ROOT CELLAR KIT how to use large culvert as a root cellar

The information on this page is current as of 7.28.2026

"Cross-section diagram of largeculvert.com horizontal root cellar kit with integrated bulkhead door assembly and floor tracking"
BASIC 120″ RAW CAN FOR VERTICAL OR HORIZONTAL ROOT CELLAR

“Why Our 3/16″ Reinforced End-Plates Outperform Concrete” and “The Infinite DIY Flexibility of Our Pre-Welded 2×2 12-Gauge Bolt Trak System.”

We start with our US STEEL US MANUFACTURED large corrugated metal pipe.

Large corrugated metal pipe for root cellar is typically made with 96″, 100″, or 120″ diameter pipe.

All kits include lifting lugs as a standard to provide a positive lifting connection.

The ends are available with 11g, 3/16″ or 1/4″ steel.

The 11g and 3/16″ ends have 2- pieces of strut channel attached vertically to enhance structural integrity and provide a point of attachment for shelving, benches, safe, etc.

When installing the ends we leave the square plate un-trimmed and they are installed relative to the lifting lugs which provide a perfect leveling and anti rocking solution when installing in the ground.

Then we add 2x2x12g angle “bolt traks” (punched angle iron) with holes on 1″ centers, for floor support, another set on the top to provide a mechanism to have vertical bolting capability, setting the versatility stage for adding shelving, benches, etc. at anytime “without welding.”

The 2x2x12 bolt traks with holes on 1″ centers, (punched angle) floor trak and ceiling trak installed on 4′ or 6′ provides the perfect structure in order to connect vertical pieces to make shelf brackets, benches, dividers, etc. and endless options that can be added by simply bolting together.

How the Interior Bolt Track System Functions:
    • The Subfloor Support: Running the tracks horizontally along the bottom curve creates a perfectly flat, level shelf line. Instead of trying to build framing that matches the round, corrugated bottom of a 96″, 100″, or 120″ pipe, you have a rigid steel ledge ready to receive your 3/4″ plywood subfloor.
    • The Upper Utility Line: Running them across the upper curve mirrors the bottom layout, giving you an overhead anchor line that keeps everything square.
    • The Interlocking Frame: Having the top and bottom horizontal tracks allows you to drop vertical tracks directly between them. This creates a solid structural grid inside the cylinder to easily attach:
        • Wall framing or paneling
        • Heavy-duty storage shelves for canning jars
        • Benches, hooks, and lighting fixtures

By utilizing the strut channels and these interior bolt tracks, you can transform a round industrial culvert into a clean, square walk-in room with flat walls and a stable, flat floor.

ROOT CELLAR KIT how to use large culvert as a root cellar

The largeculvert.com root cellar kit is the ultimate sweet spot of a truly great DIY project. You have the absolute hardest, most stressful part—the heavy engineering, the water protection, and the unyielding structural hull—completely locked down and taken care of by the factory.

When we hand you a blank canvas lined with universal 2×2 angle iron “bolt trak” from end to end, you don’t need to have every single detail figured out today.
You can literally walk into that 40-foot steel chamber after it’s buried, look at the space, and let your imagination dictate the build as you go.
If you want to spend the first winter using the whole thing as one giant cold room, you can. If you decide next spring that you want a divider wall, an integrated gun safe, or massive hanging meat hooks, you just grab a wrench, some hardware, and a few more lengths of perforated angle iron.
It is a brilliant, lifetime-grade setup.
When ever you do decide to tackle that interior layout, their 2×2 bolt-together skeleton is going to make it an absolute blast to build!

ROOT CELLAR KIT how to use large culvert as a root cellar

CUSTOM MADE ROOT CELLAR KIT WITH ENDS BOLT TRAKS FOR FLOOR AND SHELVING, DIVIDERS, BUNK FRAMES, etc.

