Oberwil:
The Multi-family housing estate Stallenmatt
Oberwil:
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| Country: | a) Western Europe | ,b) Switzerland |
| Language: | |
| Type: | Project, 1 |
| Area: | Outskirts, < 20,000 |
| Actors: | Economic sector |
| Funding: | Economic Sector |
| Topics: | Architecture and construction |
| Building materials | |
| Energy | |
| Health | |
| Housing (and new settlements) | |
| Renewable resources | |
| Objectives: | Increase use of ecological building materials |
| Increase use of renewable resources | |
| Reduce energy consumption | |
| Reduce resource consumption | |
| Reduce water consumption | |
| Instruments: |
The "Stallenmatt" multi-family housing settlement consists of 64 residential units in eight single-storey or multi-storey buildings arranged in a number of different-sized blocks at a right angle to one another on a gently terraced slope. The entire site has an area of 12,410 m². The main objectives behind the settlement were to succeed in keeping primary en-ergy consumption low during building as well to create energy- efficient house-holds, and in addition to offer a healthy, architecturally pleasing high- quality living environment at an affordable price.
The Project has been included mainly for the following reasons:
The "Stallenmatt" multi-family housing settlement is located about five kilometers from the city of Basel in the landscape of the Swiss canton of Basel. The settlement consists of 64 residential units in eight single-storey or multi-storey buildings arranged in a number of different-sized blocks at a right angle to one another on a gently terraced slope. The entire site has an area of 12,410 m². The main objectives behind the settlement were to succeed in keeping primary en-ergy consumption low during building as well to create energy-efficient house-holds, and in addition to offer a healthy, architecturally pleasing high-quality living environment at an affordable price. The quality of the settlement was to be reflected in the diversified, eco-sensitive design of the site's open spaces. The construction period was divided into three building phases, beginning in 1989 after a planning and approval period of nearly five years. Upon comple-tion of the first building phase, the buildings were ready for occupation by 1990, and after completion of the last building phase, by July of 1991. According to the architect the settlement's floor space index is 0.65.
Following a competition adjudicated by Professor Steiger for a laboratory building for the Ciba Geigy Co., a first contact meeting took place in 1983 between the developer/initiator and the architect about the settlement project. The Ciba Geigy Co.'s pension fund wished to realize a ground-breaking project to commemorate their ten-year anniversary and to this end were looking for an architect "with a good reputation" for qual-ity building and good architecture. As a result of their cooperation with Prof. Peter Steiger of Zurich over the course of the competition a decision was made to commission him for the project. The developer was less interested in holistic sustainable architecture and more in using natural and healthy building materials and creating a high-quality living environment. The planning period and approval procedure stretched to over five years, primarily due to indecision on the part of the developer.
Doubts arose mainly in regard to potential difficulty letting the dwellings, al-though these were later proved unfounded as all residences were rented very quickly after completion. In the run-up to building the planned settlement, the strategy adopted involved presenting the project to the higher district decision-making authorities on a number of occasions, even in the pre-design phase. The pres- ence of the architect was of paramount importance on each occasion, as he ad-vocated the project with great persuasiveness and lent the planned settlement greater significance through his public commitment.
The village of Oberwil, with its 8000 inhabitants, is located approx. 5 kilome-ters from the Basel city centre. The settlement is located at the edge of the village and borders on the municipality of Bottmingen. The arrangements of blocks of buildings placed at right angles to one another form a central yard designed with green areas and a freshwater eco-system. Alongside the yard is a pedestrian walkway connecting all of the buildings in the upper centre of the site and leading to two community spaces. Retail spaces such as a hair-dresser's, an architect's office and a creche are either also positioned alongside the passage or else are located in the southern front of the buildings that are planned longitudinally. Four hundred square meters of retail and studio space are planned, which will strengthen the courtyard's function as a focus. The rest of the other buildings are further down the slope and in some cases are separated from one another by a residential street. They can mainly be seen to belong to the set-tlement by their architecture.
