Quick Answer: A 20ft sea can makes a workable root cellar on rural Ontario property when it is earth-bermed, not fully buried. A shipping container’s structural rating handles lateral cargo loads, not soil weight on the roof. Berm three sides, insulate the exposed roof, vent passively, and target 0 to 5 degrees Celsius. Van Blanc is three decades family-run with 124+ verified Google reviews, and we deliver in 1-3 days from our 4 Brantford yards across Ontario.
In This Guide
- Should you bury or berm a shipping container root cellar?
- Can a shipping container hold the weight of soil?
- What does a bermed root cellar layout look like?
- How do you insulate a shipping container root cellar?
- How do you ventilate one without power?
- How do you keep a container root cellar from flooding?
- What temperature should a root cellar be?
- Who uses a shipping container root cellar in Ontario?
- When do you need a structural engineer to bury a container?
- FAQs
Reading Time: 14 minutes
Should you bury or berm a shipping container root cellar?
For a shipping container root cellar on rural Ontario property, berm it rather than fully bury it. A standard CSC-plated container is engineered for lateral ocean-cargo loads, not soil weight pressing down on the roof. Banking soil against three walls with the roof left exposed and insulated delivers most of the geothermal cooling without overloading the steel. Full burial needs a P.Eng-stamped reinforcement design.
Every spring at the yard we get the same conversation a few times over. A buyer drives in from Norfolk County, or down from the Bruce Peninsula, and tells us he wants to bury a sea can on the back of his property. He has seen a YouTube video. He is going to use it as a root cellar for the carrots, potatoes, and beets coming out of his market garden. He wants a 20ft, and he wants it cheap. Paul walks him out to the row and pulls him aside before the deposit comes out of his wallet.
“You are buying the right tool for the wrong job,” Paul tells him. “We will sell you the bin. We will deliver it. But you are not going to bury it the way you are picturing. Let me show you what a sea can is built to take, and what it is not.”
Paul LeBlanc, owner, Van Blanc Ent. Inc.: “A standard CSC-plated container is rated for ocean stacking. Six or seven of them piled on top of each other on a ship, deck loads pressing down through the four corner posts. That is the load path the steel was designed for. Push two metres of wet Ontario clay sideways against the long wall, or pile a foot of frozen soil on the roof, and you are loading the bin in a way it was never tested for. The roof panels are 14-gauge steel. They will dish in. The side walls will buckle. I have 19 years in containers, and I have watched every one of those backyard burial projects either fail in the second winter or get rebuilt at four times the original price. Berm it instead. Three sides of soil, exposed roof, insulated like a Northern bunkhouse. That bin will outlast the homestead.”
That is the whole topic in one paragraph. The rest of this guide is the practical detail: what bermed means, how to insulate the exposed surfaces, how to ventilate without a fan, how to manage the floor moisture that ruins half the projects that survive winter one, and what produce actually wants to live in there. We have been delivering sea cans across Ontario from our Brantford yards since 1995. We are not a YouTube channel. We are the family that drives the truck.
Can a shipping container hold the weight of soil?
A shipping container can take soil pressure against its walls far better than it can take soil weight on its roof, and that distinction is the whole structural story. The corner posts and rails carry stacking loads down their length; the flat roof and side panels were never engineered to hold up earth. Here is what the certification actually covers.
What the CSC plate actually certifies
The International Convention for Safe Containers (CSC, IMO 1972, currently maintained as amended) certifies a shipping container for one thing: handling and stacking in ocean and intermodal shipping. The structural test specified in ISO 1496-1:2013 racks the container by its corner castings, loads the corner posts in compression, and tests the floor for cargo distribution. There is no specification in CSC or ISO for soil load on the roof, lateral earth pressure on the side walls, or hydrostatic load against the doors. Those load paths simply do not exist in the design envelope. That is a fact about steel and physics, not about quality. A premium one-trip container has the same limit as a Wind & Watertight used bin: roof was built to keep weather out, not hold soil up.
Here is what that means at the yard. A 20ft container has four cast-steel corner blocks at the top and four at the bottom. The eight blocks are the load-bearing skeleton. Between them, the roof is corrugated 14-gauge sheet steel braced by the side rails. The side walls are corrugated 16-gauge steel braced by the bottom rail and top rail. Those panels have impressive in-plane stiffness, which is why a sea can does not collapse when an overhead crane lifts it from the corner castings. They have very modest out-of-plane stiffness, which is why a single shovel of wet soil against the side wall does almost nothing, but a metre of saturated Ontario clay against the same wall is a different story.