ROOT CELLAR KIT how to use large culvert as a root cellar

96″ Diameter Horizontal Root Cellar Kits

LENGTH DIA. $400 P.F. ENDS 4- 11G 4’X8′ # STRUT $75 EA. # L.L. $200 EA. BOLT TRAK 5$ FT. 4XL COST
  96″ 4- pcs 4- pcs 2- pcs 10′ PCS.  
10′ $4,000 $2,400 $300 $400 $200 $7,300
15′ $6,000       $300 $9,400
20′ $8,000       $400 $11,500
25′ $10,000       $500 $13,600
30′ $12,000       $600 $15,700
35′ $14,000       $700 $17,800
40′ $16,000       $800 $20,900
45′ $18,000       $900 $23,000
50′ $20,000       $1,000 $25,100
100″ Diameter “No-Permit Freight” Horizontal Kits
LENGTH DIA. $500 P.F. ENDS 4- 11G 4’X8′ # STRUT $75 EA. # L.L. $200 EA. BOLT TRAK 5$ FT. 4XL COST
  100″ + 4- 1/8″ X 6″X 10′ 4 2 10′ PCS.  
10′ $5,000 $2,400 $300 $400 $200 $8,400
15′ $7,500       $300 $10,900
20′ $10,000       $400 $13,500
25′ $12,500       $500 $16,100
30′ $15,000       $600 $18,700
35′ $17,500       $700 $21,300
40′ $20,000       $800 $23,900
45′ $22,500       $900 $26,500
50′ $25,000       $1,000 $29,100
             

120″ Commercial-Scale Horizontal Kits

LENGTH DIA. $600 P.F. ENDS                                4- 3/16″ X  5′ X 10′ # STRUT $75 EA. # L.L. $200 EA. BOLT TRAK 5$ FT. 4XL COST
  120″   4 2 10′ PCS.  
8’5″ (101″) $5,050 $2,900 $300 $400 $200 $8,850
10′ $6,000       $200 $9,800
15′ $9,000       $300 $12,700
20′ $12,000       $400 $16,000
25′ $15,000       $500 $19,100
30′ $18,000       $600 $22,200
35′ $21,000       $700 $25,360
40′ $24,000       $800 $28,400
45′ $27,000       $900 $31,500
50′ $30,000       $1,000 $34,600
             

Modular DIY Add-On Menu

Some components can be modified, and extra components can be shipped with the root cellar.

1. EXTRA 2″ X 2″ X 12G BOLT TRAK +$40 EACH 10′ PC. ($4 PER FT.) WHEN SHIPPED WITH UNIT.

2. 11g x 4′ x 8′ STEEL PLATE +$300EA.

3. 3/16″ x 5’X10 +$400EA.

4. 12″ ROOF VENT NIPPLE +$250

5. 8′ STRUT CHANNEL +$65 EA.

6. LIFTING LUGS (WELDED) +$200 EA.

96″ RTW KITS INCLUDES 4- 11G x 4′ x 8′ STEEL FOR 2- ENDS, 2- SETS OF BOLT TRAKS, 2- SETS OF STRUT CHANNEL, 2- LIFTING LUGS, 2- 6″ NIPPLE FOR VENT

100″ KITS RTW INCLUDES 4- 11G x 4′ x 8′ STEEL + 2- 1/8″ X 6″ X 10′ FLAT BAR FOR 2- ENDS, 2- SETS OF BOLT TRAKS, 2- SETS OF STRUT CHANNEL, 2- LIFTING LUGS, 2- 6″ NIPPLE FOR VENT

“Get a Custom Freight Quote: Ask How Our 100-Inch No-Permit Model Saves You Thousands in Shipping.”

120″ KITS RTW INCLUDES 4- 3/16″ X 5′ X 10′ STEEL FOR 2- ENDS, 2- SETS OF BOLT TRAKS, 2- SETS OF STRUT CHANNEL, 2- LIFTING LUGS, 2- 6″ NIPPLE FOR VENT

ROOT CELLAR KIT how to use large culvert as a root cellar

CUSTOM MADE ROOT CELLAR KIT WITH ENDS BOLT TRAKS FOR FLOOR AND SHELVING, DIVIDERS, BUNK FRAMES.

