Exterior Finish of Container House

Shipping Container House Exterior

Despite the obvious ruggedness, cargo shipping containers seem to be perfectly fitting into modern, 21st-century architecture. In fact, these days metal in combination with glass makes a major part of urban architecture. Having that in mind, the concept of residential houses with metal structures instead of traditional wooden-frame ones should not sound totally foreign. So, lets explore what exterior finish of the container house might work the best for you:

What was probably a bit surprising was the speed at which containers found their way into residential construction. As it turned out, these otherwise uninspiring, shadowy corrugated steel blocks opened new dimensions to the art of structural construction letting us into the familiar world of fantasies from Legoland, where the limits are set only by our imagination. By shifting, rotating, and tilting individual CorTen-steel blocks, combining metal with glass, and adding vivid colors, suddenly, these boringly looking, clearly lifeless industrial structures started new episodes of vibrant this time life. The trend became so powerful that it gained its own name – Cargotecture.

 Exterior Finish of Container House

Escape Den: The rustic romanticism that containers evoke is taken delightfully by architects to recreate a place that is impeccably out of the world, almost surreal. Source: River and Rain (Bangladesh), photos by Hasan Chandan & Maruf Raihan

Impressive container house exterior
Joshua Tree Home rising from the ground in Californian desert is an example of modern cargotecture perfectly blending with the surrounding nature. Source: Whitaker Studio (UK)

The Escape Den slowly drowning in the darkness of the late evening and the Space Odyssey-like Joshua Tree with its arms bursting into the open sky – prove that impossible is a word of the past. The dull blocks of painted steel in the skillful hands of architects became pieces of artwork beautifully blending into the surrounding landscape. The Beast as it turned out has quite an unexpected face – the Beauty.

The bottom line – the stylishness, and elegance spiced with a dose of extravagance is born from rugged corrugated steel boxes. The common characteristic of these designs is the lack of traditional siding that on top of protection from weather elements is also used to beautify the structure’s appearance.

In fact, overwhelmingly containers do not need any extra cladding for weather protection. The corten steel has self-sealing properties (a thin film of oxidation seals underlying metal from progressing corrosion), and if required, the paint coating adds extra protection.

But there are cases when container-based structures may need exterior cladding, and these are

a. Visual Harmony with surroundings (be it urbane ambiance, local neighborhood, or nature).

Such requirements can be imposed by local administrations, or self-imposed by nature- conscious owners trying to minimize the visual impact of their incursion into nature.

b. Exterior insulation

Sometimes the benefits of exterior insulation outweigh its technical complexity and extra cost. First, it’s the gained interior space (especially noticeable in cold climate zones where the insulation must be thick to minimize the cost of heating). Secondly, by moving the thermal insulation to the outer side of walls, we eliminate the effect of vapor condensation – usually quite a difficult task when the insulation is installed inside of the structure.

c. Personal Touch

This includes situations when you would like to add personal preferences to your container-based house regardless of local ambiance and backdrop. The shrewd combination of different materials, grains, colors and orientation of panels can highlight the structure’s unique architectural details differentiating it this way from the “pack”. It’s a sort of an individual, loudly pronounced public statement that lasts!

 Exterior Finish of Container House

This 1,500 sq. ft residence is anchored on a rock outcrop to take full advantage of panoramic views. The exterior cladding is a combination of different materials, their geometrical orientations and colors. Source: Tomecek Studio Architecture (Photos by Braden Gunem).

Popular Cladding materials for containers:

Out of popular cladding materials traditionally used by the residential housing industry only a few found applications for containers. It’s understandable that the widely used low-cost vinyl siding is not an exciting option for containers. On the other hand, some more expensive sidings like stone, brick, or stucco so often used in higher-end residential constructions are not only highly impractical and laborious) but also “not in tune” with the distinctive style expected from cargotecture.

