<p>Most off-grid systems fail in the second week of January. Not because the equipment breaks, but because it was sized against an annual average instead of against the worst nine days of the year. If you take one thing from this piece, take that.</p>
<h2>Size against the dark week, not the year</h2>
<p>A solar quote will usually tell you how many kilowatt-hours your array produces annually and compare it to your annual consumption. Those two numbers can match perfectly and you can still be sitting in the dark. What matters off-grid is the longest stretch your site goes without meaningful generation, and in the Pacific Northwest that is routinely four to nine days of heavy overcast in midwinter.</p>
<p>We size every off-grid unit for four consecutive days of no useful generation at winter loads, with the battery never planned to drop below twenty per cent state of charge. On our Ridgeline 40 that works out to a 6.4 kW array against a 20 kWh lithium bank. A lot of quotes you will see pair a similar array with 10 kWh, because the battery is the expensive half and shrinking it is the easiest way to win a bid.</p>
<h2>The battery needs to be warm</h2>
<p>Lithium iron phosphate loses usable capacity below about 40°F and should not be charged at all below freezing. An uninsulated steel box in a mountain winter will happily sit at 20°F for a week. This is the single most common failure we are called out to look at on systems somebody else installed: a perfectly good battery bank bolted to the inside of an uninsulated container wall, quietly refusing to accept a charge every morning until the sun has been on it for two hours.</p>
<p>Our battery banks sit in a conditioned service bay inside the insulated envelope, with its own small ventilation path and a temperature sensor tied into the system monitor. It costs floor area. It is not optional.</p>
<h2>Loads you forget to count</h2>
<p>People model the fridge, the lights and the laptop. Then they move in with:</p>
<ul>
<li>A well pump or pressure pump, which is a large intermittent load with a nasty starting surge</li>
<li>An induction hob, which will pull 3 kW the moment somebody boils a pan at dusk</li>
<li>A kettle, a toaster and a hair dryer, all of which arrive in the same box as the person who uses them</li>
<li>Standby draw from an inverter that never sleeps, which is small but runs 8,760 hours a year</li>
</ul>
<p>We model consumption hour by hour rather than as a daily total, because the daily total hides the evening peak, and the evening peak is when the array is producing nothing.</p>
<h2>Water is the half nobody plans</h2>
<p>A 40 ft container roof catches roughly 900 gallons from an inch of rain. That is a genuinely useful number in a wet climate and a useless one in a dry summer, so the cistern has to be sized for the dry gap rather than the annual rainfall. We generally specify 1,500 gallons buried below the frost line, fed through a first-flush diverter and a four-stage filter to potable standard.</p>
<p>Greywater from the shower and basin is separated at the trap. Where local code allows it, that goes to a reed bed or a subsurface irrigation loop. Where it does not, it goes to the same tank as the blackwater and you should know that before you design the bathroom, not after.</p>
<h2>What it is actually like</h2>
<p>Quieter than people expect, and more attentive. You develop a relationship with the weather forecast that grid-connected people do not have. You run the washing machine at one in the afternoon rather than nine at night, because that is when the array is making more than the house is using, and after a month you stop noticing that you are doing it.</p>
<p>The Okonkwo family have been on our Ridgeline 40 for two winters. Their bank has not dropped below forty per cent state of charge, including a nine-day January overcast. That is not because the site is unusually sunny. It is because the system was sized for that week specifically.</p>

