Spatial Flexibility for Housing in Urban Kampung toward Sustainability

Essentially, spatial flexibility and sustainable settlement share the same objective, which is easily adapted to change. The necessity for spatial flexibility in housing design stems from the expectation that houses will accommodate their inhabitants’ changing needs. The difficulty in achieving spatial flexibility might occasionally be attributed to the changing needs of users. This article will discuss the adaptability of space in urban kampung dwellings. A primary survey is utilized in the qualitative research method. Investigating the spatial management carried out by the users is made easier with the use of visual documentation utilizing photographs and drawings during surveys and interviews. Following a comparison of three case studies, it is found that the spatial flexibility of housing in urban kampungs is due to high user activity, particularly in multifunctional areas. Indoor spatial, on the other hand, has less flexibility due to the use of fixed and semi-fixed features.


Introduction
Housing as a process is inextricably linked to the occupants.House, as a result of human civilization, can convey the experience of space to its users.Changes and shifts encourage the adaptation of space by its users.This adaptation requires the flexibility of its environment.Because we live in an ecosystem (environment and house) with many known and unpredictable variables, space flexibility is vital [1] [2].
Due to the vast body of literature on space flexibility, there is no shortage of definitions as Estaji have shown in their list of definitions based on an in-depth literature review [3].It reviews many different definitions of space flexibility in housing design and divides into several concepts.The definition of flexible housing is housing that can adapt to changing user demands, including changes in physical house layout.Many studies look at the spatial flexibility of housing, with some focusing on apartment or mass-production housing.For this context, architect had a significant role in directing the design phase by determining and predicting the activities will occur in the housing [4].
One of flexible housing principle is the relationship between the size of the space and the potential to be flexible.The direct relationship between space and flexibility is that limiting space affects flexibility.The usage of space with varied activities is influenced by limited space.Hence, studying in the kampung becomes critical.Kampung is identical with a tiny, restricted amount of space/land that is close to one another, with narrow alleys, and with those limits, numerous space adaptations may be developed.We strive to analyse the user's style of thinking and how to deal with any changes in their activity to housing space layout by utilizing urban kampung housing as a case study.

Theoretical Framework
Space organization, as a manifestation of social interactions, is the result of individual ideas about the level of privacy he wants.The differences in the privacy level of each person could affect the differences in spatial organization.It is necessary to know about the extent of social interactions occurred from the activities to understand the spatial configuration.The main concept of flexibility is how a space able to accommodate several changes during some certain of time [1], [4]- [6].This ability is related to sustainability which enabling the capacity to extend their lifetime through adaptation [7]- [9].

Flexible Housing
The terminology of flexibility has become one of the terminologies that have unique appeal since the era of modern architecture.Architecture needs to be flexible to accommodate the dynamics of human activities [5].The basic principle of flexibility begins with the opposite, namely inflexibility, that should be found in the design principle [4].
For this research, spatial usage consideration being the main topic to investigate.It could be investigated by revealing the activities which were done by the inhabitants.Since flexibility is the level of adaptation needs that requires direct control from users, means that buildings cannot adapt themselves [3].In different term, polyvalent, it can accommodate different uses without undergoing changes in its own form so that minimal flexibility can still produce optimal solutions.Polyvalence in the housing context relates to the interchangeability of activities between different rooms.Rooms will derived their meaning from their status rather than from function [9], [10].In addition, sometimes changes will be made without prior determination by the inhabitants.As time goes by, inhabitants will have indetermined changes for responding their needs [2].
Space flexibility can be manifested in various ways.In a previous study of the flexibility of productive and domestic spaces in the case of coastal housing, changes in space could be in the form of permanent space expansion, non-permanent and vertical-horizontal space changes.Permanent space expansion refers to space expansion in a long-term period, while non-permanent space can be changed every day depend on several thing [11], [12].