Note that container metal walls are impermeable, so it’s important to make the exterior layer of cladding breathable. This way any moisture or water vapor that may accidentally infiltrate the space between the exterior cladding and the container’s wall can eventually escape in favorable weather conditions. Otherwise, the accumulated moisture will damage the structure because the CorTen steel is not 100% corrosion-proof, most insulations are permeable and prone to mold and mildew while eventually supporting the wooden frame – to rot.

In practice, the choice of material(s) for exterior cladding of container houses is determined Not Only by aesthetics (includes colors, texture, finish, geometrical profiles, etc..) but also by the cost (materials and labor), R-factor (if part of the overall insulation strategy), durability and maintenance requirements.

Timber

Since long timber has been used in residential housing, mainly in the form of logs as the main construction material. No wonder that with the recently observed trend of “getting closer to nature” (of which container-based houses play a major share) wood is regaining its popularity, although this time as an exterior cladding material. Stained or painted (usually in natural colors) it offers classy elegance much sought in urban ambiance. In the countryside, thanks to its rustic look, timber cladding will softly blend with nature mitigating the outcome of “human intrusion”. In both cases, wood adds a sort of visually enhanced warmness into usually undistinguishable, colorless structures. Needless to say that timber is a renewable and eco-friendly material!

The most popular types of wood used for exterior cladding are correspondingly Canadian Western Red Cedar and Redwood (both belonging to the class of softwood) as well as Larch (especially Siberian and Canadian), chestnut, and Oak (the last three belonging to the class of hardwood). All these species have common characteristics making them usable for outdoor applications in non-treated forms. Due to the presence of tannins, they have quite good resistance to decay and rot. Additionally, larch. chestnut and oak due to their much higher density than softwood, are also more resistant to penetration by moisture, decaying organisms, and termites which makes them more durable in outdoor applications.

They all come in a mix of warm light colors – from golden through reddish, making them exceptionally attractive for exterior claddings. Unfortunately, they will change their original colors to not always pleasing greyish ones. That’s why usually they are stained or painted to preserve their original warmth. Unfortunately, such coatings deteriorate with time so here comes the painful truth of timber – every 3 to 5 years (depending on the type of coating) it will have to be re-coated! And to add the salt to this injury let’s mention here also another drawback – the timber is highly flammable! Unfortunately, when treated with flame-retardants, timber loses its “innocence” (health hazard).

Timber designed for external cladding comes in various styles and profiles – clapboards, shingles, boards, board & batten, half-logs, designed for overlapping or joining using tongue & groove, etc.). Note that timber is relatively easy to install, while the availability of different forms allows for the creation of extra visual effects (for example horizontally installed boards will optically elongate the structure while vertical ones will make it look taller). While usually the natural color of timber is preferred, it’s worth noting that wood is one of the very few cladding materials allowing for customization of colors to reflect the owner’s personal preferences.

It may be worth noting that timber has good thermal and sound insulation properties, both of important when it comes to container-based houses.

Cedar wood cladded container
The Helm – two-story container home combines cedar sidings with sections of original corrugated steel. Source: Cargo Home (TX, USA)

style log cladding exterior
20ft Container-based cabin with rustic-style log cladding. Source: Custom Container Living (Missouri, USA) 

Needless to say, that cedar is the most popular choice for timber cladding, probably not only because of its natural beauty and spectrum of available colors (from white through yellow, red to brown) but also because of its distinctive, agreeable smell (aroma). The truth is that despite the progress in the quality of composite and engineered-wood materials, Mother Nature can be maybe imitated, but it cannot be replaced.   

Cedar cladding is not only about aesthetics, but it is also very practical solution because cedar is naturally resistant to rot, and insects, it doesn’t warp in the presence of moisture, it lasts long in outdoor applications without chemical treatment…. Yes, it is expensive, but when properly sealed and maintained it will serve for long years greeting you each day with gracious natural beauty! 

Well, to make it clear – every wood is biodegradable, so if left without proper maintenance (cleaning and sealing by stain or paint), in wet climate zones mold will eventually develop leading cedar cladding to rot. It’s part of the natural process and we should accept the fact that all “natural” creations went through millions of years of proving “tests” before getting the final blessing from Mother Nature so the rot is also the Right, time-proven process! This is in sharp contrast to men-made “designs” coming out of the factory doors with men-written certificates so often proving to be worthless….. 

