In those years, how did developers go to every length to improve the percentage of usable floor space of their properties?
The usable floor area ratio is the top priority for home buyers, and it is also the main battlefield where developers engage in cutthroat competition. Home buyers naturally want to get larger space, higher utilization rate and more generous living scale within a limited budget. It is this extreme market pressure that forces developers to continuously optimize their product systems. As a result, we have seen a dazzling array of new concepts: from the early flexible balconies and adaptable spaces, to N+1 apartment layouts, and then to the 4th-generation residences and 5th-generation residences that have exploded in popularity in the past two years, as well as large terraces with a two-story height and sky courtyards staggered on odd and even floors.
Under such a background, high free area concessions are no longer just a plus point in sales pitches, but have even become the standard configuration of mainstream products. Therefore, a high usable floor area ratio is always a shiny golden signboard. Especially for small and medium-sized apartments where every square meter counts, it is not only a selling point, but also the core competitiveness for product premium. However, in a market where policies at different stages keep changing, how do developers manage to improve the usable floor area ratio of their products? By sorting out the product paths to increase usable floor area ratio in recent years, we have found some very interesting commonalities.
01 Tap space from the interior of apartment layouts to optimize space allocation efficiency
Let's start from around 2006. At that time, to ease the structural contradiction in housing supply, nine ministries including the Ministry of Construction introduced the "90/70" policy, which stipulated on the land side that over 70% of the properties on a single land parcel should be small-sized apartments with a construction area of less than 90 square meters. The 90-square-meter two-bedroom apartment was almost the standard product of that era (87 square meters of construction area, two bedrooms, two living rooms and one bathroom). As housing prices kept rising, people's demand for more functional space at the same total price was also growing day by day. The first mandatory question that developers faced was: How to fit more functions within a limited area? Real estate enterprises represented by Vanke began to make efforts within the 90-square-meter framework, launching 90-square-meter small three-bedroom apartments.
At that time, the policy had high requirements for daylighting rate. Therefore, on the premise that the width facing the sun was difficult to change, lengthening the depth was an effective way to increase the usable floor area ratio. The kitchen and bathroom were placed in the middle, freeing up more space for the north side; the two rooms on the north side were separated by light-weight partitions, which residents could combine freely according to their own needs. Of course, the two rooms on the north side are indeed not large, and the shortcomings of the apartment layout with long depth are obvious: despite poor daylighting and ventilation, the very attractive point of this apartment layout at that time was that it broke the restriction that 90 square meters could only be made into two bedrooms.
Later, developers were no longer satisfied with the simple demand of adding one more room, and paid more attention to whether the moving line was smooth, so as to further improve the spatial experience. As a result, we saw that the integrated design of living-dining room, and LDKB (Living, Dining, Kitchen, Balcony) integrated design gradually became the standard configuration of products. For example, an 83 ㎡ three-bedroom two-living room apartment in Longhua District, Shenzhen adopts the LDKB integrated design. By breaking traditional partitions, it directly integrates the originally inefficient aisle space into the living and dining room, maximizing the usable space of the living room. This practice not only eliminates invalid traffic area, but also maximizes the utilization rate of every square meter. For the 98 ㎡ four-bedroom apartment in the same project, the operation is further improved: by adopting non-load-bearing wall design and hidden partitions, the originally closed kitchen is completely opened up. After the spatial boundary is broken, the living, dining and kitchen areas can be switched to a transparent "large horizontal hall" at any time. Although the area has not changed, the utilization efficiency of the space is greatly improved. The reason why this space can be changed freely is not only the consideration at the level of apartment layout design, but also the evolution of the entire refined decoration system. With the further improvement of interior decoration components, variable custom controls such as sliding doors and hidden partitions are becoming more and more diverse.
Storage design to expand available space has also been deeply integrated with interior design. For example, in the past, small-sized apartments basically adopted the "one-line" kitchen layout, where it was even difficult to turn around; but now, even a 91 ㎡ apartment can fit a U-shaped kitchen, which enlarges the operation counter while adding enough storage space on both sides. However, on the premise that the indoor usable area is fixed, the optimization of internal moving lines ultimately has a physical limit. To make further breakthroughs, developers have tried to continuously expand the physical boundary of buildings.
