Deck Safety Before the Snow: Ledger Board, Flashing, Railings

A deck takes more abuse than almost any other part of a house. It sits in the sun all summer, soaks up rain all fall, and then holds a foot of snow all winter. Wet snow is heavy, and a deck with a rotted connection can fail under it, or under a crowd at the next cookout.

The North American Deck and Railing Association (NADRA) puts out a free consumer checklist, and most of it can be done in an afternoon with a flashlight and a screwdriver.

01Start at the ledger board

The ledger is the board that attaches the deck to the house. It carries a big share of the deck's weight, and it's where most serious deck failures start.

• How is it fastened? You should see bolts or heavy structural screws, usually in a staggered pattern. Nails alone are a red flag.
• Is there flashing? A strip of metal or membrane should cover the top of the ledger and tuck up behind the siding, so water runs over it instead of into it.
• Look for water stains, rot, or debris piled up where the deck meets the house. NADRA points to this as a sign the flashing has failed.
• Look for a gap opening between the ledger and the house. That one needs a pro now.

02Probe the wood

Take a screwdriver and push it into the wood in several spots: the ledger, the posts near the ground, the joists, the beam, and the stair stringers. Sound wood resists. If the screwdriver sinks in a quarter inch or more, or the wood feels spongy, that's rot.

03Check the hardware

• Joist hangers, screws, nails and bolts should be solid, not crumbling or flaking. Treated lumber eats ordinary steel over time.
• Posts should sit on footings or metal post bases, not buried in dirt, and should stand straight.
• Look for missing or loose fasteners anywhere under the deck.

04Railings and stairs

• Push on the railing, hard, at several points. It shouldn't wobble or flex.
• Most codes call for a guard on any deck more than 30 inches off the ground, at least 36 inches tall, with gaps narrow enough that a 4-inch ball can't pass through. That last rule exists to keep small children from slipping through or getting their heads stuck.
• Stairs should feel solid, with a graspable handrail and no loose or cracked treads.

05The deck boards

Look for split, cupped or soft boards, and nails or screws working their way up. Those are trip hazards, and a soft board can mean rot underneath.

06Before winter

• Sweep off leaves. Wet leaves trap moisture and stain the wood.
• Clear the snow off the deck after big storms, with a plastic shovel, going with the boards.
• Don't pile shoveled snow from the driveway or roof onto the deck.
• Move the grill and heavy planters off if the deck is questionable.

07When to call a pro

A loose ledger, rotted posts or beams, railings that move, rusted-out hardware, or a deck older than about 20 years that's never been looked at. A deck builder or a home inspector can tell you whether it needs repairs or replacing.

The American Wood Council publishes the standard construction guide most deck builders use (DCA 6), if you want to see what a correctly built deck looks like. Decks are also on our fall home inspection checklist.

Sources (3)

NADRA: Deck Evaluation Guide · NADRA: Deck Safety Checklist (PDF) · American Wood Council: DCA 6 Deck Construction Guide

Photo by JamesDeMers on Pixabay.

Related: Inspect Your Roof From the Ground: What Binoculars and the Attic Tell You