Decks, Patios, Porches and Docks - What 2 do with front underside edge of porch

I'm taking off my old, cracked, astroturf covered concrete front porch slab and building a new wooden porch in it's place. The porch is over a small room in my basement (built of concrete block) that houses my oil tanks.

The new porch floor will hang past the block wall on all three sides by some distance, much as a roof overhangs the exterior walls. since the space below the porch is open to the interior of the house, I need to do something with that space below the overhang... close it up, as soffit does a roof.

Did that make sense? If you understand, then can you tell me what I can do to close that? Should I simply put some plywood under there to close it off? Note--I realize that I could eliminate the 'overhang,' but I want it there for a reason... It'll make the space I need for a decorative 'shroud' that hides the block wall (probably lattice or similar).

Any advice would be appreciated. Thanks in advance for your help!

Brian

Brian

How much room do you have between the porch block wall and the new deck?
Sealing the area is a must to keep critters and rain out. A sheet of plywood with a light 2X2 under frame at a slight pitch for drainage. Then sealed down with NP1 or liquid nails and then top sealed over with felt and a rubber membrain or kool seal or roof cement under your new deck will work.

Plywood by it self will rot and cause you more problems than its worth.