Juha Salminen: Construction in the Flow

Flow production and takt time take renovations one step closer to industrial production.

“I think that in 2017, we finally cracked it,” says Juha Salminen, Development Director at Consti. “Until then, we had just studied the theory of production flow and only applied it in use gradually. Now, we are at the forefront in Finland, but I would still say that this is just the beginning.”

Consti is one of the leading renovation and technical services companies in Finland. They’ve long been involved in lean construction development projects, including LCFIN1 and LCIFIN2, and more recently in RAIN. Salminen, with a Ph.D. in construction economics, also has a long history with lean principles. In the early 1990s, he acquainted himself with the Last Planner System that Lauri Koskela brought from the USA to Finland. Unfortunately, at that time, the industry was not ready to embrace it.

Project Flow and Takt Time Applied to Construction

Project flow and takt time are powerful lean manufacturing concepts, but using them in construction has been challenging. Consti has applied lean principles in projects with repeatable units, for example in pipeline renovation. In a residential area renovation in Turku, the company applied takt time production for facade refurbishments.

In a traditional construction project, the process speed varies. That’s why buffers are often added to the schedule to compensate for variations and to try to optimize the use of resources to try and keep everybody busy at all times.

However in takt time production, the project is divided into identical work packages that follow each other with an uninterrupted pace. The production speed is consistent throughout the project. The steady flow makes the project predictable. You can tell, down to the hour, what’s going to happen, and when, in the project. Having a feedback loop in the scheduling makes it possible to adjust the pace in case packages takes less time to complete than anticipated.

Measurable Benefits

Flow production provides several benefits; for instance, completing a bathroom takes at best one week whereas it could take over one month in a traditional project. The construction team can solve any production problems early in the process as they complete the very first unit. Through continuous learning, Consti has been able to reach a zero-defect quality.

Daily briefs make clear to the teams what they’re supposed to be doing during the day, which adds confidence and reduces work-related stress. All the building materials can be delivered to the right place, at the right time. With different craftspeople working in close vicinity, communication is very important and can be efficiently achieved in this process.

Consti makes great use of prefabrication, especially for mechanical installations. “People think of prefabrication as a time saver. However, in a traditional project, time savings often don’t materialize because of the slack in the schedule. In flow production, prefabrication simplifies the process, which is an essential benefit,” Salminen claims.

Salminen names three success factors in flow production:
1.    Scrupulous planning and preparation;
2.    Committing to implementation of the takt time plan from the start;
3.    Continuous daily improvement.

He points out that it’s critical to have employees and partners who are committed to reducing waste and willing to work in a very organized manner. After some initial doubts, most employees and partners are now very happy with the new way of working.