02 Tap space from the building boundary to expand life scenarios
The planning of indoor space moving lines and smoothness has been nearly saturated, so the breakthrough naturally turns to finding space within the area calculation rules, so as to increase the actual usable floor area ratio. For example, bay windows that are not included in the plot ratio calculation area in most cities were originally just a traditional selling point in sales offices. After delivery, the bay windows are either at an inappropriate height that cannot hold any furniture or desks, or if you modify it to a higher level to make a desk, it will be very inconvenient to close the window. But now, a new concept has been derived: the full bay window system. As can be seen in a 193 ㎡ apartment in Jing'an District, Shanghai, there are as many as seven full-house bay windows. Every room except the balcony, including the kitchen and toilet, is equipped with a bay window, which is equivalent to widening the entire apartment layout outwards by a whole circle.
Other developers start from life scenarios to improve the actual utilization rate of bay windows. The first point is the height. For example, the master bedroom of a project of China Resources Land adopts a high-low bay window design: the high bay window is 45cm high, which can be made into a seating area by the window or transformed into a bar counter in the later stage; as for the 20cm low bay window, it can be used as a full-wall storage cabinet. The bay window transformation extended from height has far more possibilities than that. A Poly Real Estate project in Zhujiang New Town, Guangzhou, boldly lowers the height of the bay window to about 5cm. The bay window that could originally only be used for sitting and piling clothes is directly "integrated" into usable space. Combined with the floor-to-ceiling window design, it greatly extends the sense of indoor space.
In Shanghai, in the face of relatively strict balcony area control, some developers have made exquisite R&D within the framework of regulations. More and more small-sized apartments begin to adopt three-balcony design to unlock more space. For example, in the apartment layout above, you can see that the depth of the three balconies is controlled within 1.8 meters, roughly between 1.05 and 1.65 meters; and the photos taken on site also show that the area of each balcony is not very large, especially the large balcony connecting the living room and the second bedroom, which is deliberately divided into two parts by a partition. After being split into small balconies, the total area is about 13.44 square meters, accounting for about 12% of the total apartment area; but the balcony area of more than 13 square meters can bring about 6.5 square meters of free area. Such an area is hard to perceive intuitively, but it becomes clearer when placed in actual usage scenarios: due to the balcony setting, the daylighting and view of the second bedroom become more transparent. However, some developers are not satisfied with this, and further iterate on the three-balcony design, using flower ponds to get more free balcony area. It is imaginable that when all balconies are included in the indoor usable space, the actual experience of this 95 ㎡ small apartment will not be worse than that of a 110 ㎡ apartment at all.
But the optimization space of a single project is limited after all, and the substantial expansion of areas such as balconies and terraces depends on the shift of macro policies. To break the deadlock of monotonous apartment products and solve the pain point of shared public area, since 2023, major cities have gradually relaxed the area restrictions on balconies, which not only achieves a substantial improvement in space utilization rate, but also makes high usable floor area ratio turn from a "gimmick" into reality. Take Guangzhou as an example, the 2023 plot ratio calculation method raises the upper limit of the proportion of residential semi-open space calculated as half of the plot ratio from the previous 15% to 20%; the main landscape balconies that meet the requirements of continuous open rate also get larger depth design space.
As early as 2017, the "7·1 City Forest Garden" in Chengdu first localized the vertical forest concept. Although the concept of "4th-generation residence" was not mentioned at that time, the two-story high sky courtyard for each household plus the 6-meter overhanging terrace has already presented the core features of 4th-generation residences. The extremely high free area plus the visual impact of vertical greenery made 4th-generation residences popular in 2024 and 2025, with the usable floor area ratio once exceeding 100%. For example, the first 4th-generation residence product in the center of Kunming has a 175 ㎡ apartment with an about 31 ㎡ sky courtyard, which connects the terrace with the living and dining room, achieving an overall usable floor area ratio of 101-104%, making it the first pure zero-shared-area community in Kunming. The 4th-generation residence apartment of Poly Tianjun in Fuzhou combines an about 20 ㎡ terrace with an about 40 ㎡ public leisure platform, achieving a total super large free area of about 60 ㎡.