The numbers people repeat online vary wildly. Some sources quote 30 pounds per square foot allowable roof load, others quote 60. The honest answer is the manufacturer never published a soil-load rating because soil load was never an intended use. If you want a real number, you hire a structural engineer (Ontario P.Eng for a residential review on a project like this) and they will calculate the allowable load for that specific bin in that specific soil at that specific depth, accounting for freeze-thaw cycling on Ontario clay versus sandy loam in Norfolk versus the limestone shelf under parts of Bruce County. That is what a real P.Eng review costs and produces. Anyone telling you online “I buried mine and it has been fine for five years” is reporting a sample size of one, in soil and a climate you do not have, on a container with a wear history you do not know.
So why does bermed work? Because in a bermed install, the soil is up against three side walls and one set of doors at most, not over the roof. The roof stays exposed (insulated and weatherproofed from above, not from below). The side walls take lateral pressure, but only to the height of the berm, and lateral pressure at depth is roughly proportional to soil weight above the depth point, so a berm of a metre and a half loads the wall significantly less than full burial to the same wall height. Crucially, the corner posts are still doing their original job: holding the box square. The roof is doing its original job: shedding water. You have moved soil against the bin to get the geothermal cooling effect of underground storage, without violating the load path the container was built. That is the whole engineering case for bermed.
| Factor | Earth-bermed (soil on 3 walls, roof exposed) | Fully buried (soil over the roof) |
|---|---|---|
| Load path | Lateral pressure on side walls only, within the container envelope | Soil weight on the 14-gauge roof, outside the design envelope |
| Engineering required | None for a standard install; sound pad and drainage are the priority | Ontario P.Eng stamped reinforcement design, mandatory |
| Reinforcement steel | Not needed | Cross-roof beams, full rail reinforcement, often a concrete cap |
| Geothermal cooling | On three walls and the floor, captures most of the benefit | On all five surfaces, the maximum thermal mass |
| Typical failure mode | Pad settling or skipped drainage, both preventable | Roof dishing and wall buckling within a winter or two if unreinforced |
| Realistic DIY scope | Yes, with a proper pad and the chimney pair | No, this is an engineered structure |
What does a bermed shipping container root cellar layout look like?
A bermed shipping container root cellar is a 20ft bin set partway into the ground with soil banked against three sides to roof height and the roof left exposed. The configuration we recommend at the yard, refined over a couple decades of buyers coming back with what worked and what did not, looks like this. A 20ft Wind & Watertight or Cargo Worthy bin, the two used grades we keep ready to walk in the yard, placed on a concrete pad or a properly drained gravel pad, set into a shallow excavation about half the container height (roughly 1.2 metres or four feet down). Soil bermed up against the long walls and the back end wall to roof height, sloped gently outward for surface drainage. The roof exposed, insulated from the top, weatherproofed with a membrane or metal cap, and ideally shaded by a simple shed roof or a layer of soil-on-membrane that does not bear directly on the corrugations.
The 1.2-metre excavation depth is not arbitrary. Frost penetration in southern Ontario typically reaches between 1.2 and 1.5 metres in a cold winter (Natural Resources Canada frost depth data; deeper in northern Ontario and exposed sites without snow cover). By siting the floor at or below frost depth, the bin gains the geothermal effect: floor and lower wall temperatures track the year-round soil temperature at that depth, which in southern Ontario runs roughly 5 to 9 degrees Celsius. That is the engine of the whole root cellar. You are not chilling air with a compressor. You are letting deep Ontario soil hold a stable temperature for you, year-round, for free.
Pad construction matters more than people realize
The single most common failure in a bermed container cold storage build is not structural. It is the pad. Set the bin on a 150mm reinforced concrete slab if you are doing it once and properly, or on a 300mm compacted clear-stone gravel pad with a perimeter drain to daylight if you are doing it on a budget. Skip the pad and place a bin directly on the soil in an excavation, and within two winters the bin has settled unevenly, the doors will not close cleanly, and meltwater is sitting under the floor against the steel. We have driven out to inspect that exact failure on hobby farms in Brant, Norfolk, and Haldimand more than once. Pad first. Bin second.
