Most deck failures are not sudden. They start as a hairline crack, a loose post-base, or a rusted fastener that nobody noticed for three years. Catch them early and the fix is $40 of materials and a Saturday morning. Miss them and the same problem becomes a $4,000 structural repair. Here is the inspection we run on every deck we built, every spring.
Bring three tools
- A flat-head screwdriver (probing for soft wood)
- A 3-inch level (checking for movement)
- A flashlight (looking under the deck)
That is it. The whole inspection takes 30 minutes.
1. The under-deck walk
Start underneath. This is where 80% of problems hide.
Look for: dark stains around joist hangers (water intrusion), white powdery residue (fastener corrosion), sagging joists (overloading), and anywhere the wood feels soft when you push on it with the screwdriver.
Pay special attention to the ledger board where the deck attaches to the house. Loose ledgers are the single most common cause of catastrophic deck failure. If you can move it by hand even slightly, call us.
2. The post-base check
Every vertical post should be sitting on a metal post-base bracket, not in the dirt. Wood touching soil rots from the inside out in this climate.
Push each post laterally. It should not move. If it does, the post-base may be loose or the footing has shifted. This is a 1-hour fix if caught early.
3. The fastener pass
Walk the deck surface and look for any screw or nail that has popped up. In a year of expansion and contraction, three or four fasteners on a 500-square-foot deck will work loose. Drive them back in. Replace any that are rusted, broken, or stripped.
If the same fastener keeps backing out, the board underneath has a problem. Pull it, check the joist, and replace as needed.
4. The board surface
On a hardwood deck: probe with the screwdriver every 18 inches. A healthy board resists; a rotted board takes the screwdriver tip 1/4 inch deep with light pressure. Replace any board that probes soft.
On a composite deck: look for surface scratches, stains, and color fade. Most stains lift with warm soapy water and a soft brush. Avoid pressure washers above 1,500 PSI; they will gouge the cap.
5. Railing test
Grab the top rail at the center of each section and give it a firm push. It should not flex more than half an inch. More than that, the railing is no longer safe and the post-to-deck connection needs to be re-anchored.
6. Drainage
Walk the deck after a hose-down or after rain. Water should run off, not pool. Standing water is the leading cause of rot, mildew, and slip-fall accidents. If you have pooling, your slope has shifted or the gap spacing between boards has filled with debris.
The yearly add-on
If your deck is hardwood (Ipe, Cumaru, Garapa, Tigerwood), oil it once a year. If it is pressure-treated, re-seal it once a year. If it is composite, do nothing other than the inspection.
The owners who do this in March every year are the ones whose decks hit 25 years without a major repair. The owners who skip it are the ones who call us in year eight with a structural issue.
Thinking through your own outdoor build?
Send us your space. We will walk it, design it, and quote it free.
Get a free quote