"Largeculvert.com horizontal root cellar kit 72 inch floor layout drawing"
horizontal-root-cellar-kit-floor-layout.jpg

BOLT TRAK LAYOUT OPTION 48″ OR 72″ OR BOTH

ROOT CELLAR KIT how to use large culvert as a root cellar

NOTE:

  1. BOLT TRAK IS 2″ X 2″ ANGLE IRON (LOOK LIKE AN “L”)
  2. FLOORING IS ACCOMPLISHED USING 3/4″ PLYWOOD AND LAYING IT DOWN ON THE BOLT TRAK
  3. WHEN USING THE 72″ FLOORING LAYOUT, THERE WILL BE A 2′ X 4′ DROP PIECE THAT IS PERFECTLY SUITED SIZE FOR A SHELF
  4. BOLT TRAK CAN BE ADDED VERTICALLY TO PROVIDE STRUCTURAL CONNECTIONS FOR SHELF/ BENCH/ WALLS ETC.
  5. FRAMING WOOD CAN BE EASILY LAG BOLTED TO THE BOLT TRAK
horizontal root cellar kit component installation drawing
BOLT TRAK DRAWING DEPICTING SHELVING/ BENCHES FRAMING 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NOTE:

root cellar kit component
12G 2X2 BOLT TRAK

 

THE MAIN UPPER AND LOWER BOLT TRAKS ARE STITCH WELDED FULL LENGTH AT THE FACTORY.

root cellar kit component
12G 2X2 BOLT TRAK
strut track for the ends of a horizontal root cellar kit installation drawing
STRUT TRACK 2- PCS WELDED TO ENDS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

    • “Our horizontal root cellar kits feature dual 3/16” heavy steel plate end-caps reinforced with vertically welded channel struts, creating a rigid interior framing track to effortlessly bolt down custom shelving, safes, and benches.
    • The entryway features a precision-cut opening designed for a seamless, weld-in steel door frame.”

SEE COMMON ACCESSORIES READILY AVAILABLE AT THE LINKS BELOW, ESPECIALLY THE SPRING NUTS WHICH OFFER UNLIMITED OPTIONS TO BOLT SAFES/ SHELVING ETC.

https://www.menards.com/main/electrical/conduit-conduit-fittings-raceways/strut-support-systems/phoenix-support-systems-strut-channel/a12h1000pgr/p-105480403511-c-12477.htm

https://www.lowes.com/pd/Adamax-Adamax-14-Gauge-Channel-Strut-EG-10-FT/5001904579

root cellar kit component
STRUT TRAK
root cellar kit component
STRUT TRAK
root cellar kit component
STRUT TRAK
root cellar kit component
SPRING NUT

