This is an obvious sign that your deck may need some attention. If you are under capacity, there should be NO movement when you are using your deck. Be sure to know what the maximum deck load is. Decks Go has a great tool for helping to determine this. http://build.decksgo.com/calculators/deck-load-calculator.php
2) Ledger Board
The correctness of the ledger board is very important. Not only is it weight-bearing, but it actually connects your deck and home together. Be sure that it is fastened with ½” galvanized lag bolts, instead of nails. Many times, the ledger boards on older decks used nails. This is dangerous because nails have a tendency to pop out of place. The ledger board should sit up against the home. A gap between your home and ledger is unsafe. The bolts may need tightening or attention in some other form.
3) Loose or corroded Fasteners
Over time fasteners may become weakened or corroded. If you notice any of the following symptoms you might have a problem.
A) Loose Railings
Wobbly railings are a sign that fasteners are loose and/or corroded. This is a big safety hazard. Also check the height of the railing? Is it at least 3’ high? If not, they might not meet local code criteria.
B) Wobbly Stairs
Do you feel movement when walking on your stairs? Have any of the floor boards popped up? Both of these circumstances are indicative of loose or corroded fasteners.
C) Gap between ledger and house
As we stated above, if you notice the ledger board pulling away from your home, screws may need to be tightened.
4) Difficulty Opening Deck Door
Trouble opening your deck door might indicate movement within the deck structure. It could be that the ledger board is pulling away from the home or that structural elements have become compromised.
5) Missing Joist Hangers
Older decks may not have joist hangers. This can be dangerous over time, and is not built to code.
6) Premature Rot
Industry standards and building codes deliver building practices that will keep your deck healthy for up to 20 years. If your deck is rotting before 20 years, it may not have been built properly. A common mistake is a failure to install flashing around the ledger board to prevent moisture from being held within the wood. If the flashing was not installed properly or left out of the design completely, often times, you will notice wood rot.