Platform on new construction, renovation, restoration and transformation
On the Zonnesteen in Hoorn, an Integral Child and Expertise Center (IKEC) was completed just before the construction vacations. IKEC De Zevensprong fulfills an important regional function and combines specialized (primary) education, care and childcare for 450 children aged 0 to 12. In addition, the project provides space for a double gymnasium, green outdoor space and parking for student transportation. IKEC De Zevensprong was designed by KRFT and stands out for its rich use of natural materials, such as bamboo and wood. Partly for this reason, the construction was awarded to De Nijs bouw en ontwikkeling, which is one of the forerunners in building with wood.
Building a school or IK(E)C is a desire for many architectural firms, but without experience it is difficult to get such projects awarded, knows Oscar Vos, architect and, together with Thomas Dieben, founder of KRFT. “That is why it was so special that in 2018 we were invited to participate in a research project initiated by the Mevrouw Meijer Foundation, which aims to improve school architecture. The goal here is for schools to think about what is possible with their buildings. But also that architects who have never built, renovated or expanded a school are connected to new tasks. The municipality of Hoorn was so pleased with this that it made a selection from the participating architects.”
“The goal of IKEC De Zevensprong was to bring together five school sites and their users under one vision and one new roof,” Vos says. “To make this possible, the IKEC was designed together with the users. The main ambitions here were a healthy, safe and low-stimulation learning environment with soft colors, a good relationship between inside and outside and ample attention to sustainability. As an office we have given substance to this by working with natural materials. From main supporting structure to façade finishing. An idea that was immediately embraced by the municipality and users.”
The classrooms are situated around a play/learning area, Vos says. “This creates a transparent layout with long sightlines, making it excellent to maintain the four-eye principle.” For the structure of the building, KRFT chose a division into five ‘houses. ’The desire was to make a small building, but 7,000 m2 is not small. So we broke up the scale into five smaller houses, staggered in relation to each other and given their own identity, finish and entrance. By then dividing the houses programmatically, users maintain an overview at all times.”
The design includes two teaching houses, filled entirely with traditional classrooms. But also a workhouse with a cooking and handicrafts room. “There is also the talk house with the main entrance, childcare, teachers” rooms, consulting rooms and a consultation café,“ Vos said. ”The last house involves the sports house with a large double gym on the second floor and primary care functions on the first floor. From speech therapy to physical therapy. Extracurricular care is distributed throughout the school and takes place in the play/learning squares."
In April 2024, De Nijs construction and development started construction. “IKEC De Zevensprong stands on a traditional foundation with piles and insulated hollow-core slab floors,” says Edwin Swart, business manager at De Nijs construction and development. “Houses 1 through 4 then have an all-wood main bearing structure with laminated columns, laminated beams, CLT walls, CLT floors and Lignatur floors; a kind of hollow wooden hollow-core hollow core slab with ribs and a top and bottom plate, which together form the structure. In this, the bottom plate is also the finished ceiling at the same time.” From an acoustic point of view, the lower slabs are perforated, which required an additional wooden intermediate layer to ensure stability. “In addition, the floor construction was filled with crushed stone for good airborne sound attenuation. Over this, insulated Fermacell floor panels were laid with linoleum from Tarkett as a finish.”
House 5 received a steel structure, with a hollow-core slab floor as the second floor. Mainly because of the large spans and loads of the double gymnasium, Swart says. “The roof construction of all houses consists of wooden laminated beams and wooden roof panels, and the facades are HSB facades, with wood wool for high thermal insulation and CO2-reduction.” Vos: “For the façade finish, we largely chose pressed bamboo fiber, which gives the whole thing a natural look. Moreover, bamboo is low-maintenance and stores an enormous amount of CO2 up to a maximum of 1.662 tons/m3” On some facades, the bamboo is combined with an exterior wall insulation system and stucco.
Vos provided a comprehensive calculation of material-related CO2-emissions and biogenic storage in Phase A of the Whole Life Carbon footprint in this project. “This shows that we emitted about 285 kg of CO2eq/m2 GFA stored in the natural materials of the new building, while we saved 315 kg of CO2eq/m2 BVO have emitted to realize this building. This is mainly due to the concrete foundation and floor and construction of the sports house. A quick calculation shows that with this project we have emitted ‘only’ 30 kg CO2eq/m2 BVO have added. I don't think there is any school in the Netherlands that has achieved a similar feat.”