Living Off-Grid in a Container Home

<p>Search for small space design and you will get four hundred photographs of a bed that folds into a wall. Transforming furniture has its place, but it is the last move, not the first. The decisions that actually make a small home feel large are made in the plan and the section, before anything is built.</p>
<h2>Never drop the ceiling</h2>
<p>A high-cube container gives you 9 ft 6 in of external height. After the floor build-up and the insulation you can hold a clear 8 ft 6 in, which is taller than most modern houses. The temptation, always, is to drop a ceiling to hide ducting and lighting. Do not do it.</p>
<p>In a room that is 8 ft wide, the ceiling is the only dimension you have any generosity in, and volume is what stops a small room feeling like a corridor. We run services in a floor plenum or a shallow bulkhead over the service band only, and leave the ceiling at full height everywhere you actually stand.</p>
<h2>Put the wet things in one band</h2>
<p>Kitchen, bathroom, plant and laundry all want the same drain and the same supply. Group them into a single service band across the middle of the plan and two things happen. The plumbing gets short and cheap. And both ends of the container are left clear, which means the longest sightline in the house runs corner to corner past the service band rather than stopping at a wall six feet from the door.</p>
<p>This is the entire idea behind our Shelf 40. It is one 40 ft box with the wet core in the middle, and it reads as two generous rooms rather than one long one.</p>
<h2>Sightlines beat square footage</h2>
<p>The perceived size of a room is set by the longest distance your eye can travel, not by the floor area. A 160 sq ft room with a clear diagonal to a corner window feels bigger than a 220 sq ft room chopped by a partition at the halfway point. So:</p>
<ul>
<li>Glaze the corners, not the middle of walls. A corner window has no visual stop at the edge of the frame, so the room appears to continue outside.</li>
<li>Put the longest sightline on the diagonal, which in a 20 ft container is about 21 ft rather than 20 ft or 8 ft.</li>
<li>Where you need a partition, make it stop short of the ceiling or slide away entirely. Our Shelf 40 uses a sliding steel partition for the sleeping end so the volume is only divided when somebody is asleep in it.</li>
</ul>
<h2>Storage belongs in the thickness of things</h2>
<p>Freestanding storage eats floor area. Storage built into an element you already needed does not. The stair up to a sleeping platform is 30 in deep whether or not it has drawers in it. The bench under the window has to be something. The wall between the bathroom and the living space has to be at least 6 in thick to take the drainage, so make it 12 in and put shelves on the dry side.</p>
<p>The rule is simple: before you add a piece of storage, look for something structural or circulatory that is already occupying that volume, and hollow that out instead.</p>
<h2>One material, used everywhere</h2>
<p>Small rooms are ruined by material changes. Every junction between two finishes is a visual stop, and a room with eight of them feels like eight small zones. We line most units in a single birch ply throughout, floor to wall to joinery, and leave the original corrugated steel exposed on one wall as the only contrast in the room. Two materials. That is the whole palette, and it is why the rooms photograph larger than they measure.</p>
<h2>The things worth spending money on</h2>
<p>If the budget is tight, spend it in this order: glazing, ceiling height, joinery. Skimp in this order: appliance brand, floor finish, fixtures. A cheap tap in a room with a good window is a fine place to live. An expensive tap in a room with a small high window is not.</p>

Maximizing Small Spaces

<p>We have never had a container dwelling refused on the grounds that it is made from a container. We have had them refused on structural adequacy, on energy compliance and on character. Those are the three, and all three are answerable in the drawing set if you know they are coming.</p>
<h2>Apply as a permanent dwelling</h2>
<p>The most damaging piece of advice on the internet is that you should apply for a container home as a temporary or accessory structure to avoid scrutiny. It works right up until you want to sell, insure, finance or occupy it year-round, and then it does not work at all.</p>
<p>We submit every unit as a permanent single-family dwelling or accessory dwelling unit, to the same residential code as a stick-built house. It is a harder application. It is also the only one that produces a building you can get a mortgage against.</p>
<h2>Structural adequacy: the stamp is the answer</h2>
<p>A plans examiner is not required to know the racking capacity of a Cor-Ten corner post, and will not take your word for it. What they will take is a calculation package stamped by an engineer licensed in your state.</p>
<p>The moment you cut an opening in a container you have removed part of what makes it stiff. A container gets its racking resistance from the corrugated side panels acting as shear walls, so a large window is a structural event, not a finish detail. Our submissions include:</p>
<ul>
<li>Stamped calculations for every opening over a defined size, with the reinforcement detailed at the jamb and head</li>
<li>Wind and seismic calculations for your specific site classification, not a generic case</li>
<li>Foundation and tie-down details, including uplift resistance at the corner castings</li>
<li>Where a party wall has been removed, the moment frame design that replaces it</li>
</ul>
<p>That last one matters more than people expect. On our Meridian 80 the shared long wall between two containers is deleted to give a 16 ft clear span, and the frame that replaces it is the single most scrutinised drawing in the pack.</p>
<h2>Energy compliance: model it, do not argue it</h2>
<p>Steel is an exceptional conductor, which means every uninsulated point of contact between inside and outside is a thermal bridge and a condensation risk. Examiners know this and will look for it.</p>
<p>We spray closed-cell foam directly onto the corrugation so there is no cavity for air to move through, insulate outboard of the frame wherever the detail allows, and submit a full energy model rather than a prescriptive checklist. Every unit is blower-door tested in the yard before it ships, and we submit the test result. A measured 0.6 air changes per hour ends the conversation faster than any amount of narrative.</p>
<h2>Character: this is a design problem, not a code problem</h2>
<p>The refusal that catches people out is the subjective one. An officer writes that visible corrugated steel is incongruous with the prevailing character of the street, and there is no calculation that answers it.</p>
<p>On an infill lot in Olympia we were refused on exactly this. The resubmission clad the street elevation in vertical charred cedar and left the corrugation exposed only on the courtyard side, so the building reads as timber from the sidewalk and as steel from inside its own plot. Approved without further conditions.</p>
<p>That is not a defeat. Most of what an officer is protecting is the view from the public realm, and container architecture is entirely capable of being quiet on one elevation and honest on another.</p>
<h2>What to do before you buy land</h2>
<p>Check the zoning for minimum dwelling size, because some jurisdictions set a floor area below which a structure cannot be a dwelling. Check whether accessory dwelling units are permitted by right or by variance. Check for a design review overlay or a historic district, which is where character objections come from. And ask the department directly whether they have permitted a container dwelling before. If they have, ask who did it. If they have not, budget an extra six weeks and expect to educate.</p>

