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Extension made of Ligno® for the municipal elementary school Obering

Class goal: schools made entirely of wood!

In Germany, many school buildings are currently clearly reaching their limits. They are in need of renovation, are only partially suitable for modern teaching and learning concepts, or are simply too small. New space is needed - preferably made of wood, because this renewable natural material is ideal for constructing educational buildings quickly, sustainably and in an environmentally compatible manner. The city of Herford also opted for a wooden building for the extension of the Obering municipal elementary school: Walls, ceilings, roof and even the facade are made of configurable cross-laminated timber components from the Black Forest manufacturer Lignotrend. The modern wooden architecture provides a pleasant, natural learning environment as well as the best sound and fire protection and establishes good speech intelligibility in the interior rooms.
 

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In the Friedenstal district of Herford, the Obering municipal elementary school has been given a two-story extension made entirely of wood. The reason for the extension was the increasing number of pupils in the North Rhine-Westphalian Hanseatic city. The new building was created according to plans by IAB Herford, the city's real estate and wastewater company, and was implemented in cooperation with the architectural firm xtraplan from Detmold. The timber construction work with configurable cross laminated timber components made of Ligno® was carried out by the company Terhalle Holzbau from Ahaus.

 

Clear floor plan concept ensures good orientation

The modern flat-roof building connects directly to the existing school building with a connecting corridor and opens up to the nearby meadows and fields in the east with a floor-to-ceiling glazed window front. Individual glass fields are designed in color and conjure up cheerful light reflections on the interior walls. On the first floor, the rooms have large French doors, direct connection to the outside. The large roof and facade overhang along the window front forms an effective rain and sun protection.


The floor plan concept is clear and uncluttered: both school floors are organized almost identically - with two classrooms each for up to 23 students and one subject room and one support room, which are lined up next to each other. The main entrance area to the new building is located at a representatively designed, fully glazed corner between the old and new buildings. In bright signal red, the school gate offers elementary school students quick orientation. In the foyer, the eye is immediately drawn to the wave-shaped blue wall behind which the entrance zones to the classrooms and to the specialist and support rooms with their checkrooms and sanitary facilities are sheltered. In this way, the "public" circulation areas are separated from the more "private" rooms belonging to the classes - which gives the elementary school children a feeling of security in their often hectic everyday school life.


Vis-à-vis: the single-flight main staircase to the upper floor. The space below is used for three large niches that provide additional retreat space for the children.A second staircase is accessible separately from the courtyard and is mainly used by the teaching staff. This part of the building houses a team room for the teachers, a room for early care, and the server and building services room.

Configurable wood components meet the special requirements

There are special requirements to be met when building schools: In classrooms, large spans have to be bridged, extensive cable routing has to be implemented in the ceilings, and the requirements for fire resistance and sound insulation are also high. Lignotrend was able to respond to these needs with its configurable ceiling and roof components for the project in Herford, thus offering architects and woodworkers high added value in terms of planning. Depending on the load, the ceiling and roof components Ligno Rippe Q3 and Ligno Block Q3 can span up to ten meters, in the roof even more - and come with a finished, room-acoustically effective real wood soffit ex works.  


In the classrooms in Herford, they span over eight meters from inner wall to inner wall without supports. Among other things, this has the advantage that the large window front could be glazed as a filigree post-and-beam construction without being interrupted by ceiling supports, thus allowing plenty of daylight to enter the classrooms. 


The tested structure of the ceiling components made of Ligno® with a lime chippings filling and a matching layering ensures the best sound insulation even in the low-frequency range and efficiently prevents impact sound transmission between the floors. Another advantage of the fill is that it makes the ceiling elements safe components with a fire resistance of up to REI 90 because they are free of cavities. Bulkhead solutions tested for the system allow cables to be routed through in compliance with fire protection requirements.

 

 

Constructive details for special design

The walls were constructed from wall elements Ligno Uni Q3. Towards the interior, they have a closed surface in silver fir. In the stairwell, the wooden surface is visible throughout over two floors and is structured by a precise joint pattern. In the classrooms, narrow shadow gaps at the transition to the ceiling surfaces create the impression that they float above the rooms like the sky.

 

"While we already had experience with the ceiling system from Lignotrend from other construction projects, the use of the walls was new to us," reports master carpenter and energy consultant Martin Lenz, who managed the construction project at Terhalle. "However, the system makes it easy for us timber builders: the precise components prefabricated in the factory convinced with their high fitting accuracy - this allowed very clean work and fast construction progress on the building site. In addition, the structural details also make it possible to realize special design features, such as the installation of joists in the cross-laminated timber rib element at the same level as the ceiling."

 

 

Slim wooden partition walls with the partition wall system Ligno uni*versa

For the interior walls with higher sound insulation requirements, the cross laminated timber elements with a wooden face on one side were given an additional shell with the uni*versa construction profiles on the back. The separating profiles are installed here within the wall in an oscillating manner. The wall structure can thus be realized much more slenderly overall and is made of wood through and through. With the sound reduction index Rw of up to 54 dB, the requirement for classroom walls is met.

