For fifteen years, the Dutch architectural office cepezed resided in a self-designed, clean-lined office building on the western fringes of the historical Delft city center. Now, the office has moved moved to a listed property more than a century old on the south side of the city’s heart. The three halls on the Ezelsveldlaan were built at the start of the twentieth century as a laboratory for the department of Mechanical and Marine Engineering at what was then the College of Technology.
For years on end, the students carried out tests here with various types of engines and turbines. After Mechanical Engineering moved to the new college district in phases during the second half of the 1950s, the complex changed function several times. From 1993 to 2008 the halls housed the Technology Museum whereupon cepezed became the owner of three halls and a 38-metre-high chimney. The largest hall is in use by cepezed itself; the other two are rented to companies in the creative sector. The middle-sized hall is now in use by a company involved in sustainable transport; the smallest one houses a company that specializes in multimedia productions for museums and exhibitions.
The three halls that together make up the ensemble were built between 1905 and 1911 to a design by the architect Jan Vrijman (1865-1954), who, as Chief Government Architect, also fulfilled the function of ‘Government Building Engineer for Education’. The building style was described by the Cultural Heritage Agency – the complex has been a listed building since 2003 – as ‘Neo-Dutch Renaissance’. Characteristic elements are the façades rich with springstones and bands of different colours and the pitched roofs covered with blue slates, which are interrupted by a clerestory with continuous strips of glass. Together with the large windows, this allows a great deal of natural light into the interior.
In architectural terms, the halls are strongly akin to each other; their main difference is size. The middle hall, directly next to the chimney, functioned as the boiler house; the open slats in the roof still serve as a reminder. The steam that was used to drive the machines was produced in the boiler house. These machines stood in the largest hall, directly alongside the Ezelsveldlaan, where they could be relocated using a lifting installation with a capacity to lift 6000 kg; it is still in working order. Connected to each hall is an annexe, which had a specific function. The boiler house annexe was used to store coal, while the annexe to the smallest hall on the Nieuwelaan side functioned as an auditorium.
Inside, one of the features that makes the halls so beautiful is the contrast between the massive walls and the light, elegant roof construction with the characteristic ‘Polonceau trusses’, which each consist of two segmented triangles connected by a tension rod. The construction of the halls was such that in the event of an explosion, only the roof would be blown off; the walls would remain standing.
Although cepezed’s various transformation assignments differ greatly from each other, in principle the office ultimately employs the same approach for all of them. It begins with a thorough analysis of the existing situation – aspects relating to architecture, construction, building performance and installation engineering, but also elements such as spatial quality, functionality, routings, orientation and integration within the context. Bringing things back to the essence almost naturally leads the way to innovations that result from the individuality of the existing buildings. The approach is always to achieve the greatest possible effect and end result with minimal interventions. That also includes preserving and utilizing the existing situation as much as possible. After all, excessive ‘pruning’ diminishes the authentic character of a building, while existing features actually emphasize its nature. In addition, it is often possible to turn any disadvantages into advantages. cepezed adds new value by means of, for instance, more natural light, improved view, spatial diversity and a pleasant internal climate. And naturally a good functional organization. An important feature of cepezed transformation projects is the sharp contrast between what was already there and what is being added.
For the restoration of this complex, cepezed followed the approach described above; here too, for instance, maximum effect has been realized with a minimum of interventions and there is also a contrast between old and new. The latter can be seen, for example, in the end elevation of the middle hall, the former boiler house, where the windows on the underside have been enlarged. A well-considered choice was made not to implement the added lower windows in the style of the existing windows. They are clean-lined and straight and have no frames. In addition, they are not recessed, but are aligned exactly with the surface of the external wall.
