Designing for Disassembly
When designing buildings, our vision usually ends with the project being enjoyed, admired, and happily occupied with all systems running smoothly. However, if we were to let that vision continue 40 or so years down the road to when that building reaches the end of its useful life, what we would likely see are containers of waste from the demolition site being dumped into landfill. With that image in mind, the question becomes: do we continue to design in the same way or do we try to reduce the waste going into landfill? Do we stop and think ahead and incorporate into our design features which would allow that “waste” to be reused and recycled?
One such strategy is designing for disassembly, which refers to the concept of planning projects in such a way as to facilitate future renovation and demolition. To be effective, disassembly must be considered at the beginning of a building’s life cycle (during design) and in the middle (during renovation), not at the end (during demolition). The concept involves altering traditional design and construction practices in order to facilitate future disassembly.
Designing for disassembly addresses both environmental priorities and building adaptability. Waste management, resource conservation and reductions in atmospheric emissions are among the environmental benefits that are gained by this approach, as building components can be reused or recycled, reducing the requirement for ongoing resource extraction to produce newly manufactured materials.
Standing in the way of designing for disassembly are, in large part, tradition and industry skepticism. Standard practices for construction, renovation and demolition are heavily geared towards the fastest, easiest and most economical way to get the job done. Designing and constructing for disassembly, when viewed in isolation, can seem costly and laborious compared to the norm. However, the incremental cost will be diminished or even eliminated when practices become more standardized and when the cost savings in terms of recycling and reuse as well as the environment are factored into the overall equation. Potentially, less money will be spent on new materials or landfill, making designing for disassembly a more economical venture.
Industry skepticism is also reflected in national and provincial building codes, traditionally modelled on a prescriptive basis, defining acceptable assemblies and practices. Some practices and products which promote future disassembly, particularly in residential construction, are not covered by the codes, and their use makes code compliance difficult and/or costly. Proving that a used material is acceptable within the context of building codes–possible under Part 2: Equivalents–can take time, effort and money. The new National Building Code, currently in development, will identify performance- and objective-based requirements in an effort to eliminate aesthetic and material biases.
Another factor which is holding the industry back from embracing the concept is the perceived lack of consumer demand. But this is not necessarily an accurate perception. Consumers are becoming environmentally aware and expect more from their buildings with respect to sustainable performance, and this awareness is being brought from a niche market to the mainstream. Increasingly, people want to know that their home or office was designed according to best practices with respect to resource conservation, ozone protection, indoor air quality and other environmental criteria.
Other industries, from automobile manufacturing to industrial design, have embraced the idea of designing for disassembly. In fact some countries, like Germany, have legislated compulsory “take it back” programs which are motivating industry to move in this direction. Under this type of program, a car produced today must be taken back by the manufacturer after its useful life to reuse or recycle components. Clients of the construction industry are beginning to expect the same adaptability in their buildings, with features that can be changed, revitalized and rehabilitated to fit a company’s changing image and needs.
Designing for disassembly need not involve compromising aesthetics. Exposed steel framing and post-and-beam construction are examples of designing for disassembly that can also become significant architectural features. Minimizing the use of finishes altogether allow structure and materials to be exposed, requiring the designer to explore new opportunities for building and interior design.
Getting down to the nuts and bolts of designing for disassembly involves exactly that. The simple act of incorporating exposed, bolted connections, rather than welds, lends itself to deconstruction of a building’s assembled elements at a later time. While the specifics of disassembly vary from one building to the next and between various components within a building, there are some basic principles that can help clarify the implications that design choices have on the ease of future disassembly:
Design for versatility, which allows for a component, assembly or system to accommodate different uses with little change.
Design for durability to allow a material to remain unchanged over its expected life while performing its function.
Plan for easy access, which allows for a component of an assembly to be easily approached with minimal damage and impact to it and adjacent assemblies.
Favour simplicity of design, which reduces the complexity of assembling materials, thus facilitating disassembly.
Opt for independence of material assemblies to allow for minimal damage to adjacent assemblies during their removal, repair and disassembly.
