The underside of a deck can tell you about the condition of your deck boards. If the deck framing is rotting, chances are the deck is bad also. Most owners have no idea how bad the moisture problem has gotten until the deck has failed. If the decking is soft to the foot, there is a danger of "stepping through" the wood.
The advantage of a second story deck is that you can easily see the underside framing members. The deck in the pictures shows how dry rot has destroyed the structural strength of the deck. It was removed and replaced before the new decking was installed.
If you are unsure about the condition of your deck, ask a qualified general contractor in your area to help evaluate the condition. Most contractors will do this free of charge.
Placerville general contractor working in Sacramento, Ca