Repair a deck when the problem is cosmetic: faded boards, popped fasteners, a tired finish. Rebuild when the structure is failing: rotted posts or ledger, heaved footings, a frame that racks, or guards too low or loose. Safety and structure make the call, not looks, which is why we inspect the bones before any deck rebuild
Start with the structure, not the surface
A deck is two things stacked together: the structure that holds you up, and the surface you see. The surface is the decking boards, the stain, and the railing infill. The structure is the posts, the footings under them, the beams and joists, and the ledger that ties an attached deck to the house. When people ask us whether to repair or replace a deck, they are usually looking at the surface. The answer almost always lives in the structure.
Here is the rule we work by. If the bones are sound, you can repair almost anything on top of them. If the bones are failing, new boards and fresh stain are money spent on a deck that is still unsafe. So before we talk about looks, we check whether the frame, the footings, and the connections are doing their job.
Cosmetic problems you can repair
Plenty of a tired deck is just wear, and wear is fixable. None of the following means the deck has to come down:
- Faded or greyed boards: a clean and a fresh coat of stain bring the colour back.
- Popped or rusted fasteners: screws and nails can be reset or replaced.
- A few cupped or cracked deck boards: individual boards swap out without touching the frame.
- Splinters and a rough surface: sanding and resealing handles it.
- A loose railing section that is otherwise the right height: it can often be refastened.
These are surface repairs. They make a structurally sound deck good to walk on barefoot and good to look at again. If your deck only has problems on this list, you do not need a rebuild, you need maintenance.
Structural problems that mean a rebuild
This is the other list, and it is the one that matters. These are not cosmetic. Each one is a sign the deck is failing where it counts, and patching the surface will not fix it.
Rotted posts or ledger
Where rot sits tells you everything. Surface checking on a board is cosmetic. Soft, punky wood in a support post, a beam, or the ledger is structural. Press a screwdriver into a post near the ground or into the ledger behind the house. If it sinks in, the wood has lost its strength. A rotted ledger is the most dangerous of all, because the ledger is what stops an attached deck from pulling away from the house and dropping. Rot in the structure is a rebuild conversation, not a repair.
Footings that have heaved or a frame that racks
Footings must bear on undisturbed soil below the frost line. In the Hamilton area that is roughly 1.2 m, about 4 feet, down. Footings set shallower than that get pushed up when wet ground freezes and dropped when it thaws. Our local ground makes this worse: the heavy clay common on the Mountain and around Ancaster holds water and heaves hard, and the shallow soil over rock along the escarpment edge in Dundas gives footings less to grab.
The signs show up as a deck that has lifted unevenly, posts that no longer sit plumb, or a frame that racks, meaning it sways or leans sideways when you push on it. Heaving and racking are structural. You cannot stain your way out of them.
Guards that are too low or too loose
A guard, what most people call a railing, is required by the Ontario Building Code wherever the walking surface is more than 0.6 m, about 24 inches, above grade. Height matters: the code wants at least 900 mm, about 36 inches, where the deck is not more than 1.8 m above grade, and at least 1070 mm, about 42 inches, where it is higher than that. Openings have to be tight enough that a 100 mm, about 4 inch, sphere cannot pass through, which keeps a child from slipping between balusters.
A guard that wobbles when you lean on it, or one that sits below those heights, is a safety failure. Sometimes a guard can be rebuilt on a sound deck. When the posts the guard bolts to are themselves rotten or loose, the railing is only as good as what holds it, and that points back to the structure.
How to read your own deck
You can do a first pass yourself before anyone comes out. Walk the deck and look for these deck rot signs and structural red flags:
- Bounce or sway: a solid deck feels firm. Movement underfoot or side to side points to framing or footing trouble.
- Soft wood: test posts, beams, joists, and the ledger with a screwdriver. Soft means rot.
- Gaps at the house: a ledger pulling away, or fasteners backing out where the deck meets the wall.
- Uneven or lifted areas: a sign footings have heaved.
- A wobbly railing or one that feels low underhand.
- Rust streaks and failed connectors: corroded joist hangers and bolts let go over time.
One soft post or one heaved corner does not always condemn the whole deck. But two or three of these together usually means the structure, not the surface, is the problem, and that is when to replace a deck rather than keep patching it.
When a repair is the wrong call
Sometimes a repair is technically possible but still the wrong move. If the framing was undersized or the footings were never set deep enough, fixing one rotten post just shifts the load to the next weak point. If the deck is old enough that the boards, the railing, and the frame are all near the end together, repairing one part means you are back at it next season for the next. And a deck that was built without a permit or to a lower standard may not meet today's code, so a real repair can end up being most of a rebuild anyway. We will tell you honestly when good money is about to go after bad.
The rebuild path and permits
When the question is rebuild or repair a deck and rebuild wins, a permit is usually part of it. In Ontario you need a building permit when a deck is attached to the house, sits more than 0.6 m above grade, or serves a pool, so a full rebuild often pulls one. The permit is not red tape for its own sake. It means the new footings, framing, ledger, and guards get built and inspected to current code, which is the whole point of replacing a deck that failed on structure.
A small freestanding ground-level deck can be exempt, though zoning setbacks still apply to where it sits. We sort out which path your deck falls under before any digging starts, and we book the free, legally required Ontario One Call locates before a single post hole goes in.
Frequently Asked Questions
How do I know if my deck needs to be replaced or just repaired?
Look at where the problem is. Faded boards, loose screws, and a worn finish are cosmetic and repairable. Rotted posts or ledger, heaved footings, a frame that racks, and guards that are too low or loose are structural. Cosmetic means repair. Structural means rebuild, because the deck is no longer safe to use.
What are the warning signs of a rotting deck?
Soft, punky wood you can push a screwdriver into, especially in posts, beams, joists, or the ledger against the house. Add to that a spongy feel underfoot, dark staining around fasteners, rust on connectors, and gaps where the deck meets the wall. Surface rot on a board is minor; rot in the structure is a rebuild sign.
Can you repair just part of a deck?
Often, yes, if the rest of the structure is sound. A single cracked board, one section of railing, or a set of stairs can be replaced on a solid frame. The catch is shared weakness: if the footings or framing were undersized to begin with, fixing one spot just moves the load to the next failing point.
Not sure whether to repair or rebuild? We will tell you straight
At The Hammer Construction, we are a Hamilton-based crew, licensed and insured. We will inspect the posts, footings, ledger, and guards, tell you honestly whether yours is a repair or a rebuild, and put a real plan on paper. Get a free quote at our online estimator, call or text (647) 424-1148, or email hello@thehammer.construction