Waterproofing to keep under deck area dry

by Brad
(Surrey BC Canada)

At present I have a deck that covers a portion of basement stairwell. The deck itself is vinyl covered plywood.

I want to extend the deck and add a second section to it, all at the same height, however I want to use cedar or composite deck boards. Yet I dont want the gaps between the deck boards over the basement stairwell as I do not want rain to fall through the deck over the basement stairwell.

I am looking for suggestions as to how to keep that section of the deck - to waterproof the deck so the underdeck is dry - overtop of my basement stairwell rain proofed. But I want a consistent look of deckboards over the entire deck.

I had thought about just laying the deck boards overtop of the existing vinyl deck, however if I do that the final height of my deck is almost the same height as the door sill for my back door and I am just wondering about rain (or snow) splashing up against and under my door.

Ideas are welcome.

Send ideas to gilesflyerattelus.net