Kreuzbau (Hamburg)

Refurbished cross building at Corvey-Gymnasium , southeast side with two main window walls

Schematic floor plan with type of use:

_  Stairwell	_  Anteroom / cloakroom
_  classrooms	_  WC / washrooms
_  Group rooms	_  Escape routes / stairs

The cross construction (also class cross ) is a type construction for school buildings in Hamburg . Between 1957 and 1963, cross structures were erected there at over 60 locations of state schools . They have four wings on a cross-shaped floor plan, from which the name is derived. The cross structure has three floors and a flat roof. Each floor has four classrooms and associated small group rooms , which means that the Kreuzbau offers space for twelve school classes . The classrooms are accessed directly by a central staircase - without a corridor and in the style of the cobbler type. The design for the cross building came from the Hamburg building director Paul Seitz . The main advantage of this type construction was the quick assembly, the disadvantage from today's perspective is the lack of thermal insulation . More than 80% of the cross structures erected in Hamburg are still standing and mostly serve as classrooms in primary schools .

story

prehistory

After the end of the Second World War, almost half of the former 463 school buildings in Hamburg were no longer usable: 21% of the schools were destroyed and 26% so badly damaged that they could hardly be used. From 1945 to 1947 the number of students in Hamburg doubled from 95,000 to 186,000. The reasons for this increase lay in the return of families from the 1943 evacuation after the “ firestorm ”, including the schoolchildren returning from the “ Kinderlandverschickung ”. The settlement of displaced persons from the German eastern regions and refugees from the Soviet occupation zone had a reinforcing effect . Up until 1948, school building was limited to the makeshift repair of damage and the use of barracks and other temporary arrangements. The shortage of space could only be countered by "shift lessons".

This situation created considerable public pressure, as the parents' employment was severely hampered by shifting several children in shifts. In Hamburg state politics, the lack of space at schools was the hot topic alongside the lack of housing and contributed to the loss of the majority of the SPD in the Hamburg elections of 1953 , although top candidate Max Brauer in the election program "A blooming Hamburg" completed the completion of a new school per month promised. The winner of the elections in 1953 was the bourgeois Hamburg block , which used the theme of the missing school buildings to stop the school reform promoted by the SPD. But that didn't change the urgent task of multiplying the speed of school building. At the same time, however, the city's funds were limited - there were enough other, expensive tasks in housing and industrial development.

In 1952, Paul Seitz appointed to Hamburg for the first building director and head of the building department, so that as Deputy Senior Construction Director of the Building Authority in Hamburg, Werner Hebebrand . Seitz held these offices until 1963 when he left Hamburg for a professorship at the Berlin Art Academy. During his ten-year tenure, Seitz mainly designed schools, university buildings and other public buildings. For schools, he relied entirely on series designs that were used according to the modular principle . In doing so, he pursued two concepts: the “school in the countryside” and the “growing school”.

The “School in the Green” was supposed to implement reform pedagogical ideas of a return to nature by setting up smaller school buildings with a maximum of two storeys on generously dimensioned school grounds in the countryside, ideally with direct access to the garden from the classroom. This type of construction was deliberately different from the imposing “school barracks” of the Wilhelmine era and should appear transparent and light. The dimensions of these buildings should have a human dimension, a deliberate contrast to the old school buildings, in which an “entire generation was drilled into racial ideological and militaristic values”. School building was not the focus of National Socialist architecture , because hardly any schools were planned and completed between 1933 and 1945. However, the new school buildings were also intended to express a departure from the secondary virtues that the Nazi state and World War had made possible.

The “growing school” should be available quickly and then grow with the needs of the school. Initially, according to this concept, school buildings were also required to be easily relocatable, which was accompanied by the abandonment of complex foundations and basements. Based on this concept, the first series of pavilion schools was created in Hamburg ; a prototype for this type of construction that was highly regarded at the time is the listed Mendelssohnstrasse school in Bahrenfeld . The series construction developed in the process was the Type A pavilion, made from lightweight materials by Polensky & Zöllner . By 1961, 459 new classrooms of this type had been installed.

Design phase

The design task for Seitz and his working group in the building department was clear: How could the construction of a new school in Hamburg be drastically accelerated, despite the shortage of skilled workers and budget restrictions, without giving up the ideals of the “school in the countryside”? What could a series design look like that also works on smaller or dense school lots? And how would this series design have to be designed in order, as the nucleus of a “growing school”, to map all the functions of a school in an autarkic manner in the first phase of construction? The answer to these questions was the building of the cross.

