If you’re building a new deck on your home, get the most for your investment with an under-deck drainage system. You can create a dry, usable space below a two-story deck when you protect your deck substructure from moisture.

Why Install an Under-Deck Drainage System?

Instead of debating over having a deck vs patio, consider having both. With a two-story deck, meaning you have an elevated deck to create a room beneath, you can install a ceiling to create a more finished living space with lights and fans. With a protected area, you can be as creative as you like! Here are a few ideas:

  • Add a big screen TV, sound system, comfortable seating, and a wet bar, and you instantly expand your party space by finishing the area beneath your two-story deck. Be sure to buy a weatherproof TV for outdoor use.
  • Install a full outdoor kitchen or roll out a portable cart to your patio table and chairs for your next dinner party. Eat outside without having to worry about the forecast with your under-deck living space. Add some screening, and you won’t even have to worry about the bugs.
  • Create a comfortable seating area. Think about how you’d like to use your deck for yourself, your family, and for entertaining with friends. Instead of uncomfortable lawn chairs, maybe you need a couch and chairs with fun and functional cushions. Perhaps you’d like to add a hammock or bed-sized swing. Really great seating will make you want to spend more time on the deck!
  • Relax and enjoy. Nothing beats a hot tub in the quiet, private space beneath your two-story deck. Make it your weekend oasis.
  • Increase your storage. Everyone these days could use a little more storage. Check out some of these creative storage ideas for under your deck.

Now that you’ve decided you want to include a drainage system with your new deck, how do you choose the right one? Here’s what you should look for:

Over or Under Joist System?

Different deck drainage systems can be installed either above or below the joists. This difference in wood and rot protection is significant. Watch how damaging an under-joist system can be in this video.

Below-joist drainage systems cause damage and wood rot in three ways:

  • First, they allow the wood to get wet repeatedly as rain drips through the deck boards, over the joists, and into the drainage system below. The water hits the pan and runs out, but not before drenching the joists.
  • Second, a below-the-joist type of system can trap moisture. If a ceiling is installed beneath the decking (whether you have wood or composite decking boards), there’s no air coming in to dry out the wood. The only ventilation is through the quarter-inch or less spaces between the top deck boards
  • Third, in the hot months of summer, the temperature further cooks this trapped, wet wood and accelerates the rotting. Over time, this is the perfect formula for wood rot: moisture + heat – ventilation = destruction.

That’s why the best option is to install a deck drainage system above the joists. This type of system will provide 100% protection of all the joists and beams from moisture penetration and helps to hold the screws and fasteners in place longer.

What to Know About Installing an Under-Deck Drainage System

Choose a deck drainage system that is simple to install. If you’re building your own deck, it will save you the headache of a difficult installation and ensure that your deck drainage system is put in place correctly. If you’re contracting the work, you can save money by choosing an efficiently installed system that uses a minimal number of tools to get the job done and does not require specialized contractors.

What Are Other Considerations when Choosing a Deck Drainage System?

Some deck drainage systems may not provide options for installing features in the dry space beneath your deck. Choose a drainage system that allows you to add a ceiling and utilities such as gas and electricity. These added features will enable you to design an outdoor living space with lights, ceiling fans, entertainment components, and more.

How Much Do Deck Drainage Systems Cost?

Some deck drainage systems could cost you up to $8.00 retail per square foot. You can get a high-quality product on the market for about half that cost. Once you find the product that meets all of your criteria, look at the price per square foot to find one that offers the best quality and value for the dollar without busting your budget.

Deck Drainage Systems Market Comparison Table


Should you Add Lighting?

Lighting can take your outdoor living experience to the next level with beauty and ambiance. Your deck will also be safer, more enjoyable, and more usable year-round.

Trex® RainEscape® Soffit Light comes in bronze, black and white, can be added by any DIY homeowner or builder without an electrician. No need to split wires or create additional wiring. Plug one strand of lights to the next, much like Christmas lights. Two steel spring tension clips hold the light in place on any soffit material. With an optional remote control and dimmer, you can customize the lights for your space. Part of the Trex® RainEscape® deck drainage system, this new plug-and-play lighting system works seamlessly with the Trex LightHub® connection system.

With you’re a deck drainage system, you can enjoy a new outdoor living space all year round. What are you waiting for?