Jurigerhalde Students Accommodation Constance

Herbert Schaudt

Subject | The provision of low-cost housing is becoming an ever more important aspect of building. One particular group of users needing special attention is students. Low incomes, relatively short periods of residence and a tendency to share accommodation are the most important requirements for this group. In 1989 the German Association for Student Affairs in Constance promoted an open competition to design a hall of residence for students. The building plot was situated on the edge of a residential area within sight of the university. Schaudt Architekten won first prize and was awarded the contract to proceed with the detailed design and realization of the project. Their design was favoured because of the skilful arrangement of the individual buildings on the site, which achieved an optimum density but at the same time a good standard of living for the occupants. Moreover, cost-savings were anticipated as a result of the proposed timber-frame construction, the use of a standard planning grid throughout and the well-conceived layout which allowed for possible conversion into independent family-sized homes. Following an intensive planning period and short construction time, the buildings were ready to move into in September 1992.

Design | The hall of residence comprises 17 more or less identical, two-storey terraced houses arranged in five units, each with a different length. Each terraced house is intended to provide shared accommodation for six students. The individual buildings are grouped around common open spaces in such a way that private, semi-private and public areas are created. The same principle is applied inside the buildings, with a common staircase and entrance hall which also serves as a communal area. Owing to the high water table caused by a nearby wet area, the buildings were raised on stilts. The ensuing space underneath is used for storage and parking. All the buildings have their own entrance doors reached via a common external walkway. Besides the entrance area, staircase and kitchen, the ground floor level of each house also contains two (11 m2) bedrooms; both the first floor and the second floor also each contain two further bedrooms. The bathroom is located on the first floor and the utility room on the second floor. Each house is allocated a garden at the rear.

Location

Studentenwohnheim Jungerhalde, Am Schmerzenmösle 36, 78464 Constance, Germany

Client

Studentenwerk Konstanz Architect

Schaudt Architekten BDA, Constance Project Architect Helmut Hagmüller Design Team: Thomas Bald-auf, Gregor Mertens, Jürgen Jakob, Thorsten Gabele

Structural Engineer Arlt, Constance

Sound and Thermal Insulation

Prof. Dr.-lng. Karl Gösele, Leinfelden-Echterdingen

Timber Construction Kaspar company, Gutach

General Contractor Wieland company, Singen

Date of Completion 1992

Costs

The costs of construction, excluding land and internal furnishings and fittings, was 6 718 700 DM for a total volume of approx. 8470 m3 and a total living area of approx. 1780 m2.

5 | Section through facade, scale 1:25. i Roof construction: profiled aluminium sheeting, 120 mm thermal insulation, vapour barrier, 28 mm boarding, 120 x 180 mm rafters. 2 Floor construction: rubber floor covering, 40 mm cement screed, polyethylene sheet, 25 mm impact-sound insulation boards, 30 mm chipboard (or gravel),

96 28 mm boarding. 3 Wood windows: fir frame with solar-control double glazing. 4 External wall construction: 120 x 120 mm columns, 12 mm plasterboard on 40 x 107 mm timber framing, vapour barrier, ioo mm thermal insulation, 2 No. 13 mm bituminous soft boards, 24 mm rough-sawn fir weatherboarding on 40 x 60 mm battens. 5 Ground floor construction: as for upper floors but with additional thermal insulation and fire protection, each 40 mm thick. 6 Walkway: hot-dip galvanized steel.

6 | Section through roof showing clerestory window, scale 1:50. Internal wall construction: 19 mm ViooEi chipboard, 48 x ioo mm timber framing on all sides, special "Compriband" seal all round, 80 mm mineral fibre board, 19 mm V100E1 chipboard; total thickness 120 mm.

7 | Horizontal section through facade, scale 1:25. The external corner according to the "Mies corner" principle. The separating joints between the individual houses are filled with thermal insulation. The construction deviates from the i m grid at this point: the centre-to-centre spacing is 240 mm, hence the gap of 120 mm. All joints on the outside are sealed with a special "Compriband" seal.