The Relationship between Spatial Flexibility and Sustainability
The basic concept of sustainability is strategies to meet present needs without compromising future generation.This concept was sharpened by Sustainable Development Goals with their 17 goals.Goal number 11, which is sustainable cities and communities, have a close relation with how community and city should be like to achieve sustainability or to adapt with many changes of the past, present and future [8].This ability to adapt to change is closely linked to the concept of flexibility which has same purpose.So, it can be said that flexibility is one of the strategies to achieve sustainability with ensuring the efficiency of space utilization [7].

Housing in Urban Kampung
Kampung should be considered as a settlement that is unique and developed by its people long before the city itself exist.The pattern is organic, does not follow the formal planning method determined by the government [13], [14].In Surabaya, urban kampung has a potential role in city development.Kampung people with their settlement, as a capital, has encouraged each other, together with the government, in developing the city.Surabaya's urban kampung has developed with productive activities and being prominent kampung.As a result, kampung inhabitant can innovate to improving their capabilities, then improving their housing condition to a better one [8].One characteristic of kampung is the high-density housing and narrow alley.With limited space due to the dense, some space should utilize more than one function and then become multifunction space.Hence, it is a crucial component to any micro-house; the kitchen can double as dining areas, or a bedroom can also be a recreational space.In some cases, some space is not clear in function nor have specific activities in it .Kampung Surabaya, which has survived until now, is the evidence of the adaptation done by the inhabitants itself.Kampung dwellers with the idea of locality adapt to all changes from the district level, neighbourhood level, block level to dwelling and room level [18].

Spatial needs
The spatial needs of every person could vary for every condition depends on an economic level, social, culture and climate condition.Some guidelines lead us to calculate the minimum spatial need for each person for dwelling.According to Indonesia National Standard (SNI) 03-1733-2004, the minimum floor area for a decent and modest house (with the assumption that one family consists of 4 people) is 36 m 2 or 9 m 2 per person (Badan Standar Nasional Indonesia, 2004).This calculation is from the fresh air need/ person/ hour (in m 3 ) divided by ceiling height (in meter) (referred to Data Arsitek, Neufert, Ernst, I-II).Different from research from Indonesia Housing and Human Settlement Research Centre in 2010, Suryo, (2017) calculated the floor area with Indonesia people anthropometric as a basis.The result of the research is 47,56 m 2 per family consist of 4 people or 11, 89 m 2 per person.It can be seen the significant difference in the calculation of floor area between those two methods [19].

Methods
This article aims to examine the phenomenon of space adaptation in urban kampung and then investigate the potential of flexibility.For gathering the data, a primary survey was carried out in 20 houses in Kampung Candirejo, Surabaya.This kampung were chosen due to its uniqueness on gated and closed spatial arrangement.Interviewing and drawing the actual condition of the house were done by the researchers to portray the phenomenon.Every room dimension was measured (width, length, and height) and the activities were investigated by interviewing the inhabitants and how they arranged the furniture.During the survey, photographs and videos were also taken so that any document could be discussed.All the data were processed and tabulated.The room dimension was calculated then divided by the number of people inhabit the house to figure out the average floor area per person.The activities in every room were documented to see the phenomena of multifunctional room/space in the small house in kampung.From primary data, the floor plan and activities were translated into room connectivity graph.The analysis will conduct by the descriptive qualitative way.The discussion is limited to three houses in Kampung Genteng Candirejo, which is the total floor area is below 60 m 2 and have production or economic activities inside.

Result and Discussion
Kampung Genteng Candirejo is one of the old urban kampung in Surabaya (Indonesia) located in central Surabaya.The inhabitants of this kampung are 150 families that occupied 55 houses, so that one house is inhabited by three families (average).With a total area of 3.942 m 2 and inhabited by 150 families, the average land plot area is 26,28 m 2 (including the pathways, infrastructure, etc.) for each family.Figure 1 shows the illustration of Kampung Genteng Candirejo layout.

Figure 1. Layout of Kampung Genteng Candirejo
Low average of land area for each family in this kampung is a typical condition of living in a kampung.Sometimes people thought that it is difficult to live that way, but they enjoy living in the dense settlement.Besides, they have a strong relationship among inhabitants so that they trust each other.Even, they leave their house unlocked sometimes.Kampung Genteng Candirejo is now famous for its production of herbal drinks and most houses currently produce it.The addition of production activities is one of the drivers of space adaptation at the dwelling level.The figure below shows the condition of Kampung Genteng Candirejo.