The shortage of skilled workers in the construction industry was a major obstacle to accelerating the school construction program. Conventional buildings needed trained bricklayers, foremen , scaffolders and roofers. Public school construction competed for these skilled workers with housing construction and the private sector. The use of precast concrete parts reduced the need for such specialists on the construction site, while the fast assembly time of 15 days made it possible for the assembly crew to move on, after which the expansion continued. The standardized school building reduced the need for skilled workers in the shell construction phase to specially trained fitters - the construction time was already reduced to a fifth with the “Pavilion A” assembly system.

The pavilion schools were cheap and quick to build, but they usually only had one, or a maximum of two floors, and a correspondingly high space requirement. For an elementary school with the usual class frequency at the time, this required a plot of land of at least 24,000 m². This was still possible in the planned new building areas in the expansion areas of Hamburg (e.g. Rahlstedt and Bramfeld ), but these plot sizes were not available in densely populated areas such as Wilhelmsburg and Wandsbek or to replace school buildings near the city center that were destroyed in the war, such as in Horn and Hamm . In addition, it was found that the influx and the number of births in the new development areas were higher than expected, so that the schools that had already been designed had to accept higher numbers of pupils. A classhouse of more than two storeys with a good ratio of usable to traffic area was essential in order to achieve the necessary space efficiency .

As an answer to the design task, Seitz developed the cross structure from 1955. The arrangement on three floors made better use of the ground than a single-storey pavilion. In addition, the direct access to the classrooms from the stairwell resulted in a very favorable ratio of 80% usable area to 20% traffic area. However, the lower grades of a school should continue to be housed in pavilions accessible at ground level. The design relied on precast concrete elements on a large scale and placed great emphasis on quick assembly. Thanks to the small boiler room with oil firing, it was possible to start school immediately, even in winter, regardless of the progress made in further construction phases.

In 1955/56 a pre-series type of the class cross was built for the school near the Katharinenkirche . In contrast to series production, this prototype had four storeys because the property at Katharinenkirchhof was only 7,000 m² and there was therefore no space for the erection of further school buildings. The school at the Katharinenkirche was a listed building, but was demolished in 2011 in favor of the new "Katharinenquartier" to be built.

Construction phase

Scheme of the "growing school" with construction phases:

_  1. Cross construction

_  2. Pavilions

_  3. Administration, caretaker's apartment, break hall

_  4. Specialist wing, sports hall, gymnastics hall, auditorium

From now on, the class cross was to serve as the centerpiece and first construction phase of the “growing school”. After installation, the lessons in the cross construction could begin immediately, while other school buildings were added all around. The following order was ideally typical:

• First construction phase: class cross
• Second construction phase: classrooms with differentiation rooms in pavilions
• Third construction phase: administration rooms, caretaker's apartment, common room / break hall
• Fourth construction phase: specialist class wing, gymnasium (Seitzhalle), smaller gymnastics hall, auditorium

The space available in the class cross corresponded to the requirements of the room and furnishing program for Hamburg schools from 1958. The " Arbeitsgemeinschaft Kreuzschulen", which consisted of Polensky & Zöllner and Paul Thiele AG , was commissioned with the production of the prefabricated parts for the cross structures .

The prototype at the Katharinenkirche was accepted on August 9, 1957. Still in August 1957 was followed by four further reductions of Kreuzbauten. In October 1961 the topping-out ceremony for the 50th Kreuzbau was celebrated on Corveystraße . On October 21, 1963, the last cross structure was removed on Krohnstieg. In just over six years the type had been built 67 times in Hamburg, 796 classrooms were built. Cross structures were also erected outside of Hamburg, for example in a modified form in the Gottfried Röhl elementary school in Berlin, which was built in 1961–1964 .

From the beginning of the 1960s, school building in Hamburg no longer kept up with the pace of new residential construction. In Bramfeld 1961 in the newly established Hegholt settlement of the layer classes were reintroduced, and 1965 of the announced school board responsible for school construction superintendent William Dressel public, have "lost the race with the new housing" that one. As an emergency solution, “classrooms and more classrooms” had to be built in the outskirts, the construction of gyms, break rooms, specialist rooms and auditorium buildings was postponed.

While the new school building was going ahead in absolute numbers throughout the city, the concept of the "growing school" stalled at the individual school locations, or from the mid-1960s only led to growth in classhouses of the newer series "Type 65", " Honeycomb "and" Type-68 "(" Double-H "). In some locations, gyms were only built ten years after the school opened, auditorium buildings only rarely. After the abolition of elementary schools in 1964 , the need for specialist rooms was concentrated in secondary schools; many of the Kreuzbau school locations from the early 1960s are now elementary schools.

