Decks are a challenge to any inspector.  From older decks that are decaying to newer decks that have not been built properly, we routinely find problems.  Many decks are poorly constructed and poorly maintained.  As a result, decks can collapse catastrophically.  While this type of failure is not frequent, in my opinion they do occur too often.  A properly constructed and maintained deck should last 30 years.  Decks framing should consist of lumber that has been pressure-treated to resist wood- destroying organisms.  Exterior hardware should be manufactured to be corrosion resistant (most chemicals used to treated lumber are corrosive).
The structure should support the deck, resist seismic movement, as well as provide some provision to prevent water from damaging the home.  Railings should be constructed to help prevent falls.
Look carefully at these two pictures. The metal hangers (and beams) are not aligned. My guess is the nails used in the hardware are too small and are pulling out. Ultimately, this could result in deck collapse. Unfortunately, the deck will probably have to be largely disassembled to find out the actual cause. An expensive problem that should not have happened.By not providing proper flashing where the ledger abuts the siding, trapped water damaged the siding. Water should be directed away from vulnerable areas, such as ledger connections. 4x4s are not rated for horizontal loads. This deck is located close to the ground, so when it fails, it is unlikely to cause serious injury. Nonetheless, it is wrong. The use of untreated lumber in deck framing that is exposed to the weather will eventually result in decay and weakening of the structural members. Decks built with chemically pressure-treated lumber will last longer. In this case, the deck ledger was attached directly to the house. Over the years, water penetrated behind the ledger and has damaged the siding. Properly installed metal flashing would have prevented this damage. It will now be necessary to dismantle the deck and replace sections of siding.Look carefully at the bottom of the metal joist hanger hardware. It has completely corroded and failed. Unfortunately, the chemicals used to treat lumber are corrosive. It is vital to use corrosion-resistant hardware to support a deck.
Click on these thumbnail images for a nifty little slide show and descriptions.
Home inspections in Santa Rosa, Petaluma, Windsor, Healdsburg, Sebastopol, Sonoma,
Cloverdale Geyserville, Guerneville, Oakmont, and most other communities in Sonoma County.
Phone:  (707) 528-7010
Email the office

Office Hours
Monday - Friday 9:00 AM to 4:30 PM