Building design needs a whole new paradigm

With sustainability becoming such a driving force in construction, the idea of reusing building materials has gained ground in the last five years. Many of the large demolition companies have become a clearing house with some even marketing building components to a network of clients in advance of demolishing a building, says Vince Catalli. Catalli is a long-time proponent of reusing building materials who lives in Ottawa and now works as a project manager with MHPM.

It’s one thing to salvage materials, but in the future we’ll be taking the concept a whole step further and designing buildings expressly with the idea of disassembly and reuse, says Catalli.

Catalli was vice-chair of the Canadian Standards Association committee that developed the “Guideline for design for disassembly and adaptability in buildings,” labelled CSA Z782-06.

At the Construct Canada conference in Toronto last December, Catalli gave a presentation on the standard, with examples of buildings from around the world that have been designed expressly to be capable of being dis- and re-assembled. This design approach is all about looking at materials and connections, Catalli explained. He said you have to think of building designs as systems: the core, structure and slabs, the mechanical and electrical systems, and the interior spaces that can be designed to change for different functions.

Catalli showed an example of a “plug and play” building in Sweden, which had beams with holes for easy connections. In the Netherlands, Catalli said, public housing has been designed with the top three floors of a large complex capable of being removed and reassembled somewhere else as the need for housing in different districts changes.

A Canadian example was a Mountain Equipment Coop where the wall panels were removable to allow access from the outside so that maintenance and installation could be done without disrupting the activities inside the store. Another example was a cultural centre in Quebec where 35% of the building envelope was made of insulated precast panels that were recovered from an old Canadian Tire store. Catalli also showed a parking garage which was disassembled, moved and modified to become the structure for a new community centre, and a school addition where the structural slabs have a hollow core through which hot air is circulated.

What about liability issues when you are re-using materials, especially key structural components? Catalli says that designers have to use their professional judgment, but can go on site for visual inspections, and send samples for testing. Testing is not expensive, Catalli suggested, if you compare the savings from using recovered materials and the benefits of preserving the earth’s resources. Catalli says to make design for disassembly work, the building team has to be truly integrated so that the systems all work together: “We need to collapse the boundaries between the designers, the contractor and the supplier,” he said. Catalli is hoping that the CSA guideline CSA Z782-06 will become a standard.

A conference devoted to reusing building materials and equipment, entitled “Decon ’09” is being held at the University of Illinois-Chicago on April 28-30. It is being held by the non-profit Building Materials Reuse Association in the U.S., see www.bmra.org/events/conference

For the CSA guideline, see http://www.csa.ca/sustainablebuilding/guidelines/Default.asp?language=English