Off-site Construction: How Do We Move it Forward?

Off-site Construction, Off-site Manufacturing, Manufactured Construction, Modern Methods of Construction, no matter what the name, the fundamental idea is to move some effort away from the construction site to a more controlled environment of the manufacturing floor. Although people have traced back the history of manufactured construction to the mid-nineteenth century, I would actually go one step further and argue that the use of big boulders instead of smaller bricks in pyramids is no different than using prefabricated wall panels. Mankind has always looked for better ways of building faster; and the use of pre-cut rocks and boulders leveraged the opportunity to fill large volumes of pyramid structures more quickly. Although we have come a long way with cranes, robotics and laser guided precision construction; fundamentally, the focus of all these innovations is to speed up the construction process, minimising waste and inefficiencies, maximising quality, and improving health and safety. The benefits extolled by manufactured construction have been documented extensively in the literature by academics and are discussed regularly among practitioners. However, despite such an extensive body of evidence available to us, the uptake of manufactured construction is low. The first question that comes to my mind is, why?

Having worked in this sector for a bit, I have realized that most people adopted manufactured construction without realizing what it actually entailed. Maybe, the process seems deceptively simple. Maybe, the benefits sound too good to be true, or are they? Having looked at the issue of poor uptake or in some cases, poor performance of off-site construction project I have realized that people try to run an off-site construction project without changing the mindset from regular on-site construction scenario. It is like someone trying to fly a jumbo jet because they have car’s driving license and they feel that the difference won’t be much as both of them are transportation devices. Well here lies the trouble. There are three major elements in an off-site construction project: design, construction and manufacturing. All three of these elements need to come together seamlessly for the off-site construction system to work well. Processes and constraints at each of these three steps are different from the conventional construction process.

The design process of a manufactured construction project should resemble more an automobile or aerospace design process rather than a construction design process. The reason being, that in order for the team to harness maximum benefits of moving effort from construction site to the manufacturing floor, one has to take advantage of philosophies like Design for Assembly (DFA), Design for Manufacturability (DFM), and modular design. The designer has to be aware of manufacturing process as well as processes and constraints on the construction site, where the final assembly of the building has to take place. Since it is very difficult to get individuals with all these skills, an efficient implementation of concurrent engineering is necessary. Through the implementation of concurrent engineering one can actively engage professionals from manufacturing and construction domains and produce a design that is both easy to manufacture with the existing machineries and fixture, as well as easy to construct, once the pre-fabricated component reaches the construction site.

One more significant piece of information that the designer has to be mindful of is the associated logistics. The logistics of moving the prefabricated component from the manufacturer to the construction site, the kind of road network available, and the staging area available near the site. The manufacturing process could be different as well, as each building is unique in most cases. Therefore, the manufacturer has to be able to adjust/readjust its existing fixtures and machinery to deal with the variations in design. At times, this creates a job-shop kind of scenario on the manufacturing floor. The manufacturer has to be aware of the order in which the assembly on-site, has to take place and has to schedule their production sequence accordingly. In case of modular buildings, the manufactured product is so voluminous that it is not possible to store it for too long at the manufacturer’s facility. Therefore, the production schedule needs to be in-synch with the assembly schedule of the construction site. As soon as the module is manufactured, it should be transported to the construction site. In order for the manufacturer to take advantage of the quantity discount on components, it is important that they influence the designers on the selection of components in the building. The manufacturer should also be cognizant about the challenges faced on the construction site and should do all they can to ensure that the transportation and handling of the manufactured goods is easy and safe. This could be accomplished by proper packaging and having a provision for lifting and moving through the inclusion of temporary hooks and wheels.

The construction process in an off-site construction project requires a very different type of planning. The construction project planner has to be aware of design and manufacturing schedules. The site manager has to ensure that as soon as manufactured components (especially when it comes to modular construction are concerned) are ready and are delivered, they are lifted and put in the final intended place in the building. This actually reduces the need for large staging areas especially when the construction is taking place in a built-up neighbourhood. The site crew have to be trained in handling the pre-fabricated components. Scheduling of heavy equipments like large cranes are another issue, since the rental costs for these cranes is quite high. In order to make it cost efficient, the planning should be detailed and very accurate. Use of simulation packages to simulate the assembly process also comes in handy. The level of complexity involved in assembling a building in an off-site construction scenario sometimes may require the use of planning and monitoring software packages. The old adage “If you fail to plan, you plan to fail”, applies quite well to the manufactured construction.

Having said all this I do want to point out that in order to create a workforce that is capable of handling complexities of manufactured construction, specialized programmes are needed at the college and university levels. Mindful of this, and building up on the research expertise in the area the School of Built Environment (SoBE), the University of Salford has introduced a new MSc programme in Advanced Manufacturing in Construction. This programme was developed with active involvement and feedback from an European Union funded research consortium called ManuBuild which had members from both the industrial and academic communities. This programme is designed to train middle and top level managers to better manage off-site construction projects with a firmer grasp of issues relating to process efficiency, both on the manufacturing floor and on the construction site. They will be able to effectively use management and IT tools in order to improve productivity and process flow. Students will also develop a strong background and broader picture in design decisions that have an impact on overall quality of off-site construction. The programme will be offered in full-time, part-time and distance education modes. The programme will train professionals who will be able to meet the challenges of the manufactured construction sector for the future. It provides a very unique interdisciplinary perspective on manufactured construction to students and will train them to harness maximum benefits of off-site construction through effective strategizing, planning, design and execution. For further information please contact Dr Mohammed Arif via email at m.arif@salford.ac.uk or by phone at 0161 295 6829.