Is Your Deck Safe?

Why decks fail around here

Southwest Washington is hard on a deck. We get eight months of wet, the ground stays soft well into spring, and a lot of the decks I get called to look at were built before anyone around here was bolting them to the house properly. Add a hillside lot in Kelso or Kalama and the posts are doing more work than they were ever sized for.

The decks that worry me are not the ones that look rough. A gray, weathered deck with solid framing under it is fine. The ones that worry me are the ones with new boards on top and twenty year old framing nobody has looked at underneath.

The five things I check first

How it is attached to the house. This is the one that drops decks. A ledger board held on with nails or deck screws instead of lag bolts or through bolts will pull away from the house under a crowd. If you can see a gap opening between the deck and the siding, or the ledger is bowed, stop using the deck until someone looks at it.

What it is standing on. Posts should sit on concrete footings above grade, not buried in dirt. A post that goes straight into the ground rots at the soil line, and you will not see it until you push on it. Footings that have heaved or settled show up as a deck that is no longer level.

Rot in the framing. Push a screwdriver into the joists and the beam, especially where boards meet and where water sits. If it goes in easy, that wood is done. Soft spots in the walking surface usually mean the joist under them is worse than the board.

The railing. Grab the top rail and lean on it hard. It should not move. A railing that wobbles will not stop a person, and on anything more than thirty inches off the ground the code requires one that will. Rail height, baluster spacing and how the posts are fastened all matter.

The hardware. Look at the joist hangers, the bolts and the nails. Rust streaks down the wood are the hardware telling you it is giving up. Old galvanized hardware against treated lumber corrodes faster than people expect.

When to stop using it today

A few things are not a repair conversation. They are a get off the deck conversation. A ledger pulling away from the house. A post you can move by hand. A beam with rot you can put a finger into. A railing that gives when you lean on it. If any of those describe your deck, keep people off it and call me, or call somebody.

Repair or replace

A deck with good framing and bad boards is a resurfacing job, and a good one. A deck with bad framing and good boards is a tear out, no matter how new the boards are, because the boards are the cheap part and the framing is what holds you up. I will tell you which one you have, and I will tell you when the honest answer is to leave it alone.

If it is coming out, the next question is what goes back. That is a different page.

What drives the cost of a new deck →

Deck joist and beam span tables →

What the check cannot tell you

It cannot push a screwdriver into your beam. It works from what you can see and what you tell it, and it is deliberately cautious, so a deck that scores badly might be fine and a deck that scores well might still have a problem under the boards. It is a screen, not an inspection. Thirty years of this and I am on every job. If the check says get it looked at, that is me.