Transformation of National Housing’s Layout Design in PERUMNAS Sarijadi Bandung

PERUMNAS (“Perumahan Nasional”/National Housing) was established in 1974 to provide decent housing for the lower middle class in Indonesia by the government. One of their projects was done in Sarijadi area, Bandung in 1976-1978. The typical PERUMNAS house in Sarijadi was based on Type 36, named after the building area which was around 36 m2. As time changed, the people’s needs, and behaviour also evolved, and it also affected the contemporary PERUMNAS layout. As such, Type 36 house may be evolved into a growing house, in a sense that it is able to be developed, usually vertically, by stages based on standard housing minimum cost to accommodate the evolving needs of the occupants. This paper will analyse one such growing type 36 PERUMNAS house case, which is located in PERUMNAS Sarijadi, Bandung, West Java. The house was initially built in 1976-1978, and several renovations were done in 1994, 2007, and 2017 as the family grew. By observing the layout transformation, the results showed that the occupants adapted to the original layout by developing the building vertically to add private areas and utilizing the front and the backyard to make new service areas. In the future, homeowners can adapt to shifts in activity by carrying out sustainable transformations in the form of additional functions which then result in different zoning.


1.
Introduction Population growth in urban areas is a dynamic process that results in the emergence of various kinds of urban problems.This results in the city's capacity being almost unable to accommodate population growth over time [1].The high price of land in urban areas means there is increasingly limited space for affordable housing development [2].Based on the existing land problems and possible impacts, the government offers a solution through PERUMNAS (National Housing) by building housing with a growing house concept where the main house can be developed according to needs [3].Main houses are generally classified as simple type houses, with a building area of 36 m 2 on a land area of 60-90 m 2 [4].
A type 36 house is a house with a building area of 36 m 2 usually called a type 36/60 or 36/72 house [5].This type of house is included in the simple house type, namely multi-story houses with a building floor area of no more than 70 m 2 , built on a plot of land with an area of 54 m 2 to 200 m 2 with construction costs per m 2 not exceeding the highest unit price per m 2 for the construction of official housing type C is applicable.Type 36 houses have a minimum standard layout for an urban residence, namely a family IOP Publishing doi:10.1088/1755-1315/1324/1/012033 2 room, bedroom, kitchen, bathroom, terrace, and backyard (green area).Over time and with the addition of family members, families who live in this type of house usually experience an increase in activities which results in the need for additional space requirements, so this type of house is very likely to develop into a growing house [6].
Growing houses are built in stages over an unlimited period according to the needs and desires of the occupants but are limited by the land area [7].Good spatial planning is needed so that the effectiveness and efficiency of the existing space when growing can be optimal and able to improve the quality of life of the people who inhabit it [8].The spatial transformation that occurs often pays little attention to this, resulting in a decline in the quality of life of the residents, both physically and psychologically.Growing houses itself can be one of the sustainable housing solutions used to answer the above urban problems because it is able to develop on limited land and can be built based on the standard minimum cost of housing so that it is affordable by the community [9].Home grown as a residential concept that can be built in stages according to the times and the needs of its inhabitants.However, it is necessary to develop a spatial layout concept in the growing house so that the quality of life of the occupants, both physically and psychologically, is maintained.
In Bandung City, PERUMNAS began building several housing projects, especially type 36 in 1976-1978, including the PERUMNAS Sarijadi housing complex.At that time, PERUMNAS Sarijadi was surrounded (according to the cardinal directions): by Jerokaso village, Cilandak village, Cilangreuh village, Dangdeur village, Cibogo village, Cibarunai village, and Awingahgar village.PERUMNAS Sarijadi consists of Blocks 1-18 and Blocks 23-26.PERUMNAS Sarijadi is located in two areas, namely Block 1-18 in Sarijadi sub-district, Sukasari sub-district and Block 23-26 in Sukawarna sub-district, Sukajadi sub-district [10].PERUMNAS type 36 in the Sarijadi area is included in the Simple House type with a core plan of 3 rooms, a bathroom, and a service area.Along with its development, PERUMNAS has the potential to become a Core House by the Growing House concept.This research will examine the transformation in the layout of the PERUMNAS house during the initial construction period (1976)(1977)(1978) and compare it with the condition of the house in 2023.Data was collected in the period June-July 2023 through interviews with informants and field observations.

Transformation
Transformation is a process of changing or developing a form anew by considering space and time aspects, and it is done in stages where the new form becomes the final one.Design process, thus, in a way also a way of transformation.Transformation occurs in several stage, which are: 1) The change happened gradually.
2) The start and finish time of the transformation is hard to predict and depend on the influencing factors.
3) The changing process moves in a sustainable and comprehensive manner.4) Societal behaviours and values are linked to the change process.There are also several factors which influence the transformation process, which are social changes, cultural changes, economic changes, and political changes.Other things to be considered including [11]: 1) Identity and self-existence need.
2) Lifestyle changes related to intersection with new cultures.
3) Usage of new technologies which also affected the environment.4) Community pressure to keep up with rapidly changing trends, where something that is still usable is forced to change to follow the fashion.There are several categories of transformation's characteristics, which are: 1) Topological: related to changes in space-forming elements that have the same spatial function.2) Grammatical (ornamental): related to changes that reflect the community's cultural values.3) Reversal: related to changes that occur by reversing the transformed object's image.4) Distortion (confinement): related to changes made by giving the designer freedom to change an object.
Transformation happens sequentially where each component is linked to the built environment where they will experience change in stages that is influenced by the inhabitants' activities and adapted to evolving needs and developments.Lifestyle changes happened due to shifts in the socio-cultural values and cultural orientation that became the guideline, which also became a form of consequence of changing the society's perspective.The transformation process then changed the perspective of a group of people who contribute to changes in the building elements' physical forms.