The principle of maximum effect with minimal interventions is based, as said, on the conviction that the restoration should focus on allowing the original building to speak again. In this case, it meant that the adaptations that had been made over the years at the expense of the architecture had to be removed. Most of the interventions had been carried out to make the arrival of the Technology Museum possible. They were important adjustments, made in consideration of the function the complex was being given, but that did not take away from the fact that they harmed the original architecture. Intermediate floors were introduced in the two smaller halls and, as a result, the monumental space could no longer be experienced in all its glory. In the cepezed design, they were replaced with new mezzanine levels along both long sides, so that people on the ground floor can once again experience the full height of the halls. In the largest hall, which has been taken into use by cepezed itself, the original gallery was still intact. It was even possible to bring the original wooden floor here back into view.
Furthermore, as part of the conversion into a museum, the strict rectangular structure of the halls was undermined by the introduction of slanting lines, which were rather popular 25 years ago. cepezed acted to correct this situation as well; the slanting staircase placed in the smallest hall has been replaced with lengthwise stairs. In order to disrupt the spaciousness of the halls as little as possible, smaller functions such as toilet blocks and pantries have been housed in the annexes. In the two smallest halls, the functions have been placed behind the piers, so the in-between spaces at the windows could be organized as meeting areas. The entrances – each hall has its own entrance – are also situated in the annexes.
Unlike the other two, the annexe in cepezed’s own hall is almost completely new. Of the original building segment that connects the three halls, only two façade parts have been left standing. As a result, it is the component where the contrast between old and new is the most strongly evident. This can be seen very clearly at the new entrance, for instance. On the left we can see the richly detailed end elevation of the existing hall, where brickwork alternates with natural stone string courses and artificial stone coping. In comparison, the skin of the new-build is almost entirely without detail, with glass panels no less than seven metres in height.
With such contrasting building segments, creating the link between the two is often a difficult task. Here it provided the architects from cepezed with an opportunity to indulge themselves in their ambition to devise the cleverest imaginable solution. How do you connect a glass roof to a façade where the brickwork is interrupted in countless places by wall clamps and other façade elements? Fortunately a single layer of bricks was found that was uninterrupted. After contemplating milling a continuous groove into it, on closer examination it turned out to be sufficient to bond the roof panels to that one course of bricks using sealant. The frame of the glass roof is secured to the original building by means of double anchors on either side of the original anchors. That was possible because a gauge was established for the new annexe that was precisely one third of the gauge in the hall. Finally, a subtle form of contrast can be found at the place where the new-build segment meets the large hall. In order to underline the difference between the two building segments, the choice was made to set the façade of the new-build component a little back with respect to the façade of the existing building.
Just as in the existing annexes to the two smaller halls, the entrance and most of the smaller functions have been situated in the new annexe to the large hall. The ground floor includes the reception, toilets, the kitchen and the lunch area. A staircase (with steps we recognize from aircraft steps) leads up to the meeting areas on the first floor.
As already mentioned, one of the reasons for cepezed’s move was the wish to accommodate all the employees (around 50 at the moment) in a single space. The large hall of the ensemble on the Ezelsveldlaan turned out to be eminently suitable for this purpose. The generous height of 16 metres under the ridge is responsible for a singular experience of the space. New elements, such as the plain anodized aluminium acoustic panels secured to the decking, conform effortlessly to the interior due to their modest design and materialization. For air conditioning and ventilation, the BaOpt system has been
implemented in all three halls. As a result, a single air duct is sufficient; the control technology creates ‘chaotic’ movement in the air, so the same temperature is maintained throughout the space. The cold downstream at the windows is also eliminated. The system not only generates a pleasant working climate, there are also no longer any radiators and air ducts in view.
For the workspaces in its own hall, cepezed has developed a workbench. The cable duct is situated above the tables; this prevents the usual tangle of cables and cords on the floor. There is room for a row of document files above the cable duct. The ground floor is the domain of the project teams. The tender teams that work on acquisition and the departments of public relations, finances, cepezedinterior and cepezedprojects (cepezed’s own developer) have their workplaces on the gallery, which has been restored to its original condition.