“From its fully-welded seams to its storm-ready sealing, Rival Underdeck Boxes aren’t just built to endure, it’s built to outlast. Trusted across Canada’s toughest worksites, it’s protection you can count on.”
Underdeck Boxes
Extreme-Grade Aluminum Underdeck Boxes with No-Compromise Weather-Resistant Performance.
Rival Underdeck Boxes are the trusted choice of professionals who demand uncompromising performance in every condition. Built from 5052-H32 millplate aluminum, these boxes are fully welded for maximum strength and weather resistance. Featuring flush-mount strap hinges, locking whale-tail handles, and an aluminum drip rail to divert rain, every underdeck box is engineered to survive the harshest Canadian winters and roughest terrain. With self-draining Venturi hoods, optional 90-degree door chains, and customizable step or barn-door upgrades, Rival delivers practical durability for any truck configuration. Designed for installation beneath decks or platforms, these boxes provide premium storage and protection where it matters most.
Starting At
$710.00 CAD
What is the availability of the Underdeck Boxes?
May be in stock. If not, we usually have components to assemble at a faster timeline than from-scratch. Contact us!
What vehicles does Rival make Underdeck Boxes for?
Theoretically compatible with any platform/surface/etc. – Need us to add brackets or mounting accomodations? Just ask!
How much does an Underdeck Box weigh?
A 3′ Underdeck Box weighs approximately 45lbs. Need a specific weight check? Chat with our team.
What materials are Underdeck Boxes made from?
Aluminum 5052-H32 Millplate
Aluminum 6061-T6 ExtrusionsRubber
How much, and how long does it take to install a Underdeck Box?
Please contact us for installation cost/time estimations. We can install boxes onto your truck.
What is the typical application for a Underdeck Box?
#1) Construction & General Contracting
#2) Utility & Service (Hydro, Electrical, Telecom, Gas)
#3) Welding & Fabrication Rigs
#4) Transportation & Logistics (Tow, Recovery, Hauling, etc.)
How are Underdeck Boxes attached?
Primarily when we are assembling: our boxes are welded-on. However, there are some use-cases where we use a bolt-on instead (see Dumper Frames, etc.). If you need us to add brackets, feet, or any mounting accomodations, no problem.
What models are available?
(We build these in-house 100% from scratch. Dont see your ideal size here? Np. Contact us.)
11″D x 18″L x 16″H (80″W Bodies Ideal)
11″D x 24″L x 16″H (80″W Bodies Ideal)
11″D x 36″L x 16″H (80″W Bodies Ideal)
11″D x 48″L x 16″H (80″W Bodies Ideal)
11″D x 60″L x 16″H (80″W Bodies Ideal)
14″D x 18″L x 16″H (86″W Bodies Ideal)
14″D x 24″L x 16″H (86″W Bodies Ideal)
14″D x 36″L x 16″H (86″W Bodies Ideal)
14″D x 48″L x 16″H (86″W Bodies Ideal)
14″D x 60″L x 16″H (86″W Bodies Ideal)
19″D x 18″L x 16″H (96″W Bodies Ideal)
19″D x 24″L x 16″H (96″W Bodies Ideal)
19″D x 36″L x 16″H (96″W Bodies Ideal)
19″D x 48″L x 16″H (96″W Bodies Ideal)
19″D x 60″L x 16″H (96″W Bodies Ideal)
Where can I purchase or order an Underdeck Box?
Rival Boxes are exclusively sold at Express Custom. Express Custom can arrange shipping to anywhere in North America.
MSRP’S:
11″D x 18″L x 16″H: $710.00
11″D x 24″L x 16″H: $800.00
11″D x 36″L x 16″H: $900.00
11″D x 48″L x 16″H: $1020.00
11″D x 60″L x 16″H: $1130.00
14″D x 18″L x 16″H: $770.00
14″D x 24″L x 16″H: $830.00
14″D x 36″L x 16″H: $930.00
14″D x 48″L x 16″H: $1060.00
14″D x 60″L x 16″H: $1180.00
19″D x 18″L x 16″H: $770.00
19″D x 24″L x 16″H: $830.00
19″D x 36″L x 16″H: $930.00
19″D x 48″L x 16″H: $1060.00
19″D x 60″L x 16″H: $1180.00
What finishes are available for Underdeck Boxes?