Note that cedar is a fast-growing tree (only bamboo is growing faster), so it can be really considered a renewable resource. The whole manufacturing process: harvest, transport, and processing (cutting the boards) use the fraction of energy required for the production of composite cladding materials. 

Timber Protection 

       Raw wood, regardless of its natural resistance to weather elements and insects, will degrade with time when exposed to sunlight (especially UV) and moisture. The first effects will be only visual – a gradual transformation of natural colors into grayish ones, but that is also the sign of the beginning of the deterioration process. The most popular means of protection is coating – either by stain or paint.  

Stain seems to be the better solution because it penetrates deeper layers of wood compared to paint. Thanks to such penetration, the stain is becoming an integral part of the close-to-surface layers of wood so it will not start peeling off like paint. The latter creates rather a thin film on the surface of wood, so it’s more prone to cracking and peeling.  

There are several versions of stain:  

  1. Surface Stains (water-based) – breathable, have excellent adhesion to fibers of wood, great for vertical claddingoffer excellent UV protection 
  2. Hybrid Stains (based on water in emulsions of drying oils) – partially breathable, can penetrate shallow layers of wood, excellent UV protection, and leave a thin film on the surface of the wood that may be prone to cracking and peeling.  
  3. Deep-Penetrating Stains (based on non-drying oils) – water-impermeable (not breathing) penetrate deep layers of wood, have poor UV tolerance (so their colors will quickly fade), prone to crack and peel. 

Notes: 

  • The breathable coating allows the water to escape from the timber. As we know – “all sealed joints are leaking” (Murphy laws) so rainwater will eventually infiltrate behind the cladding. Also. each raw wood (if not aged and dried) will contain some amount of water that is trapped inside will lead to rotting. 
  • Stains (in contrast to paintscan be only applied on raw, untreated, and unpainted wood. 

  Just as an example, we would like to also mention an “unorthodox” technique protecting timber from weather elements. It’s based on an old (it also means “proven”) Japanese wood waterproofing technique known as “Shou-Sugi-Ban”.  It consists of charring the surface of wood by temporarily applying open flames from the blowtorch. Once a black layer of charcoal develops, the surface should be cleaned with a wire brush to remove the loose particle of charcoal, dusted by compressed air, and then eventually sealed.  Apparently, the charred wood can last for 80 to 100 years if unprotected (longer if coated with oil for protection). Obviously, there is a science behind the Shou-Sugi-Ban method – the high temperature shrinks cells of the wood, creating this way a protective layer with a significantly reduced ability to absorb moisture and more resistance to the decaying process. 

wood for home siding

Phases of Shou-Sugi-Ban method: correspondingly deeply charred pine wood (left), cleaned with a wire brush (center) and sanded (right). Source: Eastern White Pine 

It’s amazing, although to make it clear – not every wood is suitable for this process. Originally, back in Japan, it was applied to cedarwood as it has unique natural chemical components favoring the efficiency of this method. It seems however that the Shou-Sugi-Ban methods will also give good results on maple, oak, cypress, and even pine.  And here is the proof: 

waterproofing: charring the surface of the cedar wood

First step of waterproofing: charring the surface of the cedarwood

 Exterior Finish of Container House Cladding

The Final effect – custom exterior yellow cedar siding was finished with a Japanese wood-burning technique shou-sugi-ban. (Location: Whitehorse, YT, Canada). Source: Northern Front Studio (Canada)

Bamboo

Bamboo is the fastest-growing tree, which makes it truly a renewable material. It’s worth mentioning that giant bamboo stems are ready for harvesting after about 4-to-6 to years of growth compared to several tens of years necessary for hardwood. Also, after cutting, bamboo plants will regrow new stems so there is no devastating deforestation. Bamboo can be used for decorative cladding in its natural form of hollow stems. They do not warp or swell when exposed to moisture, they are quite durable although unfortunately may lose their natural colors and develop mildew. That’s why bamboo stems for outdoor applications are usually processed and coated to delay the process of fading.


