Post & Beam Repair for Rotten Support Posts on the North Shore

Why posts and beams rot on the wet North Shore

North Vancouver and West Vancouver sit in a marine rain-forest climate, and the numbers are unforgiving: pressure-treated posts and beams that aren't detailed and sealed correctly can start to soften within a handful of years, not decades. Our lots make it worse — steep, forested, and shaded, so structures stay damp and dry out slowly. Add wind-driven rain off the water and constant ground moisture on rock-and-clay soils, and untreated end grain wicks it up like a sponge.

The damage almost always starts where wood traps water: the base of a deck post, the buried or embedded end of a crawl-space post, and the beam ends where a carrying beam bears on a post or pockets into a wall. That's rot you can't see from the top of the deck — it's happening at the connections that hold everything up. If you want the full checklist, see our guide to the signs of structural problems.

The real culprit: post bases in water and hidden beam-end rot

Nine times out of ten, the failure isn't the middle of the post — it's the ends. We repeatedly find:

• Posts poured into or sitting flat on concrete. A post cast into a footing, or planted on a pier with no standoff, wicks moisture straight into the end grain and rots from the bottom up while looking fine at eye level.
• Post bases with no drainage. Older galvanized bases collect water in the cup and hold it against the wood; on the coast that shortens post life dramatically.
• Beam ends buried in wet wall pockets or damp crawl spaces. A carrying beam can be sound across its span and completely punky where it bears — which is exactly where the load lands.
• Corroded connectors. Salt air and constant damp eat undersized or wrong-grade fasteners and hangers, so the connection fails before the wood does.

Damp crawl spaces make all of this faster, and invite carpenter ants and mould into the softened wood. This is core structural repair work, not a surface cosmetic fix.

Warning signs your posts or beams are failing

Catch it early and a post swap is straightforward. Ignore it and a small repair becomes a partial rebuild. Watch for:

• A deck that sags, dips, or feels bouncy underfoot, or rails and stairs that have started to lean.
• Posts leaning, twisting, or no longer plumb — often the first visible sign the base is gone.
• Wood you can push a screwdriver into, dark staining, soft spots, or mushrooms/fungus at a post base or beam end.
• Inside the house: springy or sloping floors, cracked drywall, and doors or windows that suddenly stick — signs a crawl-space post or beam has dropped.

Sagging floors deserve their own look — see sloping and sagging floors. If any of this is showing up, don't load-test it yourself; keep people and furniture off a suspect deck until it's inspected.

How we repair post & beam failure properly

Doing this right is about controlling the load before you touch the rotten member, then rebuilding so it can't happen again:

• Temporary shoring first. We support the beam and structure on properly rated shoring so nothing shifts, cracks, or drops while the failed post or beam is out.
• Replace, don't patch. Rotted posts and beam ends get replaced with correctly sized, rated material — sistering or splicing a load-bearing member is not a fix.
• Get the wood off the water. New posts land on elevated, standoff post bases that hold the end grain up off the concrete so it can drain and breathe — the single biggest change to how long the repair lasts here.
• Correct footings and connections. Proper footings, code-grade hot-dip galvanized or stainless connectors and hangers, and detailing that sheds water instead of trapping it.
• Engineering when it's load-bearing. Anything carrying real load, or in our seismic zone, gets a proper design and permit. Where the failure runs into interior carrying beams or a wall, that crosses into beam replacement.

Why this is a structural job, not a handyman one

A post holding up a deck or a floor is carrying live load over people. Swap it wrong — wrong size, no shoring, a base that traps water again — and you've either created a hazard or bought yourself the same rot in a few years. A handyman can replace a rail; taking load off a structure, replacing a carrying member, and putting it back safely is structural work.

We're a North Shore structural-repair specialist, family-run since 2008 and into our third generation, working out of 3063 Lonsdale Ave. We know how this climate attacks wood because we repair it constantly across North Vancouver and West Vancouver. Start with a free structural assessment and we'll tell you honestly what's failing, what isn't, and what it takes to fix it — or get in touch directly.

Frequently asked questions

Can you repair a rotten support post, or does it have to be replaced?

If a load-bearing post has rot, we replace it. Sistering or patching a structural post doesn't restore its capacity and the rot usually continues inside. What we can save is your structure: we shore the load, remove the failed post or beam end, and rebuild the connection correctly so the repair lasts in this climate.

How do I know if the problem is my deck posts or my crawl space?

Outside symptoms — a sagging, bouncy, or leaning deck — point to exterior posts and beams. Inside symptoms like springy or sloping floors, cracked drywall, and sticking doors usually mean a crawl-space post or carrying beam has dropped. Often it's both, since the same moisture attacks both. A proper assessment tells us which members are actually failing.

Is a leaning deck post dangerous? How urgent is it?

Treat it as urgent. A leaning or twisting post usually means the base has rotted and the post is no longer carrying load the way it should — that's how decks partially collapse. Keep people and heavy loads off it and get it inspected. Caught early it's a simple swap; left alone it becomes a much larger rebuild.

Will I need a structural engineer?

For load-bearing posts and beams, and anywhere in our seismic zone, yes — the repair should be designed and permitted. It protects you, satisfies the District, and matters at resale. We coordinate the engineering as part of the job so the fix is sized and detailed correctly, not guessed at.

Why can't a general handyman just swap the post?

Because taking load off a structure and replacing a carrying member is structural work. Without proper rated shoring, correct sizing, an elevated post base, and code-grade connectors, you either create a safety hazard or reproduce the same rot within a few years. It needs someone who does structural repair, not general carpentry.