Coming from Basel towards Oberwil by tramcar the settlement on the slope is easily recognizable. The unique architecture here is a welcome contrast to the perceptibly suburban character of the surroundings and the somewhat dreary adjacent development. Symmetrical rows of basic elements such as columns and architraves provide structure; the concept of addition, reflection and order lends harmony. The composition of a simple core building with a cross gable and a skeleton-like secondary structure encompassing the building is characteristic. The secondary structure which is covered in vegetation contains circulation areas such as stairs to the residences, and to the north, storage rooms, balconies, glazed verandas or conservatories. The secondary structure also serves to protect the facades from climatic conditions. The structure provides a gradual temperature transition between inside and outside and with the greenery, creates a microclimate around the building which has a positive effect in terms of energetics. On the subject of the zoned structure of his building, Professor Steiger stated the following: "Quite apart from the en-ergy gain, this type of transitional zone generally regulates the relationship of the building to its environment. The outer skin of a building has various func-tions relating to the transition from inside to outside, quite apart from temper-ing heat and cold: daylight, sounds, smells, views in or out, etc. The changeableness of the transition between the protective interior space and the outside world characterizes the building architecturally in its regional integration and seasonal use. Time and space are fused with regional character-istics and the lifestyles of the residents: these are the elements of regional archi-tecture that are being rediscovered."
The principle of the layout - a so-called Plenar-Domus type building (planning-energy-architecture) - was developed by Professor Steiger before the realization of the "Stallenmatt" settlement on the premise of energy conservation. The en-ergy elements that make up the Plenar-Domus are designed to turn the building into "an energy-efficient system that remains nonetheless influenceable, fulfill-ing contemporary living needs without leaving the resident feeling constricted". The core of the building with as few external walls as possible contains all living spaces, kitchens and bathrooms. These generally have a higher internal temperature with fewer temperature fluctuations than the bedrooms, which are positioned on the sides. All rooms, including the bathrooms are designed to be naturally ventilated without requiring additional energy consumption. The above-mentioned secondary structure, the front of which is covered in vegeta-tion, and the conservatories, storage rooms, glazed verandas or balconies pro-vide a third buffer zone. This zone is interrupted by the living space to allow direct sunlight to penetrate into the core area.
The above-mentioned measures go far beyond simply conserving energy, giv-ing the residences a quality of life far above that of most rented housing. Each apartment is designed to have a unique quality. Thus for example, the ground floor apartments have direct access to the garden, and the loft apart-ments have their own roof terrace. For the most part, 3 1/2 to 4 1/2-room apartments were planned and realized, including two wheelchair-accessible apartments suitable for differently-abled or elderly people, in a separate building with a garden seating area. Each residence has a separate, spacious basement. Normally basements are not part of the Plenar-Domus concept as the building costs and energy used in producing them outweigh their usefulness. This ap-proach was revised because of the sloping site on which the settlement is built.
Effort was made to go as far as possible towards fulfilling the requirements of a toxin-free living environment and interior climate by carefully selecting build-ing materials. The heat storage capacity of the materials was also taken into consideration. Exposed concrete elements form the supporting scaffolding on the level of the car park. The space-enclosing external cavity walls consist of two courses of porous or burnt brick sandwiching mineral insulation. The core of the floor plan contains the living-room and kitchen and includes massive and hard materials with a high storage capacity and is provided with south-facing windows to allow solar access. Natural paints were used in all interior spaces on principle. Natural adhesives were preferred to ad-hesives containing solvent for the natural cork flooring, which is difficult to lay. The remaining surfaces were clay tiled. The glass surfaces of the conserva-tories, south-facing windows and verandas are equipped with operable protective shades against sun and heat to accommodate the varying conditions of summer and winter as well as day and night and to prevent overheating.
Upon completion, the representative of the Ciba Geigy Pension Fund, Mr. Tschopp, himself moved into one of the settlement's lofts for a time, experien-cing the high quality of the living environment first-hand, and confirming the deci-sions made on the type of realization and the choice of architect.
