adjust strike plate, lubricate

Gate won’t close: Check hinge post for lean, adjust hinges

Rubbing ground: Raise gate on hinges, cut bottom

Calculate Your Fence and Gate Materials

Ready to build? Use our free Fencing Calculator for complete material lists including gates.

Pro Tip: Build your gate before setting the gate posts. This way, you can set the posts to fit your gate perfectly rather than building a gate to fit imperfect post spacing. It’s easier to adjust concrete than to rebuild a gate.