Spatial need for each person
By using samples of 20 houses, the research was conducted to figure out how inhabitants manage their dwelling space.With a wide range of variants of land area and the number of people in one house, it is found that the average area per person in their house is 17, 1 m 2 (shown in Table 1).This number is above the minimum floor area per person (Indonesia National Standard).In this case, the floor area per person is quite high, but we have not considered the area for furniture yet.The inhabitants put the furniture that inherited from their parents and added some other new furniture.This condition makes the houses feel so packed and cramped.Table 1 shows the average area for each person in Kampung Genteng Candirejo.

Indoor spatial arrangement
In the first case, there is sample of one-story house with total area is 31,6 m2 and divided into 5 rooms.This house is inhabited by four people so that the floor area per person is 7,9 m2.As shown by Figure 3 and Table 2, room 1 contain three activities that occupy the space in most daytime.With the area of 10,5 m2 and 2,5 m height, the pace was almost fully occupied by furniture and electronic appliances, such as water dispenser, dining table, television, cupboard, and some stools.Room 3 is a corridor that connects room 1, room 2 and room 4, but room 3 containing activities manifested and shown by the furniture arrangement.
From the floor plan and the connectivity graph, it is found that room 2 (for sleeping activity) is surrounded by room 1, 2 and 3 which accommodate production process.The use of parallel rooms has a value of flexibility because adjoining rooms can accommodate each other's needs.However, because two rooms with the same activities are separated by a bedroom, it makes room 1 and 2 are less flexible.The second case is a two-story house with total floor area is 25,67 m2 where the first floor is 13,8 m2.This house is divided into four rooms and inhabited by five people so that the floor area per person is 5,1 m 2 .Room 1 accommodates seven activities and were used interchangeably.With the area of 8,3 m2 and the height is 3 m, the furniture in room 1 occupies 70% of the floor area.Most of the furniture is fixed cannot be moved freely.The furniture in room 1 are bed, refrigerator, water dispenser, washing machine, drawer, television, table, and birdcage (hang on the ceiling).Room 4 was used together by all inhabitants in this house for sleeping and studying.Quite different from the first case, in this second case, all activities other than sleeping are carried out on the 1st floor.The separation of activities with different floor clarifies the status of the 1st floor as a multifunctional space.The multifunctional space in the second case is seen from the manifestations marked by furniture for each activity which makes the space tight.With so many single-function furniture, it makes space for movement limited and reduces the value of flexibility.
The third case is a two-story house with a total floor area is 27,07 m 2 .The land area is 14,2 m 2 .This house is divided into eight rooms and inhabited by three people so that the floor area per person is 9 m 2 .From Figure 5 and Table 4, room 1 and 2 have five activities for each.The area of room 1 is 6,7 m2 and 3,1 m2 for room 2 and the height is 2,8 m.Room 3 is the extension for room 2 if room 2 is not large enough to accommodate four activities mentioned in table 4 (expansion).Room 5 accommodate packaging activity which is part of production activity.The production activity become less efficient since the separation of room and floor.If packaging activity were placed on the first floor, the inhabitants could use room 5 to accommodate domestic activity.
The third case is quite like case 2, but the difference is the inhabitants use quite many fixed partitions (wall) to divide the room.For example, room 6 and 7 (case 3), even they have similar activities, they have different room since the inhabitants need more privacy (room 6 and 7 are bedrooms).It can be said that privacy can affect how flexibility is produced.Besides, there are some activities (for example, sleeping) which were conducted in room 1, mixed with other activities involving other inhabitants.So, the separation between privacy and no privacy was blurred in this case.