The bermed sides should be sloped, not packed vertical against the wall. A 1:1 slope (every metre out for every metre up) is conservative and stable in most Ontario soils. Steeper slopes (1:0.5) work in clay-rich soil but need a geotextile fabric between the soil and the container wall to prevent abrasion and to manage moisture. Whatever the slope, the bermed surface needs vegetation cover (sod or seeded native grass) to prevent erosion, and the slope grade should direct surface water away from the doors and away from the foundation, not toward them.
One end of the container stays exposed. That is the working face. Doors on that end, ventilation chimneys penetrating the roof near that end, shelving running down the long axis on both inside walls. Buyers sometimes ask whether they should bury the door end too. Do not. The original container doors are gasketed for weather but not for hydrostatic soil pressure, and you need access to your produce in February without shoveling snow off two metres of berm.
How do you insulate a shipping container root cellar?
Insulating a shipping container root cellar means treating only the surfaces that face the weather, because the bermed sides are already insulated by the soil. Insulation is where the bermed approach earns its keep. The bermed sides are insulated for free, in the geothermal sense. Ontario soil at depth holds temperature better than any rigid foam you could install. The exposed surfaces are the work. They are the roof, the end wall around the doors, and the upper part of the side walls above the berm.
We recommend two approaches at the yard, and we have customers running both successfully:
Insulation option 1: closed-cell spray foam, interior application
- Roof interior: 75mm to 100mm (3 to 4 inches) closed-cell spray foam directly to the underside of the roof corrugations. R-value approximately R-21 to R-28 at that thickness.
- Side walls above berm line: same spec, 75mm closed-cell to the interior corrugations.
- End wall around doors: 75mm closed-cell to the inside face of the end wall and the inside face of the doors. Doors get the foam after gasket inspection and replacement.
- What drives the cost: the spray-foam thickness you choose, the square footage of exposed shell to cover, and whether you hire a certified applicator or rent a kit. Most buyers find a 20ft is faster and more predictable to quote than the earth-cap build below.
- Why it works: closed-cell is a vapour barrier in addition to insulation. Critical in an Ontario root cellar where the interior is humid and the exterior shell stays cold. Without a vapour barrier the cold steel will sweat and the foam will trap moisture against it.
Insulation option 2: exterior rigid foam under a green roof or earth cap
- Roof exterior: 100mm extruded polystyrene (XPS, blue or pink board) over an EPDM membrane on the roof.
- Earth cap: 200mm to 300mm of soil over the XPS, planted with shallow-rooted ground cover. Do not put soil directly on the corrugations even with insulation between. Frame the soil load on perimeter posts so the load goes to ground, not to the roof panel.
- Side walls above berm line: 100mm XPS sheathed with metal siding or treated plywood, exposed to weather.
- What drives the cost: the rigid-foam and membrane materials, plus the framing labour to carry the earth cap on perimeter posts rather than on the roof panel. Framing the green roof properly is the line item that pushes this build above the spray-foam option.
- Why it works: the earth cap above the insulation gives you a third thermal mass layer in addition to the bermed sides. The cold-storage interior tracks soil temperature on five surfaces instead of three. Best-performing build on paper, more work in practice.
For most Ontario hobby farms and homesteads, the closed-cell spray foam approach is what we steer buyers toward. It is faster, the cost is more predictable, and it does not require framing the green roof off the container structure. If you would rather have the insulation, vents, and door work done before the bin arrives, that is part of the conversion work we handle at the Brantford yard under engineered drawings. The earth-cap approach is right when you want the storage to look like a hill in the landscape rather than a steel box, or when the property is in cottage country where township aesthetic guidance steers you away from visible steel.
How do you ventilate a shipping container root cellar without power?
A shipping container root cellar ventilates itself through a pair of passive chimneys, no fan or electricity required. A root cellar without ventilation is a humidor that ferments your potatoes. The classic homestead solution, validated by every Old Farmer’s Almanac and Mother Earth News article on the subject for the last fifty years, is a pair of vent chimneys arranged for passive convective air exchange. The principle is simple. Warm air rises, cool air falls. You give the warm air a path out the top and the cool air a path in the bottom, and the cellar self-regulates.
