We are Hebei Leeter Import and Export Co., Ltd ("Leeter"), a manufacturer of chain link fence fabric, framework and fittings in Hebei, China. Sag is the #1 service complaint on installed chain link — here's the diagnosis-first repair sequence, and the spec choices that prevent it.

First, diagnose which sag you have

  • Belly along the whole run, posts straight → fabric tension (or missing top support).
  • Sag worst near an end/corner, terminal post leaning inward → terminal bracing failure.
  • Top edge scallops between posts → no top rail / slack top tension wire.
  • Gate dropped at the latch side → hinges or missing gate truss.
  • Fabric loose at posts, ties broken → age: ties and tension bands have let go even though the stretch was fine.

Fix 1: re-tension the fabric

  1. Detach ties along the sagging section and unbolt the tension bar at the nearest terminal.
  2. Weave a stretcher/tension bar into the fabric a panel short of the terminal; hook a fence stretcher or come-along between that bar and the (braced) terminal post.
  3. Pull until the mesh gives a firm, springy resistance — the field test: the diamonds should barely squeeze by hand, and the top edge should sit straight. Don't over-pull woven fabric; you're removing slack, not stretching wire.
  4. Re-seat the tension bar in the tension bands, then re-tie the fabric to posts (~every 12 in) and rail (~every 24 in) with new ties. Old aluminum ties that stretched are why "tight last year" is loose now.

Fix 2: brace the terminal posts

Fabric tension all resolves at the ends. If a terminal (end, corner, gate) post leans, either its footing failed or it was never braced:

  • Add a brace rail from the terminal to the first line post with a diagonal truss rod back down to the terminal base — the classic H-brace geometry that turns pull into compression.
  • Re-set failed footings in concrete, sized up for the post (terminals take a bigger hole than line posts).
  • On long runs, tension should be pulled between braced terminals, not against bare line posts — line posts only guide the fabric.

Fix 3: give the top edge something to hold

  • Top rail (1-3/8"–1-5/8" pipe in 21 ft swaged lengths through loop caps) is the standard residential/commercial answer — it carries the top edge and stiffens the whole line.
  • Where a rail isn't wanted (some security specs), run a 7-gauge top tension wire, stretched taut and hog-ringed to the fabric — the same job, lighter look.
  • Sagging bottom edges (pets pushing under) get a bottom tension wire, stretched and clipped every ~24 in.

Fix 4: the sagging gate

Gate sag is frame geometry:

  1. Tighten and re-seat the hinges — the top hinge pin points down, the bottom pin up, so the gate can't be lifted off; snug the bolts so the gate hangs plumb.
  2. Add a truss/anti-sag kit: a rod or cable with turnbuckle running from the top hinge-side corner to the bottom latch-side corner, then take up the turnbuckle until the latch realigns.
  3. If the gate post itself leans, treat it as a terminal: bigger footing, concrete, brace.

Speccing sag out of the next fence

Sag prevention is mostly a buying decision: 9-gauge fabric (not 11.5) for anything beyond light residential; terminal posts one size up from line posts, set in concrete with brace bands and truss rods at every end, corner and gate; a top rail or 7-ga top wire on every run; line posts at the 10 ft maximum; steel ties or double-wrapped aluminum. Our chain link buying guide covers gauges and framework, and the materials calculator guide counts the bands, bars and ties so the tension system arrives complete.

Frequently asked questions

How do I tighten a sagging chain link fence?

Unhook the fabric at the nearest terminal, weave a stretcher/tension bar into the mesh, and pull it with a fence stretcher or come-along anchored to the braced terminal post. Re-seat the tension bar in its bands, then re-tie fabric to posts about every 12 inches and to the rail every 24 with new ties. If the terminal post leans, brace it first — stretching against a weak post just moves the sag.

Why does my chain link fence sag in the middle of the run?

Either the fabric has lost tension (stretched ties, loosened bands) or the top edge has no support. Long runs need a top rail or a taut top tension wire; without one the fabric's own weight bellies between posts. Re-tension the fabric and add the missing top support — and check that both end terminals are braced, since all tension resolves there.

How do I fix a chain link gate that sags?

First re-seat and tighten the hinges so the frame hangs plumb (top pin down, bottom pin up). Then install a truss or anti-sag kit — a diagonal rod or cable with a turnbuckle from the top hinge-side corner to the bottom latch-side corner — and take it up until the latch lines up. If the gate post itself leans, re-set it like a terminal: bigger footing, concrete, brace.

Do I need a top rail on a chain link fence?

The top edge needs something — either a top rail (21 ft swaged pipe through loop caps) or a taut 7-gauge top tension wire hog-ringed to the fabric. Runs with neither will scallop and sag between posts no matter how well the fabric was stretched. Rail also stiffens the line and gives ties a fixing point.

What spec prevents sagging in the first place?

Heavier fabric (9 gauge for anything beyond light residential), terminal posts one size larger than line posts set in concrete with brace rails and truss rods at every end, corner and gate, a top rail or top wire on every run, line posts at no more than 10 ft centres, and steel ties. Sag is usually bought, not built — it traces back to light fabric and unbraced terminals.

Sources