Second Hand Shipping Container Houses Problems to Consider:
The interior height of a standard cargo shipping container is about 7ft 10 inches. This height is slightly lower than the normal 8ft-9ft range in residential buildings. However, this already tight headroom is further decreased once the floor and ceiling are adapted for habitable spaces. That is the first thing to consider when opting for second hand shipping container houses.
Problems related to ceiling height
When the size of the container is limited to a single 20ft-equivalent unit, it’s not the biggest problem. It may be just a kind of nuisance. Things will dramatically change in multi-modular habitable spaces, residential facilities, and large public buildings. Combining two-three 1-TEU modules into an extensive living area without interior walls presents a visually disappointing effect of “Low ceiling”.
The ceiling height wouldn’t be the limiting factor when 1ft taller High Cube shipping containers are used as construction blocks. Unfortunately, they are much less prevalent in the transport industry than standard ISO 8.5ft tall cargo containers. This translates to their small supply on the market and higher prices.
Shipping containers are designed to transport goods tolerating a wide range of temperatures. So, in contrast to Refrigerating and Thermal ISO shipping containers, they do not have any insulation.
Thermal insulation of steel containers
Given that steel is a good heat conductor, such containers must be thermally insulated before their use as habitable spaces. However, it is not an easy task because sidings of cargo shipping containers are made from corrugated steel.
Due to their “rippled” shape, traditional, inexpensive blanket insulation will take extra inches from the already tight container’s internal width.
The easiest solution would consist of spray-foam insulation. However, it’s pretty expensive and, unfortunately, potentially toxic. So it may have to be applied on external walls and then protected by cladding.
Cargo shipping containers may contain some hazardous materials. Be it original construction materials (usually known) or residues of potentially toxic payloads (relatively unknown).
Hazardous material from paint
Most cargo SCs may be protected from atmospheric and seawater exposure by marine-grade paint. Unfortunately, such paints are lead-based (if not more complex and toxic chemical compounds). As it is generally known – they are not safe for human beings (since long they were eliminated from residential structures).
In such an aggressive environment (changed temperatures, UV, salty moisture, splashes of water), even CorTen steel needs extra paint protection.
Hazardous material from plywood floors
Plywood floors used in most cargo shipping containers need chemical treatment to prevent rot, mold, and in general, decay. And if this is not enough, please note that containers are also generously treated with insecticides. This is to prevent the spread of local species to other geographical regions.
Role of CSC
Rare good news regarding chemicals – some requirements are defined by the Convention for Safe Containers (CSC). Applied insecticide’s name and last application time must be listed on the CSC plate attached to the container.
On a good note:
It is relatively easy to replace plywood floors (even in the DIY scenario). After years of serving for cargo transport, they will be in a state of sorry (or close to).
Hazardous material of potentially toxic payloads
The residues of potentially toxic payloads accumulated during the years of service as cargo containers, unfortunately, it’s a big unknown. Good tests of the whole metal structure will undoubtedly require a qualified person and equipment (read it $). Then, before starting the “remodeling” process, they will have to be removed (or sealed) to prevent direct contact.
Necessary Modifications of Second Hand Shipping Container Houses
Adaptation of cargo shipping containers for habitable space requires several serious modifications, including
- Earlier insulation
- You will have to cut through thick steel walls to accommodate windows, door(s), electrical and plumbing installations, etc.
In case of making an extension
Things get even more complex when two or more container modules must be integrated to form one more extensive structure. This will require cutting entire walls and may also affect the container’s structural integrity. In DIY-approach, it is a long-term project. On the other hand, by hiring contractors, the advantage of the low initial cost may vanish.
Certifications of Second Hand Shipping Container Houses
It should not be a problem for most temporary (not permanent) container-based structures like sheds, storages, garages, etc. However, all modified cargo containers will need relevant compliance certifications with building codes for residential units.
Given the state of pertinent legislation (in many forms), getting such certifications may be a time-and-nerves-consuming process.
The Customized Container Houses (CCH) do not suffer from these problems because they are initially certified for “residential” applications. Taller than GP containers, they are factory-insulated using sandwich panels with an R-value adapted to climate at the user’s destination.