Chapter 1
Global Urban Renewal: From Incremental Expansion to Stock Renewal
Compiled by Guangdong Fortune Stone New Material Co., Ltd.
Key Points
- Global urbanization is shifting from incremental expansion to stock renewal. Land resource constraints and the concentrated aging of existing buildings are the fundamental drivers of the facade retrofit market.
- Regulations and programs such as the EU Renovation Wave, the New York FISP program, and China’s urban renewal action have turned existing building renewal from an optional choice into a mandatory compliance requirement.
- Facade retrofit exterior wall materials must simultaneously meet six requirements: safety, lightweight, durability, low disturbance, economy, and environmental protection. Traditional materials cannot fulfill these due to performance shortcomings. Flexible stone, with its balanced comprehensive performance, has become a new choice in generational replacement.
1.1 An Irreversible Historical Process
The evolution of human cities has roughly gone through three stages. In the incremental expansion era, city scale expanded rapidly, the logic was “seeking land outward,” and new construction was dominant. In the stock renewal era, the development focus shifted from “building new” to “renovating old,” the logic is “tapping potential inward,” and facade retrofit has become dominant. In the smart operations era, digitalization, intelligentization, and greening are superimposed on stock renewal, and full life cycle building management has become dominant.
At present, major global economies are at a critical juncture of switching from “incremental expansion” to “stock renewal.” This switch is not a local phenomenon but a universal law of urban development. Its irreversibility is jointly constituted by three driving factors.
1.1.1 Physical Constraints of Land and Space
The land development intensity in core areas of major global cities has approached its limit. The space for new projects is continuously narrowing, the stock of existing buildings continues to expand, and the focus of urban development can only shift to “tapping potential inward.”
Engineering Case: Renovation of an Old Industrial Zone in Shenzhen
Originally an electronics factory plant built in the 1990s, covering an area of about 30,000 square meters. If demolished and rebuilt according to traditional thinking, it would require a cycle of 3 to 4 years, during which there would be no rental income; renovation and renewal would require only 6 to 8 months, and the rent after renovation could increase by more than 50%. The project party ultimately chose the path of “no demolition, only renovation,” completing exterior facade renovation, internal function upgrading, and equipment renewal.
Case insight: When incremental land space is exhausted, stock renewal is the most economical choice, and its decision basis is economic calculation rather than value orientation.
1.1.2 Concentrated Aging of Building Stock
A large number of buildings built from the 1950s to the 1990s have a structural life of usually 50 to 100 years, while the life of enclosure structures such as exterior walls, roofs, and doors and windows is often only 20 to 30 years. The common phenomenon of “structure not old, cladding fails first” constitutes the most direct source of demand in the facade retrofit market.
Engineering Case: Investigation of a Residential Community Built in 1995 in Shanghai
A residential community built in 1995 with 12 buildings had ceramic tile facing on exterior walls. A safety investigation in 2023 found: the average hollowing rate of ceramic tiles reached 18%, with some buildings exceeding 25%; the average substrate strength was 0.35 MPa, with some areas below 0.3 MPa; the annual water seepage complaint rate was 12%. The testing conclusion was that the exterior wall facing had entered an “accelerated aging period,” and renewal and renovation should be completed within 3 years.
Case insight: The aging speed of building envelope systems is faster than that of structural systems, which is the underlying logic that distinguishes the facade retrofit market from the new construction market.
1.1.3 Mandatory Promotion by Policies and Regulations
The EU Renovation Wave strategy, the UK Building Safety Act[3], the New York FISP program[4], and China’s old residential area renovation deployment[9][10][11] all forcibly promote existing building renewal through regulatory and policy forces. Facade retrofit has thus changed from an “optional” choice to a “mandatory” compliance requirement.