Indoor multifunction space analysis
Pre-existing spaces must adapt to the addition of production activities.Added production activities include cooking, packaging, storage, and sales activities.These production activities were inserted into existing spaces so that the production process is not occupied in separate rooms.Room 1 (and room 2 in case 3) can be considered as a multifunction room.Room 1 (and room 2 in case 3) in three study case accommodates more than three activities.Primary activities in this room are gathering, eating, and producing (economy activities).These three activities were done in all study cases, but there are several extra activities done by inhabitants in that room.The extra activities are sleeping, studying, washing, and ironing.For some inhabitants, sleeping is no longer an activity that needs privacy.From table 5, in cases two and three, sleeping activity was done in the multifunction room.The table below shows the connectivity graphic from 3 case studies.From table 5, the blue circle shows us the multifunction room which is positioned in the front.The multifunction room is in the front since it will be easier for the inhabitant to oversee their house and neighbourhood, and it has direct access to outdoor space.Besides, those rooms accommodate their most activities in the most daytime.From these 3 cases, the multifunction room has no label for naming the room since there is no significant activity that is done in that room.All primary activities are carried out interchangeably and sometimes simultaneously.From Table 5, it can be seen if the space in the multifunction room of case two and case three were mostly occupied by the furniture.It means less space for circulation or other activities that need vast free space.In case one, space occupied by furniture was almost balanced in size compared to the free space.It can be said that the furniture selection has a tremendous impact on space flexibility, particularly in multifunction space.Furniture in multifunctional space is to accommodate various activities (as shown in table 5).From the three study cases, the multifunction space accommodates different activities without undergoing any changes.For this reason, free space becomes narrower than furniture space.

Conclusion
In theory, the level of adaptation needs requires control from the users.In this article, we discuss that users have full control in spatial arrangement and how to manage the space.Lack of land area gives consequence to room size.For inhabitants that were economically capable to build vertically (more than 1 story), they tend to have more flexibility in arranging the space rather than users that only can build a one-story house.
The three case studies in this article feature a slightly different level of flexibility.From the graph, we can see that those three have a quite similar graph.The similarities lie in how the user manages the multifunction room which they put in the front.Primary activities for all three case multifunction rooms are gathering, eating and production process.A difference can be found in the activities accommodated in the multifunction room, for case study 2 and 3, the multifunction room also accommodates other activities.The more activities accommodate in the room consequence in denser the room/space.The other difference is case studies 2, and 3 accommodate sleeping activity also in the multifunction room, even though they specific room for sleeping on the second floor.It showed the blurred boundary between privacy and non-privacy by multitasking in same space.
If we calculated the area per person in the Kampung Genteng Candirejo, we could find that the average area per person is 17,1 m2 which is quite high.Nevertheless, the calculation has not considered the various activities in each room and how the furniture took over the area of the room, exceedingly, they use single function furniture.The weakness of this calculation is that we always see in two dimensions, we should see space volumetrically so that verticality has great potential to support space flexibility.
From the study, the potential of flexibility lies in a multifunction room which accommodates three primary activities, i.e., gathering, eating, and production process.Fixed space boundaries and heavy furniture make the multifunction room become challenging to be flexible.Existing furniture has a particular function and not for another function, result in a packed and cramped room full of furniture.The furniture was arranged horizontally so that it fulfils the floor area.Even though it is a semi-fixed feature, which means it may be moved, the large, heavy furniture makes relocating it difficult.
Besides, there is one condition in which there is not much awareness of the importance of verticality on the wall.The arrangement of furniture on the wall is only limited to what can be reached directly by hand (maximum 1.8 m height).There are still many areas of the wall and maybe ceiling and floor that can be explored further in its utilization to develop space flexibility for the multifunctional space of urban kampung dwellings.

Figure 3 .
Figure 3. Floorplan and room connectivity graph of case 1

Figure 4 .
Figure 4. Floorplan and room connectivity graph of case 2

Figure 5 .
Figure 5. Floorplan and room connectivity graph of case 3

Table 1 .
Table of average area per person in Kampung Genteng Candirejo

Table 2 .
Spatial information for case 1

Table 3 .
Spatial information for case 2

Table 4 .
Spatial information for case 3

Table 5 .
Spatial information of multifunction space from 3 case studies

Table 5 .
Spatial information of multifunction space from 3 case studies