Perform checks and come up with creative solutions

Reuse of the existing concrete shell

Sustainability plays a leading role in the redevelopment of the Dulon College in Ede. For this reason, the old college building will not be demolished but stripped so that the existing concrete shell can be reused for the new educational building. This does require quite a bit of creativity.

With the redevelopment of Dulon College - part of Christelijke Onderwijs Groep Vallei & Gelderland-Midden (COG) - the school board wants to move toward an educational building that better fits the school's educational vision. Therefore, the wings at the ends of the former school building will be connected, creating logical walking routes and making the school building a natural whole. In addition, the ambition is to carry out this redevelopment in a sustainable and future-proof manner.

Drawings versus practice

Now this sounds simpler than it is. "For a project of this size - some 14,500 m2 - you immediately start ordering the building materials," says Gerben Jan van Harten, project manager of Rots Bouw. "The old, existing drawings and our own observations formed the basis for this. After the demolition work, we made a pointcloud with a drone, which recorded the actual dimensions. These deviated here and there from the existing data, requiring several parts to be adjusted. Because these deviations only emerged after the demolition work and we had already begun construction, this did cause some stress." 

Value and height differences

And there are more issues that Rots Bouw encounters in the execution phase. An important point of attention is the inspection of the existing concrete structure. Van Harten: "This must comply with the values currently being calculated, even though it is an existing construction. Now, for example, the sand-cement floor is higher in some places than indicated on the drawing, so the desired thickness is not possible. This would make it too heavy. Here we still have to come up with the solution. On the other hand, these are the challenges that make the work fun."

Delay caused by bats

To get the building ready for remodeling, the school board began several years in advance to avoid the bats present in the facades. Unfortunately, with insufficient results. At the time Rots Bouw and ITN were in the starting blocks, it turned out that the bats were still present in several places. Van Harten: "The work came to a standstill for thirteen weeks as a result. The overall planning had to be adjusted, machinery leases had to be converted and all kinds of temporary provisions had to be made. This came as a complete surprise."

But as much as COG's sustainability ambition surprises, Van Harten is happy to deal with it. "You know this is the only right way. Sustainable building is already quite normal at Rots Bouw. Good insulation, solar panels, WKO installations, floor heating and airtight construction are the order of the day." Students at the new Dulon College are expected to be able to move into their new building in early 2024.