There has been a growing expansion in the use of modular construction methods across Canada for homes – especially rental homes, and other residential applications such as employee housing, student accommodation and budget hotels.
The need for employee housing for large energy and resource projects in remote areas across Canada — especially in the North — has been a particularly strong driver of modular construction.
Factory-built homes alone accounted for 11% of all the single-family homes started in 2012, up from roughly 3% to 4% in 2000. Part of the reason is that advances in technology have enabled more innovative designs on the factory floor that have helped to make modular building more attractive – and more competitive.
While the names may differ, the methods all involve off-site fabrication of building components, from window frames right up to pre-cast concrete structural elements. The items manufactured off-site are then delivered when work on site has progressed to the installation stage. An entire modular unit can even be delivered to site, complete from framing to internal finishes, including mechanical and electrical installations and mounted cabinets and millwork.
The key advantages of the modular approach are:
- Decreased construction time on site, on-site running costs, and material waste.
- Increased quality – and cost control from fabrication in a controlled environment.
- A safer work environment.
As with any construction method, there are some issues, such as:
- Size limitations of modular units due to transportation.
- Cost savings from labour efficiency gains can be offset by transportation costs.
- Potential for construction delay from damage during delivery and on-site installation.
- Large volumes of manufacturing for both individual projects and greater industry adoption needed to realize higher cost savings.
- Need for strict control of tolerances on site.
- Less flexible design compared to traditional construction.
Need for design teams to be familiar with the method and process, and to be involved as early as possible. There are also financial considerations when undertaking a modular building project:
- Cashflow varies significantly from the standard construction project.
- Modular suppliers can require deposits prior to final design and again prior to manufacture.
- Modular construction is best suited where unit absorption rates are expected to be high.
- Depending on the procurement method, lenders may require additional security, information, coverages, and measures to be in place due to deposits and storage of units off site.
The modular method has shown itself to be particularly well suited to student accommodation or budget hotels, which are typically built when a high occupancy absorption rate is more or less assured. High rise residential apartments or commercial spaces have an absorption rate or a timeline to get to full occupancy. Since both contain some element of tenant customization, creating a standard unit only slows down the absorption rate.
More widespread adoption of modular construction will require volume orders that will enable the economics of scale that will reduce costs. Developers and building contractors working with traditional methods will need to adapt their business models to deliver the full benefits of modular building to their clients.