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

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Dec 29, 2012
Lots of Under Deck Waterproof Systems
by: Editor - Rich Bergman

There are many under deck waterproofing systems to choose from these days. Most are centered around the concept of using proprietary soffit panels that connect to the underside of the joists and channel the water to the perimeter of the deck.

For that kind of solution check out:


Then you could also use a deck board that snaps together and actually is the waterproofing element of the deck. See www.lastdeck.com. This is an aluminum waterproof deck board system.

And finally, you could also look at a structural underdeck water drainage system. This is a system where the joists assemble together and drain the water.


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