Repair a fence when the damage is local: a few cracked boards, a sagging gate, or one bad section. Replace the line when the posts have rotted or heaved down its length, because posts are what hold a fence up. If you are weighing a repair against a new fence installation, start at the posts.
The posts are the real tell
A fence is only as good as what holds it up. Boards, pickets, and rails take the weather, but the posts carry the load and keep the line straight and plumb. When you are deciding between a patch and a full replacement, walk the line and grab each post. A solid post barely moves. A post you can rock back and forth, or one that has pushed up out of the ground, is telling you the problem is structural, not cosmetic.
That is why a leaning fence fix almost always comes back to the posts. A panel does not tilt on its own. It tilts because the post next to it has heaved up, rotted at the base, or worked loose. Fix a board and the lean stays. Fix or replace the post and the line comes back square.
When a repair makes sense
Plenty of fence problems are local, and local problems get repaired. If the posts are still solid and plumb, the rest is straightforward:
- A few damaged boards: cracked, split, or rotted pickets swap out without touching the structure.
- A sagging or dragging gate: usually hinges, a loose latch, or a gate post that needs re-securing, not a new fence.
- One bad section: if a single span took a hit, like a fallen branch or a backed-in trailer, and the posts on either side are sound, we rebuild that section and tie it back into the line.
- Surface weathering: grey, fuzzy wood that is still solid underneath cleans up and re-finishes. That is maintenance, not replacement.
The rule of thumb: if the bones are good and the damage is contained to one spot, repair it. You keep the rest of the fence, and the work stays where it counts.
When to replace the line
Now the other side. Here is when to replace a fence instead of chasing repairs down the run:
- Rotted or heaved posts down the line: one bad post is a repair. Several failing posts spread along the run mean the whole line is near the end of its service life. Replacing them one at a time costs more in labour than doing the line once.
- Widespread fence post rot: if you push a screwdriver into the base of post after post and it sinks into soft, punky wood, the fence is coming down on its own schedule. Better to plan the replacement than react to it.
- The line no longer holds plumb: when multiple posts lean in different directions, the fence has lost its structure. Re-stretching panels onto bad posts does not hold.
- A patched-over history: a fence that is already half mismatched repairs is usually cleaner to replace as one straight, matched line.
Replacement is not a failure on your part. Wood fences in southern Ontario have a working life, and freeze-thaw shortens it for any post that was not set right in the first place.
Why posts heave and rot here
This is the part homeowners do not always see. The reason posts fail early in the Hamilton area is almost always how deep they were set.
A fence post has to be set down toward frost depth, about 1.2 m (4 ft) below grade in this part of southern Ontario, on a frost-stable base. Set it shallow and you get frost heave: when wet ground freezes it expands and lifts the post; when it thaws the post drops. A season or two of that, and the post racks and pulls the panel out of plumb. That is the leaning fence you are looking at.
Rot is the other failure. A post sitting in trapped water at the base, with no drainage and no frost-stable setting, stays wet and breaks down where the wood meets the soil. By the time you see the lean, the base is already gone.
The fix for both is the same, and it is why we do not just drop old posts back into the same shallow holes: dig to depth, set on a frost-stable base, and move water away from the post. A repair that ignores why the post failed is a repair you do again next year.
Permits and a like-for-like replacement
Good news on the paperwork. In Hamilton, a standard residential fence does not need a permit. Under the City of Hamilton Fence By-law 10-142, a rear-yard or side-yard fence can go up to 2.0 m (6 ft 6 in) without a permit, and replacing an existing fence with one of the same height in the same spot is a like-for-like swap.
The by-law still applies even though no permit is pulled, and the front-yard and corner sightline limits are lower. But for your decision it means this: replacing the line does not drag you into a permit process. If your old fence was a standard back-yard fence, the new one in its place is straightforward. That removes one reason people keep patching a fence that should be replaced.
Frequently Asked Questions
Is it cheaper to repair or replace a fence?
It depends on the posts. If the posts are solid and the damage is a few boards or one section, a repair is the sensible, lower-cost call. Once posts have rotted or heaved down the line, repeated repairs add up in labour and stop holding. Replacing the run once is usually the better value at that point.
How do I know if my fence posts are rotten?
Push a screwdriver or an awl into the post at ground level, where the wood meets the soil. Solid wood resists the tip. If it sinks into soft, dark, punky wood, that post is rotting at the base. Check several posts along the line, not just the one that is leaning, before you decide.
Can you fix a leaning fence without replacing it?
Sometimes. If a single post worked loose but is still sound, it can be reset properly to frost depth and the panel pulled back to plumb. If the post has rotted or heaved, resetting the same post in the same shallow hole does not last. The real fix is a new post on a frost-stable base.
Not sure whether to patch it or pull it?
Whether your fence needs one section rebuilt or the whole line replaced, the answer lives at the posts, and that is what we check first. The Hammer Construction is a licensed and insured builder serving Hamilton and nearby towns. Get a free quote at our online estimator, call or text (647) 424-1148, or email hello@thehammer.construction