What Your Planning Department Actually Wants to See

<p>A shipping container will outlast almost anything you build next to it, on one condition: that water is never given somewhere cold and dark to collect. Get the insulation wrong and you will grow rust on the inside face of a wall you cannot see. Get it right and the frame will outlive you.</p>
<h2>Why steel is unforgiving</h2>
<p>Steel conducts heat roughly four hundred times better than the timber a conventional house is framed in. Any point where the inside surface touches the outside surface without insulation between them is not merely a heat loss, it is a cold spot, and warm interior air meeting a cold spot deposits its moisture there. In a timber wall that dries out. In a sealed steel wall it sits against bare metal.</p>
<p>This is the whole problem, and it is why the two obvious approaches both fail.</p>
<h2>What does not work</h2>
<p><strong>Batt insulation in a stud wall built inside the container.</strong> This is the cheapest route and the one most self-builders take. You have now created a cavity between the batt and the corrugation, that cavity is connected to the interior air by every screw penetration and service hole, and the corrugation is the coldest surface in the building. Water condenses on the steel, runs down the ribs and collects in the bottom rail where you will not see it for four years.</p>
<p><strong>Rigid board cut to fit between the ribs.</strong> Better, but the corrugation profile means every board has an air gap behind it somewhere, and cutting rigid board to a perfect corrugated profile at scale is not realistic. You end up with intermittent voids, which is the same problem distributed more evenly.</p>
<h2>What we do</h2>
<p>Closed-cell spray polyurethane foam, applied directly to the inside face of the corrugation at a minimum of two inches, before any framing goes in. It works because it is three things at once:</p>
<ul>
<li><strong>Insulation</strong>, at roughly R-6 to R-7 per inch, which is why two inches in a corrugation profile is worth more than four inches of batt in a stud bay</li>
<li><strong>An air barrier</strong>, because it is continuous and bonded, so there is no cavity for air to move through and nowhere for it to deposit moisture</li>
<li><strong>A vapour retarder</strong>, at the thicknesses we apply, so warm interior vapour never reaches the steel in the first place</li>
</ul>
<p>Framing goes on after the foam, not before, and it is held off the steel so that no stud ever touches the container wall. Services run in that framing zone, not through the foam.</p>
<h2>The details that actually leak</h2>
<p>The wall build-up is the easy part. The failures we are called to look at are almost always at four places:</p>
<ol>
<li><strong>The floor.</strong> The original marine ply deck sits directly on steel cross members that are exposed to outside air underneath. Insulating above the deck alone leaves those members cold. We insulate below the deck between the cross members and above it under the finished floor.</li>
<li><strong>Openings.</strong> A window jamb welded into the side panel is a continuous piece of steel from outside to inside. The reinforcement has to be thermally broken or wrapped, and the reveal detailed so the foam runs into the frame.</li>
<li><strong>Corner castings and the roof rail.</strong> These are heavy sections that stay cold a long time. They need more foam, not the same amount.</li>
<li><strong>Where two containers meet.</strong> A welded joint between units is a straight steel path. It is insulated as a single continuous line across the joint, which means planning the sequence before the two boxes are welded together.</li>
</ol>
<h2>Coatings and the outside face</h2>
<p>Cor-Ten weathering steel forms a stable oxide layer that protects the metal underneath, but only if it gets alternating wet and dry cycles. Where a container is buried, permanently shaded or in constant contact with soil or standing water, that layer never stabilises and it corrodes like ordinary steel. We shot-blast every unit back to bare metal, prime with a zinc-rich primer and finish with a low-VOC topcoat, and we never set a container directly on the ground.</p>
<h2>How you know it worked</h2>
<p>You test it. Every unit gets a blower-door test in the yard before it ships, and we are looking for 0.6 air changes per hour at 50 pascals or better. That number is not a marketing figure, it is the evidence that the foam is continuous. A unit that leaks air will leak vapour, and a unit that leaks vapour will eventually rust from the inside. Testing before delivery is the only point at which fixing it is still cheap.</p>

