An outdoor deck is a great place to gather with friends and family to enjoy your yard and each other.  Regardless of the type of deck material you have, you should do a thorough annual inspection to ensure it's safe.  Here are 10 areas you can include in that annual inspection:

Splitting, Warping and Rotting

Lack of protection from moisture allows wood to swell and then shrink which leads to splitting and warping which can be a tripping hazard. It could mean your wood doesn't have the proper stain/sealant or that you'd don't have the proper drainage away from your deck. Use a strong screwdriver to explore any soft areas for wood rot and keep an eye out for any signs of bugs boring into the wood.

Signs of Mold and Mildew

Mold, mildew and rot can be cause by inadequate water drainage or the type oil-based stain you've used that can be a food source for mold and algae.  In addition to being unsightly, mold and mildew can be slipping hazards and promote wood rot.

Water Drainage

Ensure your deck has the proper pitch to keep water from standing on your boards and that the ground underneath your deck has the correct grade to drain water away from the deck.  Make sure roof gutters aren't blocked and allowing water to splash onto your deck. 

Conduct a Splash Test

Splash some water on your deck.  Wait 15 minutes to see if the moisture beads up or if it absorbs into your wood.  If the water gets absorbed, it's time to re-seal or re-stain the give it the protection it needs.

Loose nails or screws on the deck surface

Walk the deck with a hammer (or screwdriver if that's how the boards are fixed) and fix any places where they have come up.  Loose nails and screws are tripping hazards.

Railings and balustrades

Check to make sure they are still strong and firmly attached.  Any that are loose need to be fixed immediately to prevent accidents.

Support Posts

Ensure there aren't any loose connections between posts and deck beams.  Tighten bolts as needed.

Flashings and Ledger Boards

Flashing is the sheet metal where your deck meets the walls of your home and is there to deflect water to keep it away from the ledger boards which attach your deck to your house.  Repair or re-caulk any damaged flashings and if you can get under the deck, check the ledger boards for bolts that need tightening and any signs of rotting.

Electrical Sockets on the Deck

If you have outdoor sockets near your deck, these shold be protected by Ground Fault Interrupters (GFIs). Press the buttons on the GFI to see if they are operating properly.  If not, they need to be replaced immediately.

Trees Hanging Over the Deck

Consider pruning limbs of trees overhanging the deck to reduce sap stains, pollen accumulation and reduce risks of limbs falling and damaging it.