MARGIN Builders By Dave Kile
Fill out deck packages with under-deck drainage
S
ometimes it’s what
clients don’t see that they appreciate most. An under-deck drainage system is a perfect example. While not something homeowners typically know to ask for, these systems add tremendous value to any deck project and practically sell themselves once their benefits have been explained.
Advantages of Adding an UnderDeck Drainage System
Using a network of troughs and downspouts, a deck drainage system captures and diverts water away from a deck to protect the substructure from moisture and to a create dry, usable space beneath an elevated deck.
These systems act like shingles on a roof to shield the wooden foundation from moisture penetration and damage. Without protection, an average wood substructure can begin to deteriorate after just 10 years, while a deck drainage system can extend the life of a deck and its framing for decades. Once protected, the area below the deck surface can be used like any room inside a house. Homeowners can add electricity, water and gas lines, as well as furniture, lighting, ceiling fans and entertainment components to create additional outdoor living space. This area also is ideal for use as bonus storage space for stowing everything from lawn and garden equipment,
DECK DRAINAGE systems are easy to install for the builder, but expand margins for both contractor and dealer. (Photos by Trex)
14
n Building Products Digest n February 2022
pool supplies and off-season patio furniture to bicycles, boats and ATVs. With a drainage system in place, the possibilities are limitless for how the space below a deck can be used.
Under-Deck Drainage Systems Options & Differences
While there are numerous options for under-deck drainage systems with various configurations, components and price points, these systems largely fall into one of two categories—those that are installed beneath the substructure framing, and those that are applied above the joists. Below-the-joist systems consist of metal or vinyl panels retrofitted to the underside of deck’s joists with the panels sloping to a gutter installed at the deck beam for drainage. Advocates of this type of system will tout that installation does not require the dismantling of an existing deck. However, these systems are best installed by specialized contractors so dismantling shouldn’t ever be an issue. A disadvantage of systems that install below the joists is that they leave wood and metal exposed to the elements and more susceptible to water damage and corrosion. This type of system can also trap moisture in the core supports of the substructure, which can accelerate rotting and deterioration. For optimal protection and aesthetics, most contractors prefer drainage systems that install above the joists between the substructure and the deck boards. This method uses poly or rubberized membranes that drape over the joists and down into each joist bay from above the substructure, ensuring that Building-Products.com