ROOT CELLAR KIT how to use large culvert as a root cellar

ROOT CELLAR KIT how to use large culvert as a root cellar

Key takeaways

1. Indestructible End-Cap Engineering
Standard flat metal caps easily crush or buckle (“oil-can”) under the immense lateral pressure of deep dirt burial. Largeculvert.com solves this by building the horizontal ends out of heavy 11g or optional 3/16″ steel plates structurally reinforced with vertically welded 1-5/8″x1-5/8″x12g strut track. This gives the unit massive structural rigidity against soil caving while providing a rigid universal option to permanently attach anything with bolts, such as a safe, shelves etc..
2. The Universal “Bolt Trak” Chassis
Instead of leaving you with a smooth, curved interior that is nearly impossible to drill or anchor into, they weld 4-bolt tracks full-length along the bottom and top. This converts a round cylinder into a standardized, square-plane industrial Erector set.
Because everything inside anchors directly to this 2×2 12-gauge perforated angle steel, no further field welding is required. It hands you a blank canvas where you can use simple 3/8″ bolts to adapt the layout to your imagination as you go:
    • You can drop a 6-foot plywood floor directly onto the 2-inch perforated track lips.
    • You can easily frame out custom 2-foot side benches or tip-up shelving networks.
    • You can bolt in custom micro-climate divider walls, heavy safes, or tool racks using basic hand tools.
The Final Verdict
If you are looking for a cheap, temporary root cellar, this heavy-duty steel setup is likely overkill and will require heavy machinery (like an excavator) to drop its massive weight into the ground safely.
However, if you want an absolute tank of a structure that completely eliminates cave-in risks, skips the need for expensive wide-load state highway freight permits (on the 100-inch model), and gives you a modular, bolt-together playground to customize over a lifetime, this kit is an exceptional investment.
How does steel compare to concrete?
When engineered with the bolt-together layout, the largeculvert.com steel kit is not just an alternative to concrete—it fundamentally beats concrete across almost every metric.
Here is an objective evaluation of how these two systems actually perform in the field:
1. Thermal Stability: Peerless Performance
    • The Reality: The earth itself is the thermal battery, not the structure.
    • The Steel Advantage: Concrete acts as an insulator, slowing down how fast the earth’s cool temperatures can penetrate the cellar. Steel, because of its high thermal conductivity, acts as a perfect heat conductor. It instantly and continuously transfers the deep earth’s stable 50–55°F temperature straight into your storage chamber.
    • The Verdict: With 3 feet of dirt insulation over a massive 30-to-40-foot steel tube, the thermal stability is flawless and highly responsive, outperforming concrete’s sluggish thermal lag.
2. Humidity: Active Precision vs. Passive Wetness
Concrete cellars are notorious for “sweating,” cracking, and bringing in unpredictable, localized dampness that can breed mold or ruin dry-crop zones.
    • The Steel Advantage: The steel hull provides an absolute, 100% predictable vapor barrier around the entire perimeter of your crop rooms.
    • The Simple Design Win: Because your 6-foot floor layout sits perfectly above an open gravel belly, you have total control. Earth moisture rises uniformly through the 1-inch track perforations. If it runs dry, a simple drip line on the gravel or a wet burlap mat right at the air intake gives you exact humidity management.
    • The Verdict: You get a split-climate system where your dry room stays dry, and your deep room hits a targeted 90–95% humidity without the structural dampness or mold risks inherent to porous concrete.
3. Structural Longevity and Peace of Mind
    • The Reality: Concrete shifts, settles, and develops micro-cracks over the decades. Once a concrete cellar cracks underground, fixing water intrusion or root penetration is a costly, muddy nightmare.
    • The Steel Advantage: A 12-gauge corrugated steel cylinder with 11g or optional 3/16″ reinforced end plates is physically flexible enough to handle ground settling, earthquakes, and heavy frost heaves without cracking. When properly coated on the exterior, it provides an uninterrupted waterproof seal for a lifetime.
ROOT CELLAR KIT how to use large culvert as a root cellar
The Ultimate Comparison
Feature Largeculvert.com Horizontal Steel Kit Precast / Poured Concrete Cellar
Thermal Stability (at 3+ ft burial) Superior (Instant thermal conduction to deep earth) Good (High mass, but acts as a temperature insulator)
Humidity Control Excellent (Predictable vapor barrier + open gravel bed) Unpredictable (Porous; prone to sweating and mold)
Structural Integrity Excellent (Flexible; immune to cracking or cave-ins) Variable (Rigid; prone to settling cracks over time)
Interior Adaptability Infinite (Universal 2×2 angle iron bolt-together chassis) None (Fixed, unchangeable stone bunker)
The Final Evaluation
The horizontal steel kit from largeculvert.com completely redefines underground storage. It eliminates the logistical headaches of concrete (heavy transit mixers, crane rentals, and forms) while delivering a highly controllable, thermally perfect environment. Paired with their modular 2×2 perforated angle iron framing system, it is objectively a superior design for a modern, functional homestead.
Side-by-Side Technical Specification Sheet

