How AmeriDex Works
Integrated PVC decking and Dexerdry seal stop water at the surface and create dry, finished space below.
The Two-Part System
One product. Two engineered components working together, so the deck surface itself is the waterproof layer. See how that compares to other waterproof decking.
Cellular PVC Deck Boards
Cellular PVC core with a proprietary ASA cap and a wood-grain finish. A low-maintenance alternative to wood decking.
Dexerdry Integrated Seal
Automotive-grade TPE seal designed to fit between the boards and help direct rain and snowmelt off the deck surface when installed to the specified details.
How It Works in 3 Steps
Plan the framing and drainage details.
Use the specified residential joist layout and drainage pitch. Confirm framing condition, flashing, overhang, board direction, and fastening against the current installation instructions.
Install AmeriDex boards with the integrated Dexerdry seal.
Interlocking fit creates a continuous water-diverting deck surface.
Direct water away from the space below.
The installed board-and-seal assembly directs surface water toward the planned discharge edge. Open-sided areas can still be exposed to wind-driven rain.
New decks and full re-decks on sound, pitched framing
The seal is installed with the boards, not pushed into a finished deck. A full re-deck may be possible when existing boards are removed and the framing meets the installation requirements. Check the re-deck requirements.
Specs At A Glance
| Board | Cellular PVC with proprietary ASA cap |
| Seal | Dexerdry automotive-grade TPE |
| Profile | Tongue-and-groove with integrated water-diverting seal |
| Lengths | 12 ft, 16 ft, 20 ft. Standard runs top out at 20 ft. Custom lengths up to 25 ft available on request. |
| Joist Spacing | 16" o.c. residential |
| Fasteners | Use approved fasteners. Confirm fastener type, quantities, and pricing in your written project quote. |
| Warranty | 25-Year Residential, 10-Year Limited Commercial |
| Fire Rating | Class A flame spread (ASTM E84) |
| Application | New decks and full re-decks on sound framing that already has the right pitch; not an add-on to installed boards. |
Frequently Asked Questions
Everything builders, dealers, and homeowners ask before specifying AmeriDex.
What makes AmeriDex different from other under-deck drainage systems?
AmeriDex combines PVC boards and a Dexerdry seal at the deck surface. Separate above-joist systems place a drainage layer beneath the boards; below-joist systems collect water under the framing. Compare installation location and project requirements.
Can AmeriDex be installed on an existing deck?
AmeriDex is for new decks and full re-decks on sound framing that already has the right pitch. It cannot be added to boards that remain installed. For a re-deck, remove the old boards and have your builder assess framing condition, pitch, flashing, and all installation requirements.
What is the Dexerdry seal and what is it made of?
Dexerdry is the integrated drainage seal that ships between every AmeriDex deck board. It is made from automotive-grade TPE (thermoplastic elastomer), the same material category used in car door and window seals. It is designed to form the water-diverting joint between compatible boards. Correct installation and the specified edge details are essential.
What are AmeriDex deck boards made of?
AmeriDex boards are cellular PVC with a proprietary ASA cap and a wood-grain finish. They are made in the USA. Follow the installation and care instructions for the specified application.
What joist spacing does AmeriDex require?
AmeriDex specifies 16 inches on-center joist spacing for residential applications. Also confirm the required drainage pitch, flashing, board direction, fastening, and perimeter details in the current installation instructions.
What lengths and colors are available?
AmeriDex deck boards are stocked in 12, 16, and 20 foot lengths and in seven PVC colors. Standard runs top out at 20 ft, and custom lengths up to 25 ft are available on request for projects with non-standard runs. You can request free samples to see all seven colors in person.
What is the AmeriDex warranty?
AmeriDex carries a 25-year residential limited warranty and a 10-year limited commercial warranty on the deck board system.
What is the fire rating of AmeriDex deck boards?
AmeriDex lists a Class A flame-spread rating under ASTM E84. Request the applicable report and confirm local requirements with the project authority. This is not, by itself, a statement of wildfire approval or a fire-resistance rating for the complete assembly.
Related Reading
- Waterproof decking: how AmeriDex compares to membranes, aluminum planks, and coatings
- What is an above-joist deck drainage system?
- Above-joist vs below-joist deck drainage: a builder's comparison
- About AmeriDex: the engineering origin behind the system
- Why decks rot from the top down
- Installing AmeriDex: a step-by-step guide