Hørsholm is home to several large residential buildings from the 1970s, which, with their considerable size and sculptural presence, define both the urban and rural landscape.
The largest of these buildings is 25 meters wide and 250 meters long, originally built with eight floors—now expanded to nine. The roof was in need of complete renovation, but instead of opting for an expensive roof repair, the developer explored the possibility of adding an extra floor.
The result was a new 6,250 m² floor with apartments of approximately 100 m² each. Prefabrication was a necessary solution to execute the project efficiently—both financially and with minimal disruption to residents in the existing building and surrounding properties. A large-scale temporary relocation of the 350 existing apartments was not feasible and would have faced significant local opposition.
Financially, the project proved to be an excellent investment. The rooftop, used as the “building plot,” was essentially free, and the costs of the required roof renovation were incorporated into the new construction. Prefabricated construction was about half the price of traditional building methods. Additionally, using prefab allowed the existing residents to stay in their homes, saving the developer relocation costs and avoiding resident protests.
The project resulted in 40 attractive penthouse apartments with panoramic views of the Øresund Strait, enabling premium rental prices. This turned out to be a highly profitable venture with a strong return on investment—a true goldmine for the developer.
The project was particularly demanding during the planning phase. Integrating existing installations such as water, electricity, drainage, and heating, while also adapting the structural integrity of the existing building to support an additional floor with increased wind exposure and fire safety requirements, required significant effort. However, the greatest challenge was designing all technical parameters within a prefabricated system. Once the method and strategy were established, the remaining planning work became more straightforward. The planning phase took two months.
The construction proceeded without issues over a nine-month period, with six main deliveries. Each main delivery was completed and installed within two days. The interim periods were primarily used to connect the prefab apartments to the existing building’s infrastructure.
The first apartment, however, was delivered separately and very early in the process. Our intention was to use it as a reference for the client and various consultants. This turned out to be a wise decision. Whenever a major consulting firm assigned a new representative to inspect the site, they often introduced new perspectives and numerous revisions. By comparing their input to the approved reference apartment, it was easy to determine whether we or they were on the wrong track.
We also used the reference apartment internally for training new craftsmen and for quality assurance. The overall process was successful, primarily because everything was fully defined and planned before construction began—a necessity for prefabricated projects.
This approach places significant demands on architects and engineers, who must complete all planning before construction starts. One of the biggest challenges in prefab construction is getting consultants to change their working methods and finalize all project details before breaking ground. The construction industry is often conservative, accustomed to planning as issues arise during the building phase. This approach does not work for prefab construction, where every detail must be thought through in advance. Otherwise, costs can quickly escalate for the client.
Of course, challenges arise in large-scale projects like this. However, there were no major disputes. There was a mutual understanding that conflict drains energy from the real task—building the project. Conflict only benefits lawyers; for everyone else, it results in losses.
We believe that as long as people communicate respectfully and acknowledge each other’s challenges, common solutions can always be found—solutions that work for everyone.
The client is a public housing association, a non-profit organization that develops and manages rental housing at reasonable prices. The goal is to ensure quality housing for all, regardless of income. Operations are financed through rent, and residents have a say in decision-making through a democratic governance structure.
Ladegaard Architecture
Part of Ladegaard Group ApS