Planning / Design
Osaka Gas and NEXT21 Planning Team (Utida, Tatsumi, Fukao, Takada, Chikazumi, Takama, Endo, Sendo)
Yositika Utida, Shu-koh-Sha Architecture and Urban Design Studio
Building Architect
Construction
Obayashi Corporation
Initial Construction
1994 (continuous ongoing renovations/transformations since)
Design System Planning
Kazuo Tatsumi, Mitsuo Takada
Dwelling Design Rules
Mitsuo Takada, Osaka Gas, KBI Architects and Design Office
Modular Coordination
Seiichi Fukao
Owner
Osaka Gas Company
Dwellings
18 (some have been combined and divided over time)
Reinforced concrete + Façade System
Support (Skeleton)
Various companies
Infill Provision
Background
Within the context of Open Building, the NEXT21 project introduced a number of innovations, some of which still have not been equaled by later initiatives.
Professor Yositika Utida, the leader of the team of architects invited by Osaka Gas to design NEXT21, once described the project as ‘three-dimensional urban design.” This concept is indeed a logical result of the separation of Base Building and Infill (S/I). This large building is no longer a building but becomes part of an “urban tissue.” Just like a city is extended by the design of streets and squares complete with trees and sidewalks and the utility lines underground, NEXT21’s Base Building provides public space of bridges, elevators, stairs and corridors / pathways connecting a public garden on the ground floor with another one on the roof. The public circulation in three dimensions from the street level to roof garden connects individual dwellings to the urban street network, and just as in urban design, these individual dwellings can be built, changed, removed and replaced like buildings along a street.
Although the NEXT21 project fills no more than half a block, it is easy to imagine its concept applied on a larger scale accommodating a very large number of individual dwellings in a three-dimensional urban fabric. The transformation of the large building into a neighborhood, offering internal public spaces that give access to dwellings that can be shaped individually, is perhaps the greatest potential of the Open Building approach. NEXT21 shows how this can lead to a new architecture and urbanism that is different from just ‘flexible buildings.’
Professional cooperation on two levels
A design team in collaboration with architect Shinichi Chikazumi guided the entire project. Thirteen different architects were initially invited to design the 18 individual houses contained within the NEXT21 framework. This was a logical step once this vision of a three-dimensional urban fabric had been adopted.
In all Open Building projects, design decisions are made on several levels: the lower level of the interior fit-out is to accommodate the user, while the higher level contains all that the users have in common: the load-bearing structure, the main utility systems and the public spaces.
To have separate architects do the lower level design is consistent with conventional practice in urbanism, office and shopping center construction. The traditional urban designer expects other architects to do the buildings along the streets and squares she proposes. In the case of office buildings and shopping centers, large areas of empty floor space are made available and leaseholders are expected to hire their own architect to design interior layout and finishes. The same can work in residential Open Building as well as other kinds of buildings shown in this part of the book.
In the case of NEXT21, only a few of the dwellings were designed in direct response to the demands of the inhabitants. In most cases, Osaka Gas submitted “user scenarios” as “guidance documents” for the architects to follow. This was done to obtain a wide range of different lifestyles that could demonstrate the buildings’ capacity to accommodate a variety of dwelling solutions. It also secured a broad base for ongoing research. Having the individual dwellings designed by different architects could stimulate variety even more. At the same time, this way of separating and delegating design responsibility suggested a new model of professional cooperation among designers to better serve an emerging, consumer oriented real estate market.
Dimensional and positional coordination grids
Organizing all the different players and all of the piping and cabling infrastructure without conflict, in combination with the deployment of internal partitioning and the equipment of bathrooms and kitchens, posed a very difficult methodological problem. The NEXT21 design team confronted this problem in a sophisticated way. By doing so they have expanded our knowledge about the use of coordinating grids and zoning. Based on the careful studies of Professor Seiichi Fukao, in close cooperation with Shinichi Chikazumi of Shu-koh-sha Design Studio, coordinating grids on several levels, closely interrelated, organize the design of all the subsystems. This methodological aspect of the NEXT21 project should be studied carefully.