Engineering Vector LargeCulvert.com Steel Root Cellar Kit Standard Poured Concrete Cellar
Material Composition 12-Gauge Hot-Dipped Galvanized US Steel 4,000 PSI Porous Portland Cement Mixture
Structural Profile 2.66″ x 0.5″ Alternating Corrugated Ridges 6″ to 8″ Thick Rigid Flat Walls
End-Cap Engineering 11- gauge or optional 3/16″ Steel Plates with Welded Strut Channels Monolithic Pour or Block Walls with Tied Rebar
Load Mechanics Flexible Ring Compression (Yields to soil pressure without breaking) Rigid Tension Resistance (Prone to cracking under lateral earth stress)
Thermal Conductivity High (approx. 50 W/m·K): Instantly transfers earth-chilling temperature directly into the chamber. Low (approx. 1.5 W/m·K): Acts as an insulator; traps harvest heat and causes severe thermal lag.
Vapor & Liquid Barrier 100% Impermeable Welded Endss (Zero ground water or vapor penetration) 

  • Continuous Interlock: The edges of the flat metal coil fold over each other.
  • Pressure Rolling: Rollers press the folded metal hard to create a tight, mechanical lock seam without welding.
  • Seam Types: Common types include lock seams (spiral)

 Hydroscopic Porous Matrix (Naturally absorbs and weeps ground moisture)
Climate Interface Suspended floor over an open gravel bed via integrated tracks for uniform, mold-free humidity control. Solid floor slab; prone to surface water pooling and localized damp mold zones.
Internal Framing System Factory-Welded 2×2-inch Bolt Trak Chassis full length (No drilling required) Blank Masonry Interior (Requires heavy rotary hammer drilling and concrete anchors)
Ventilation Integration Pre-welded 6″ or 12″ roof nipples for immediate, air-tight vacuum siphons. Manual field-cutting or custom wood form-outs (High risk of post-pour leak points)
Long-Term Failure Mode Gradual superficial zinc oxidation (Prevented completely with basic exterior coating) Structural stress fractures, mineral weeping, and unfixable subterranean leaks

This data is the blueprint for dismantling the concrete tradition
ROOT CELLAR KIT how to use large culvert as a root cellar
Frequently Asked Questions (FAQ)
Do I need to weld anything inside the horizontal root cellar kit?
No field welding is required. Every kit features our factory-welded 2×2 12-Gauge Bolt Trak chassis running full-length along the top and bottom. All interior outfitting—including flooring, vertical supports, divider walls, and shelving—can be built using standard grade 3/8″ bolts directly through the 1-inch centers on the track.
How do I prevent the steel hull from rusting underground?
Our kits utilize premium, heavy-duty galvanized US Steel. You may thoroughly coat the exterior of the pipe and the 11g or optional 3/16″ end-plates with rubberized undercoating, or asphalt mastic paint before backfilling. This creates a permanent waterproof shield that ensures a multi-generational lifespan.
Can this kit be installed in areas with a high water table?
Yes, but site preparation is key. Because our horizontal kits feature heavy 11g or optional 3/16″ structurally reinforced steel end-plates, the unit acts as a sealed, completely predictable vapor barrier. If you have high local groundwater, you must install a proper gravel bedding layer and a drain or sump line beneath the unit to allow ambient water to bypass the structure safely.
Why is the 100-inch diameter model so popular?
We intentionally engineered our 100-inch internal diameter kit to maintain a 101.5-inch outer diameter. This specific measurement allows the massive structure to be transported on standard shipping trailers without triggering expensive state-by-state DOT wide-load freight permits, saving you thousands of dollars in logistical delivery fees.
What heavy equipment is required for installation?
Because our 96″, 100″, and 120″ diameter steel kits are incredibly robust (constructed from thick-gauge steel with reinforced plates), a 30-to-40-foot unit will weigh several thousand pounds. You will need a standard commercial excavator on-site to dig the trench, utilize our pre-welded lifting lugs to safely drop the cylinder into place, and handle the earth-berm backfilling.
Ready to Map Out Your Build?
Every homestead setup is unique.
Contact JB directly at largeculvert@gmail.com with your custom specs, or call to verify current local availability and freight routing.
ROOT CELLAR KIT how to use large culvert as a root cellar
ROOT CELLAR KIT how to use large culvert as a root cellar
ROOT CELLAR KIT how to use large culvert as a root cellar
ROOT CELLAR KIT how to use large culvert as a root cellar