Deck Inspection:
What Gets Checked, From the Footings to the Railing
Wet winters are hard on wood, and a deck takes the weather on every side. Here’s what an inspector looks at on a deck, in the order the load travels, and what you can check on your own.
A deck inspection follows the load. Weight on the deck boards goes into the joists, then the beam, then the posts, then the footings and the soil. On an attached deck, a big share of the load also goes into the house through the ledger. A problem anywhere along that path matters.
Wood in the Portland area spends half the year wet. That’s why decks show up in so many inspection reports here, and why the underside of a deck usually tells more than the top. Trusted Home Inspections looks at attached decks, balconies, stairs, and railings as part of every home inspection, and gets under the deck when it can be reached.
Footings and posts
Start at the ground. Posts should sit on concrete footings or piers and be held off the concrete by a metal standoff base, so water can drain away and the end of the post can dry.
What gets flagged:
- Posts buried directly in soil
- Posts sitting flat on concrete with no standoff, especially with dark staining or softness at the base
- Footings that have sunk, tipped, or cracked
- Posts that lean or have moved off their piers
- Soil, bark, or leaves piled against the post bases
Rot at a post base can look minor from a distance. Up close, a screwdriver or awl often sinks in with little pressure. The inspector probes accessible wood for soft spots, but a probe only reaches the surface, so hidden decay inside a post can still be there.
The ledger and the house connection
The ledger is the board bolted to the house that holds one side of the deck. It’s the single most important connection on an attached deck, and the one most likely to fail when water gets behind it.
A sound ledger has flashing over the top to keep water from running down the wall into the joint, and it’s attached with bolts or structural screws through the house rim, not just nails. Without flashing, water gets trapped between the ledger and the house, and both start to rot.
The inspector looks for flashing, the type and spacing of the fasteners, staining or soft wood at the ledger, and any gap opening between the ledger and the house. The deck ledger guide covers this connection in much more detail.
Framing: beams, joists, and hardware
Under the deck, the inspector looks at the beam and joists for rot, cracking, sagging, and how they’re connected. Joists should hang in metal joist hangers or bear fully on the beam. Older decks are sometimes just toenailed together, with no metal connectors at all.
Other things that come up:
- Rusted or corroded hangers and fasteners
- Hangers missing nails, or nailed with the wrong fasteners
- Notched or cut joists
- Beams spliced between posts instead of over them
- Joist spans that look long for the lumber size, which shows up as a bouncy deck
- Signs of past repairs, like sistered joists or extra posts
Real Inspection Photos
Deck Findings From Russ's Reports
Real photos from recent inspections, from the footings up.
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A deck post sitting in soil and leaves, with rot where it meets the ground. Posts kept off the soil on a standoff base can dry out between rains. -
A corroded metal post base on a precast pier block. The connection at the bottom of a post is one of the first places to look on any deck. -
Deck joists without metal hangers where they meet the framing. Hangers help hold each joist in place under load. Deck ledger attachment -
Measuring joist spacing under the deck boards. Joists spaced too far apart for the board size can leave a deck bouncy and boards prone to sagging.
Decking, railings, and stairs
Deck boards get checked for rot, cracks, loose or popped fasteners, and trip hazards. Composite decking doesn’t rot, but the framing under it is still wood.
On a deck built before 2004, the lumber itself is worth knowing about. Unless it’s cedar or redwood, it was most likely CCA pressure-treated wood, which contains arsenic.
Some early composite boards had trouble of their own, including two CPSC recalls and a Trex settlement over flaking. The post on composite decking recalls and class actions lists the brands and years.
Railings and stairs are what keep people from falling, so they get a hands-on check:
- Railings that wobble or pull away when pushed
- Railings lower than about 36 inches on a deck more than 30 inches above the ground, which is the common standard for homes today
- Openings between balusters wide enough for a 4-inch sphere to pass through
- Stairs with uneven risers, loose treads, or rotted stringers
- Stairs with no graspable handrail
- Missing or broken lighting at the stairs
Older decks were often built to lower railing heights than today’s standard. The report notes what’s there. This post on handrail and guardrail safety covers railings inside and out.
What a deck inspection can’t tell you
A home inspection is visual and non-invasive. It can point to visible conditions and the places that need a closer look. It can’t pull boards, open siding to look at the ledger, test footings, or tell you how much weight a deck will hold. It also doesn’t certify that a deck is safe or meets current code.
When the inspection points to structural concerns, the next step is a licensed deck contractor or a structural engineer. Decks were also a common do-it-yourself project for past owners, so it’s worth checking whether a permit was pulled. A property history report lists the permits on record for the address, and this post on unpermitted work in Portland covers what a missing permit can mean.
On a deck, the problems that matter most are usually underneath and at the house, not on top. Post bases, the ledger, and the railings are where to look first.
A quick spring check you can do yourself
If you already own the house, a few minutes each spring catches most problems early:
- Push on each post base with a screwdriver and look for softness or dark staining
- Look for flashing above the ledger and staining on the siding below it
- Shake every railing and stair handrail
- Walk the stairs and look for loose or cracked treads
- Clear leaves, soil, and debris from post bases and between deck boards
- Look under the deck for rusted hangers or sagging joists
Buying a home with a deck? Every Trusted Home Inspections home inspection includes the attached deck, stairs, and railings. You can book online any day of the week.
Deck Inspection FAQ