Private Gardens
Another innovation consistent with the idea of a “three-dimensional urban structure” was to provide individual units with their own exterior green space distinct from the common gardens on the ground level and on the roof of the building. Several of the units had small outside spaces for plantings as part of the private residential territory. Of course, the size and number of such little “gardens” depended on the individual unit designs (which could change over time). But the addition of green outside spaces was encouraged as part of the overall experiment and the high space available for ducts under the floors made it easier to grow plants.
The Facade System
A façade system was designed specifically for the NEXT21 lower level design. Using the system, each architect could design a façade reflecting the interior layout of individual dwellings. Keeping in mind future changes, the façade system was designed in such a way that it could be taken apart and installed again “from the inside,” without need for exterior scaffolding.
In the Open Building experience, the role of the façade has been a difficult but important issue. A range of solutions has been considered over time. Proposals have been made that each unit should be entirely free to publicly express – on the exterior - its own interior as well as its owner’s personal stylistic preference. Le Corbusier’s famous Algiers proposal already suggested this possibility more than 70 years ago, and among the ill-fated “Operation Breakthrough” ideas for innovative housing solutions in the early 1970’s in the U.S. was a proposal for a minimal loadbearing framework containing a variety of house designs.
At the other end of the spectrum are the many OB projects that limit themselves to interior variety behind a fixed façade designed for the entire building.
Making façade parts demountable and replaceable requires sophisticated detailing. If, moreover, the façade’s position must be flexible as well, parts of the floor and ceiling that first were interior may become exterior or the other way around, posing a number of difficult technical problems. For practical reasons alone, a strong case can be made for a fixed façade design behind which interior variety is possible.
In many countries in history, facades always sought to express individual dwellings within a given typology, resulting in a rich and thematic variety along an entire street wall. In contrast, the Parisian boulevards show how uniform and monumental facades can shape urban space without expressing interior variety. The same can be observed around the Bloomsbury squares in London and the public spaces of St. Petersburg. Different cultures seem to have different preferences in different times. The question whether the façade – or parts of it – should follow higher-level design or lower level design is not just technical but has important cultural aspects.
The NEXT21 project offered a new possibility: its façade system is part of the higher-level concept intended for overall application. But the actual use of the system is part of the lower level design. This combines lower level variety and change over time with higher-level harmony on an urban scale. Here, too, NEXT21 set a most interesting new precedent.
Changing dwelling unit interiors
Over the years, many of the original dwelling units have changed, part of the experiment with adjusting Infill to changing lifestyles and needs of a variety of household sizes and needs. During those changes, the interior Infill elements are stripped out, leaving only the Skeleton and the insulated façade, as shown in Figure 7.
One such change is pictured in Figure 8, in which Unit 404 changed within the boundaries of the original space.
Another dwelling (Unit 304) also underwent changes, as shown in the following Figures 9 and 10.
An open building research laboratory
In the years after its initial completion in 1994, the NEXT21 project has served as a laboratory for a large number of experiments. This was consistent with Osaka Gas’ solid reputation for innovative research in building technology and environmental control systems in buildings. There is no precedent in the Open Building experience of a similar long-term commitment to research by a single company and here again the NEXT21 project sets an example.
As already noted, not all research projects done in the NEXT21 context are specific Open Building issues. Development of new heating/cooling sources and waste management systems are stand-alone subjects. But the distribution of utility lines, including cabling, ducts, and piping of all kinds to each unit is very much an Open Building issue. For future “three-dimensional urban frameworks” to serve future generations, service lines must coincide with public spaces in the frameworks to allow their renewal, maintenance or replacement as new technology develops. Moreover, the testing of a “computerized energy providing service,” for instance, could be done because users actually participated in it, contributing valuable feedback information.in Figure 7.
Many other parts of the extensive research agenda have direct bearing on the Open Building approach. All were related to the re-design and change of dwelling units, a process that led to a re-examination of many issues.
There are, of course, the experiments dealing with the technical issues of changeable or flexible Infill, and also the displacement of parts of the façade system as examples of new product development and evaluation.
There are also the life-style oriented social studies where the small-scale interaction between user and equipment and space is considered. And there are also design oriented research items on the agenda, like the scenario-based technique of housing planning, and also the study of the capacity of a given floor plan in which an entire range of possible use scenarios could be accommodated by shifting the position of the kitchen unit combined with a few minor alterations of doors and partitions.