8, right | Corner detail of the Alumni Memorial Hall, NT Chicago (1945) by Ludwig Mies van der Rohe: the "Mies corner".

Structure | Each of the terraced houses consists of a timber framework in the beam-and-column system laid out on a 1 x i m grid. Each house is an independent structure, totally separated from its neighbours both in terms of the centre-to-centre dimensions and the construction. The loadbearing columns of the framework are 120 x 120 mm glulam members and rise from foundation to roof in one piece. Intermediate columns, starting at ground floor level, are also 120 x 120 mm glulam members. Beams and floor joists are all in the same plane and consist of standardized solid 120 x 220 mm members. The connections between these and the connections to the columns are formed by plates with welded-on flats screwed onto the loadbearing members; the flats are then let into slots in the beams and bolted through. As the joists for the upper floors are exposed, this type of hidden joint represents a significant visual improvement. Using the 1 m grid throughout resulted in equal-length beams and identical connections which in turn allowed for extensive préfabrication and considerable simplification during production and assembly. Wind bracing is provided by steel ties with screw tensioners, arranged as X-bracing. This bracing is placed within appropriate bays in the framework and is then covered over by the wall construction.

The external walls are provided with 100-mm-thick thermal insulation in the bays of the framework, covered by a vapour barrier and 12 mm plasterboard on the inside. The plasterboard is fixed flush with the inside face of the structural members, i.e. the columns remain exposed, and together with the exposed floor joists determine the internal appearance. This flush arrangement is achieved by attaching the plasterboard to 40 x 107 mm members recessed into the bays of the timber-frame construction. Covering the insulation externally are two layers of 13 mm soft boards. These are then covered by horizontal or vertical 24 mm rough-sawn fir weatherboarding on 40 x 60 mm battens. All in all, a form of construction offering a high degree of thermal insulation. The detail at the external corners is interesting, reminding the viewer of the famous "Mies corner". However, owing to the low overall height, the exposed corner columns could be made from timber and do not require any cladding. Avoiding the use of a different material makes this corner detail almost more logical. The fir-frame windows are screwed onto the structural members from the outside and are sealed with a special "Compriband" seal let into a groove in the wood. The solar-control-glass, double-glazed windows have a special gas filling enabling them to achieve the very favourable U-value of 1.3 W/m2K.

The floor construction above the joists is made up of 28 mm tongue-and-groove boarding with either a 30 mm V100G chipboard covering or, for living areas, a 30-mm-thick gravel layer to improve sound insulation. This is covered by 25 mm impact-sound insulation boards, a 0.2 mm polyethylene sheet and a 40 mm cement screed. A rubber floor covering is used throughout as a floor finish. The ground floor, open to the air underneath because the building is raised on stilts, has an additional 40 mm of thermal insulation fixed to the boarding and 40 mm fire protection cladding underneath.

The roofs are offset monopitch roofs with a pitch of 320 and a clerestory window in between. The 120x180 mm rafters carry the 28 mm tongue-and-groove boarding (visible from underneath), a polyethylene vapour barrier and the 100 x 120 mm members for the profiled aluminium roof sheeting. The 120-mm-thick thermal insulation is placed between the members carrying the roof sheeting and is, therefore, ventilated from above due to the profile of the roof sheeting. The only steel elements are the stairs, stair stringers and handrails, made from hot-dip galvanized steel sections, and the external common walkways with their steel supports and open-grid flooring. The whole design is characterized by a very thorough attention to detail.

9 | This view during construction shows the structural concept. Also visible are the steel ties. On the right, an entrance facade before adding the timber cladding.
10 | External corners of two buildings showing the stilts on the foundations and exposed continuous corner columns.
11 | Staircase at first floor level. Beechwood treads on steel stringers. The entire gallery is made from beech-wood planking with open joints and no insulation or ceiling underneath. Also visible are the exposed solid timber joists which emphasize the construction.

i | South elevation, scale 1:500. The decreasing sizes of the balcony openings to the street are clearly visible. Here on the south side the balconies on the top floor are provided with walls for shade or, in the case of the centre block, a framework for climbing plants.

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