When the competition for plane area reaches its extreme, developers and customers will inevitably turn their attention to "three-dimensional space". As a result, vertical space forms such as duplex apartments, void spaces, basements and sunken courtyards emerge as the times require, and begin to carry higher space utilization rate.
03 Area expansion develops from plane to three-dimensional
A very representative case is the combination of stacked villas and 4th-generation residences, which brings the extension of three-dimensional space to the extreme. Recently, a 4th-generation villa in Taihu Bay, Suzhou, has an upper duplex apartment with a construction area of about 118 ㎡, equipped with an about 63 ㎡ roof garden, two terraces, two 270° corner balconies, bay window space and a 10 ㎡ free void space in the living room. The total expandable area exceeds 108 ㎡, and the actual utilization rate reaches 192%.
Even for villas that already have a high free area ratio, new changes have emerged. In the past, when selling villas, salespeople always said that the villa has open sky, private ground and a garden, but after delivery, customers often find that except for a few small pieces of green lawn, the actual outdoor activity space is extremely scarce. But this villa project in Xihu District, Hangzhou, adopts a unique L-shaped layout from the very beginning of design, forming a courtyard area of about 200-300 square meters through space enclosure. Meanwhile, with the wide eave design, the terrace is extended into an extremely spacious semi-outdoor display space.
The second point is the breakthrough in underground space. As is known to all, the basement is the largest part of the free area in villas, but it always cannot avoid the pain points of darkness and dampness. However, the basement of a courtyard project in Pudong, Shanghai, does not feel oppressive at all. It deliberately raises the indoor daylighting patio, and places the water retaining glass slab not on the first floor, but directly at the height of the second floor. The only purpose of doing this is to allow light and sight to penetrate in without dead angles. Thanks to the vertical height difference, the basement can even be designed with vertical greenery; also because of this, the underground space has more sense of scene, and the overall living moving line becomes more pure.
In fact, the fundamental reason why developers go to such great lengths on the area of these physical spaces is the change of customers' logic of space usage. In the past, what customers most wanted to get was an extra room; but now, some families who want to improve their living quality are willing to generously allocate the very precious extra space to a terrace or a garden. The indoor space is basically sufficient, and people begin to hope to sunbathe, plant something, or just stay quietly on the terrace or in the garden. Although they are all striving for higher usable floor area ratio, people's living demands have long stepped into a new dimension.
04
Writing here, some people may think that the residential iteration over the past 20 years is just an extreme involution around the usable floor area ratio. But looking back on these 20 years, the reason why this extreme exploration of space can always be a selling point hides every family's desire for better living space: within a limited budget, people always hope that the house can hold a little more life. In the early years, it was to accommodate one more person, later it was to leave one more spare room, and today people have new expectations for sunbathing, growing flowers, staying alone and receiving friends. It is certainly worth studying how developers get a few more square meters for customers; what is more worthy of continuous research is how to make a family live more comfortably and freely after getting these extra square meters.
We have witnessed a kind of "awakening" in the industry: whether it is the 4th-generation residences that blindly expand the area outwards, or the 5th-generation residences with raised slabs that expand downwards, they are all updates and changes to the architectural forms of the past 20 years. But the future competition in the residential sector no longer lies in who can play more fancy concepts, but in whether every square meter can be actually used and loved for a long time. The ultimate proposition of residential evolution will return to: it must be able to carry real, high-frequency daily living life. In the second half of China's real estate industry, returning to the long-termism of "focusing on quality and experience", the enterprises that can win in the end may be those that turn every inch of space into a better life.
This article is from the WeChat Official Account "Zhen Jia Lu Jun", written by the Zhen Jia Lu Jun team, and authorized for release by 36Kr.