Decorative cladding of the shipping container house was made from bamboo screens (stems were treated using the “Burn-and-Wax” process based on an old Japanese “Shou Sugi Ban” technique used for waterproofing and preserving the wood). Source: Bamboo Suppliers of Ireland (Project commissioned for Ceardean Architects)

In most cases, hollow bamboo stems are split along their lengths and after removing the outer skin they are steamed to preserve their natural (light yellow) color or are thermally treated to acquire a dark brown. Individual bamboo strips are then compressed to form solid, high-density boards suitable for outdoor use. One of the leading companies (MOSO-Bamboo) claims that their bamboo boards designed for exterior cladding not only have the highest durability, hardness, and stability over time but also in sharp contrast to natural woods, they meet relevant fire-safety requirements without any chemical treatments! The bottom line is that this eco-friendly, fast-growing wood stays Ecological forever.

bamboo-processing for cladding

Stripping hollow bamboo stem along its length is the first processing step. After treating and drying, the strips are ready to be connected in several ways to make the final product. Source: Bamboo Suppliers of Ireland

Such engineered panels made from “baked” bamboo strips keep their original color much longer than traditional timber. Once sealed by oils (with anti-mold and rot protection), they are durable and weather resistant and so a perfect choice for outdoor applications. While still not very popular, engineered bamboo panels represent an excellent ecological alternative to widely used traditional timber. The sad truth is that since long the harvest of tropical trees became unsustainable. Unfortunately, the tropics are quite far from the centers of the Western World, so it is easier to pretend that deforestation does not happen at all (some will claim that it happens somewhere else, so who cares, forgetting that we have only One Earth).

Bamboo Cladding

Examples of bamboo cladding (left) and decking (right). Source: BothBest Bamboo Flooring Co. Ltd (China)

Note that most manufacturers of bamboo claddings offer some kind of “Clip & Lock” systems that make the installation an easy, no nails project.

container-home-bamboo
Cladding from compressed bamboo strips (here also used for patio floor). Source: MOSO-Bamboo

Engineered Wood

Engineered wood is designed to combine the highly valued aesthetics of natural wood (color, texture, warmness…) with the durability and weather resistance of man-made composite materials. Known as WPC (Wood-Plastic-Composite), engineered wood contains about 50% of wood flour (powdered wood fibers), 35-to-40% of HDPE plastic (High-Density Polyethylene) while the remaining 10 – to-15% are other additives. The HDPE is considered a health hazard-free component (does not contain BPA and as a matter of fact it is approved for use by the food industry). Much less is known about additives (bonding and color agents and more ….), however as we talk about outdoor applications, eventual off-gassing may not be of major concern.

The bottom line is that these days engineered wood offers the best of two worlds (actually, you may miss only the characteristic smell of the natural wood). WPC boards are weather-resistant (no mold, mildew, rot), UV-resistant, and most likely non-toxic although the latter characteristic strongly depends on the “recipe” of manufacturers so you should check relevant certifications before committing to buy. Unlike traditional timber, WPC boards are fireproof (well, additives once again, because powdered wood fibers and HDPE are flammable).

Engineered wood comes in a large variety of styles, shapes, and textures/colors (most manufacturers will imitate traditional timber like cedar, redwood, red pine, and larch, but will also offer a selection of colors including custom choices). It does not require maintenance (so no need to paint, stain and so no cracks, or peeling …). As a matter of fact, engineered wood CANNOT be painted or stained so once selected and installed you will not be able to change its appearance and feel (in other words: the benefits of “maintenance-free” comes with strings attached). The good news is however that in the majority of cases, engineered wood panels are recyclable (if by the chance one day you will decide to get rid of them).