Across the various types of buildings, the assembly construction program operated in the Hamburg school building was “unique in terms of scope” compared to other major West German cities. Nowhere else in the Federal Republic of Germany was there such a strong reliance on assembly and type buildings between 1950 and 1980 for new-build schools as in Hamburg, accompanied by a largely renouncement of individual designs. In the German-speaking area, this is only exceeded proportionally by the type school building in the GDR.

description

Window fronts (depiction aligned to the north )

_  Main window wall

_  Side window wall

West wing with main window wall ( left) and south wing with secondary window wall and front side with exposed brickwork (right)

Scheme of the window walls and orientation of the sashes

The Kreuzbau is a three-storey building with a cross-shaped floor plan. There are four classrooms on each floor, which are accessed by a central staircase, dispensing with corridors. From the stairwell, the schoolchild reaches his classroom through a small anteroom that serves as a cloakroom. Each classroom is assigned a smaller room for differentiation, which is separated by a glass wall. The classrooms are between 65 and 68 m² in size, the differentiation rooms 8 to 11 m². There are also toilet rooms on every floor.

Room layout

The floor plan of the cruciform building is not mirror-symmetrical . The shape of the cruciform floor plan is sometimes compared to the wings of a windmill because the surfaces of the wings are laterally displaced from the center of rotation. However, in contrast to the windmill, the floor plan of the cross structure is not rotationally symmetrical because the wings are not of the same length. This results from the fact that the wings are "pushed into" the floor plan of the stairwell to different degrees, because only two wings accommodate the toilet rooms and emergency stairwells and are correspondingly longer. In the usual setup, the north wing protrudes farthest from the building at around 17 m, while the shortest wing at around 12 m is either the west wing (tapered variant on the right) or the east wing (tapered variant on the left).

The floor plan of each classroom is in the shape of a right-angled trapezoid . With each of the four wings, one side goes off the stairwell at a right angle, while the other side of the wing tapers towards the front. The tapering side is the same for every wing, with some cross structures it is always the right, with others the left side. The four front sides are always parallel to the stairwell.

The depth of the classrooms is up to 8 m. If the room height is economical, this requires double-sided lighting, which also enables cross ventilation. Typologically, the class cross is therefore a cobbler type , as there are no corridors and each classroom is lit and ventilated from two sides. Each classroom has a main window wall with high windows and, on the opposite side, a secondary window wall with a light-diffusing glazed ribbon of windows close to the ceiling. The panel wall is always the front of the building.

Whenever the respective plot of land permitted, the cross building was always erected with maximum use of sunlight: the main window wall of the east and west wings faces south, while the north and south wings face east. Thus, when viewing two wings, there is a characteristic sequence of main and secondary window walls, from which the cardinal direction of the respective wing results.

Development

The concept of the pavilion school envisages a loose, organic arrangement of the buildings on a spacious plot of land, which are connected to one another by means of open arcades . These arcades were used regularly in Hamburg schools in the 1950s and early 1960s. These arcades were designed as elevated flat roofs supported by unadorned tubular frames. The arcades in Hamburg usually have a clear height of a little more than two meters and connect to the pavilions at the top of the doorway.

Apart from the emergency exits, the Kreuzbau has two entrances. These are arranged at the point of the adjoining wings, one entrance on the southeast side and the other entrance diagonally opposite on the northwest side. Thus, one entrance is between two secondary window walls and the other entrance between two main window walls. Due to the height of the windows in relation to the height of the arcades, only the north-west entrance can be connected to the arcade system, where the roof area of ​​the arcade can be guided under the lower edge of the side window strip. On the deeper main windows, the roof would otherwise run in front of the window area. Many cross structures are not (no longer) connected to the arcade system at their locations.

Behind the not very wide entrance glass door leads a porch in the central stairwell . The vestibule on the ground floor is placed in the same place in the floor plan as the escape connecting corridors on the two upper floors, which serve as a separate escape route there. The stairwell has a rectangular shape, the long side of which is oriented in the direction of the north-south axis. The actual staircase is located in the southwest corner of the stairwell and leads with two mutually perpendicular flights of stairs on a pedestal in the next bullet. The stairwell has the shape of a dragon square with strongly rounded corners. Together with the narrow metal handrails, this design looks very typical of the 1950s. The stairwell is on the inside, so it has no windows. Both the entrance doors on the ground floor and the escape connecting corridors on the upper floors are glazed, but on both sides of the vestibule or corridor. This prevents excessive daylight from entering the stairwell. Two circular skylights have been incorporated into the roof for additional lighting .