Growing House
The house has a concept as a residence or place to live where the existing space functions reflect the behavior of the occupants.A growing house is a house whose layout has developed and changed gradually from the main house over time considering changes/developments in the number of occupants, the need for spatial functions and the economic level of the occupants.Tipple 1999 [12] reveals the tendency for design development to occur in almost all low-to-middle income countries due to a lack of housing provision.
According to Turner and Fichter 1972 [13], a house is not a one-time physical product but a process that continues to develop and is related to the socio-economic mobility of its inhabitants over a period of time, where there are times when the house is no longer able to serve the needs of its inhabitants flexibly.This condition then triggers occupant improvisation to change or develop the layout of the house.To avoid major overhaul due to the above process, it is necessary to design a core house that is able to grow flexibly and in accordance with development possibilities so that the changes that occur minimize the loss or damage to the main building.
Meanwhile, according to Antoniades 1990 [14], there are three strategies in layout design transformation that are often used by designers in designing a design formation, there are; 1) The traditional strategy, is a progressive evolution of a form using a simple strategy, namely designing by taking into account aspects that already exist around the object and adjusted to the boundaries; environmental criteria, site, view, orientation, wind direction (external factors), and structural criteria, function, spatial program (internal factors), as well as the ability, willingness and attitude of designers to manipulate forms (artistic factors).2) Borrowing strategy is the adoption of an existing design or art form which is then transformed into a new design by considering the feasibility of the application and its validity.3) The strategy of deconstruction or decomposition is the development of renewal of design concepts that produce works that are completely new.This process produces a new unity and order with a structural strategy in a different composition.The transformation strategy is related to the emergence of new ideas that consider the selection of the three strategies.
Najoan's 2011 [15] research, which adapted Anthoniades' theory above, produced a transformation analysis of interior layouts by taking into account the following aspects; 1) Scale: increase or decrease in space, 2) Interrelationships between parts (whole vs parts): unity between the whole space and its parts, 3) External influences (forced externalities): the influence of the external environment on the design transformation that is carried out, 4) Semantics: visual language in the form of forms, shapes, typologies, images, looks, and shadows.In this study, the first thing to do is analyze the macro and micro conditions of the building.Then a comparison was made of the initial plan, first renovation, and second renovation to find the spatial transformation that occurred by taking into account the four aspects described above.[16] Layout transformations in growing houses that are carried out independently by residents are the most effective way of reading behavior in residential houses Manalang 2002 [17].Manalang emphasized that this understanding should be taken into consideration in the design stage so as to reduce the possibility of changes in the future.The transformation that is carried out is the result of the process of its inhabitants.This should be considered by public housing developers, in this case PERUMNAS.

Figure 1. Design Transformation Chart on Growing Houses
According to Aryani 2016 [18], there are several possible transformations to the layout of the growing house, based on an evaluation of the PERUMNAS growing core house, including; 1) Room added (bedroom, bathroom, drying room, business area, work area, warehouse/storage area, garage), 2) Room that was expanded (terrace, living room, kitchen, family room), 3) Room that was moved (kitchen, living room, bathroom), 4) Fixed room (bedroom).The room whose layout is maintained is probably because it is in accordance with the needs of the occupants, while the room/area whose layout and area has changed must be considered in designing a growing house in the future.

Sustainable Housing
Sustainable housing has received significant attention in recent years as communities around the world grapple with pressing environmental, social, and economic challenges.As urbanization increases, the need for housing in line with sustainable principles becomes increasingly important.
Sustainable housing aims to minimize environmental impacts, encourage social equity, and ensure economic sustainability.This definition is in line with the objectives of the "Growing House" theory which emphasizes adaptability and sustainability over time: 1) Environmental Sustainability: Sustainable housing prioritizes energy efficiency, use of renewable energy, and reduction of carbon emissions.Green building practices, including passive design, solar panels, and environmentally friendly materials, play an important role.2) Social Sustainability: Sustainable housing aims to provide homes that are affordable, safe, and accessible to everyone.Inclusive design, universal accessibility, and community involvement are important aspects.3) Economy Sustainability: Sustainable housing must not only be cost-effective to build but also economical to live in over time.Energy savings, reduced maintenance costs, and longterm affordability are key factors.[9]

PERUMNAS
The PERUMNAS house is included as a growing house that meets the minimum standard requirements for a house or the forerunner of RSS (low budget housing).The concept of PERUMNAS itself is to build a public housing that can be developed/built in stages to achieve RSS standards and spatial division sizes based on standard sizes and human ergonomic international modules [19].PERUMNAS should have considered these aspects from the planning, design and implementation stages of its development, so as to support the concept of sustainable development.The PERUMNAS house represents a mass product resulting from the generalization of the property industry which at the time of its construction was still oriented towards product availability in a short time [18].
Type 36 houses have a minimum standard layout for an urban dwelling, namely a living room, bedroom, kitchen, bathroom, terrace and backyard (green area).Over time and with the addition of family members, families living in this type of house usually experience developments in activities which result in the need for additional space requirements, so that this type of house is very possible to develop into a growing house.