The predominantly south orientation of the buildings is of prime importance for the energy measures mentioned above. Unavoidably, this results in the need to keep the front grounds of the adjacent buildings free so as not to block di-rect sunlight. Of prime importance for energy efficiency was the above-men-tioned thermal zoning of the layout, the heat storage capacity of the various building materials and the use of passive solar energy through conservatories and glazed verandas. The Plenar-Domus concept incorporates the following ideas as formulated by Professor Steiger: "We have set ourselves the objective of suggesting wide-scale measures of shifting energy consumption from na-tional to regional energy supply systems and by improving the efficiency of energy transference on every level, of gradually altering the consumption of high-quality primary energy to fit the structure of energy needs. (...) What the optimal use of primary energy means is that once power and heat are produced they are not lost without having been used. This is why, when considering fu-ture energy needs, energy planning must reckon with quantitative and qualita-tive changes in energy demand being accommodated. Any deviation from this overall principle - be it on the level of the individual house, the region or the nation - means, in terms of the national economy, further losses of heating en- ergy, preventable environmental damage through waste heat and toxins, and nothing less than wasted national investment in heating energy conservation for the consumer."
Within the framework of research led by Professor Steiger at the University of Darmstadt, monitoring over a period of many years has demonstrated that a Plenar-Domus building - depending on the degree to which it is fitted out in terms of energetics - uses up to three times less energy than the average modern building. The readings revealed that the issue of double or triple-glazing for example has little bearing on the energy balance of the building. The heating balance is more strongly influenced by such things as so-called surplus heat from the kitchen, bathroom and living spaces. To this end heat-retentive materials are adopted that have the capacity to store and radiate surplus heat in the building as well as solar energy gain from direct sunlight. These findings have been incorporated in the "Stallenmatt" settlement.
The estimated mean interior surface temperatures of all of the external and in-terior walls allow the buildings to be equipped with low temperature heating. In order to utilize the advantages of the solar gain to the full, an easy-to-regulate radiator heating system with a low temperature adjustment time was installed. Each apartment has individual gas heating with an integrated hot-water storage heater which saves the trouble of complicated heating bills. This also aims at encouraging a personal sense of responsibility for environmental issues by al-lowing the tenant to determine the interior space heating temperature. Termporary forced ventilation is only provided in the kitchen above the stove; all remaining rooms are provided with operable windows for natural ventilation.
The settlement is surrounded by a residential street that existed before planning began. It is rare to see cars parking in the settlement although in this case this does not mean to say that the settlement was planned as a pedestrian zone, but rather that facilities for the residents' vehicles are provided in the form of a number of small underground car parks. At least one covered parking space in one of the three underground car parks is allocated to each residence. Access to the car park is gained by a ground level passage or alternately from the resi-dential street. Two places for car-washing are also available.
The outdoor spaces were planned according to strict environmentally-sensitive precepts, primarily with useful plants. A manmade pond provides diversity of flora and fauna and captures rainwater. All tenants can benefit from the crops of the fruit trees, mirabelle and greengage trees. Apart from civic areas all unbuilt-up areas are designated for private gardening. These private gardens are not subjected to any organic guidelines but can be planted at will. Also, twelve of the settlement tenant allotments were created on an area of the site unsuitable for building. As mentioned above an important element of the energy and cli-mate concept is the fact that the facades are covered with vegetation.
In accordance with Swiss building regulations, the site was regulated by a district zoning plan to which changes could be made as long as the district council approved of the proposed design. The "Stallenmatt" set-tlement was unanimously approved by the district representatives. The respon-sible official from the town planning authorities, Mr. Dieter Wronsky also sup-ported the project and therefore sped up the planning permission process. Once the building proposal had been approved, bids were invited to find a general contractor for site management and implementation. The cheapest bidder proved to be MOBAG, who consequently received the commission. The preliminary design contained some very innovative sustainable building pro-posals conceived of by the architect. A tenth of the residences were to be built with loam, equipped with radiant heating walls, photovoltaics, solar collectors for water-heating, and were to contain composting toilets. Sewage recycling through a reed aquatic waste purification system was also planned. The devel-opers, however, were not interested in these proposals as in their view they would have led to "unnecessary complications and expenses for the project". The developers' initial concern that "a professor can afford to have a new idea every day" led them to hire a general contractor and to stipulate a fixed price in an attempt to ensure greater con- trol of the feasibility and expense of the architect's proposals.