The fire protection concept of the cross structures stipulates that the main escape route leads through the stairwell, which thus forms the " necessary staircase ". In addition to this main staircase, there are two emergency staircases, which are located on the front sides of the north and west wings, and lead from there to the outside via emergency exits on the side. Each classroom therefore has a second escape route, either through a direct connection to an emergency staircase or through an escape connecting passage to an adjoining classroom, from where an emergency staircase can be reached. The escape connecting corridor is smoke-proof and separated from the main stairwell. This concept corresponded to the building police ordinance of 1938 valid at the time of construction, which was confirmed in 1957 and 1958 in deliberations of all responsible specialist commissions (so-called “theater commission”). In 1961 it was approved by the building authorities, which was confirmed again in 1974 by the building regulations office. First, cross structures of the "K1 V1" series were erected. In this first series, the two emergency staircases on the front surfaces of the north and west wings are glazed. Later series were made less complex, the emergency staircases are still there, but no longer visible from the outside.

Interior decoration

In 2012, the Hamburg Monument Protection Office commissioned an investigation into the post-war buildings of the Uferstrasse vocational school, which included a cross building, an eight-class wing and an administration building. This ensemble was placed under monument protection in 1973 together with the buildings by Fritz Schumacher . The following original design of the cross structure was worked out:

The interior of the cruciform building was designed on the vertical surfaces with glass elements, floor-to-ceiling wooden panels and light yellow exposed brickwork . These areas were structured both vertically and horizontally. The ceilings of the rooms were clad with rectangular acoustic panels, which were framed with simple wooden moldings at the transition to the wall surfaces. The doors leading from the stairwell were embedded in wood-clad wall surfaces and designed with exposed wood. The radiators and inner doors of the toilets were painted a light yellow-red shade. The doors leading from the classrooms were also designed with exposed wood and had glass panels. The slim staircase was made of exposed concrete , the handrail made of metal. The floor was covered with dark, iridescent floor tiles.

The classrooms were equipped with mobile chairs and tables, which was in contrast to the rigid school desks of the pre-war period. The rooms were permanently equipped with sound-absorbing ceiling cladding and built-in cupboards.

More than half of the cross structures were furnished with works of art that were purchased with funds from the building authority's “ Art in Architecture ” program . Mostly it was a wall painting or relief in the stairwell. The Hamburg artists supported in this way included (Street names of demolished cross structures (as of 2020) in italics): Ulrich Beier (Stephanstraße) , Gerhard Brandes (Walddörferstraße), Annette Caspar (Potsdamer Straße), Jens Cords (Schenefelder Landstraße, Fahrenkrön), Hanno Edelmann (An der Berner Au), Arnold Fiedler (Alsterredder), Heinz Glüsing (Beltgens Garden), Erich Hartmann (Vermoor), Helmuth Heinsohn (Wesperloh), Volker Detlef Heydorn (Windmühlenweg), Fritz Husmann (Sanderstraße), Diether Kressel (Brucknerstraße, Humboldtstraße), Nanette Lehmann (Fährstraße) , Max Hermann Mahlmann (Heinrich-Helbing-Straße), Maria Pirwitz (Schimmelmannstraße), Ursula Querner (Benzenbergweg), Albert Christoph Reck (Rahlaukamp), Walter Siebelist (An der Berner Au), Herbert Spangenberg (Stockflethweg), Eylert Spars (Francoper Straße, Hanhoopsfeld , Krohnstieg), Hans Sperschneider (Hinsbleek), Hann Trier (Struenseestraße) and Johannes Ufer (Neubergerweg).

Building construction and assembly

Main supports with slats for sun protection (Thomas-Mann-Straße, renovated)

In terms of construction, the cross structure is a skeleton structure made of precast concrete parts, which was erected on a foundation without a full basement and is closed off by a flat roof.

After the construction site had been set up, the basement and foundation were constructed using the conventional construction method: a boiler room was excavated and expanded under one of the four wings . The ceiling over the basement and the rest of the foundation were then made of reinforced concrete . All other ceilings of the cross building were assembled from 16 cm thick precast concrete parts. All these precast elements were special truck brought to the site where it means a single car crane were lifted to the installation - a tower crane was not needed.

The cross structure was assembled using auxiliary scaffolding that extended over two floors. This scaffolding was precisely aligned and served as a falsework for the temporary fastening of the reinforced concrete columns and wall parts as well as for supporting the ceiling panels. The largest components were the 10.7 m long vertical main columns that run through all three floors. The ceilings are designed as T- beams, with two to four main ribs (webs) transferring the load. Connection steels protrude inwards from the main supports, to which an edge beam made of in-situ concrete is attached, which connects the main supports with the ceilings. After the inner corner part was assembled, the building had enough stability against twisting and the auxiliary scaffolding was removed.

15 days after the start of the work, the concrete skeleton was in place and the flat roof could be provided. The construction was therefore practically independent of the weather, which can be seen from the completion dates, which did not have a winter break. After completion of the roof, the installation work and the drywall were carried out , while the front surfaces of the wings were bricked up at the same time .

