With the Slimline floor system, there’s essentially no necessity for a structural distinction in building parameters for offices or housing; buildings become truly multifunctional. There’s no need for a suspended ceiling or a raised floor, which defeats the purpose of increased floor heights in offices to compensate for these features. All building installations can be placed in the hollow floor system.
The IFD (Industrial, Flexible and Demountable) construction philosophy describes the flexibility aspect in a solution which separates the building structure and installations by using a ‘raised floor’. Professor Jos Lichtenberg, with a chair in construction product development at the Technical University of Eindhoven, has acquired extensive expertise regarding the bottlenecks in transforming traditional construction to an industrial process which allows changing the layout or function in during the design, construction and operational stages of the building lifespan. His ‘Slimbouwen’ methodology offers a practical guideline for the implementation of these principles. Lichtenberg’s analyses proofs, among others, the assumption that the floor construction is paramount for the positioning of installations in relation to building flexibility. The question remains if the installations should be placed ‘on’ or ‘under’ the floor, which has been extensively analyzed. The application of floor heating is great solution in terms of comfort and energy efficiency. The requirement for sufficient cooling is increasingly found in both offices and housing projects. Heat from the floor and cold from the ceiling is generally the best option, as this fits the thermo physical comfort principles of ‘warm feet and a cool head’. This also results in energy savings due to the reduction in required ambient temperature (mean of the air temperature and the radiation temperature) because of the lower radiation temperature while cooling compared to cooling using refrigerated air. There are, however, limitations to the cooling; research by the Dutch TNO Institute concludes the use of floor heating for cooling purposes shows a strong layering near the floor, which limits convective cooling. Although heating through the ceiling also has is limitations, it’s very well possible to cool and heat using the ceiling and the floor respectively and create a good indoor climate, under the prerequisite the design team works closely together.
Conventional distribution boxes aren’t necessary with the Slimline floor system. The lighting connection is now a relatively flat box which also solves any questions with regard to the fire-resistance (please refer to the fire report). According to the NEN1010 guideline, distribution boxes aren’t mandatory. All installation junctions should be accessible from the own legal space. The light points are fed through the concrete ceiling slab, operated traditionally or through remote control. The power to the wall outlets is connected from the own floor and distributed through the floor, walls and hollow plinths. Accessibility of the installations (enabling easy relocation of, for example, data terminals) can be guaranteed by locally inserting small hatches in the subfloor. In principle, the ceiling of the house remains solid.
When using the Slimline floor system, all installations are placed in the own legal space, as close to the user as possible. The concrete slab creates the legal and acoustic separation to the neighbors in apartments, provides the fire separation and supports the installation components. Air is discharged downwards through the wall. Cooling can be achieved by thermally activating the ceiling and the floor (‘cool head, warm feet’).
To be properly understood, particularly in speaking and meeting rooms, the reverberation time is important. Too much reverberation, but also a too dull sounding room is undesirable. The Slimline floor system offers the option to integrate acoustic strips in the concrete ceiling slabs, which are invisible when finished with open acoustic plaster. Sound absorption can also be achieved using a suspended ceiling. Some of the disadvantages are the lost height and the fact it can’t be combined with thermal activation (concrete ceiling cooling). The reverberation time can also influenced by adding sound absorbing materials, like acoustic islands, carpeting and furniture, to the room.
Yes. It’s possible to add insulation between the beams of the Slimline floor system when applied as the roof. Next, ‘thermal bridge break’ is applied before the roofing and any tapered insulation is placed. For ground floors, the Slimline floor system can be factory-fitted with insulation. All installations can be placed in the hollow space between the beams, which allows building without the need for a crawlspace.
The Slimline floor system is calculated on the required useable floor load. If the user doesn’t know the values yet, or the requirements are still subject to change, it doesn’t make sense to settle for a high load like 8 kN/m2. Most office loads aren’t that high, especially when taking in to account the ongoing decrease in the amount of paper we need to store. The more sensible solution could be to strengthen (for example) the mid-section of the building by reducing the mutual distance between the Slimline beams to allow higher floor loads in specific areas without making the entire building heavier than necessary. A great example of this strategy can be found in the ‘Red Rooster’ building in the city of Delft. Workstations are generally situated along the façade. If at any given moment in the future a higher floor load is required in a specific area, it’s possible to position a heavier (for example HE) beam between the Slimline IPE beams, resulting in a much more cost efficient solution than making the entire building needlessly heavy to begin with.
No, these parts are situated in an indoor climate (on the ‘wrapped side’) which makes conservation unnecessary.
Effectively, the available space is comparable to the wide slab floor. The required space is determined by the pipe diameter and the necessary slope according to construction guidelines. The guideline suggests a slope of 10 mm per meter. It’s good to keep in mind this guideline is the result of the (broad) margins which are commonplace in construction. A perfectly level sewage works fine, as long as there’s no negative slope. The guideline calls for a slope to prevent the negative slope. It should be possible to secure sufficient slope within a much more limited height, as the Romans had already figured out before our era. Archaeological sites have revealed waterworks including aqueducts with a slope of less than 1 mm per meter over a length of tens of kilometers.
Slimbouwen® can be seen as a specialization of IFD (Industrial, Flexible and Demountable) building.

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Slimline can be combined with a fully flexible subfloor (tiles), removable tiles or accessible zones. If floor heating is applied, it’s possible to add provisions which allow creating additional floor covers/hubs over the planned cable ducts. In case of major renovation, the subfloor can be partially or completely removed to add, upgrade or modify installations. In all scenarios, it’s possible to modify the building installations without affecting the constructive floor. This even allows for functional changes within the building, for example from residential to office and vice versa.