Normally they go either Bare Aluminum, Powdercoated Sandtex Black, or Powdercoated Commercial/Fleet White. We can accomodate nearly any finish request; powdercoat, paint, vinyl wrap, decal – whatever you need.
What is the Warranty of Underdeck Boxes?
2 Year Limited
(learn more)
Got more questions? Contact our team!
Strength Beneath the Surface.
The (not so) secret strength behind Rival’s Underdeck Boxes lies in the overkill construction and all-weather endurance. Each box is precision-built from 5052-H32 aluminum with TIG and MIG welded seams, combining light weight with extreme strength. Self-draining and ventilating via an integrated Venturi hood scoop, these boxes thrive under harsh conditions, keeping your gear dry and your hardware corrosion-free. Weather-resistant neoprene D-seal compression gaskets create a watertight closure, while flush-mount strap hinges and locking whale-tail handles deliver a clean, professional finish. Each unit is topped with an aluminum drip rail to deflect rain and road spray, ensuring year-round reliability on or off the highway.
Available in multiple depths (11″, 14″, 19″) and lengths up to 60″, Rival Underdeck Boxes are tailored to fit 80″, 86″, and 96″-wide truck bodies. Options include door-stop chains, barn-door configurations, and integrated step kits for added accessibility. With their modular fitment and universal mounting system, these boxes can be bolted or welded beneath nearly any deck or flatbed platform. Rival’s in-house installation services and rapid build times ensure your gear is protected fast, and for fleets of five or more, volume pricing is available. Rugged, refined, and field-proven, the Rival Underdeck Box delivers the confidence your tools deserve.
Default / Base Configuration
Drip Rail
Powdercoated Sandtex Black Drip Rail for Rain Dispersion
Locking Whale Tail Handle
Your Box will include Locking Whale Tail Handles
Less than 60″ = Single Handle
61″ & Wider = Two Handles
Includes two keys
Flush-Mount Strap Hinges
Available in Black or Chrome.
Same HD Hinges used on our Truck Bodies.
D-Seal Weather Resistant Sealant
- Door is flush when closed
- Compresses into “D” Seal Rubber Neoprene sealant on all 4 sides of door when closed.
Self-Draining Venturi
- Integrated Venturi Scoop to pull out air while you drive, keeping interior moisture accumulation to a minimum and allowing damp items to breathe (reduces chance of Moldy/Damp Gear)
Default / Base Configuration
Drip Rail
Powdercoated Sandtex Black Drip Rail for Rain Dispersion
Locking Whale Tail Handle
Your Box will include Locking Whale Tail Handles
Less than 60″ = Single Handle
61″ & Wider = Two Handles
Includes two keys
Flush-Mount Strap Hinges
Available in Black or Chrome.
Same HD Hinges used on our Truck Bodies.
D-Seal Weather Resistant Sealant
- Door is flush when closed
- Compresses into “D” Seal Rubber Neoprene sealant on all 4 sides of door when closed.
Self-Draining Venturi
- Integrated Venturi Scoop to pull out air while you drive, keeping interior moisture accumulation to a minimum and allowing damp items to breathe (reduces chance of Moldy/Damp Gear)
Options & Extras
Built in-house, from start-to-finish. We can tailor your boxes to suite your exact needs. We can add, remove, augment, or modify any aspect of your build. When ‘basic’ just wont cut it, chat with our team about what we can do to make your boxes yours.
Chains to Stop Door
We can add chains to stop the door at 90-degrees, or wherever you like.
Wireless Actuated Handles
Is premium your motto too? Well, do we have the option for you. Upgrade your toolbox and add wireless-FOB control just like your vehicle.
Interior Rope L.E.D.
Work evenings? Or even just after 4:00PM during Canada’s Winter? Add L.E.D. Ropelight to your toolbox with an automatic killswitch to avoid battery drain.
Add Drawers or Shelves
We can add drawers, shelves, or anything else that makes your life easier.
Change Hinge Orientation
Want your door to open left, right, or even up? Sure – No problem.
Not just boxes for trucks, either.
Go big or go home, right? We can build these style of boxes in any size you can imagine. Want one 6’H? Contact us!
Rival Manufacturing
Delivering premium product, everytime.
1365 Alberni Hwy
Parksville, BC, V9P 2B9
PO BOX 487
Parksville, BC, V9P 2G6
Prices posted online may not be kept up-to-date in realtime due to human delay. We make our best efforts to update information online as soon as possible.
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