Working With A Deck On An Uphill Slope

Building a deck on an uphill slope seems a bit counter-intuitive.

After all, with the land sloping towards the house, there better be some excellent drainage around the foundation.

But building a deck in this situation can be done.

This bright and inviting vinyl deck is perfectly designed for a wet west coast environment. The decking if PVC sheet vinyl welded into a waterproof surface. Aluminum railings finish it off.

You will see a beautiful little walkway over the garden and a set of stairs: two entry and exit points for free flow and great southern exposure when the sun does shine.


Vinyl decks can be an excellent replacement choice for an old rotting wood deck. The original deck on this house was a typical 2x6 cedar wood deck in disrepair and had some dangerous rotting deck boards.

It needed a significant facelift and something to change it and make it more functional and inviting so the family would want to spend more time on it.

The Site

Take a close look at this deck and notice how the land actually slopes uphill from the house.

It's a particular building site.

The original wood deck was about half the size of the finished deck - extending outwards about 10' leaving a 2' gap before the land abruptly sloped up and beyond the deck surface.

But the backyard was facing south and had an overall upward slope to it. The plants and trees grew like crazy back there, and the landscaping was already beautiful.

It just needed a deck that could do it justice.

The Clients

These people didn't want any radical changes but they did have a couple non-negotiable desires.

They wanted something waterproof and required low maintenance, unlike their wood deck, which was rotting away.

And they wanted to effectively deal with the uphill slope and the gap around the existing deck (which was almost like a water-less moat around a castle) because it was useless space.

The picket railng offered a more open view rather than 2x2 wood pickets.  This aluminum rail system also withstands the rain far better.

I immediately suggested they consider using a waterproof 40 mil vinyl flooring membrane. There were many different colors available. A 40 mil vinyl was extremely durable and absolutely waterproof.

I then suggested an aluminum picket railing system with 5/8" pickets (balusters) to create an open airy feel and not obstruct the view of the beautiful flowers and landscaping around the backyard. These two suggestions addressed their maintenance concerns.

The other design idea they liked was extending the existing deck outwards to fill the gap. And where it couldn't quite make it, I decided to "bridge the gap" - literally.

This one decision gave this deck on an uphill slope a uniqueness that they were looking for. And it was totally functional and hid the swayle in the grade. The landscaping around it brought it all together.

The Layout

This layout was designed to increase the size marginally and bring the edge of the deck closer to the uphill sloping grade.

The bridge served two purposes. It hid the swayle below it and provided another access point to the rest of the back yard.

Usually, a rectangular deck can suffer from the boredom factor. But here is a case where other factors take your mind off the simple shape and towards the landscaping surrounding the deck and the bridged walkway.

Were it not for these unique factors, I would have tried to change the shape of the deck a bit to make it more interesting because it would then be the only focal point.


This new vinyl deck was a vast improvement - from maintenance and a design point of view.

The vinyl decking surface would now be waterproof, maintenance-free, and eliminate the worry about rotting deck boards.

Notice the color of the vinyl decking material was soft and didn't clash with the color of the house. The deck's overall size was about 25% larger and nestled in nicely over the upwardly sloping grade beneath it - making better use of that previously unused land.

The other benefit to vinyl decks like this one is that they can handle huge temperature swings during the summer and winter months. Snow can quickly be cleared off with a plastic snow shovel, ensuring the vinyl surface remains impenetrable to water for many years to come.

So there you go. A design approach to building a deck on an uphill slope using some advanced building materials.

Is Vinyl Decking For You?

You may wish to check out some of the reputable companies in the business of installing vinyl decking. Duradek is a veteran in this business. But these other companies are steeped in the experience as well.

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