Make important information (labelling, ingredients, compositions) explicit on each component or material of an assembly. This information will be useful for the reuse and recycling of materials after disassembly.
Expose connections wherever possible to facilitate disassembly.
Make materials or components with the shortest anticipated life cycle more accessible than those with longer anticipated life cycles. This will reduce the generation of unnecessary waste during the replacement or maintenance of materials or components.
Use materials with an inherent finish and avoid contaminating material with finishes that hinder reuse or recycling activity.
The features of the design which lend themselves to disassembly during renovation and demolition should be documented via as-built drawings, a disassembly manual or other means to transfer information and encourage participation of the future renovation or deconstruction team when the time comes. This will help to ensure that the extra effort and thought invested at the design and construction stage is rewarded down the road. It will also help pass on the message that our responsibility towards our buildings extends beyond the ribbon cutting ceremonies and well into the time when the building is no longer standing.
Case Study: Mountain Equipment Co-op Store
In their design of the new Mountain Equipment Co-op (MEC) store in Ottawa, architects Linda Chapman and Christopher Simmonds incorporated features into the building’s design and construction that lend themselves to future reuse and recycling. Working with Vince Catalli and Derek Badger of by dEsign consultants as waste management and deconstruction consultants, the team orchestrated the painstaking disassembly of the old MEC store located in the New Edinburgh area of Ottawa, with over over 86% of the materials being reused or recycled. This work was carried out according to a waste reduction work plan and specification that by dEsign consultants prepared for the project, setting the stage for existing building disassembly and the selection of new products that accommodate disassembly.
Notable features of the design intended to facilitate future disassembly include exposed timber structural framing with bolted connections and timber decks that are screwed down. Steel structure from an existing one-storey building on site was reassembled on the second floor, also with bolted connection
Interior features lend themselves to future reconfiguration of the space, accommodating the dynamic nature of a retail environment. Features that promote future disassembly and reuse include exposed structural members, reduction of interior finishes and the assembly of interior partitions between the retail and office spaces consisting of movable steel Unistruts with veneered plywood and fabric panels, with the components screwed together. Electrical components are contained in suspended raceways that run along structural bays, allowing for lights and fixtures to be changed or moved, providing a degree of flexibility very valuable in the retail environment.
Features involved in designing for disassembly were communicated through detail drawings and ongoing discussions with the contractor throughout construction. As-built drawings for all disciplines were provided to the owner along with well-developed Operations and Maintenance manuals, and components of the building were labelled. Training sessions were provided for senior staff members and building management on the materials, equipment and systems of the new building, and staff was given appropriate background on the design intent.
The entire building was constructed with only a 13% incremental cost over a standard retail store of a similar size. Although the extra cost of designing for disassembly is difficult to determine, some cost savings can be attributed to the restricted use of interior finishes. Some increased labour, time and expense may be incurred at the time of disassembly and even during construction. However, extra efforts made by the project team during the design stages will curb these considerably, as the extra costs incurred by the disassembly process will be offset by a significant reduction in landfill fees.
As long as they stand, and even as they are taken down, projects like the Ottawa MEC store serve as ongoing examples of how an environmentally motivated client and project team can achieve designing for disassembly and other sustainable objectives without compromising building aesthetics, practicality or performance.
Vince Catalli is president and Maria Williams is an associate of by dEsign consultants, Ottawa. They can be contacted at (613) 759-4605.
Client: Mountain Equipment Co-Op
Architect team: Linda Chapman, Christopher Simmonds, Pawel Fiett, Kristen O’Connor, Christopher Moise
Construction Manager: Justice Construction
Structural: Cleland Jardine Engineering Limited
Mechanical/Electrical: Leslie Jones & Associates Inc.
Energy Modelling: Leslie Jones & Associates Inc.
C-2000 Facilitator: Enermodal Engineering
Landscape Architect: Jim Lennox
Waste management consultants: by dEsign
Area: 2,484 m2
Budget: $2.9 million
Completion: June 2000
3-D wall sections: The Design Guild
Photography: Ewald Richter Photography Ltd.