3.
Discussion Type 36 houses have a minimum standard layout for an urban dwelling, namely a living room, bedroom, kitchen, bathroom, terrace, and backyard (green area).Over time and with the addition of family members, families living in this type of house usually experience developments in activities which result in the need for additional space requirements, so that this type of house is very possible to develop into a growing house.The site to be analyzed faces south so that not much sunlight enters the room.As a result, it is not desirable for direct sunlight to enter the house because it will cause heating and glare [20].The potential for natural scenery (South Bandung) and noise levels are sourced from the front of the house which is sourced from the main residential road.Wind potential comes from Mount Tangkuban Parahu which leads from the back to the front of the building.While the ventilation circulation comes from the front of the building.Design on this 1979 original site has a simple residential concept, with the main requirement is a bedroom.This building has 3 bedrooms, bathroom, kitchen, living area, backyard, core and front yard.Ambience from each room is quite comfortable according to its function as a residence, with inadequate natural lighting and poor ventilation when viewed from the whole room.In the 1984 first renovation, there was a function change in the backyard to become an expansion for the kitchen and bathroom, which also made the living room area wider.On a grid basis, this displacement results in a more regular and symmetrical spatial layout.In the 1994 second renovation, a second floor was added to be used as a warehouse and laundry area (see Figure 7 and Table 1).Partitions in the form of cupboards are used to emphasize the separation of the living room and dining room zones, so that when viewed from the function of the room there is an additional special area for dining.

Layout Transformation
Another factor that influences the transformation according to Anthoniades 1990 [8], is by analyzing the transformation in the interior layout by paying attention to aspects, namely that there is a lot of additional space adjustment based on the needs and number of occupants, such as adding the building vertically upwards due to the need for additional bedrooms, then a carport, a larger service area, and the addition of a bathroom.
As a result of the latest renovation, there was a change in zoning area, several areas such as the foyer, living room, dining room and kitchen were made into one large room from front to back which was partitioned by non-permanent space dividers such as partitions and stairs.The ventilation factor has also been considered, because the position of the house is in a dense residential area, when adding the building vertically upwards, the ventilation is managed with openings in the upper facade area (windows, balconies), green areas in the upper terraces and voids, as well as openings (alley) as service area, the ventilation in the house is quite good.Based on the circulation flow, the division of space between public, semi-public, private, and service areas is quite good.Visually, the material used on the stairs does not have a visual unity, where the bottom steps before the board desk use ceramics of a 1324 (2024) 012033 IOP Publishing doi:10.1088/1755-1315/1324/1/0120339 different color from the ceramic used on the kitchen floor, then after the board desk, the stairs use wood material.The design of the decorative elements on the stair railing and void railing are different, even though they use the same iron material (see Figure 8).

Conclusion
Based on the discussion regarding the transformation that occurred in the development of the core grow house, the following conclusions can be drawn: 1) The most frequently carried out transformation is the addition of new functions that previously did not exist, such as carport area, laundry area, dining room, storage room, sitting room, and TV area.This indicates that homeowners need new space functions over time.
Area transfers also occur in several room functions such as bathrooms, kitchens, and bedrooms.In the bedroom, there was even a move and expansion of the area.Meanwhile, on the other hand, there is also a bedroom (children's) where the area of the room becomes narrower because it is taken up by the need for a carport area.In addition, the kitchen area increased almost 10 times from the initial space allocation (1.08 m 2 to 10.5 m 2 ).This indicates a shift in residents' habits and behaviour regarding activities carried out in the kitchen, resulting in the need for more spacious space.
2) The loss of the backyard area creates problems related to the narrowing of the previously existing service area.The homeowner's solution was to add a second floor to accommodate the need for a second living room, a larger bedroom, a service area in the form of a laundry area, and additional space for storage.
3) The 1980s PERUMNAS house in the Sarijadi area had an initial layout that did not accommodate the needs of the service area.However, homeowners can adapt to shifts in activity by carrying out sustainable transformations in the form of additional functions which then result in different zoning.
As a conclusion, sustainable housing represents a multidimensional approach that addresses environmental, social, and economic problems.As the world grapples with the challenges of climate change, urbanization, and housing affordability, the concept of sustainable housing is more relevant than ever.This offers a promising path to creating a resilient, just, and environmentally friendly society.

Figure 2 .
Figure 2. Original Layout of the PERUMNAS Sarijadi House Type 36