In order to provide another perspective to the already heated discussion about the ‘greenness’ of ISBU construction, let us now place it in the warm and humid climate of tropical regions. In this region too ISBU has for the past few years become increasingly trendy. For majority of people however the idea to live inside a container box in the tropics is a cringe worthy idea. Container homes are still largely perceived as temporary homes where the poor lives in the sweltering heat or temporary post-disaster shelters. Let us examine some of the common concerns voiced by potential ISBU home owners and the way these concerns can dealt with.
FIRST and foremost of course there is this issue about the heat.
Metal and heat goes hand in hand like fire and dried grass. Metal of course is a good heat conductor. In order to make containers habitable in the tropics as it is in another climatic condition, an extensive work of insulation is needed to reduce the heat in the interior cavity.
Solution: According to ISBU Association, the heat problem can be tackled easily by insulation, in this case, ceramic paint for exterior surface coating (originally developed and perfected by NASA for space shuttles) is recommended. Ceramic coating is said to be safe and it acts as a thermal barrier that prevents heat and cold from conducting. For interior surface, ISBU association recommends ccSPF (closed cell spray polyurethane foam). This type of spray-foam is claimed to provide insulation against heat, cold, mold and also noise.
In developing countries like Indonesia, were most ISBU building are used as temporary structures, the most common wall insulation used is glass wool. Ceramic coating whilst available is costly and main used in auto mobile industries. Spray-foam on the other hand is relatively a common coating option.
Study done at the Federal Institute of Technology in Zurich (ETH) showed that shading of the containers are far more important than the insulation on the inside to control the interior climate. Architect Felix Heisel and Marta Wisniewska (both now affiliated with FCL – Future Cities Lab) for their containers affordable housing project in Ethiopia called the MULU however chose to tackle to control the interior climate by shading and interior insulation. On the inside, they clad the wall with compressed straw panel which is basically an agricultural waste. The straw panel was produced locally. The result was a surprising insulation values and insect resistance. On the outside, they shaded the wall with combination of greenery, posters and solar heater pipes.
SECONDLY, how will ISBU perform against heavy rainfall, a typical characteristic of the tropical regions?
It was said that Cor-ten can’t stand moisture entrapment as it will make Cor-ten to keep on oxidizing and eventually corroded.
Solutions: In the tropical context where there is typically high rainfall and high humidity, we need to take care that the ISBU is well protected. As we know by now, ISBU homes need to be insulated both in the interior and exterior parts anyway. Assuming the insulation works are done properly, it can also protect the ISBU wall surfaces so they are protected from rain at the same time. Placing ISBU structures under a big roof can also solve this problem.
THIRD, what about the shape?
The basic shape of ISBU does not really sit well in the tropical architecture book of wisdom. Without further modification, ISBU construction of will result in a cube home with a relatively low ceiling and flat roof.
Here is measurement of dry freight containers:
20’ GP (standard) : 20’x8”x8’6” (LxWxH)
40’ GP (standard) : 40’X8’X8’6” (LxWxH)
40’ HQ or HC (High Cube) : 40’x8’x9’6” (LxWXH)
45’ HQ or HC (High Cube) : 45’x8’X9’6” (LxWxH)
(Measurements are taken from www.maerskline.com)
The most common shipping containers that can be found is 20’ and 40’ ones, with the internal height is 7’10 3/16’ or equivalent to 2,393 mm. 40’HQ units are also common and considered more ideal for ISBU homes due the bigger height which is 8’9 15/16″ or equivalent to 2.690 mm.20’ GP units are mostly used for BizPod.
Solutions: ISBU construction in the tropics calls for creativity and climatic adaptation which is not unlike in other regions. When people express their interest to build an ISBU home, they do not intend to live in plain steel box (think of those illegal immigrants and port workers’ dilapidated shelters that can be found in many major ports in developing countries).
In tropical architecture, roof is arguably the most crucial element in a building design. It is to offer protection from harsh sunlight and high rainfall. Ideally roof has to protect the perimeter walls of a building. We can apply the same wisdom with ISBU construction, regardless of the building materials. The roof can be rested on the walls or can be floated above them. Incorporating a big roof on ISBU home design can also protect the units from heavy rainfall and thus prevent moisture entrapment.
In Costa Rica, architect Erwin Schuster built an ISBU home that is modified to suit the tropical climates. Two 40’ container units were placed under a large pitch roof that is equipped with a vent to let the warm air escape. This is an excellent example of ISBU home for tropical context. The architect also incorporated bamboo paneling to layer some part of the exterior walls. A lot of ventilation opening which necessarily for this warm climate context were also cut out from the containers walls.
A soccer academy in Singapore, set up their supporting facilities in several shipping containers. Their office, changing rooms, storage and canteen are all place under a big ten that also shade the waiting area. This is one way to make it more climate appropriate without spending too much investment on insulation and instead put their money where it is most needed; good pitches and good coaches.
FOURTH, do you we have the urgency to utilize shipping containers as it is the case in US or in many countries in Europe?
While they are relatively readily available they are not as abundant as in US or Europe. Many countries in Asia, import bulk cargo which is not containerized such as oil, iron, and other raw materials and in return they export in containerized cargo (eg.textile, food, electronics and other customer good).Availabilities of used containers often depend on the commercial traffic. Several Southeast Asian countries recorded a fluctuation of balance of trade for the past few years. For example, during the peak of financial crisis in 1998 in Indonesia, there was an increased of quantity of empty containers as the export activities slowed down. This period marked the beginning of container modification businesses growth.
A trade surplus recorded in one country however does not imply that there are lack of used containers in that certain country. Insiders’ information from industry players though imply that due to the complicacy of empty containers traffic management, many companies would save the hassle of locating ones that they often purchase new containers even though existing empty ones are available locally.
Generally speaking, the price of empty containers in Asia is higher than it is in the export destination countries. They can be purchased from a container depot which is the place where reparation works take place when needed. When the containers have too much damages and become irreparable thus ineligible to attain certificate of safety, they are then being disposed. This is the point where the used containers can be bought by public for various purposes at a cost and then be transported to the next owner’s place of delivery at a certain cost charged according to the distance involved.
Solution: Make sure that you are using used containers that are bought locally. Please don’t special order them from a factory overseas and then have them shipped to your country, it just doesn’t make any green sense to build ISBU homes that way.
FIFTH, it is relatively easy to build ISDU homes in our region?
Building ISBU homes in tropical Asia generally needs a lot of DIY efforts as there are a very few companies or may be none at all that offer ISBU building services that specialize on homes design. Companies that deal with ISBU mainly focus on its application as temporary structures. They offer modification for used containers to be used as to name among other; site offices, portable toilets/ bathrooms and labs, workers quarter, shops, storage facilities, guardhouses etc. Most of these ISDUs still retain the basic shape of the containers.
Solutions: Hire a designer and contractor who are ready for a challenge. Do make sure that your contractor has the proper equipment. Please make sure that the design works well with the ISBU module and that it fits your lifestyle. For a more elaborate design, a lot of trial and error is to be expected. In the end, the whole project might or might not cost as a cheap as we expected. For countries where building safety guideline is considered strict like Singapore, please take care that all authority requirements such as fire safety is met.
Some people are drawn toward ISBU homes due to the low price, the strength, the pre-fab form and also due to the aesthetic form. However, if you are building ISDU homes as an option to create sustainable buildings, do your homework! Always make an informed and well-researched decision to make it a truly green endeavor.
Read the first part of this article: Building With Shipping Containers In The Tropic (Part 1)
By: Devisanthi Tunas