Insulating a Steel Box Without Trapping Water In It

<p>The most common misconception about container homes is that the container is the expensive part. A used 40 ft high-cube in good structural condition costs a few thousand dollars. On a build that finishes near $134,000, that is under five per cent. Everything else is the house.</p>
<h2>The rough proportions</h2>
<p>Across the units we deliver, the money lands roughly like this. Percentages shift with specification but the order almost never does.</p>
<ul>
<li><strong>Fabrication labour, around 30 per cent.</strong> Stripping, shot-blasting, cutting openings, welding reinforcement, framing, fitting. This is skilled work and it is the single largest line on every job.</li>
<li><strong>Interior fit-out and joinery, around 20 per cent.</strong> Kitchen, bathroom, built-in storage, linings. Also the line with the widest range, because this is where a $62,000 unit and a $186,000 unit genuinely diverge.</li>
<li><strong>Mechanical, electrical and plumbing, around 15 per cent.</strong> Higher on off-grid units, where the battery bank and filtration alone can add $20,000 or more.</li>
<li><strong>Envelope, around 12 per cent.</strong> Insulation, glazing, external cladding, roofing and coatings. Glazing is the sensitive variable here; a full-width glazed gable is not a small decision.</li>
<li><strong>Design, engineering and permitting, around 10 per cent.</strong> Drawings, stamped structural calculations, energy modelling and the submission itself.</li>
<li><strong>Transport and installation, around 8 per cent.</strong> Low-loader, crane, crew and connections. Driven almost entirely by your site access.</li>
<li><strong>The containers themselves, around 5 per cent.</strong></li>
</ul>
<h2>The four line items that ruin budgets</h2>
<p><strong>Site works.</strong> This is the big one, and it is the one we do not control. Foundations, access track, drainage, excavation and utility trenching are quoted against your specific site and can range from almost nothing on a flat, serviced plot to more than the unit itself on a steep one with no access. Get this quoted before you fall in love with a piece of land.</p>
<p><strong>The utility connection.</strong> A rural grid connection quote can arrive at $40,000 or more if the nearest pole is far enough away. On one Hood River project the connection quote exceeded the cost of the house, which is precisely why that build went off-grid. Ask the utility for a budget estimate early; it is usually free and it is occasionally decisive.</p>
<p><strong>Crane access.</strong> A crane needs somewhere to stand, and it needs to reach. If it cannot get within range, you are into a larger crane, a road closure or both. This is a survey question, and it is why we survey before we price.</p>
<p><strong>Changes after fabrication starts.</strong> Moving a window on a drawing costs an hour. Moving it after the opening is cut, reinforced, primed and foamed costs several thousand dollars and pushes the schedule. Every change we can talk you into making, we want to make during design.</p>
<h2>Why fixed price is possible here and not on a site build</h2>
<p>A conventional build prices in risk it cannot see: weather, ground conditions, subcontractor availability, material price movement over a fourteen-month programme. A yard build removes most of that. The work happens indoors on a known schedule with a known crew, materials are bought at the start, and the container is a known quantity.</p>
<p>So we issue a fixed price with the contract, before any steel is cut, and it does not move unless you move it. Site works are quoted separately and honestly, because that is the part that genuinely varies.</p>
<h2>Financing, briefly</h2>
<p>This is where applying as a permanent dwelling pays for itself. A unit permitted as a temporary or recreational structure is difficult to mortgage and difficult to insure. A unit permitted as a permanent dwelling, on a permanent foundation, with stamped engineering, is a house, and lenders treat it accordingly. Construction-to-permanent loans are the usual route, and the fixed-price contract helps considerably in that conversation.</p>
<h2>Run your own numbers</h2>
<p>Our cost calculator will give you an estimated starting range with the same breakdown used above, based on size, complexity and the add-ons you actually want. It is an estimate rather than a quote, but it is built from the numbers on real jobs, and it will tell you within an afternoon whether the plot you are looking at is realistic.</p>

