We are replacing existing deck floor (15 *30) and 2 story height. As option to water proof the space underneath the deck, a contractor suggests to build a roof with singles on deck bins. Roof pitch will be 3'. Then a 2nd frame would be built on top of the roof to level deck floor which will raise floor a total of 5' leveling the floor to the house floor. To avoid raising steps, he recommends to create a down step on the deck so the transition from deck to steps would be at the same level. Hardy plank will be lifted to install roof flashing to avoid leaks and gutter system will be install at the end of the roof.

Deck is bolted to the house and with good support to hold additional weight as previous owner added additional bins to support medium size hot tub. (hot tub is no longer on deck)

I researched the internet for several days now, and I have not found anything like this under deck roof system.

Can someone comment on this option or suggest where can I find information about this type of system. Thanks