The chimney pair, sized for a 20ft container root cellar
One 150mm (6-inch) diameter intake duct enters low on the exposed end wall, drops to within 200mm of the floor inside, and brings cool outside air in at the bottom of the storage zone. One 150mm exhaust duct exits high on the roof or upper end wall, with the interior intake near the ceiling, drawing warm humid air out the top. Both ducts get screened (16-mesh stainless or galvanized hardware cloth) at the outside opening to keep mice, snakes, and insects out. Both get adjustable dampers inside so you can throttle the air exchange in extreme cold (to prevent freezing the produce) and open them fully in shoulder season for maximum cooling. Insulate the duct sleeves where they pass through the insulated shell or you will condense moisture inside the duct and drip it onto your shelves.
Why passive rather than fan-driven? Three reasons. First, passive ventilation does not need power. A rural Ontario property loses grid power for stretches every winter; the root cellar should not care. Second, passive ventilation self-regulates with the seasonal temperature differential. In October when the outside is cooling, the inside is warm from the summer, and the convection runs hard, driving the cellar temperature down toward target. In February when both inside and outside are cold and close, the convection slows down naturally, holding the cellar steady. Third, fans are mechanical parts that fail. The chimneys are sheet metal with no moving parts. Build it once.
The two-chimney pattern is the minimum. Larger builds (40ft containers, or 20ft buried deeper for more storage) benefit from a third intake at the opposite end of the floor, creating cross-flow rather than a single-end loop. Cross-flow distributes the temperature more evenly along the long axis, which matters more than people expect if you have shelving on both walls and produce stacked toward the back.
How do you keep a container root cellar from flooding?
A container root cellar stays dry through a sloped slab, a gravel sub-base with a perimeter drain to daylight, and a vapour barrier under the concrete. Root cellars want humidity. The Old Farmer’s Almanac and the Michigan State University Extension root cellar guidance both put the target relative humidity between 85 and 95 percent. That is what keeps the carrots crisp and the apples from shriveling. But humidity wants somewhere to go when temperatures shift, and a sealed steel box with no drainage will pool water at the floor every freeze-thaw cycle. The build has to handle that.
The configuration we recommend:
- Slope the slab. A 1.5% slope from the back of the container toward the door end, with a 50mm drain at the door-end low point. The drain runs out through the doorway threshold or under it, daylighting on the slope of the berm. No standing water inside, ever.
- Gravel sub-base under the slab. 300mm of compacted clear stone (19mm crushed limestone is the Ontario standard) under the slab, with a perimeter drain tile at the footing wrapped in geotextile, daylighting to grade. This is your insurance policy against groundwater rising against the slab from below. On clay soils in Brant and Norfolk this matters more than people credit.
- Vapour barrier under the slab. 10-mil polyethylene under the concrete to block soil moisture from wicking up through the slab. Standard residential basement practice, fully applies here.
- Interior shelving raised off the floor. The bottom shelf at least 150mm off the slab, on legs not stringers, so air circulates underneath. Wooden slat shelving (cedar or pressure-treated, smooth-sided to avoid produce abrasion) lets cool air find every surface of every jar and every produce crate.
- A bucket of agricultural lime in the corner. Old homesteader trick, still works. Lime absorbs odours and moderates ambient ammonia from any produce that does start to go. Change it every spring when you do the cellar walkthrough.
Why this matters more on Ontario clay than on sandy loam
The Brant clay belt, the Haldimand clay belt, and the heavier soils across most of southern Ontario hold groundwater for longer than the lighter sand-and-loam soils on the Niagara peninsula or along the Norfolk sand plain. A bermed container built on Brant clay without a properly drained pad will sit in a perched water table from October to May. We have seen it. The same build on Norfolk sand will dry out between rain events on its own. If you are on clay, do not skip the perimeter drain. If you are on sand, you can sometimes get away with less, but do not assume. Dig a test pit in the proposed footprint in late March when groundwater is highest, and watch it for 48 hours before you decide.
What temperature should a shipping container root cellar be?