Where the Money Goes on a Container Build

<p>Almost every first conversation we have starts with a floor area. It is the wrong place to start. The number of containers you use changes the structure, the transport, the foundation and the resale far more than it changes how the house feels to live in.</p>
<h2>The three shells</h2>
<p>A 20 ft high-cube gives about 160 sq ft of internal floor and arrives as a single load on a standard trailer. A 40 ft high-cube gives about 320 sq ft and needs a longer trailer and a longer crane reach, but costs less than two 20s and has half the joints. Two containers side by side gives 640 sq ft and a decision to make about the wall between them.</p>
<p>All three are 8 ft wide externally. After insulation and lining you are living in about 7 ft 2 in. That constraint does not change no matter how many boxes you buy, which is the thing most people have not internalised when they arrive.</p>
<h2>The 8 ft problem, and the only two answers</h2>
<p>A 7 ft 2 in internal width is fine for a corridor, a bathroom, a galley kitchen or a bed with a walkway. It is not fine for a living room you want to put a sofa and a chair in facing each other. There are exactly two solutions.</p>
<p><strong>Delete the shared wall.</strong> Weld two containers together, remove the long wall between them and replace it with a moment frame. You get a 16 ft clear span, which is a normal room. This is what our Meridian 80 does, and it is the single most expensive structural decision in our catalogue, because that wall was doing real work. It is also the one that most changes how the house feels.</p>
<p><strong>Push out.</strong> Add a framed extension, a notched deck or a glazed link between two separated boxes. Cheaper than a moment frame, and it gives you a room with a different character rather than a wider version of the same one. Our Longwater 60 uses a glazed link between two 30 ft units, which splits living from sleeping and doubles as the rainwater catchment.</p>
<h2>Transport is a real constraint, not a detail</h2>
<p>A 40 ft unit is one crane lift and one trailer, but that trailer needs a turning radius and the crane needs somewhere to stand within reach. On tight urban infill and on steep rural tracks, two 20 ft units are often the only thing that will physically arrive.</p>
<p>We survey access before we price the build for exactly this reason. It is not unusual for the survey to change the model, and it is much better that it happens before the drawings than after.</p>
<h2>If you might ever move it</h2>
<p>A single 20 ft unit on screw piles can be craned off, put on a tilt-bed and taken somewhere else. That is a genuine property of the building and it is why our Basecamp 20 uses bolted foundations and no concrete anywhere. Leased land, family land and sites with an uncertain future are all good reasons to stay at one container and keep everything demountable.</p>
<p>The moment you weld two containers together and pour a slab, you have built a house. That is usually the right decision. It should be a decision, not something you discover.</p>
<h2>A rough guide</h2>
<ul>
<li><strong>One person, or two who are out a lot, on a tight budget or a temporary site:</strong> a single 20 ft. Datum 20 or Basecamp 20.</li>
<li><strong>Two people living in it full-time, wanting a real kitchen and a separable sleeping end:</strong> a single 40 ft. Shelf 40, or Ridgeline 40 off-grid.</li>
<li><strong>A family, or anybody who wants a room wider than 8 ft:</strong> two or three containers with a moment frame or a courtyard. Meridian 80, Courtyard 100, Cantilever 120.</li>
</ul>
<p>Every one of those has been built more than once, and every one started as a standard shell that moved. If none of them is quite right, that is expected. The configurator is the fastest way to find out what your version looks like.</p>

Field notes from the yard

Living Off-Grid in a Container Home

Maximizing Small Spaces

What Your Planning Department Actually Wants to See

Insulating a Steel Box Without Trapping Water In It

Where the Money Goes on a Container Build

One Container, Two, or a 40 Instead

Tell us about your site and we will tell you what fits on it