Demolition or renovation?

Some of the series and prefabricated buildings of the Hamburg building authority from the post-war period are now considered not to be redeveloped. This applies particularly to the type A pavilions, the wooden frame walls of which were provided with an outer skin made of “Fulgurit” and an inner wall made of “Lignat”. "Fulgurit" and "Lignat" are brand names for fire-retardant asbestos cement panels . At the beginning of 1987, the city of Hamburg had its schools examined for asbestos and some of them closed. From 1988 onwards, 182 school pavilions in Hamburg were disposed of or torn down due to asbestos contamination. As of 1993, the use of asbestos in new buildings was generally prohibited. Cross structures are structurally not exposed to asbestos, so the question of renovation was primarily based on economic efficiency and space requirements.

Space requirements and state of construction

Unrenovated cross building (Eberhofweg)

From 2010, the decision to renovate or demolish or replace most of the cross structures became urgent: The cross structures were now around 50 years old and no longer met the current requirements, especially for thermal insulation . The barrier-free access required with increasing inclusion of handicapped students is only available in existing buildings on the ground floor. Unrenovated cross structures were therefore consistently rated 4 or 5 in the building classification of the Hamburg authorities from 2019 (1 = new building, 2 = basic renovation and compliance with all current standards, 6 = practically no longer usable). A building classification (GKL) of 2 is aimed for through renovation. At the same time, the number of students in Hamburg has risen sharply since the turn of the millennium. Between 2011 and 2020 alone, the number of schoolchildren increased by a total of 11%, and the number of primary school students by more than 17%. The increase of 11,600 primary school students from 2011 to 2020 alone corresponds to more than 500 classrooms with a maximum class frequency of 23 students. The number of pupils is expected to be around 240,000 by 2030, a further increase of around 20% compared to 2020.

In view of this development - the need for renovation on the one hand, and the rapidly growing space requirement on the other - the decision between renovation or demolition with a replacement building had to be made at most locations. In most cases, the Hamburg School Building Office (SBH) decided to renovate. If a school location was abandoned altogether or a comprehensive new building concept was implemented, the cross structures were also torn down. Cross structures are difficult to integrate into existing or new buildings, as there are no options for horizontal access . If a corridor is to lead from a directly adjacent building into a cross building, this can only be done via the front surface of a wing, which thus becomes a passage area and is lost as a classroom.

Around 80% of the cross structures were still standing in 2020 and were mainly used as classrooms by primary schools. The majority of the preserved cross structures have been renovated. A few cross structures are under ensemble protection , so they are listed. The accessibility for physically handicapped children has only been realized in one case - an elevator was installed in the stairwell in the cross building of the Hinsbleek school.

• 

  Demolition (Königstrasse), facade panels and end face insulation removed

• 

  Refurbished school with massive thermal insulation (Hohe Landwehr)

• 

  Refurbished school with careful design (Schierenberg)

• 

  Art in architecture (Kurdamm)

Thermal insulation

Due to the almost always missing monument protection, the Energy Saving Ordinance applied without any compromises in these renovations . This led to "large thermal insulation package [s]" and an often "coarse renovation". The slender profiles of the windows and pillars were often lost, and in some cases the shading slats were also removed. A positive counterexample is the renovation of the cross building on Schierenberg, in which the reinforced concrete pillars were removed from the insulation. These only have direct contact with the building structure at the ceilings and therefore contribute little to heat loss. The non-load-bearing walls and windows, on the other hand, were rebuilt instead of packing the old construction with an insulating layer on wooden battens, as is usually the case.

The yellow clinker bricks of the original buildings will be lost in any case, as the thermal insulation layer requires a new attachment. At Schierenberg, green and white glass mosaics were chosen for the parapets and black clinker bricks on the end walls - a quote from the architecture of the 1960s, but not a reconstruction. On the other hand, strong color contrasts were used in some renovated cross-shaped buildings (Beltgens Garten, Stengelestrasse), but often a color scheme that matches the original materials is sought.

architectural art

In front of and in some of the cross structures planned for demolition, works by well-known artists were set up or attached. As far as these works were easy to dismantle, they were mostly moved to other buildings at the school site. Sculptures in front of cross structures were moved. Wall paintings or frescoes , on the other hand, are firmly attached to the building.

There were three wall paintings by Eduard Bargheer from 1959 in the cross building of the Rahlstedt high school . The expansion of the image carriers with the listed images was calculated at 150,000 euros. In 2019, two of the three paintings were installed in the atrium of the new high school building; the remaining painting was damaged during the expansion.