A shipping container root cellar should hold 0 to 5 degrees Celsius at 85 to 95 percent relative humidity for most stored produce. The standard root cellar target is 0 to 5 degrees Celsius (32 to 40 Fahrenheit) with relative humidity in the 85 to 95 percent band. That is the published guidance from the Old Farmer’s Almanac, the Michigan State University Extension root cellar publication (Biernbaum, MSU College of Agriculture and Natural Resources, 2009), and essentially every Canadian provincial agriculture extension publication on cold storage of fruits and vegetables.
| Produce | Ideal temperature | Ideal humidity | Realistic storage life |
|---|---|---|---|
| Potatoes (storage varieties) | 4 to 7 degrees Celsius | 90 to 95 percent | 4 to 6 months |
| Carrots, parsnips, beets | 0 to 2 degrees Celsius | 90 to 95 percent | 5 to 8 months |
| Cabbage, kohlrabi | 0 to 2 degrees Celsius | 90 to 95 percent | 3 to 5 months |
| Apples (storage varieties) | 0 to 4 degrees Celsius | 85 to 90 percent | 3 to 6 months |
| Onions, garlic, shallots | 0 to 4 degrees Celsius | 60 to 70 percent (drier zone) | 5 to 8 months |
| Winter squash, pumpkin | 10 to 13 degrees Celsius | 50 to 70 percent (warmer, drier) | 4 to 6 months |
| Canned preserves | 5 to 15 degrees Celsius | any (sealed) | 1 to 3 years |
The table tells you something important: not everything wants the same conditions. A real homestead cellar has zones. The lowest shelves (coolest, most humid, closest to floor air intake) hold the carrots and beets. The middle shelves hold the apples and cabbages. The upper shelves and the warmer, drier corner near the exhaust chimney hold the onions and garlic. The canning jars go on whatever shelf has the most overhead clearance. You are not trying to hit one perfect number. You are letting the natural temperature stratification of a passively-ventilated bermed cellar create three or four micro-zones in the same 20ft footprint, and you place produce in the zone that fits it.
What about the freezer risk in deep Ontario winter? In a properly bermed and insulated container, the cellar floor temperature should not fall below 1 to 2 degrees Celsius even in a -25 Celsius cold snap, because the floor is tracking the soil temperature at 1.2 metres of depth, which in southern Ontario does not freeze. The vulnerability is the exposed end wall around the door. If the cellar is well-insulated there and the doors gasket cleanly, you will not lose produce to freeze. If the cellar is poorly insulated at the door end, you will. We have seen both. Put the insulation effort into the door-end wall and the upper exposed shell, not the bermed sides.
Who uses a shipping container root cellar in Ontario?
Shipping container root cellars on rural Ontario property tend to be built by hobby farmers, cottage canners, market gardeners, and orchard owners. The buyers who put bermed sea cans to actual work cluster into a few real groups, and cold storage is only one of the jobs a 20ft does on these properties, as our roundup of the many jobs a 20ft handles on Ontario acreage lays out. Here is what we see at the yard.
The hobby farm with a serious garden (Brant, Norfolk, Haldimand, Wellington)
Three to ten acres, a market garden the family eats out of and sometimes sells from at a roadside stand or farmer’s market. Storage produce: Yukon Golds, storage carrots, late cabbage, garlic curing in late summer, apples from the orchard, canned tomatoes and pickles from August canning. A 20ft bermed bin gives them roughly 12 to 14 square metres of usable floor space, enough shelving for a year of root vegetables plus the canning shelves. We deliver these regularly to properties between Brantford and Simcoe, and across into Haldimand and northern Norfolk. Sea can grade for this use is Wind & Watertight; surface rust is irrelevant once the bin is bermed and the interior is foamed.
The cottage canner (Muskoka, Haliburton, Kawartha, Bruce Peninsula)
A seasonal property where the owner does serious preserving in late summer and wants somewhere to leave the canning jars and a few crates of root vegetables between visits. The cellar runs colder than 5 degrees in winter (closer to 1 to 2 degrees at the floor), which is fine for sealed canned goods and excellent for any storage roots brought up from a southern Ontario garden in October. Bermed against a hillside on a cottage property is often easier than digging a flat berm because the hillside is already half the work. A bermed sea can is the difference between eating from the garden until December and eating from the garden until April. The 20ft footprint typically holds enough produce, eggs (in waterglass or sand), butter, hard cheeses, and home-cured meat to bridge the cold months for a household of four. The passive ventilation matters here more than anywhere. No power required, no parts to fail in February.