 

 

High room quality - room acoustic, visual and climatic

The supervision rooms are each located between two classrooms. Instead of a closed wall, floor-to-ceiling fixed glazing allows visual contact with the classrooms and makes it easier for teachers to supervise both the school class and the care group at the same time. The high quality of quiet in the rooms is striking: Since the floor ceilings are equipped ex works with acoustic profiling and integrated sound absorbers to reduce noise levels, all target values for speech intelligibility are met and quiet and concentrated teaching is already spatially guaranteed.

 

With their aesthetically high-quality surfaces, the elements also ensure high architectural quality: In Herford, the planners chose the popular light-colored, knot-free silver fir with uniformly wide strip profiling, which allows for calm, design-oriented interior architecture. In schools, special attention is paid to building biology: Here, too, Lignotrend products make their contribution through certified natureplus® quality and ensure good and healthy indoor air.

 

Configuration overview

Components used

  • LIGNO Rippe Q3  |  Ceiling component

    Product code:LIGNO Rippe Q3_185_r0_s0_z26_p26_a50g_625-12-4_WTL_gb_buv
    Installation top


    Whether the element is open or closed at the top is determined by the area of application. If, for example, the element is to be filled with fill on site as a storey ceiling or roof terrace (LIGNO Rippe Q3-x), its cavities are open at the top (feature _r0). To guide pipes at the top of the element, a cross grid (_r25, _r50) can be added to some superstructures. For roof superstructures, there is usually a flat closed finish _rg0 (LIGNO Block Q-x, LIGNO Block Q3-x or corresponding versions of LIGNO Akustik klassik).

    Installation top

    _r0 Open, without cross grid

    Statics


    The height of the load-bearing webs of the element is variable and determined according to static requirements from load and span. Within the framework of this configurator, the selection is limited to four height ranges. A more precise definition is made later during pre-dimensioning or verification with the LTB-x calculation programme. Bulk volume and/or necessary space for installations can also be decisive for the height.

    Statics

    _150-210 Small span

    Fire resistance


    If fire protection is required, an additional layer is added below the web area (for elements with strip profiles _z26, _z53, _z80, for elements with board profiles Akustik klassik _k50g). Their height determines the fire resistance duration of the cross-section from 30 to 90 minutes. The fire resistance must be statically verified. If there are no requirements, the standard versions _z0 or _k50l are to be selected.

    Fire resistance

    _z26 REI 30 Fire resistance 

    Cavity

     

    Panel designs with slat profiles and additional layer can be configured with an additional cavity (_p26, _p53) below the additional layer for installation guides, fixtures or to improve sound absorption. Cables laid there then do not penetrate the fire-protection layer. If required, the cavity is filled with insulating material (_p26mw, _p26ha) to improve acoustic absorption. If no cavity is necessary, the characteristic _p0 is selected.

    Cavity

    _p26 26 mm Height 

    Room acoustics


    If the soffit of the element is to have a good sound-absorbing effect, the penultimate layer is configured as absorber _a50g. Otherwise, this layer is configured as a solid wood layer _a0.

    Room acoustics

    _a50g 50 % Absorber 

    Profile


    The visible layer is profiled with joints. The code for profiling indicates in millimetres: Element width, strip width (rounded, from/to if applicable) and joint width (rounded) as well as a letter identification for variants, e.g. with chamfered strip edges or with additional height gradation.

    Note: Some profiles indirectly cause exclusions for other configuration options.

    Profile

    _625-12-4 Slat profile 

    Wood type

     

    Various wood species are available for the visible layer. For quality reasons, individual wood species cannot be configured for all profiles; for technical reasons, surface treatments are excluded for some wood species.

    Wood type

    _WTL Silver fir knotless, patterned 

    Strukture

     

    The face is subjected to a brushing _gb as standard, which produces a stronger or weaker structure depending on the type of wood and makes the surface less sensitive to scratches.  Alternatively, a smooth sanding _gs can be carried out, or on request a bandsaw cut _grimitated.

    Strukture

    _gb Brushed

    Treatment


    Depending on the type of wood, the optional application of a surface treatment is possible ex works. Individual colour finishes are always sampled for coordination. For elements in individual lengths, colour treatment is limited to max. 5 m length.

    Treatment

    _buv UV-protection stain

  • LIGNO Block Q3  |  Roof component

    Product code:LIGNO Block Q3_275_rg0_s0_z26_p26_a50g_625-12-4_WTL_gb_buv
    Installation top


    Whether the element is open or closed at the top is determined by the area of application. If, for example, the element is to be filled with fill on site as a storey ceiling or roof terrace (LIGNO Rippe Q3-x), its cavities are open at the top (feature _r0). To guide pipes at the top of the element, a cross grid (_r25, _r50) can be added to some superstructures. For roof superstructures, there is usually a flat closed finish _rg0 (LIGNO Block Q-x, LIGNO Block Q3-x or corresponding versions of LIGNO Akustik klassik).

    Installation top

    _rg0 Closed, without cross grid

    Statics


    The height of the load-bearing webs of the element is variable and determined according to static requirements from load and span. Within the framework of this configurator, the selection is limited to four height ranges. A more precise definition is made later during pre-dimensioning or verification with the LTB-x calculation programme. Bulk volume and/or necessary space for installations can also be decisive for the height.

