How to Install a Deck Drainage System

Introduction: How to Install a Deck Drainage System

About: The official instructable for Popular Mechanics magazine, reporting on the DIY world since 1902.

If you’re one of the many homeowners who have an elevated deck built off the back of your house, then you’re in luck. Here, we’ll show how to install a deck-drainage system, called DrySpace, which allows you to use the area below the deck for storage, dining or entertaining.

The DrySpace system consists of two main components: F-shaped brackets and PVC panels. The vinyl brackets are nailed to the sides of the deck floor joists. Then the panels are slid into the brackets. When it rains, water drips down between the deck boards, collects in the panels, and then runs out to a gutter at the deck edge. An optional component, called a joist cover, is also available. This decorative PVC accessory slips over the bottom of the joist so that no wood is visible from below once the drainage system is installed.

The DrySpace system is designed for joists spaced 16 in. on center (the actual space between the joists is 141⁄2 in.). However, the 141⁄2-in.-wide panels can be trimmed down to fit between joists that are spaced closer together. If the joists are farther apart, you must add wood blocking to reduce the space. The PVC panels and F brackets come in 6- and 12-ft. lengths and cost about $3.25 per linear foot. The optional joist covers cost about 65 cents per foot. For more information, contact Crane Plastics, P.O. Box 1898, Columbus, OH 43216;

This project was originally published in the July 2002 issue of Popular Mechanics. You can find more great projects at Popular Mechanics DIY Central.

Step 1: Installation Sequence

Begin by snapping a chalkline along the inside of each joist to guide the bracket installation (Photo 1). To ensure proper drainage, be certain that the lines slope down and away from the house at least 2 in. for every 12 ft. Next, measure the space between two joists and cut a piece of F bracket to fit. The easiest way to cut the extruded vinyl bracket is with a power miter saw, but tin snips also work. Apply a bead of exterior-grade caulk to the back of each bracket before nailing it in place. Hold the short bracket with its ends on the chalklines, and secure it to the ledger with 1-in. roofing nails (Photo 2).

When fastening the brackets, center the nails in the nail slots, but don’t drive them all the way in as the vinyl must be able to expand and contract with changes in temperature. Next, measure and cut the F brackets that will run along the sides of the joists. Set the bottom of the brackets on the sloping chalklines and fasten them with roofing nails (Photo 3). Note that you can run the brackets past a support beam at the outer edge of the deck, but only if there’s enough clearance space above it.

There must be at least 2 in. between the bottom of the F bracket and the beam. Another option is to cut the brackets 3 in. short of the beam. That eliminates any interference with the beam and allows plenty of space for water to run off. Once all the brackets are installed, measure and cut the panels to length. You can cut them individually with tin snips, but we found it much easier to use a sabre saw to cut through several pieces at once. If the F brackets run past the beam, simply slip the end of the panel into the brackets and pull it in place (Photo 4).

If the brackets stop short of the beam, slip one edge of the panel into one of the brackets, then bend the panel slightly and insert the other edge. Slide the end of the panel into the short bracket that’s nailed to the ledger. Stand near the ledger and press up on the bottom of the panel to flatten it out. At the same time, have a helper push the outer end of the panel toward the house. Finally, it’s a good idea to install gutters and downspouts to collect and carry away rainwater. Without gutters, the water may puddle up on the grass and run back under the deck.

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    2 Discussions


    5 years ago on Step 1

    what is the name of this product, channel and v-panel?