The Best Drainage Panels for Under Decks

Maintaining the integrity of your beautiful new deck requires installing high-quality under deck drainage panels, like Polyflow® BD Sheet Molded Drainage Mat. Drainage panels will protect the deck’s substructures from moisture, keeping the space below the deck dry and usable for recreation, storage, etc. In addition, preserving your deck’s attractiveness and integrity requires a design that protects against heat and provides adequate ventilation to remove accumulated water.

The Best Drainage Panels for Under Decks

What Are Under Deck Drainage Panels?

Under deck drainage panels installed under the decking, either above or below the joists will catch and redirect water in one of three parts of the deck – the deck’s surface, between the joists and decking, or below the joists. Maintaining a dry deck frame preserves its integrity and extends the deck’s overall lifespan.

Below the Joist Deck Drainage Systems

Below-joist drainage systems consist of rigid vinyl or metal pieces that attach below the joists of the deck. They create a slope that moves water to a gutter that is attached to the ridge of the deck beam, and directs it to a drainage area.

Below-deck joint drainage provides an ideal system for retrofitting a deck because you don’t need to dismantle the deck for installation.

Problems with Below-The-Joist Deck Drainage Systems

Installing a deck drainage system below the joists creates an attractive ceiling for the space under the deck, but it can lead to several significant problems, especially in hot-humid climates:

  • Drainage panels below the joists allow the rain to soak the deck boards as rainwater leaks through the boards, over the joists, and into the below drainage system.
  • The drainage system encloses the framing, so it can take longer for the beams and joists to dry, which can lead to rot damage of the wood.
  • Below the joist systems allow debris to accumulate at the top of the drainage system, and they require a removable panel so you can regularly clean the spaces between the joists.

Installing the deck drainage panels above the joints offers the best option for providing 100 percent protection from moisture penetration, and it also helps to hold the screws and fasteners in place longer.

Above-Joists Deck Drainage Systems

Above-joist drainage systems installed between the joists and the decking consists of a series of gutters made from a waterproofing material like rubber polypropylene that drapes between the joists.

When water falls between the decking’s cracks, the system captures and funnels the water to the deck’s outer edge, where it drops into a gutter that guides the moisture to a drainage area.

When properly installed, an above-joist deck drainage system provides the best protection for the deck’s framework, and a drier space below the deck.

Unfortunately, it is difficult to retrofit a deck with an above-joist deck drainage system, making it best suited for new deck construction. Installing an above-joist system to an existing deck requires removing all the decking then reinstalling once completing the drainage system installation.

How Much Do Deck Drainage Panels Cost?

Drainage panels for under decks cost between $4 and $9 ft2, depending on your needs and the quality of the panels. Under-joist systems that create a finished ceiling are generally more expensive than an above-joist system when building a new deck. However, the above-joist systems do not include the cost of a finished ceiling.

The Best Drainage Panels for Under Decks

Choosing the proper drainage systems, whether for a new deck or existing deck, should provide a waterproofing system that maintains the deck’s integrity. In addition, the best-quality deck drainage system will create and protect the usable-living space underneath, even in foul weather. It can also provide storage space for your valuable yard equipment, and declutter your garage.

Selecting a simple-to-install deck drainage panel will help ensure a correctly placed, and functioning deck drainage system. In addition, a straightforward method to install drainage panels reduces the need for skilled workers and specialized, costly tools – saving DIYers and contractors both time and money.

You may also want to pick a deck drainage system that allows for electrical, and gas installation that will also enable you to add features like lights, ceiling fans, entertainment components, and more to the below-deck space.

Why Polyguard Has The Best Drainage Option for Under Decks

Polyguard designed our lightweight, high-capacity Polyflow® BD Sheet Molded Drainage Mat to provide a solution to lightweight drainage of a new deck. It is compatible with our engineered Polyguard’s Balconyguard™ Membrane.

The Best Drainage Panels for Under Decks

Polyflow® BD Sheet Molded Drainage Mat

The Polyguard Polyflow® BD drainage system provides under deck drainage. It comes as a sheet-molded drain, to create pathways for deck water management. The fabric allows water flow to specific drainage exits. Additionally, the punched core increases the release rate of water from within the system.

Polyflow® BD Sheet Molded Drainage Mat contains a geocomposite of a fabricated pre-punched impermeable polymeric core covered on both sides with a non-woven filter fabric. Polyflow® BD’s compressive strength of 5,200 lb/ft2 and flow rate of 12.5 g/min/ft allows for use in balcony decks with less than 3-inch of concrete and foot traffic only.

Easy-to-install Polyflow® BD ensures successful installation, ensuring the removal of water from the deck, to increase its lifespan, and save both money and time, during and after installation.

Polyguard’s Balconyguard™ Membrane

You can use self-adhesive, 60 mil Polyguard’s Balconyguard™ waterproofing membrane on wood deck balconies and terraces that are covered with lightweight concrete. However, before installing Balconyguard™ Membrane, we suggest you contact either Polyguard Technical Services or representatives of an authorized company for assistance with job-specific details or shop drawings.

Simple to install, Balconyguard™ Membranes provide several significant features and advantages specially designed for waterproofing decks, along with exposed multi-story walkways covered with lightweight concrete:

High strength PET film
Tensile strength meets ASTM D412
Treated removable release film
For easy installation and detailing, our Balconyguard™ System includes custom corner boots, saving builders time and money
Elongation meets ASTM D412
48-inch wide by 50-feet rolls (200 ft2), lessening seam occurrence by 25 percent, compared to 36-inch wide products — saving time and reducing the required seams

Polyguard Offers the Best Drainage Panels for Under Decks

Polyflow® easy-to-install BD Sheet Molded Drainage Mat and our other waterproofing products offer the best-quality under-deck drainage panels to protect the deck’s integrity and ensure a usable-below-deck space even in rainy weather.

Contact Polyguard® professionals today to learn more about the best drainage panels for under decks.