The market gardener with a CSA box program
Two to fifteen acres of intensive vegetable production, twenty to a hundred CSA shares. Storage for late-season root crop accumulation through October and November before the boxes go out. Here a 40ft bin sometimes makes sense instead of 20ft, with a wash-pack zone at the exposed end and a bermed cold-storage zone toward the back. The 40ft also lets the operator add a second insulated cooler zone (a powered reefer unit for active chilling) for shoulder-season greens. We have built and delivered both configurations across the Norfolk and Haldimand market garden belt.
The orchard owner
Half an acre to three acres of apple trees, sometimes pears or stone fruit. Storage varieties (Empire, Ida Red, Northern Spy) need cold and humid; that is exactly the bermed cellar conditions. We have delivered to small orchards in Brant, Niagara, and the apple country east of Lake Ontario. The orchardists tend to want the cellar close enough to the packing area that they are not wheelbarrowing fruit across a frozen yard in December, which is a layout consideration more than a structural one.
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When do you need a structural engineer to bury a container?
You need a structural engineer the moment soil goes over the roof, because full burial loads the container outside its design envelope. There are buyers for whom bermed is not enough. Maybe the property is too flat to berm visually. Maybe the storage needs to be invisible (rural security, predator pressure on small livestock feed, or simply aesthetic). Maybe the local climate or use case demands the extra thermal mass of full earth cover.
Full burial is possible. It is just no longer in the territory of an honest DIY project. It is now an engineered structure, and the path is:
- Engage an Ontario P.Eng with structural experience in below-grade steel. The fee scales with the scope of the review and stamped drawings, and climbs further if the engineer has to design custom reinforcement schedules.
- Reinforce the container per the stamped drawings. This typically means I-beam or H-beam steel members welded across the roof at 600mm to 1200mm spacing, full-perimeter reinforcement around the top and bottom rails, and often a poured-concrete cap that takes the soil load entirely off the container roof and transfers it to the surrounding earth via a frame.
- Build a real foundation. Reinforced concrete slab below frost, perimeter footing tied to the slab, hydrostatic membrane around the entire below-grade envelope.
- Engineered drainage. Weeping tile around the full perimeter, sumped to daylight or to a sump pump pit.
- Engineered ventilation. Same passive chimney pair principle as the bermed version, but the ducts now need to pass through the engineered cap or the perimeter wall and may require backflow valves.
- A load-bearing cap or frame over the roof. The soil load gets carried by a poured-concrete cap or a steel frame that transfers weight to the surrounding ground, so the container roof never holds the earth directly. This is the line item that turns a sea can into an engineered structure.
Add it all up and a fully buried, engineered container cold storage in Ontario carries the engineering fee, the reinforcement steel, the foundation, the drainage, and the labour, with the final number swinging on soil type, depth, and how much of the work the owner does themselves. At that level of spend the buyer is increasingly close to a purpose-built insulated concrete form (ICF) cellar, which has a structural envelope designed for soil load from the start. Many of our customers in this situation land on bermed for the budget, not on full burial.
The suspiciously cheap Facebook trap, root-cellar edition
Several times a year we hear from a customer who almost bought a bin from a Facebook Marketplace listing offering “buried-ready” containers cheaper than legitimate Ontario suppliers. Two weeks later the deposit is gone, the bin never showed up, and the customer is calling us for a real quote. There is no such thing as a “buried-ready” container at the supplier level. Burial readiness is engineering work done on your property, not a factory specification. Anyone advertising containers as pre-rated for burial is either misinformed or selling something that does not exist. If the listing is too cheap, it is the trap. Paul has watched this pattern repeat over 30 years of operating Van Blanc.
Frequently Asked Questions
Can you bury a shipping container as a root cellar?
Not without significant structural reinforcement. A standard CSC-plated shipping container is rated for the lateral cargo loads of ocean shipping, not the soil load of full burial. Roofs and side walls will deform under sustained earth pressure. The safer and more affordable path on Ontario property is earth-bermed (three sides of soil up to roof height, roof exposed and insulated from above), which gives most of the geothermal cooling benefit without violating the container’s structural envelope. Full burial requires a P.Eng-stamped reinforcement design.
