Is My Deck Safe? A Homeowner's Inspection Checklist

Deck failures are among the most common causes of serious injury at home, and they usually do not happen without warning. The signs are there for months: soft wood, wobbly rails, rusted metal. A yearly inspection takes about an hour and can tell you whether your deck needs a few screws or a professional.

Safety first. If anything in this guide makes you think the deck might not hold you, stop and keep everyone off it until it has been checked. Do not test a questionable deck by jumping on it.

Step 1: Walk it and listen

Pick a dry day. Walk slowly across the deck and along the stairs. Note any boards that flex, bounce, creak loudly or feel soft. Keep track of where you notice them.

Step 2: Probe for rot

Rot starts in places that stay wet: board ends, around fasteners, and where wood touches wood.

1. Press a screwdriver firmly into suspicious spots on the surface boards, the railings, and the stair treads.
2. Judge the wood. Sound wood resists the point. If the screwdriver sinks in easily (more than a quarter inch is a common rule of thumb) or the wood crumbles, that wood is rotting.
3. Mark every soft spot with chalk or take a photo.

Step 3: Test the railings

Railings are what keep people from falling. Push firmly on the railing and posts at several points, along the top, at each corner, and at the stairs. They should feel solid. Any wobble, movement, or loose connection at the base needs attention, and a loose railing should be treated as unsafe until it is repaired properly.

Step 4: Check where the deck meets the house

This is the most important connection, and the one most often neglected. A deck attached to a house relies on a board called a ledger that is bolted to the house. Look at it from the ground and from underneath with a flashlight.

1. Look for gaps between the ledger and the wall, rust stains, rot, or loose fasteners.
2. Look for metal flashing above the board that directs water away. If you cannot see any, water may be soaking the connection.
3. Do not pry or hammer at it. If anything looks wrong, stop and have it inspected.

Step 5: Look underneath

With the flashlight, check the joists, beams and posts under the deck.

• Posts: Are the bottoms soft, split, or sitting in standing water?
• Joist hangers and metal connectors: Are they badly rusted, bent, or missing fasteners?
• Nails that have worked up through the boards, or screws that have backed out.

What is reasonable to fix yourself

• Replacing a single rotted surface board with a matching board and outdoor-rated deck screws.
• Re-fastening loose boards with new screws.
• Cleaning and sealing the surface.

What to leave to a professional

Joists, beams, posts, stairs, the ledger, and the railing structure are what keep the deck standing and keep people safe. Repairing them can need permits, special fasteners, and the right knowledge of loads. Do not patch them with whatever is on hand.

Write it down

Make a note of what you found, with photos, and the date. It is useful for a contractor, for your insurer, and for comparing next year.