It is important to note that for all of these experiments and studies, the NEXT21 infrastructure was available and in continual use. Similar research issues have been conducted in the past, but because no real-life experimental environment was available, they necessarily had to be done in a more abstract manner. The availability of a real-life adaptable environment offered a new and very different context for study and experiment, the potential of which we have yet to fully understand.
If we look at the NEXT21 project as a permanent environment for experimentation, we begin to appreciate its almost total “openness” as compared to most other Open Building projects. To successfully realize an Open Building project in real life within the budgets normally available and for the sake of users with average needs and preferences, the question as to what can be fixed for all the inhabitants and what must be adaptable for the individual is crucial. We have learned that “maximum” flexibility is not only impractical, but also undesirable. What is fixed and common has real meaning and the balance with what is adaptable, and individual, must be studied each time with great care. The answer to that question will be different from project to project depending on the agents involved and the culture we try to serve. The question must remain on the table until enough experience has been gained. Only when Open Building has become a general and normal approach will we understand more fully how that balance can work well and will we be able to make predictions. And even then, we can safely assume, there will be more than one answer.
For an Open Building project to serve as a laboratory as in the case with NEXT21, an extremely “open” technical solution is the right answer; experiments can be done without pre-determined constraints. The NEXT21 environment is indeed a large systemic composition within which the balance between truly collective and permanent on the one hand and truly individual and adaptable on the other hand can be experimented with.
The present and future context for Next21
The completion of NEXT21 in 1994 implied a long-term commitment by Osaka Gas Company toward Open Building experimentation. That commitment continues. This too was a precedent. Many earlier projects of an experimental character had been the result of extraordinary efforts by architects, clients and government agencies, but so far, they had been one-at-a-time events. It is in the nature of the building industry to experiment on an ad-hoc basis just as the entire industry operates on a project-by-project basis.
Ad-hoc experimentation allows the demonstration of the separation of two levels of design control. NEXT21 did this in a rigorous and convincing way. But the development of new and more flexible sub-systems is another matter. This cannot be done as easily on an ad-hoc basis and here NEXT21 could do something entirely new. It offered a stable context for installation and comparison of new sub-systems that might become available over time. The desire for easier installation and better service already had moved the market in the direction of the Open Building approach. For instance, in the last quarter century we have witnessed the introduction of flexible and “home-run” water lines, snap-together drainage piping with push-fit joints, smaller and more efficient hot water units capable of heating a single dwelling and small enough to fit in a closet, electric cabling by means of click-together connections, easier to be installed partition systems, 0-slope gray water drainage systems, and many other improvements.
As the Open Building approach makes progress, it becomes increasingly desirable for new products and sub-systems to be tested in an Open Building context. Here the example of the Osaka Gas Company may lead to emulation. We may eventually witness the emergence of similar experimental sites where new sub-systems can be demonstrated and tested in a context of real-life inhabitation and management. Such permanent experimental sites might be run either by the manufacturing industry, government bodies or public/private consortia.
A note from Shinichi Chikazumi, one of the architects of Next21
“Why did the SI concept rapidly lose momentum? This is a question I ask myself.
I continue to experiment with the remodeling of NEXT21 with the exact same passion as before, having remodeled 11 units in 18 years from 1994 to 2022. I am currently planning to remodel one unit for 2025. Osaka Gas has not lost any of its ambition, and the SI concept still attracts more than 1,000 visitors during the open house period each year.
Everyone says that NEXT21 is exceptional. No other company can compete with it. Osaka Gas continues to spend a lot of money to maintain the number one position. I believe it is possible to keep the NEXT21 concept and turn it into a commercially viable approach. However, the reason why no Japanese developers are willing to ask me to do so is because Japanese developers have no challenging spirit to break out of their old framework. They have a safe business and make enough profit by selling buildings and the land as a set.
In Japan, the business of building new detached houses in large quantities is still successful. People are jumping into the new houses and leaving the houses they have lived in unoccupied. Millions of vacant houses have already been created. I do not believe that a business and an industry as distorted as this can continue any longer.” (Shinichi Chikazumi, President, SHU-KO-SHA Architecture an Urban Design Studio, April 2023)