 Coowin-cladding

Examples of engineered wood panels designed for exterior wall cladding. Source: COOWIN Group

Coowin-WPC-claddingEngineered wood exterior cladding. Source: COOWIN Group

Fiber-Cement boards

As the names point it out, fiber-cement boards are made from a mixture of concrete (Portland cement & sand) and cellulose fibers plus some “additives” (fillers, pigments, mica, aluminum stearate, polyvinyl alcohol (PVA), etc…). Roughly, concrete makes up about 50-60% of the total volume, fibers which are used to reinforce the concrete about 10%, while fillers – usually cenospheres (lightweight, hollow spheres of silica or alumina filled with air) about 30%. They are added to lower the density (and weight) of fiber-cement boards. The mentioned components are pressed to form a rigid, homogeneous material. In general, fiber-cement boards are environmentally friendly as they are made from natural ingredients.

Fiber-cement panels are UV, weather-resistant, rot, and insects-resistant, fireproof, and quite strong (although their impact resistance may not be their strongest point). They are offered in various shapes, colors, and finishes ranging from smooth to visibly textured. As a result, fiber-cement boards can surprisingly well imitate other cladding materials like timber (most popular designs), but also stones, bricks, and tiles at the much lower initial cost. It may be worth mentioning that fiber-cement boards are not cheap imitations (as we usually call poor-quality replacement parts), in fact in many cases their appearance can be very close to the real timber.

Fiber-cement boards are usually pre-colored, however, they can be re-painted after installation which makes them attractive (note that you cannot re-paint the engineered wood).

fiber-cement-cladding

House with painted fiber-cement cladding. Source: Architizer (Lewin Residence (Atlanta, GA, USA)

Notes:

Uncoated fiber-cement boards preserve the natural gray appearance of concrete. In such natural raw form, they are breathable which means they can be penetrated by moisture and vapor. If the cladding is applied to the container structure only to enhance its aesthetic, then it does not cause problems although due to the exposure to weather, the efflorescence may take place with time (migration of salts to the surface of porous materials and their permanent deposition when moisture evaporates). However, if the fiber-cement cladding is used to protect exterior insulation, then they should be sealed on both sides (transparent paint or stain to preserve the look). Another option may be the familiar Tyvek-type moisture barrier installed behind the cladding as a protective envelope.

The overwhelming majority of fiber-cement boards come completely sealed (usually by water-based acrylic paints). These coatings give them much-needed weather resistance (moisture, UV, mold …) as well as make them durable and efflorescence free.

Contrary to timber and engineered wood, regular fiber-cement cladding has a very poor R-factor, so it does not contribute to the container’s overall insulation value.

Acoustic insulation usually goes together with thermal one. When needed, you will have to add an acoustic barrier behind the fiber-cement cladding. Given the fact that in the presence of noise metal structures have a tendency to resonate, it may be a necessity in an industrial or city environment where a wide spectrum of loud noise is usually generated. Obviously, it shouldn’t be a problem in countryside locations.

Like many other claddings, fiber-cement boards are installed using tongue and groove systems, or by overlapping (horizontal lap sidings).

fiber-cement-cladding
Fiber-cement boards – horizontal overlapping siding. Source: North Knox Siding and Windows (USA) 

fiber cement cladding

Cladding with fiber cement panels. Source: Architizer (Beach House designed by Levenbetts)

Composite materials

Composite materials are combinations of at least two (in practice many more) different substances (materials) that contribute to better, stronger products than each individual component alone. In a constant “fight for survival,” Mother Nature developed countless examples of organic composite materials.

In the last 100 years, humans took this art & science much further, coming up with countless synthetic composite materials. Slowly but surely, they became part of our life to such an extent that in daily life we consider them as being always around. Materials belonging to this new class of man-made composites have “engineered” properties enabling them for use almost everywhere – from home to space applications.

Thanks to such characteristics like strength, lightweight, weather resistance (moisture, UV, high and low temperatures…), corrosion, insects, rot, mold, mildew resistance, staining & discoloring resistance, flexibility, durability, low wear & tear effect, low maintenance…. (and the list can go on and on), composite materials are ideal for outdoor applications. No wonder, composite materials are also used for exterior claddings.