Fire protection

Glazed emergency staircase (Ohkamp)

Despite the repeated tightening of fire protection regulations since 1938, the crossed structures also correspond to the current status. The Hamburg fire protection regulations for school buildings from 2001 require that every classroom on the same floor must have two independent escape routes to exits to the outside or to necessary stairwells . The length of the escape route to reach the stairwell is limited to a maximum of 35 m. Since the classrooms are 9 m long and up to 8 m wide, the most distant corner results in a diagonal of 12 m per classroom, which in the worst case has to be crossed twice. This leaves more than enough escape route length for the escape connecting passage between the classrooms. The second escape route in the emergency stairwells must be kept clear, the other requirements for door and aisle width are met. If this had not been the case, an external staircase would have to be added to at least two of the wings during renovation, with corresponding costs.

The practical suitability of the escape concept has so far been "tested" in one case: At the Eckerkoppel school, a fire broke out in the Kreuzbau while the school was still in operation. The fire started on the first floor of the east wing and from there set fire to the floor above and the flat roof construction. All students were evacuated, there was no personal injury. Two classrooms were completely burned out, a third classroom was badly damaged by extinguishing water and soot. The cross building was demolished in a row. As a replacement, after one year of planning and nine months of construction, a modular wooden building of the "Hamburg class house" type was erected, which accommodates twelve classes on two floors. The new building was occupied in January 2020. The next phase of the series construction of classhouses in Hamburg has thus begun.

Classification and evaluation

The cross construction was part of the attempt to accelerate the construction of the school and to significantly increase the space efficiency compared to the pavilion school, while maintaining the ideal of the "school in the country". These goals were partially met, but the “growing school” concept has not been able to keep pace with the need for classrooms. A balanced relationship between classhouses, communal buildings and green spaces was seldom achieved, especially not with buildings that followed the same style. Instead, many school locations in Hamburg have a mixture of series buildings of different generations and styles that are laid out like annual rings around the schoolyard - starting with lightweight pavilions, then a cross structure, plus a Seitz gym and administration with a clinker facade, and finally honeycomb structures made of concrete or a string of type 65 bars .

From a functional and aesthetic point of view, the Kreuzbau is a successful design - as a single building. The “communicative central staircase” and the “quality of the trapezoidal floor plan” of the classrooms are praised, which in addition to frontal teaching also provide a good setting for other forms of group work. The “generous sun protection” is also emphasized. After all, the “defining shape of the building” creates something like a focal point of the school grounds, especially in comparison to the low box shapes of the other Hamburg series buildings. However, the Kreuzbau does not stand alone, but is part of an ensemble . In 1961, the later Hamburg chief building director Egbert Kossak expressed a devastating criticism of the “inferior, stenciled school building” in Hamburg in a letter to the editor: “The 'famous' class cross, pavilion and gym blocks are scattered across Hamburg with astonishing but unresisting monotony. [...] Hamburg [...] prides itself on the mass production of non-proportionate buildings, which stand out for their questionable modernist design. "

The main advantage of the type construction was the quick assembly with only a few workers, as there was an immense need for school replacement buildings and new buildings in post-war Hamburg, which the construction industry could not satisfy in the conventional way. The goal of reducing costs compared to individual designs or solid buildings, however, was not achieved - this is shown in comparison with the designs for special schools, which were also carried out in the Seitz era by individual architects outside the building construction department. The poor thermal insulation compared to today's requirements results from the typical construction with slim profiles and many thermal bridges . In this respect, the Kreuzbau is neither better nor worse than other buildings from the post-war period. At least it is not contaminated with asbestos, the renovation is usually much cheaper than a replacement. Due to the design, the cross structure cannot be easily connected to new buildings. Carefully refurbished, it can be an appealing solitaire .

Locations

The following list of the Kreuzbauten in Hamburg does not claim to be exhaustive. Legend :

• #: Numbering of the cross structures in alphabetical order by name
• Name: current user of the Kreuzbau. In primary schools the name is shortened to "School", in district schools to "STS"
• Address: Street address of the school location, linked with coordinates. A map with all coordinates is linked at the top of the article.
• District: District of the location of the building of the cross
• District: District of the site of the building of the cross
• Year: Year of construction of the cross construction, defined as the year of acceptance .
• Image: Link to Commons -category to the school location: “Yes”, there are images of the corresponding cross structures; "-", no pictures of the cross structures, but information about the school building
• Notes: state of construction, monument protection, renovation. The “First Series” is the name given to cross structures of the “K1 V1” type, which have two glazed emergency staircases.

