A Five Minute Check on an Older Deck

You do not need a professional to find out whether an older deck has a problem. You need five minutes and a screwdriver.

Four places account for nearly every serious defect on a deck that has been outside for a decade in this climate, and all four are visible without taking anything apart.

1. The guards

Push hard on every section of railing, sideways and outward, and at every guard post. It should not move.

A guard that flexes is the single most common serious defect on an older deck and the one most likely to hurt somebody. The cause is usually how the guard posts were attached rather than fasteners working loose, and re-tightening does not change what the post is bolted to. This is one place where rebuilding to correct connection and geometry is the right answer.

2. Where the deck meets the house

Walk along the line where the deck meets the wall and look for staining on the wall below it, trim that has gone soft or discoloured, or deck boards that are noticeably worse at that end than in the middle.

Those all point in the same direction: a ledger without flashing above it. Water running down the wall has been getting into the joint on every storm rather than passing over it, and the wood taking the damage is the band joist inside the wall, which belongs to the house rather than to the deck. This is worth investigating properly rather than replacing the visible board.

3. The base of every post

Look at each post where it meets the concrete or the ground. Anything dark, damp, or soft gets the screwdriver. If it pushes in, the wood has lost structure.

Two causes dominate here: a post standing directly on concrete with no standoff base, so the end grain sits in whatever water pools there, or framing that was built with above-ground rated lumber where ground contact rated material was needed.

4. The stairs

Stairs take more load and more water than any other part of a deck, so they age faster. Check the stringers, particularly where they meet the ground, check that the treads are solid, and notice whether the rise feels consistent from step to step. An uneven step is a trip hazard whether or not the timber is sound.

Bonus: look at the metalwork

Rusty joist hangers and connectors suggest fasteners without the corrosion rating that modern treated lumber requires. The wood may be fine while the connections are quietly getting weaker, and connections are what is doing the structural work.

What to do with what you find

Anything soft enough to take a screwdriver, and any guard that moves, is worth a proper look from somebody who can open it up. The useful question at that point is what fraction of the structure is affected. Sound frame with surface problems is a good repair job. Rot at joist ends, the ledger, and the post bases together usually means the money is better spent on a new structure, and a contractor who opens it up before quoting will tell you which one you have.

The repair page covers where that line sits, and the maintenance guide covers the annual routine that catches these while they are cheap.