Chain Link Tension and Sagging Mesh
Slack fabric is a symptom, not the fault
When mesh starts to belly out between posts, the instinct is to grab the fabric and pull harder. That almost never lasts. A chain link fence holds its shape through a chain of parts: terminal posts resist the pull, the top rail keeps the line straight, tension bars carry load from the fabric edge into the bands, and the fabric itself only needs to be snug. Work out which link in that chain gave up, then repair that part.
Begin at the terminal posts
End, corner and gate posts carry everything. In local clay, a terminal set too shallow, or set in a hole augered while the ground was dry and then backfilled loose, will lean a degree or two toward the pull. Two degrees over a six foot post is more than an inch of slack across the run, which is plenty to notice. Put a level on the post before touching anything woven.
Line posts carry no tension at all. If a line post leans while both terminals stand plumb, the cause is soil, a vehicle or a tree root, and the loose mesh is a downstream effect.
Then the top rail
Rail sections telescope into one another. Years of wind work the sleeves apart a quarter inch at a time until a joint opens. Sight down the rail from a corner. A wave in the rail puts a matching wave in the fabric. Rails also bow after a limb lands on them, and no amount of tightening below will straighten a bowed rail.
Retensioning that holds
Fabric attaches at each terminal through a bar woven vertically down the last row of diamonds and clamped by bands. Slack usually traces back to bands that slipped, or to a bar woven through too few diamonds when the fence went up.
- Release the bands at one terminal only. Working both ends together throws away your reference point.
- Pull with a come-along against a pull bar so the load spreads over the full height, never with a single hook caught in one diamond.
- Draw the diamonds in by about an inch across a normal run and stop there. Overtensioned fabric distorts and starts dragging the terminals inward.
- Retighten bands from top to bottom, then re-tie the fabric to the top rail roughly every two feet.
The seasonal wobble
Galvanized fabric moves with temperature. A run set tight on a hundred degree afternoon feels drum hard in January, and one set during a cold snap looks lazy by July. Tension in mild weather if the choice exists, and ignore small seasonal change. The question worth acting on is whether the sag is present in both seasons.
One more thing worth checking while the tools are out: the bottom tension wire. Many runs never had one, and without it the fabric can be lifted by a dog or pushed out by mowing debris until the lower diamonds deform permanently. A wire threaded through the bottom row and tightened at each terminal costs little and takes most of that abuse.