MBI and BD+C Modular Advantage | Winter 2011
 

The Convenience of
Modular Construction

A Case Study on Modular Construction & De-constructability 


By Laurie Robert, NRB Inc.

Modular construction is a build-process that allows an entire structure to be built and substantially completed away from the project site in the controlled environment of a manufacturing plant location. It is created in large three-dimensional sub-assemblies, (also referred to as modules) that are moved onto the project site where they are set on foundations, and structurally, mechanically, electrically and architecturally connected to form a complete, permanent building.

It is important to understand this method of off-site construction in order to grasp the relative ease with which a building can be completely reused (95 – 100%) by simply reversing the process through which it was installed at the site. The building will virtually come apart in the same sub-assemblies that created it. The amount of disposed material or salvage is negligible compared to a conventionally built structure that is deconstructed on a site.  

Implementing this methodology means a building does not have to be abandoned or demolished while yet another is newly constructed elsewhere, thus significantly reducing the GHG emissions and resource depletion impact on our environment.

Following is a case study where deconstruction and complete reuse were applied to a permanent building that was intended to remain in place for its intended lifecycle.


Petro Canada Convenience Store

When Petro-Canada implemented a re-imaging program for their convenience stores in Ontario between the 1995 and 2003, they chose the modular construction build-process primarily for speed to market, reduced site disruption and downtime for their already functioning sites, and reduced project management requirements. The fact that they could inspect several stores in one (plant) location 30 miles away during construction rather than having to travel to the various project sites also saved significant amounts of travel time and energy.

The inherent advantage of deconstruction did not enter into the evaluation of this alternative project delivery method at the time, as their service station sites are carefully chosen based on demographics and traffic patterns and unlikely to have to close.

However in 2010, a site in Ontario that was originally built in 2001 was divested and slated for demolition/decommissioning. Petro Canada called NRB to investigate having the complete store disassembled and moved into storage at the NRB plant so that it could be relocated to another site and reassembled once again - rather than demolishing it to become waste and salvage, or leaving it abandoned while they built an entirely new structure at another site. This is a much more cost efficient and environmentally responsible way to close (and open) stores if the need arises. The store was taken apart in the same 4 sub-assemblies that originally put it in place, and then moved in 4 loads to the NRB yard where it awaits the next project site to be prepared with foundations after which it will be relocated and completely recycled into another functioning facility.



COST IMPACT:


To demolish an existing building and haul away the debris is an expensive undertaking that can also, even with the utmost attention to waste management and recycling, send literally tons of waste to the landfill.  Add to this the cost, energy and waste generated to construct a new building on another site where it is needed.  Modular construction's inherent benefit of simplified deconstruction and reuse in this case was evaluated, and it was determined that to reuse the store 100% by removing it from its existing site; moving it to the NRB facility for storage temporarily; and then redelivering and reinstalling it in a new location rather than building new, represented a cost that was less than 30% of the cost of a newly constructed store.

Laurie Robert is vice president of sales and marketing at NRB, Inc. in Grimsby, Ontario, Canada. She is also a former board president of MBI.



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