What temperature should a root cellar be in Ontario?
Target 0 to 5 degrees Celsius (32 to 40 Fahrenheit) with relative humidity between 85 and 95 percent. A properly bermed and ventilated 20ft container cellar in southern Ontario hits this range naturally year-round once the geothermal mass of the bermed soil stabilises, typically within three to six months of installation. The lowest shelves run coolest and most humid; the upper shelves near the exhaust chimney run slightly warmer and drier.
How deep can you bury a shipping container?
For a bermed install (soil against side walls and end wall, roof exposed), excavate roughly half the container height into the ground (1.0 to 1.2 metres for a standard 20ft). For full burial with soil over the roof, you need an Ontario P.Eng to specify reinforcement and excavation depth based on your soil type, frost line, and intended use. Numbers people throw around online (3 feet, 6 feet, 10 feet) are meaningless without an engineering review of the specific bin and site.
How long does a bermed shipping container last as a root cellar?
A properly prepared bermed sea can on a drained pad with a closed-cell foam interior and protected exposed shell can last 20 to 30 years in Ontario service. The limiting factors are exterior corrosion at the bermed-soil interface (mitigated by geotextile fabric between soil and steel, or by sacrificial paint and tar coating) and door gasket degradation (replace gaskets every 5 to 8 years). A fully-buried unreinforced container typically fails within 10 to 15 years; reinforced and engineered burial systems extend that toward 30 years.
Do I need an engineer to bury a shipping container in Ontario?
For a bermed install (no soil over the roof), generally no. Bermed loading stays within the container’s structural envelope and is widely considered DIY territory if pad construction and drainage are done correctly. For full burial with soil over the roof, you need a stamped engineering review from an Ontario P.Eng, full stop. Skipping that step is the most common cause of catastrophic failure in DIY buried-container projects.
What size container is best for a root cellar?
For a household of two to six on a hobby farm or homestead, a 20ft standard-height container is the right footprint, roughly 12 to 14 square metres of usable interior floor, enough shelving for a year of root vegetables plus canning. For market gardeners running CSA box programs or orchards storing 1,000+ kg of fruit, a 40ft or 40ft high cube makes sense, often split into a wash-pack zone and a bermed cold-storage zone. We carry both at the yard. Most of our root cellar buyers choose 20ft.
Can I use a refrigerated reefer container as a root cellar instead?
Yes, and for some use cases (market garden shoulder-season chilling, orchard high-volume apple storage) the reefer is the better tool. A 20ft or 40ft refrigerated container gives you active temperature control and does not need to be bermed to work. The trade-off is the reefer needs grid power or generator backup, and the mechanical unit needs maintenance. Bermed dry containers are passive forever; reefers are powered and serviceable. Choose based on your power situation and the produce volumes.
Sources
- International Maritime Organization. (1972, as amended). International Convention for Safe Containers (CSC). imo.org
- International Organization for Standardization. (2013). ISO 1496-1:2013, Series 1 freight containers, Specification and testing, Part 1: General cargo containers for general purposes. iso.org
- Biernbaum, J. A. (2009). Cold Cellars for Vegetable Storage. Michigan State University, Department of Horticulture, Michigan State Horticultural Society. canr.msu.edu
- The Old Farmer’s Almanac. (2024). Root Cellars: Types of Root Cellars and Storage Tips. almanac.com
- Natural Resources Canada. (n.d.). Ground frost penetration data, southern and northern Ontario stations. Geological Survey of Canada permafrost and seasonal frost references. natural-resources.canada.ca
Reach Van Blanc in Brantford
We have been supplying shipping containers since 1995. Our warehouse is at 90 Morton Avenue E in Brantford, and we deliver to communities right across the province on a cash-on-delivery basis. No surprise fees, no chase-the-paperwork.
Van Blanc Ent. Inc. 90 Morton Ave E Unit 1B, Brantford, ON N3R 7J7. Call 519-754-6844 or toll-free 1-888-509-6658.
If you are planning a bermed cold storage build on rural Ontario property and want to walk a 20ft Wind & Watertight bin before you commit, drive out to our Brantford yard. Paul or Christian will walk it with you and tell you straight what works and what does not for your specific site. Worth the drive for unbeatable quality, family customer service with 30 years of experience.