Posts tagged “prefab

Modular Architecture Q&A: Time and Money

James B. Guthrie, AIA, the President of Miletus Group, Inc, was recently approached by Norman Gray, a graduate student at the New School of Architecture and Design in San Diego, CA regarding an architectural project he was working on. As a part of his research, Mr. Gray sought our expertise in answering several questions regarding prefab and modular construction. We thought the questions were very good ones and worth sharing with a wider audience. We will post each question and answer as a separate blog post. Readers who have their own questions about modular architecture are encouraged to ask us as well.

What percentage of time and money do you think prefab can save a project?

When it comes to prefab, generalized questions can be difficult to answer. In general, on a direct apples-to-apples comparison, I would say that you could expect that a prefab project can be 0-15% less per square foot than a traditionally built project of the same design and specifications. There are too many variables, though, to allow a hard and fast rule as to discounts.

It is also important to keep in mind that when we are talking about prefab, we can be talking about prefab architecture or prefab building. When I talk about prefab architecture, I am using the idea that architecture is a high quality building designed by a professional and it is always site specific. This means that each prefab architecture project will be unique to the site it is being placed on. The quality of the end result will be high quality, and the owner will be a ‘client’ of a professional architect. Prefab building, in contrast, is a generic ‘product’ that can be non-site specific. The quality can vary dramatically from project to project and the owner of this product is a customer of a building company.

The other important thing to consider is the definition of “project”. Architects tend to think of a project as the specific building they are working on. Building owners, however, think of a “project” as the entire business model related to that building. This includes the architecture plus: land acquisition and development, operations and maintenance, financing, cash flow and other business considerations. To answer the question about prefab architecture from the architect’s side, at this time a prefab architecture project has no inherent time or money advantages to the architect except as it may add value for their clients. To answer the question from the owner’s perspective regarding prefab architecture, it can have significant time savings, which to the owner can translate into a huge financial savings to the non-architectural aspects of the project. The amount of savings is, of course, dependent on the project.

Typical Modular Home, USA
2 Offsite Stories, 1 Single Family House, 4 Modules

On the small scale, in the US right now it is very easy for a homebuyer to buy a house much like they buy a car. The homebuyer can go to a sales lot of a manufactured home builder, tour model homes, pick out their model, pick out colors and finishes, and have their new home delivered in a very short amount of time. These homebuyers are buying a prefab building, not prefab architecture. The opportunity for this kind of building to become architecture is very limited. Because prefabrication is a method of construction that takes advantage of manufacturing processes, the economic side of prefab is most successful when there is volume on the production side. One single family home does not afford current manufacturing processes the kind of efficiencies needed to be cost effective. In the case of a home or small commercial building, volume is achieved when many of the same design are produced. In this situation, the efficiency is dispersed among many buyers. This means, naturally, that each individual buyer looses the opportunity to influence the design and quality of their purchase.

Modular Housing, England
10 Offsite Stories, 162 Apartments, 630 Modules

On the large scale, the prefab building buyer is also buying the convenience of speed to occupancy, but the larger scale can allow the project to be more architectural. Fundamentally the building process is relatively the same between prefab and onsite construction, except that the offsite components can be built simultaneously with much of the onsite work. The onsite assembly of the offsite components can then occur very rapidly. On a large project this can save a lot of time, and thus a lot of money to the owner. This is important, as even if the square footage costs of onsite and offsite construction are nearly identical, the cost savings to the owner can be very significant and far exceed the 0-15% savings in square footage costs. Unlike a single family home, the size of a large project can allow the design to take on far more significant role than is possible in small projects. It is the large projects that create the greatest opportunity for all the benefits of prefabrication and the application of real architecture to meld. This is the future of prefabrication in architecture.

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