Table 1-1 Major Global Facade Retrofit Policies
| Region | Policy Name | Release Time | Core Requirements | Source |
|---|---|---|---|---|
| EU | Renovation Wave | 2020 | Double the renovation rate by 2030 | [1] |
| UK | Building Safety Act | 2022 | Exterior wall safety assessment for buildings above 18 meters | [3] |
| New York, USA | FISP | Continuously implemented | Exterior wall inspection every 5 years for buildings above 6 stories | [4] |
| China | 14th Five-Year Plan Old Residential Area Renovation | 2021–2025 | Renovate 219,000 old residential areas | [9] |
| China | 15th Five-Year Plan Old Residential Area Renovation | 2026–2030 | Renovate 115,000 old residential areas | [10] |
| China | Urban Renewal Action | 2024 | National urban renewal strategy | [11] |
Engineering Case: Exterior Wall Rectification After the Grenfell Tower Fire in London
The Building Safety Act requires all buildings above 18 meters to undergo exterior wall safety assessment. A London residential community with 8 high-rise buildings had aluminum composite panel exterior walls. The assessment found that the fire rating did not meet standards and replacement was mandatory. The owners’ committee initially budgeted 2 million pounds; using traditional stone or ceramic tiles would cost more than 5 million pounds and a construction period of up to 12 months; after switching to lightweight flexible facing materials, the cost was controlled at 2.8 million pounds and the construction period was shortened to 6 months.
Case insight: Mandatory regulatory requirements create structural market opportunities for new materials, and compliance costs force material substitution.
The superposition of the three driving factors constitutes an irreversible historical process. From the perspective of material generational replacement, traditional exterior wall materials have entered maturity or decline, and their technical potential is approaching its limit; the new demands proposed by the facade retrofit market are difficult for traditional materials to satisfy simultaneously; flexible stone is in the growth stage, and its technical potential is still being released. Generational replacement is happening, but it will not happen overnight.
1.2 Europe: A Regulation-Driven Renovation Wave
Europe is the region with the most mature facade retrofit policies and the strictest regulations in the world.
1.2.1 EU Renovation Wave Strategy
In October 2020, the European Commission officially released the Renovation Wave strategy, with the goal of doubling the building renovation rate by 2030 and achieving full decarbonization of the building stock by 2050[1]. Its core logic is: building energy consumption accounts for about 40% of total EU energy consumption[2], most of which comes from existing buildings. Compared with new green buildings, large-scale renovation of existing buildings can both create jobs and stimulate the economy in the short term and achieve carbon reduction goals in the medium and long term.
Supporting policies include: continuous upgrading of the EU Energy Performance of Buildings Directive[2], requiring member states to formulate building renovation plans and set minimum energy efficiency standards; “Green Deal” special funding support, amounting to hundreds of billions of euros; and member states need to formulate specific national energy and climate plans.
Table 1-2 Core Indicators of the EU Renovation Wave
| Indicator | Data | Source |
|---|---|---|
| Building energy consumption share | About 40% | [2] |
| Renovation rate target | Double by 2030 | [1] |
| Special funding | Hundreds of billions of euros | EU Green Deal |
| Residential stock | About 220 million units (built before 2000) | [2] |
1.2.2 Renovation Demand in Major Countries
Germany: More than 10 million residential units were built before 1979, and exterior wall insulation performance generally does not meet standards. The German government provides low-interest loans and subsidies through KfW Bank, and about 2% to 3% of existing residential buildings undergo exterior wall renovation each year, with a market size of about 30 billion euros per year[14].
France: In 2021, the “MaPrimeRénov” subsidy program was launched, providing subsidies of up to tens of thousands of euros for residential renovation, focusing on exterior wall insulation, door and window replacement, and heating system upgrades[7]. According to data from the French Ministry of Ecological Transition, about 600,000 households applied for renovation subsidies in 2023.
Italy: “Superbonus 110%” provided tax deductions of up to 110%, generating a large number of exterior wall renovation projects between 2020 and 2023, and then gradually phased out due to fiscal pressure[8], also exposing the problem of “emphasis on subsidies, neglect of quality” in the renovation market.
UK: After the Grenfell Tower fire, the Building Safety Act was introduced, requiring all buildings over 18 meters or 7 stories to undergo exterior wall safety assessment, and non-compliant exterior wall materials must be replaced[3]. It is estimated that thousands of high-rise buildings in the UK face exterior wall rectification.