Both the architect and the developer confirm that there were no significant problems during the construction period. This can primarily be accounted for by the very detailed and thorough CAD planning. A prerequisite for the smooth running of the building period and an issue of great importance was cited as being the straightforward decision-making process. During the realization phase there were only three decision-makers: the Ciba Geigy representative; Mr Tschopp, the MOBAG site manager; and Professor Steiger. This resulted in efficient and for the most part problem-free resolution of arising questions. The participation of any others would only have made decision-making more diffi-cult and slower.
The "Stallenmatt" settlement was financed in private sector housing, i.e. the total building costs were covered by the Ciba Geigy Co's pension fund. The price per cubic meter of the building after completion in 1991 was approx. 420 Swiss francs, one square meter including conservatory and glazed balcony on the north site cost 2,.072 Swiss francs. The total cost of the project was cited as 20,8 million Swiss francs, excluding the cost of the land. The developers felt that compared to other contemporary projects this was an extremely reasonable price in relation to the high quality of life the buildings offered. The explanation given for this was that "sustainable extravagances" had been dispensed with, and emphasis given to simplicity and quality.
The developers praised the "intelligent architecture" and the achievement of such a high quality of life at such low cost. This was also due, however, to the fact that building was not "exaggeratedly sustainable", i.e. that complicated solar technology, composting toilets, etc., that were supposed to make it difficult to let the residences, were dispensed with. The developer also praised the fact that the original fixed cost framework was actually adhered to. The developer also felt that commissioning a general contractor as a "controlling authority" for costs and building programme was very helpful for decision-making during the building process. Cooperation with MOBAG proved conflict-free as the company revealed itself to be exceedingly committed and open-minded.
The architect on the other hand felt that bringing in a general contractor for the building process involved additional effort since numerous detailed drawings were necessary that would not have been required if the architect had been given the role of site manager. The architect found it extremely difficult to hand over the supervision of the building process of his own design to someone else. Experience showed that many details had to be very carefully explained beforehand so as to prevent misunderstandings during implementation. The additional work that this meant for the architect was un-fortunately not reflected in his fee. In addition these explanations had to be re-peated to the various professional builders, which often led to inconsistencies. The architect could also not count as additional expenses the careful explana-tion of how to use the materials or apply new techniques uncommon to main-stream building. Larger architects' offices would not be in a position to finance projects involving this amount of work. In addition to this, 2% of the fee was to be retained until the guarantee expired two years later.
When asked for suggestions for further projects the architect mentioned more innovative materials that could be of interest for the implementation. Due to its complicated and costly production, cavity masonry was now out of the question. The architect had also had bad experiences with the submission of eco-sensitive proposals, since out of uncertainty companies calculated such high increment costs in their bid that a fictitious increase in overall costs resulted.
64 units, construction period from 1989 to 1991.
| Size of area: | 12 410 m2 |
| Plot Ratio: | 0.65 |
| Costs: | approx. 371 Swiss francs (£151) per m3; approx. 2 072 Swiss francs (£844) per m2 incl. south greenhouse and glassed-in balcony on north face |
| Total costs: | 17.7 million Swiss francs (£7.2 mill.) excl. real estate costs |
European Academy of the Urban Environment (ed.)
M. Kennedy, D. Haas: New sustainable settlements in Europe
Berlin 1994
| Name | : | Gemeinde Oberwil |
| Firstname | : | |
| Telefon | : | ++41 (0)61 405 44 44 |
| Telefax | : | ++41 (0)61 405 42 14 |
| Address | : | Gemeinde Oberwil |
| Hauptstraße 24 | ||
| 4104 OBERWIL | ||
| Schweiz |
The Swiss community of Oberwil is located in the catchment area of Greater Basel. Amongst the traditional trade and craft services there are automotive and construction work and their ancillary trades. However, commercial and service companies are increasingly playing a part here as well.
Project was added at 18.03.1998
Project was changed at 06.07.1998