Page 146 - AIT0516_E-Paper

ÖFFENTLICHE BAUTEN • PUBLIC BUILDINGS TECHNISCHER AUSBAU • TECHNICAL SOLUTIONS

T he European Schools with multilingual teaching are primarily open to the children of
people working for European institutions. Owing to the opening of new European
Central Bank, the demand for a corresponding number of school places considerably
increased in Frankfurt / Main in recent months. An extension was required – with ten class-
rooms for the preschool and another seven for the primary school. Additionally, it should
be implemented quickly and at little cost. The responsible people at the Building
Department thus turned to local architectural practice NKBAK, which is run by Nicole
Kerstin Berganski and Andreas Krawczyk, and expressed their wish for a container school.
Since the architects have children themselves, they wanted to design an adequate space
for learning and playing for the little ones. Furthermore, the demanded room sizes of 75
square metres and larger could not be implemented with containers. So the architects
developed the idea of a school building designed as a modular timber structure. An
important precondition was that the specified sizes did not have to be precisely met, but
could each differ by a few square metres. Starting out from the floor area of 75 square
metres required for the classrooms of a European School, a module dimension of three
by nine metres – and thus a base area of 81 square metres – proved to be suitable. Each
classroom consists of three such modules. Owing to these specifications, the 3-metre wide
Blick in den Speisesaal mit angeschlossener Aufwärmküche • View into the dining hall with adjoining kitchen corridor is, in turn, especially wide and perfectly suited as an area for playing and moving
around. The dining hall as well as the space for movement perfectly fit into this dimensi-
Stahl statt Holz: der große Bewegungsraum im Erdgeschoss • Steel instead of wood: the large space for movement
on. Since the latter provides a direct exit to the outdoor area and shall be used for festivi-
ties in summer, it had to be accommodated on the ground floor. From a structural engi-
neering point of view, this room was not feasible as a timber structure due to the planned
span of twelve metres and the loads it has to support due to its location. Consequently, it
was designed as a steel structure, but with exactly the same structural principle as the rest
of the school, which is resolved into columns and unsupported beams.

Using prefabricated wooden modules instead of containers

The design with linked up modules did not allow load-bearing longitudinal walls. The
beams made of so-called “BauBuche” by Pollmeier appear relatively slender despite a
cross-section of 22 by 56 centimetres and a span of nine metres. This is primarily down to
the fact that the material, which consists of industrially produced laminated veneer lum-
ber, can accept more loads than comparable beams made of coniferous woods. In addi-
tion to the grid dimension of the modules, the maximum allowed length of the school buil-
ding was 60 metres and it could only be three storeys high to still achieve fire resistance
class F30 and be able to use exposed wooden elements in the interiors. It is favourable
that the architects made this possible because the beech beams and the white glazed
wooden interior walls generate an elegant and simultaneously natural appearance. The
planners arranged the demanded rooms in three groups, which adjoin the corridor that
is angled by 90 degrees. This layout together with the complete glazing of one of the
two transverse sides of each module affords differentiated views to the surroundings.
The single modules were prefabricated in the factory of the Austrian company Kauf -
mann Bausysteme, equipped with all connections, ceiling radiators, luminaires, sanita-
ry objects and many other components, transported to the construction site by lorry and
joined on site by means of a truck-mounted crane. That way, the construction time
could be reduced to only three months. The precision resulting from prefabrication is
tangible everywhere in the completed building. Everything fits perfectly on top of and
alongside each other. In order to meet the demands on very short reverberation times,
the architects had Heradesign boards installed on the ceilings between the single
beams, which produce a relatively level surface. The light grey colour of the panels adds
a pleasantly different shade. Additionally, the inside of several transverse walls were so
finely perforated that they are acoustically effective, but maintains the flat character of
wood. Only few elements of the school are not made of wood: the 120-millimetre insu-
lation of the rear-ventilated façade are covered with aluminium trapezoid sheet metal
finished with clear varnish, the window and door elements of the façade are made of
wood and aluminium. An external shading device was installed on the south side. The
architects implemented an honest timber building with a very modest appearance both
internally and externally. Children’s drawings and pieces of handicraft add enough
colours – especially since they can be easily pinned to the wooden walls and appear in
their entirety like a large exhibition. The architects cleverly realised the wish of the
school administration for at least a little colour: Each staircase is designed in a vibrant
plain colour – green, yellow and pink –, and this helps the small children who only just
learn to read to find their bearings. The yellow staircase can be found more easily than,
for example, staircase north. That way the school actually offers both: architectural qua-
Grundrisse Erdgeschoss • Ground floor plan Grundriss 1. Obergeschoss • Floors plan Level +1 lity and excellent indoor qualities for the large and little users.

146 • AIT 5.2016