In the case of demolished cross structures, the corresponding line is highlighted in gray.

literature

• Boris Meyn : The architect and urban planner Paul Seitz. A work monograph . Association for Hamburg History, Hamburg 1996, ISBN 3-923356-73-0 .
• Boris Meyn: The history of the development of the Hamburg school building (= writings on cultural studies. Volume 18). Kovač, Hamburg 1998, ISBN 3-86064-707-5 .
• Olaf Bartels: Kreuzbau am Schierenberg . In: Bauwelt , No. 47.2015, pp. 30–33.
• The Hamburg class cross . In: Das Werk: Swiss Monthly for Architecture, Art and the Artistic Trade , ZDB -ID 2529081-2 , Volume 50 (1963), Issue 6 (“School building”), pp. 234-236, doi: 10.5169 / seals-87079 .
• Paul Seitz, Wilhelm Dressel (ed.): School building in Hamburg 1961 . Publishing house of work reports, Hamburg 1961.
• Building authority of the Free and Hanseatic City of Hamburg (ed.): Hamburg schools in assembly construction . Hamburg 1962, PPN 32144938X .

Web links

Commons : Kreuzbau (Hamburg)  - Collection of images, videos and audio files

• Energetic renovation of the Kreuzbau primary school in Surenland , brochure from SBH Schulbau Hamburg with floor plan
• Video recordings of the renovated cross building at the Meiendorf grammar school (formerly Schierenberg school): aerial photo , entrance , ground floor , stairwell

