How do I repair a sagging fence gate?

Quick answer

To fix a sagging fence gate, first identify the cause—usually a leaning post, loose/undersized hinges, or a racked gate frame. Support the gate, tighten or upgrade the hinges with longer exterior-rated fasteners, add an anti-sag cable kit or a rigid diagonal brace, and realign the latch. If the hinge post is leaning, reset or replace the post in concrete; no amount of hinge adjustment will hold a gate square on a crooked post.

Why gates sag

• Post movement: Frost heave, shallow footings, or rotted wood let the hinge post lean.
• Hardware issues: Short screws, light-duty hinges, or stripped holes can’t carry the load.
• Frame racking: Wood frames without a proper diagonal brace twist over time.
• Oversized/heavy gate: Wide or solid-board gates catch wind and overstress hinges.

Tools and materials

• Measuring tape, torpedo level, and post level
• Impact driver/drill, drill bits, and sockets
• Exterior-rated structural screws or lag bolts (5/16–3/8 in) and washers
• Anti-sag cable kit with turnbuckle or a 2x4 for a rigid brace
• Heavy-duty gate hinges (strap or T-hinges), optional third hinge
• Shims, blocking, clamps
• Wood preservative/sealant for cut ends
• Optional for post reset: shovel/digging bar, gravel, concrete mix, braces, sawzall
• PPE: safety glasses, gloves, hearing protection

Cost/time: Anti-sag kit ($10–$25) and screws ($5–$10) can fix many gates in 1–2 hours. Upgrading hinges ($20–$60) adds about an hour. Resetting a post ($50–$150 materials) can take half a day plus cure time.

Step-by-step repair

1) Diagnose and support the gate

• Check the hinge post with a level. If it’s out of plumb, plan for a post repair.
• Sight the gate: Is the latch side dropped? Are hinge screws loose or pulled out?
• Place blocks or a floor jack with a wood pad under the gate to take the weight before loosening anything.

2) Tighten, shim, or upgrade the hinges

• Remove one hinge screw at a time and replace with longer/larger exterior-rated screws or lag bolts driven into solid wood (not just fence boards). Pre-drill to prevent splitting.
• On heavy/tall gates, add a third hinge centered between top and bottom hinges.
• If holes are stripped, move the hinge slightly to fresh wood or use wood plugs/epoxy repair and re-drill.
• Consider heavy-duty strap hinges for wide/solid gates; through-bolt on metal frames.

3) Add anti-sag support (cable or rigid brace)

• Anti-sag cable kit (quick and adjustable):
  • Attach cable from the top hinge-side corner to the bottom latch-side corner.
  • Tighten the turnbuckle gradually until the gate edge is plumb and the latch lines up.
• Rigid diagonal brace (most durable on wood frames):
  • Install a 2x4 from the bottom hinge-side to the top latch-side. This puts the brace in compression and holds the latch corner up.
  • Screw or bolt it to the frame; trim to fit and seal cut ends.

Brace direction (wood 2x4): bottom hinge side -> top latch side
Cable direction (turnbuckle kit): top hinge side -> bottom latch side
Pilot hole guide for 5/16" lag into softwood: 7/32" (1/4" for hardwood)
Ground clearance target: 1–2"

4) Fix or reset a leaning hinge post (if needed)

• Minor lean: Drive a steel post repair stake or add a diagonal ground anchor, then re-plumb and secure the post; results may be short-term.
• Best practice: Remove the gate, excavate around the post, add 4–6 in of compacted gravel, re-plumb the post, and set in concrete (bell out the bottom if possible). Brace until cured.
• For rotted posts, replace entirely. Use pressure-treated 4x4/6x6, proper gravel base, and concrete up to grade with a slight slope away from the post.
• Call 811 before digging to mark utilities.

5) Rehang, align, and set the latch

• With the gate supported, adjust hinges so the gap is even along the latch side and the bottom has 1–2 in ground clearance.
• Tighten the cable/brace a bit more if needed, then install or adjust the latch/strike so it engages smoothly.
• Lubricate hinges and latch.

6) Protect and maintain

• Seal cut wood ends and any fresh holes.
• Check hinge fasteners and cable tension annually; readjust after big weather swings.

Safety tips

• Support the gate before loosening hinges to prevent sudden drops and pinch injuries.
• Wear eye/ear protection using impact drivers, saws, or when chiseling out old fasteners.
• Mind heavy lifting—large gates may need two people.
• Call 811 before digging or resetting posts.

Common mistakes to avoid

• Installing the diagonal in the wrong direction (it won’t lift the latch corner).
• Using short deck screws instead of structural screws/lag bolts.
• Skipping pilot holes and splitting the frame.
• Trying to “tune out” sag when the hinge post is visibly leaning.
• Overtightening the cable/turnbuckle in one go—adjust in small increments and recheck plumb.

When to call a pro

• Masonry or steel posts, welded/ornamental iron gates, or gates tied into brick columns.
• Severely heaved or cracked concrete footings that need removal and re-pouring.
• Very large or custom automated gates where proper alignment and load balancing are critical.

With the right diagnosis and a couple of targeted upgrades—better hinges, proper fasteners, and a correctly oriented brace—most sagging wood gates can be restored in an afternoon and stay true for years.