How DuxxBak Decking Works
How DuxxBak Decking Works: Materials, Design & Engineering Explained
When most homeowners think about waterproofing a deck, they assume it’s something that gets added later — like an under-deck ceiling system or a drainage membrane installed beneath the framing.
But DuxxBak decking approaches the problem differently.
Instead of trying to manage water after it passes through the deck surface, DuxxBak is engineered to control water at the surface level — using the decking boards themselves as a built-in drainage system.
To understand why this matters (especially here in Western Pennsylvania), it helps to take a closer look at how the system is designed and what the boards are actually made from.
The History Behind the System
DuxxBak was developed by Green Bay Decking as a response to one of the most common problems in outdoor construction:
Traditional deck boards allow water to pass directly through the surface.
This becomes a major issue when decks are built over:
Walk-out basements
Outdoor patios
Storage areas
Outdoor kitchens
Finished lower-level living spaces
Historically, solving this meant installing a secondary drainage system beneath the deck — such as under-deck ceilings, membrane systems, or suspended gutter assemblies.
These systems often:
Add cost
Add complexity
Require maintenance
Still allow occasional dripping
DuxxBak was designed to eliminate the need for secondary systems entirely by integrating water management directly into the decking itself..
Material Composition: What DuxxBak Is Made Of
Unlike traditional wood or wood-plastic composite decking, DuxxBak boards are completely wood-free.
Instead of using wood flour or organic fillers, the boards are manufactured using a proprietary mineral-based composite that includes:
High-density polyethylene (HDPE)
Biodac® polymer
Recycled plastics
Agricultural byproducts such as rice hulls
This material formulation provides several structural advantages:
No Organic Material
Because there is no wood content:
The boards do not absorb moisture
They will not rot
They do not support mold or fungal growth
They are not susceptible to termite damage
This becomes particularly important in Pittsburgh’s humid summer months and freeze-thaw winter cycles, where moisture retention can lead to long-term deterioration in traditional decking systems.
Surface-Level Water Management
This is where the engineering of DuxxBak truly separates it from other composite products.
Each DuxxBak board is manufactured with a tongue-and-groove edge profile that allows the boards to interlock during installation.
Once installed, the system creates a continuous deck surface that prevents water from falling between the boards.
Instead of dripping through the deck, rainwater is:
Captured at the surface
Directed into integrated channels beneath each board
Guided toward the outer edge of the deck
From there, water exits at the perimeter — away from the structure below.
This means:
No dripping between boards
No exposed under-deck drainage panels
No secondary membrane systems
No suspended gutter assemblies
The decking itself becomes the drainage system.
Integrated Channel Design
On the underside of each DuxxBak board is a shaped profile that forms the internal drainage pathway.
These channels:
Capture water that enters the system
Maintain consistent flow toward the deck edge
Prevent standing water from accumulating
Because the water is managed within the board itself, the system reduces:
Splashing
Surface runoff
Moisture buildup in joist bays
This helps protect not only the space beneath the deck — but also the framing system itself.
Thermal Movement & Expansion
All composite decking materials expand and contract with temperature changes.
DuxxBak is engineered with a fastening system that accommodates this natural thermal movement.
Hidden clip fasteners attach to the edge profile of each board, allowing for:
Controlled expansion
Secure board placement
Reduced surface distortion
This is especially important in climates like Pittsburgh, where temperatures can swing from below freezing in winter to above 90°F in summer.
Framing Considerations & Joist Spacing
One of the structural advantages of DuxxBak is its ability to span joists spaced up to 24 inches on center.
Most composite decking products require:
16" OC joist spacing for proper support.
Because of DuxxBak’s material composition and internal profile, installers can often use:
24" OC spacing — reducing:
Lumber requirements
Framing labor
Installation time
This can help offset some of the additional material cost associated with premium decking products.
Installation Requirements
Proper installation is critical for performance.
Because DuxxBak is designed to shed water at the surface level, the deck must be constructed with:
Proper slope away from the home
Flashing integration at the ledger
Correct perimeter drainage
These factors allow the water-shedding system to function as intended.
When installed correctly, DuxxBak can create a dry, usable space beneath the deck — suitable for:
Storage
Patio seating
Outdoor kitchens
Covered living areas
Thinking About Building a Deck Over a Patio or Walk-Out Basement?
If you're considering a deck that will be installed above a patio, storage area, or outdoor living space, it's worth evaluating whether a water-shedding system like DuxxBak makes sense for your project.
At Heritage Deck & Frame, we design deck systems specifically for Pittsburgh’s four-season climate — helping homeowners choose the right framing methods, materials, and drainage strategies for their property.
Schedule a consultation today and we’ll help you determine whether DuxxBak is the right fit for your home and how it could impact the overall design of your outdoor space