    Statics

    _230-290 Medium span

    Fire resistance


    If fire protection is required, an additional layer is added below the web area (for elements with strip profiles _z26, _z53, _z80, for elements with board profiles Akustik klassik _k50g). Their height determines the fire resistance duration of the cross-section from 30 to 90 minutes. The fire resistance must be statically verified. If there are no requirements, the standard versions _z0 or _k50l are to be selected.

    Fire resistance

    _z26 REI 30 Fire resistance

    Cavity


    Panel designs with slat profiles and additional layer can be configured with an additional cavity (_p26, _p53) below the additional layer for installation guides, fixtures or to improve sound absorption. Cables laid there then do not penetrate the fire-protection layer. If required, the cavity is filled with insulating material (_p26mw, _p26ha) to improve acoustic absorption. If no cavity is necessary, the characteristic _p0 is selected. 

    Cavity

    _p26 26 mm Höhe

    Room acoustics


    If the soffit of the element is to have a good sound-absorbing effect, the penultimate layer is configured as absorber _a50g. Otherwise, this layer is configured as a solid wood layer _a0.

    Room acoustics

    _a50g 50 % Absorber

    Profile


    The visible layer is profiled with joints. The code for profiling indicates in millimetres: Element width, strip width (rounded, from/to if applicable) and joint width (rounded) as well as a letter identification for variants, e.g. with chamfered strip edges or with additional height gradation. 

    Note: Some profiles indirectly cause exclusions for other configuration options.

    Profile 

    _625-12-4 Slat profile

    Wood type


    Various wood species are available for the visible layer. For quality reasons, individual wood species cannot be configured for all profiles; for technical reasons, surface treatments are excluded for some wood species.

    Wood type

    _WTL Silver fir knotless, patterned

    Structure


    The face is subjected to a brushing _gb as standard, which produces a stronger or weaker structure depending on the type of wood and makes the surface less sensitive to scratches.  Alternatively, a smooth sanding _gs can be carried out, or on request a bandsaw cut _grimitated.

    Structure

    _gb Brushed

    Treatment


    Depending on the type of wood, the optional application of a surface treatment is possible ex works. Individual colour finishes are always sampled for coordination. For elements in individual lengths, colour treatment is limited to max. 5 m length.

    Treatment

    _buv UV-protection stain

  • LIGNO Uni Q3  |  Wall component 

    Product code:LIGNO Uni Q3_123_625-621-4_WTL_gb_buv
    Statics


    The height of the load-bearing webs of the element is variable and determined according to static requirements from load and span. Within the framework of this configurator, the selection is limited to four height ranges. A more precise definition is made later during pre-dimensioning or verification with the LTB-x calculation programme. Bulk volume and/or necessary space for installations can also be decisive for the height.

    Element height

    _123 mm 

    Profile


    The visible layer is profiled with joints. The code for profiling indicates in millimetres: Element width, strip width (rounded, from/to if applicable) and joint width (rounded) as well as a letter identification for variants, e.g. with chamfered strip edges or with additional height gradation. 

    Note: Some profiles indirectly cause exclusions for other configuration options.

    Profile 

    _625-621-4 Closed surface 

    Wood type


    Various wood species are available for the visible layer. For quality reasons, individual wood species cannot be configured for all profiles; for technical reasons, surface treatments are excluded for some wood species.

    Wood type

    _WTL Silver fir, patterned

    Structure


    The face is subjected to a brushing _gb as standard, which produces a stronger or weaker structure depending on the type of wood and makes the surface less sensitive to scratches.  Alternatively, a smooth sanding _gs can be carried out, or on request a bandsaw cut _grimitated.

    Structure

    _gb Brushed

    Treatment


    Depending on the type of wood, the optional application of a surface treatment is possible ex works. Individual colour finishes are always sampled for coordination. For elements in individual lengths, colour treatment is limited to max. 5 m length.

    Treatment

    _buv UV-protection stain

  • LIGNO U*psi  |  Insulation joist

    Product code:LIGNO U*psi F_n_200
    Insulation joist


    The lower the U-value of a component and the lower the psi value of the details, the less heat is lost.This is precisely where the U*psi cross-laminated timber insulating uprights from Lignotrend come into effect:They implement high insulating thicknesses in natural timber and minimise thermal bridges.

    Insulation joist

    Fleece as chamber separation

Reference-related

Downloads

Projektbeteiligte

  • Hansestadt Herford

    Client

    Auf der Freiheit 21

    32052 Herford

     

    www.herford.be

  • Hansestadt Herford

    Architect

    Auf der Freiheit 21
    32052 Herford
     

    www.herford.com

  • xtraplan Döring + Harmann GbR

    Architect

    Bahnhofstraße 7
    32756 Detmold
     

    www.xtraplan.com

  • Frank Aussieker Architekturfotografie

    Photographer

    Stephanusstraße 27
    30449 Hannover

     

    www.aussieker-fotografie.de

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