Individual evidence

1. ↑ Reiner Lehberger: School in the post-war period . Extract from Lehberger, de Lorent: Schools in Hamburg . Brunswiker & Reuter, Hamburg 2012, ISBN 978-3-921174-23-4 .
2. ↑ Christel Oldenburg : Tradition and Modernity - the Hamburg SPD from 1950–1966 . Lit, Berlin 2009, ISBN 978-3-8258-1970-5 , p. 216 f.
3. ^ Boris Meyn : The architect and town planner Paul Seitz . Hamburg 1996, p. 83.
4. ^ Boris Meyn : The architect and town planner Paul Seitz . Hamburg 1996, p. 9 ff.
5. ↑ Peter Krieger: “Economic miracle reconstruction competition”: Architecture and urban development of the 1950s in Hamburg . University of Hamburg, Hamburg 1996, urn: nbn: de: gbv: 18-136 , pp. 205–207 (university publication ). The quote there on p. 205.
6. ↑ Michael Baltzer, Hartmut Gerbsch: Paul Seitz: Flying Buildings . In: Westwerk and HafenCity University (ed.): Catalog for the exhibition in the series “Stadt-Schnitt”, Part 1, Hamburg 2012, pp. 22–37. ( Online )
7. ↑ ^{a b c d e f g h i j k l} Boris Meyn: The history of the development of the Hamburg school building . Hamburg 1998, pp. 257-259.
8. ↑ Boris Meyn : The history of the development of the Hamburg school building . Hamburg 1998, pp. 256-257.
9. ↑ List of recognized monuments according to § 7a Hamburg Monument Protection Act , excerpt from Hamburg-Mitte district, as of June 25, 2007, p. 99. ( Online )
10. ↑ A matter of opinion . In: Quartier , ZDB -ID 2446508-2 , No. 07 (September – November 2009)
11. ↑ ^{a b c d e f g} The Hamburg class cross . In: Das Werk , ZDB -ID 2529081-2 , Volume 50 (1963), Issue 6, pp. 234-236.
12. ↑ ^{a b c d e f} Citizenship of the Free and Hanseatic City of Hamburg (ed.): Safety deficiencies in "cross structures" in the event of fire , written small question from the MPs Sybill Buitrón Lübcke (CDU) of October 8, 1997 and the Senate's answer of October 17 1997. Printed matter 16/5, 16th electoral term.
13. ↑ Topping-out wreath over 50th class cross . In: Hamburger Abendblatt , ISSN 0949-4618, October 18, 1961, p. 3. ( Online )
14. ↑ Meyn (1998) cites on page 259 the number of 57 cross structures up to 1962, which resulted in 684 classrooms. The number of 67 cruciform buildings up to 1963 results from the parliamentary question of October 8, 1997 (printed matter 16/5). 65 of these buildings were standard cross structures with three floors and 12 classrooms, the two cross structures on Kurdamm in Wilhelmsburg only have two floors and therefore 8 classrooms. From this arithmetically the number of 796 classrooms results.
15. ↑ It is now clear: The lessons are coming in shifts . In: Hamburger Abendblatt , March 7, 1961.
16. ↑ New school building is lagging behind . In: Hamburger Abendblatt , January 22, 1965, p. 3.
17. ↑ Resource Type 68 - Full assembly technology in school buildings in Hamburg . Lecture as part of the Hamburg Architecture Summer 2019, held on May 18, 2019 in the Aula of the Schule am See, Borchertring 38, Hamburg-Steilshoop. (Summary in the program for the Hamburg Architecture Summer 2019 , p. 104.)
18. ↑ Hanns Freymuth: Light . In: Heinz-Martin Fischer (ed.): Textbook of building physics . Vieweg and Teubner, Wiesbaden 2008, ISBN 978-3-519-55014-3 , p. 502. ( Online )
19. ↑ ^{a b} Culture Authority (ed.): Color investigation staircases Uferstraße 9 , published on February 6, 2017. (File 102-01.4 / 32/5 in the transparency portal )
20. ↑ Hamburgische Bürgerschaft (Ed.): Works of art in public space , written small request from August 7, 2018. Printed matter 21/13978, 21st electoral period.
21. ↑ "lignate" are asbestos fiber cement building boards from the Cologne timber-Werke GmbH & Christoph Unmack, "Fulgurit" was created by Fulgurit plant Luthe made.
22. ↑ These schools have asbestos . In: Hamburger Abendblatt , ISSN 0949-4618, 26./27. March 1988, p. 4. ( Online )
23. ↑ Citizenship of the Free and Hanseatic City of Hamburg: Asbestos pollution in Hamburg schools , written small inquiry from Sabine Boeddinghaus , answer of April 11, 2019, printed matter 21/16869. ( Transaction number 21/16869 )
24. ↑ Citizenship of the Free and Hanseatic City of Hamburg, 21st electoral period: Answer of the Senate to the written small question of the MP Birgit Stöver (CDU) of May 21, 2019 (“Building classification up to date?”), Published on May 21, 2019, Printed matter 21/17216. ( Online process ) Compare the unrenovated cross structure of the Eberhofweg school ("class building", building no. 3, grade 4) with the renovated cross structure of the Hohe Landwehr school ("class building", building no. 4, grade 5 - 2014, after renovation grade 2 - 2019)
25. ↑ Authority for Schools and Vocational Training: How is the number of pupils developing? , Statistics from school year 2011/12 to 2020/21. (Accessed in March 2021.) The total number of students rose from approx. 180,000 to approx. 200,000, the number of primary school students (including pre-school classes) rose from approx. 65,800 to approx. 77,400 students.
26. ↑ Free and Hanseatic City of Hamburg, Authority for Schools and Vocational Education and Training (Ed.): School development plan for state primary schools, district schools and grammar schools in Hamburg 2019 . Hamburg, September 24, 2019, pp. 4–6. (Final version, online )
27. ↑ This applies to the Wesperloh school and the Uferstraße school, the school at the Katharinenkirche was demolished despite being a listed building.
28. ↑ renovation Kreuzbau - Elementary school Hinsbleek , published in 2014. (August 20, project at ABJ architects , Hamburg)
29. ↑ ^{a b c d e} Olaf Bartels: Kreuzbau am Schierenberg . In: Bauwelt , No. 47.2015, pp. 30–33.
30. ^ Wall painting by Eduard Bargheer in the high school Rahlstedt (II) , written small request from Ole Thorben Buschhüter (SPD), printed matter 21/9098 from May 15, 2017.
31. ↑ Ole Thorben Buschhüter: High School Rahlstedt: First Bargheer painting is back . April 11, 2019, website of Ole Thorben Buschhüter
32. ↑ Building authority, Office for Building Regulations and Building Construction (Ed.): Requirements for the construction and operation of schools (BPD Schulbau), Article 3.1 (“General requirements”) and note on number 3.3 (“Necessary corridors”). In: Building Inspection Service (BPD), ZDB -ID 1016124-7 , 3/2001.
33. ↑ Hamburg Fire Brigade: Fire 2nd alert, Berner Heerweg - Eckerkoppel primary school . Press release from February 6, 2018 ( online )
34. ↑ Support after a school fire at the Eckerkoppel , description by the Association of Friends and Patrons of the Eckerkoppel school
35. ↑ Eckerkoppel primary school , SBH Schulbau Hamburg
36. ↑ Invitation to the inauguration party , Eckerkoppel School, February 27, 2020.
37. ↑ Architecture and work form . No. 5/1961, p. 247.
38. ↑ Class cross for engineering school . In: Hamburger Abendblatt , ISSN 0949-4618, October 18, 1958.
39. ↑ Made-to-measure class crosses . In: Hamburger Abendblatt , ISSN 0949-4618, Volume 10, No. 198 (August 27, 1957), p. 3. ( Online )

 Map with all coordinates: OSM | WikiMap

This article was added to the list of excellent articles in this version on May 31, 2021 .