The list of their shortcomings is short (although they may heavily weigh on our decisions). These are:

Usually high initial cost (sometimes it can be justified by low or no maintenance costs, durability and elegance)

By their nature, most composite materials are non-biodegradable and so not eco-friendly.

Nevertheless, for completeness, we have to say that the industry offers countless composite materials perfect for exterior claddings due to their mentioned earlier characteristics but also elegance, stylishness and the possibility to closely match the look of natural cladding materials.

composite-material-cladding
Perfect imitation of stone. Source: Archiproducts

 Exterior Finish of Container House
Corian cladding (to most of us associated with kitchen countertops, here underlines the architectural beauty of this modern building). Source Archiproducts


Selection of composite claddings (fragment). Source: Container Clad (UK)

Note: You will often find that Engineered Wood or Fiber-Cement siding is considered a Composite material. While in fact, they are “composite materials” (in the sense that they are mixtures of different components), given the difference in their makeup, appearance as well as popularity and suitability for container cladding we preferred to present them separately in detail.

Composite Panels

Composite panels are made as sandwiches of thick layers of insulation between laminated metal sheets (typically aluminum or steel). For that reason, they are often called Sandwich Panels. While they can be used for exterior siding as a combined integral layer of cladding AND insulation, in most cases they are used directly to build load-bearing walls. In fact, composite panels are almost exclusively used for the construction of Customized Container Houses. They often have corrugated metal on the exterior side of the sandwich to mimic Cargo Shipping Containers. When it comes to core insulation, usually manufacturers offer a large selection of materials like Polyurethane or Polystyrene Foams, Mineral Wool, Fiberglass, etc… with thickness depending on the required R-factor.

Metal sheets are factory-coated with polyester, silicone polyester, polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), acrylic paints, etc… ). Understandably, given their coated-metal finish, composite panels are weather-resistant (rain, moisture, vapor, UV…), mold, mildew, and rot resistant, insect resistant, they are durable, do not need any maintenance (well, in the dusty environment may need washing) and their initial colors practically do not fade with time.

On the negative side – it is basically the metal siding, and while there are attempts to mimic the wood, even from far it will be clear that it is not the case! Also, they may be quite expensive.


Composite Panels (here rock-wool insulation sandwiched in aluminum). Source: Xiamen Zhongjingtai Building Materials Co., Ltd.

Composite Panels

Example of the composite (sandwich) panel with Polyurethane Resin (PUR) insulation. Source: Archiproducts (USA)

Metal

While it may sound weird to put extra metal cladding over the metal container walls, sometimes such solutions may have merits. And the main one is usually – installing an exterior layer of thermal insulation while preserving the weather-related benefits of the metal envelope. After all, metal cladding is weather, UV, insect, fire (and the list can go on…) resistant, durable, and strong. Metal does not require any substantial maintenance – eventually washing, checking for corrosion (if steel) and eventually re-painting when needed.

While containers are made mostly from CorTen steel (or an equivalent one), metal claddings are manufactured from aluminum, copper, brass, zinc, stainless steel, Corten steel or regular steel (the latter must be galvanized or powder-coated to prevent corrosion). Copper or copper alloys are appreciated for their characteristic greenish patina when weathered, but they are more expensive. Also, corten steel may be used for exterior cladding. Under “normal circumstances” (moderate, dry climate zone) corten steel develops the rusty-reddish-brownish patina that creates a thin layer of firm coating preventing deeper corrosion. However, in wet and salty environments like shore locations (especially in warm climate zones), the corrosion is rather unstoppable.

 Exterior Finish of Container House
Corten-like “BlueScope Weathering Steel” cladding. Source: Metal Cladding Systems (Australia)

As already mentioned above, metal cladding cannot pretend to be anything else. It will offer a highly predictable smooth, aesthetic surface in any possible color of your choice. Compared to timber (or any porous cladding materials), the metal cladding will reflect a portion of sunlight limiting the overheating effect. Note that direct experience may be a bit misleading because metals will transfer the heat almost instantly, while the timber absorbing much more heat energy will need time for that to happen.

