Waterproof Deck System – DryJoist
Marine Grade Aluminium DryJoist. The Ultimate Time Saving 100% Waterproof Deck System For Balconies and Second Stories.
DryJoist is a high-performance aluminium structural deck drainage system engineered to create waterproof decks and balconies without the complexity of traditional membrane construction. It functions as both the structural deck support and the waterproof drainage layer, while also delivering a clean finished ceiling beneath.
For architects, engineers, and builders seeking a long-lasting deck waterproofing solution, DryJoist offers a practical and efficient alternative to conventional systems.
Structural Deck Drainage System
NexGEN DryJoist is a specialised structural deck drainage system engineered for professionals across the construction, engineering, and architectural sectors.
Combining structural support, waterproofing, and a refined finished ceiling into a single integrated solution, DryJoist simplifies deck and balcony construction while delivering long-term performance, durability, and a clean architectural finish.
Built-in Waterproof Solution
NexGEN DryJoist is an innovative aluminium deck drainage system that performs three essential functions in a single installation:
structural framework
waterproofing
a finished soffit ceiling with the appearance of traditional beadboard
Unlike conventional deck waterproofing systems that sit beneath joists, DryJoist is installed directly on top of the supporting frame. This creates a leakproof deck structure above while protecting the framing below from ongoing water exposure.
The result is a streamlined, high-performance solution that improves build efficiency, reduces complexity, and delivers a durable, minimalist finish.
Replacing traditional wooden joists while creating a 100% dry space in the area below. It’s a single-system, integrative design that eliminates add-on gutter systems, waterproofing membranes, or drainage substructures.
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Three products in One!
Why DryJoist?
Traditional deck waterproofing methods generally fall into two categories: membrane systems and under-deck drainage systems. Both are typically installed below deck joists, often requiring significant labour and offering limited long-term performance.
DryJoist offers a more efficient and robust alternative.
By integrating waterproofing into the structural deck system itself, DryJoist eliminates the need for separate membrane builds or secondary under-decking systems. Installed above the frame, it sheds water effectively at the source, helping protect the structural elements below and extending the life of the overall deck assembly.
Key Benefits
Structural + Waterproof in One System
DryJoist combines framing and waterproofing into one integrated product, reducing the need for multiple layers, trades, and installation stages.
Long Structural Spans
With a structural span capability of up to 1.80 metres between support beams, DryJoist can eliminate the need for traditional decking joists in many applications.
Clean Finished Ceiling
The underside delivers a neat, beadboard-style ceiling appearance, creating an attractive finished soffit without the need for additional lining.
Faster, Simpler Installation
DryJoist removes the complexity associated with conventional waterproofing systems, such as built-up rubber membranes and poured concrete. It installs using standard deck-building tools and methods.
Low Maintenance
Once installed, DryJoist provides a reliable, trouble-free dry space beneath the deck with no ongoing structural maintenance requirements.
Seamless Waterproof Performance
All DryJoist components are designed to fit together as a continuous system, forming a seamless waterproof structure that supports the decking surface of your choice.
Material Performance
DryJoist is manufactured from marine-grade aluminium, providing excellent resistance to weathering and environmental exposure.
This helps protect deck structural components from moisture-related deterioration and supports long-term durability in demanding exterior conditions.
DryJoist is also fire-resistant, making it a strong choice for projects in high-risk fire zones where non-combustible materials are preferred.
Sustainable Design
DryJoist is an environmentally responsible alternative to traditional timber joists and support beams.
made with approximately 50% recycled aluminium
completely wood-free
helps extend the service life of protected framing components below
By combining durability, recyclability, and reduced material complexity, DryJoist supports more sustainable deck and balcony construction.
Applications
DryJoist gives architects, designers, and builders greater freedom to create customised deck and balcony solutions that are both waterproof and structurally capable.
It is ideal for:
exterior balconies
elevated decks
rooftop-style deck structures
projects requiring dry usable space below
builds where a clean soffit finish is desired
applications where reduced maintenance and long-term durability are priorities
Product Details
DryJoist is 50 mm high and is available in two joist widths:
100 mm – Multi-Joist
152 mm – Main-Joist
Each joist functions as a box gutter, meaning only a minimal fall is required for effective drainage.
For optimal performance, a gradient of 1 in 100 is recommended to ensure efficient water shedding.
Installation
DryJoist is designed as a complete system, with all required components supplied for seamless installation.
The system can be installed using standard deck-building tools and can be handled by building professionals or capable installers familiar with deck construction practices.
Because DryJoist integrates structural support, drainage, and waterproofing in one step, it reduces reliance on slower, more labour-intensive conventional methods.
Manufacturing and Quality
DryJoist is custom-manufactured in North America under strict quality assurance and quality control protocols.
Every system is produced as a complete, coordinated solution to ensure installation compatibility, reliable performance, and consistent finish quality.
Customer Testimonials
“We needed a new deck because the timber deck we had was 25 years old and rotting. We found NexGEN and spoke to Roxanne who arranged for her and Jim to come and help with a measure and quote. Even though Jim was busy he was able to fit us in earlier than first discussed. Jim did a wonderful job and we now have a deck that will outlast both of us. Thank you Roxanne and Jim for all of your help“
“My husband and I were looking for a decking product that looked like real wood but without the maintenance as we are both busy shift workers. I found NexGen Decking and after much research and comparison with other similar products settled on what I consider to be the best out there. The initial contact with Roxanne was fantastic. Her professionalism and passion for the product sold us. When it came time for installation Jim was fabulous. A keen eye for detail, professional and wonderfully polite and easy to get along with. We both highly recommend NexGen Decking and will be looking to get Roxanne and Jim back to do our next project soon. Thanks again Roxanne and Jim. We will be in contact about the rear deck project a bit later in the year.”
“ We’re Beyond delighted with our newly transformed rooftop garden. NexGen was the perfect product for the job. The professionalism, support and communication provided by sales Manager Roxanne made a potentially stressful renovation, smooth and easy running. The installation was handled by Jim. The skill and pride taken in his work is to be admired and we’ll be forever grateful to have our home improved by such fantastic workmanship. My highest of recommendations to NexGen and team. Thank you!“
“We wanted to replace the cheap and deteriorated existing decking on a two year old home with an environmentally responsible, strong and quality sustainable product, so after much research and a few quotes we chose NexGEN Graphite decking. We couldn’t be happier, with the product that looks neat and tidy, strong and long lasting, and the incredible attention to detail of the install. Jim assembled our decks and did a remarkable and beautiful job, really taking the time to get it right the first time. Great value too and the competition just couldn’t match the value for money not to mention the warranty and support for the product. Highly recommended, and thanks to NexGEN for an easy purchase and install.”
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Direct Office Numbers
Adelaide – (08) 6316 0469
Brisbane – (07) 3041 6065
Sydney – (02) 8072 6220
