How Green are Modular Building Systems?


Someone in my network is looking for help regarding help on an effort to find modular housing for a project proposal in Libya:

I have had a request for a sample for modular housing in Libya, 5-10 units @ 100′ sq. each.

Any promo materials you have please forward and I can let you know if they’re interested… please allow 30 day turnaround from your submission

I had learned a little bit about modular systems in my past research on ecological design. In contemplating the email I realized it would be interesting to use the email as an opportunity to find out what is available as way to update my knowledge of the sub-field and update my knowledge of the field.

So a few questions (and these are the key questions for any ecologically designed project):

  1. First how does modular building compare with other building systems that are usually constructed on-site in terms of build quality?
  2. What is the cost as comparison to other building materials?
  3. What is the embodied energy cost to remove, process and construct the materials at the factory site?
  4. What are the maintenance and operational costs for the building?
  5. How much embodied energy to transport the material to the job site?
  6. What are the requirements in terms of cost and energy to assemble the building parts into a finished structure?

From Wikipedia page about modular building I gather the following:

Modular is affordable because they are mass produced in an enclosed structure that is isolated from the weather and logistical supply issues.

Basically we are removing much of the construction risk away from the construction and into a more reliable mass produced environment so modular units are often priced lower while offering similar or superior quality.

  • Speed of construction/faster return on investment. Modular construction allows for the building and the site work to be completed simultaneously, reducing the overall completion schedule by as much as 50%.
  • Indoor construction. Assembly is independent of weather, which increases work efficiency and avoids damaged building material.
  • Favorable pricing from suppliers. Large-scale manufacturers can effectively bargain with suppliers for discounts on materials.
  • Ability to service remote locations. Particularly in countries such as Australia there can be much higher costs to build a site-built house in a remote area or an area experiencing a construction boom such as mining towns. Modular homes can be built in major towns and sold to regional areas
  • Low waste. With the same plans being constantly built, the manufacturer has records of exactly what quantity of materials are needed for a given job. While waste from a site-built dwelling may typically fill several large dumpsters, construction of a modular dwelling generates much less waste
  • Environmentally friendly construction process. Modular construction reduces waste and site disturbance compared to site-built structures.
  • Flexibility. Conventional buildings can be difficult to extend, however with a modular building you can simply add sections, or even entire floors

Obviously the people who worked on this wikipedia page are not Ecological Designers because they only superficially addressed the Embodied Energy and Resource Consumption issue in their list of advantages of Modular. My understanding is that the biggest consideration in building a green building is the amount of energy it takes to transport the materials and how much it costs to operate and maintain the building (this includes heating and cooling).

I myself would say the best strategy would be to come up with an estimate of modular options made with the best possible ecological design specifications.

However it might also be an opportunity to show an alternative because my understanding is that really modular units are usually not very ecological because they are made usually distant from the end user in a massive facility that uses a lot of complicated and power intensive technologies.

The major problem is not necessarily that as I understand it but rather the embodied energy invested in the transport of the modular units as with any building material. Hence the focus has been in ecological design on locally built and sourced building materials. This its possible if the scale of production were large enough a local and possibly mobile fab unit could be established using locally building materials to make say large modular panels of possibly a locally available resource say wheat straw of waste plastic/wood. That would be the ideal.

Possibly there are so good options out there. I’m curious and I remember we did go over some options for modular systems in my Ecosa Institute Ecological Design course at Arcosanti.

I am thinking of the Cargotecture one as the best ones in which old modular truck/rail shipping containers are rehabbed and using for living spaces.

I have no pricing on this though but my rough estimate is about $4000 based on the price someone at Arcosanti gave me who is using a shipping container for a house when he gets to Hawaii. I like his way of thinking. He is following the principles of ReUse that is he is using the container for moving his stuff as the building that he will live in once he gets the container to his property.

References & Notes:

  1. NYT has a relatively positive article about modular that does not say anything about Embodied Energy but does tout some other positive aspects of the movement: Reinventing Modular Housing as Green
  2. I first heard about “Cargotecture” when it was relatively obscure and involved conceptual ideas of stacking shipping containers in interesting configurations as part of multi-story urban structures.
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