Manufacturers offer a variety of profiles for horizontal, vertical, or diagonal claddings, customized shapes (for bends, curves, etc) with numerous seam/inter-locking systems – all in a large palette of colors.

container-with metal exterior-cladding

Metal cladding. Source: LivinBiginaTinyHouse (3x 20ft Shipping Containers…)

Cladding Installation

Installing the cladding (as well as a layer of insulation) on the outer side of container walls is not as trivial as in the case of traditional wooden-frame houses. What makes the big difference (and complicates the process) is the lack of pressboard (as a matter of fact any wooden components) supporting installation with nails or staples.

Using metal screws is not only a painful and time-consuming process. Holes in the walls will jeopardize the airtightness (or rather impermeability) of the whole structure. One may say that the installation of windows, doors, vents, etc already eliminated the airtightness and as a matter of fact, airtightness (hermeticity) is not the preferable state of the habitable space. Well, the truth is that infiltration of air, moisture, and water along the windows and door frames can be seen and eliminated. The randomly distributed mounting holes across the walls will be rather invisible and inaccessible for inspection. And that’s what makes the painful difference.

The bottom line – so far there is no simple answer to this challenge. In the majority of cases, you will have to build a supporting frame (usually from treated wood). Some will only use glue to attach the wooden frame (2 by “whatever is appropriate”) to the corrugated walls, preserving this way container’s integrity. Some will add a few metal screws for extra safety, finally, DIY guys may use more complex frame designs taking advantage of already existing holes designed for lifting cargo shipping containers when in transport. It all depends on your ingenuity, skills and available time.

a. Cladding only

Applying external cladding for aesthetic reasons only makes the task much easier. It’s because you do not have to worry about the infiltration of air between the structural walls and cladding. In fact, leaving little space between container (structural) walls and exterior cladding will allow convection-forced circulation of air. Note that most likely air sucked from the ground level will have a lower temperature than that at the upper level of walls. This natural passive ventilation will help to minimize the effect of overheating due to direct exposure to the sun.

For practical reasons, you will need a supporting (most likely wooden) frame, but it can be designed the way to be only loosely attached to the container’s structure or even not attached at all. If necessary, the frame can be attached with adhesives, but bolting it to the container structure wouldn’t be justified. After all, the goal is to create the visual effect of traditional cladding materials, textures, and colors without adding any extra load and stress to the container’s structure or affecting its integrity.

In fact, some manufacturers of cladding systems already addressed these challenges by offering self-supporting cladding frames (Lion Containers, Container Clad, etc….)

b. Cladding over exterior insulation

Adding exterior insulation makes things more complex. Now, you do not want to allow air infiltration behind the cladding and especially between the layer of insulation and container walls. In the first case, you will risk the deterioration of insulation when exposed to moisture. In the second case, infiltrating outdoor air will create “heat bridges” and outdo the benefits of exterior thermal insulation.

Details are a bit out of the scope of this article, so we will only mention that closed-cell spray foam insulations are of special interest for outdoor applications. They firmly adhere to metal walls, are practically impermeable, and have a good R-factor although they are quite expensive. When exposed to moisture they may still develop mold/mildew so it may be important to install a breathable cladding to allow for the evacuation of moisture and water vapor.

Note that in this case, the off-gassing (one of the frequent arguments against the use of spray foams) is largely inconsequential because it happens outdoors!

Adhesives with bolting

Adhesives may not pass the test of time, so for safety, the frame would have to be also bolted to the structural walls at least in a few places.

Welded metal tabs

While most likely it will not be a DIY job, you will preserve the integrity of container walls (no holes). Once the taps are welded along the upper, center, and lower perimeter of the container you can attach (by bolting) horizontal 2 by 4s and then nail vertical cladding boards.

Note that in both cases you will need an overhanging roof to prevent the infiltration of the rainwater behind the cladding (especially important if you also installed the insulation).

wood-cladded-containers
One of the possible methods of installation of the cladding (is first batons are attached horizontally to the structural walls, then the Siberian Larch cladding is installed vertically using traditional methods (screws). Source: ContainersDirect

 

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