Table 1-3 Renovation Demand in Major European Countries
| Country | Residential Stock (Pre-2000) | Renovation Policy | Annual Renovation Scale |
|---|---|---|---|
| Germany | More than 10 million units (pre-1979) | KfW subsidy[14] | About 30 billion euros/year |
| France | Large quantity | MaPrimeRénov[7] | About 600,000 households/year |
| Italy | Large quantity | Superbonus 110%[8] | Phased out |
| UK | Thousands of high-rise buildings need rectification | Building Safety Act[3] | Thousands of buildings |
1.2.3 Demand Characteristics of European Facade Retrofit for Materials
The European facade retrofit market has four characteristics in material demand: integration of insulation and facing—facade retrofit usually treats exterior wall insulation and facing renewal as a whole project, requiring materials to have both insulation performance and decorative function; high fire rating—especially strict for high-rise buildings; strict environmental requirements—constrained by building products regulations and REACH regulations[5]; strict construction disturbance control—cities have clear restrictions on noise, dust, and traffic impact.
Engineering Case: Renovation of a 1970s Residential Building in Berlin, Germany
A 6-story residential building built in the 1970s had coating facing on exterior walls and insulation performance that did not meet standards. In 2022, it was renovated using an external insulation system plus flexible facing material scheme. Reasons for selection: low construction disturbance, no need to remove the old substrate; light self-weight, no increase in structural load; stone-imitation texture coordinated with the surrounding historic building appearance. After project completion, building energy consumption decreased by 45%.
Case insight: The demand of European facade retrofit for materials is a comprehensive demand of “insulation + facing + low disturbance + aesthetics”; superior single performance is not enough to support a winning scheme.
European experience shows that regulation-driven demand is the strongest driving force in the facade retrofit market. When regulations require “must renovate,” market demand shifts from “optional” to “rigid.” For flexible stone to enter Europe, certification is the first threshold—a high threshold also means great opportunity; once certification is passed, the competitive landscape will change accordingly.
1.3 North America: Mandatory Renovation Driven by Safety Regulations
The North American facade retrofit market is mainly driven by safety regulations.
1.3.1 New York FISP Program
New York City’s FISP program is one of the strictest exterior wall inspection systems in the world[4]. Its core requirements include: all buildings over 6 stories must undergo a comprehensive exterior wall inspection every 5 years; inspections must be performed by registered architects or engineers; problems found must be repaired within the specified period; inspection reports and repair records must be submitted to the Department of Buildings for filing.
According to data from the New York City Department of Buildings, thousands of buildings undergo FISP inspections each year, and a considerable proportion require exterior wall repair to varying degrees. New York has dense high-rise buildings, limited construction space, and strict disturbance control, imposing clear requirements on material lightweight, durability, and construction convenience.
Table 1-4 Core Requirements of the New York FISP Program
| Indicator | Data | Source |
|---|---|---|
| Applicable buildings | Above 6 stories | [4] |
| Inspection cycle | Every 5 years | [4] |
| Annual inspected buildings | Thousands | [4] |
| Repair requirements | Completed within a time limit | [4] |
1.3.2 Global Impact of the UK Building Safety Act
Although the Building Safety Act is domestic UK law, its impact is global[3]. The core requirements of the Act include: exterior wall materials of high-rise buildings must meet strict fire rating requirements; building owners must establish exterior wall safety files recording materials, construction, and inspection information; non-compliant exterior wall materials must be replaced within a time limit.
The Act prompts global building material suppliers to re-examine the fire performance of products for high-rise buildings. For flexible stone, this is both a challenge to obtain fire certification and an opportunity for sustained growth in demand for compliant lightweight materials.
1.3.3 Canada and Australia
Canada and Australia also face pressure from exterior wall material compliance reviews. After the Melbourne fire in Australia, states successively issued exterior wall material compliance review policies requiring high-rise buildings to investigate existing exterior wall materials. According to estimates by the Australian Building Codes Board, thousands of buildings nationwide have exterior wall materials requiring rectification.
Engineering Case: Renovation of a 1980s Apartment Building in Manhattan, New York
An 18-story apartment building built in the 1980s had ceramic tile facing on exterior walls. In 2023, FISP inspection found a ceramic tile hollowing rate of 22%, posing a detachment risk, and the owner required repair within a time limit. Scheme comparison: remove and redo ceramic tiles, cost about 4.5 million USD, construction period 8 months; use lightweight flexible facing material for direct coverage, cost about 2.8 million USD, construction period 4 months. The flexible facing material scheme was ultimately selected.
Case insight: The demand of North American facade retrofit for materials is a comprehensive demand of “lightweight + fast installation + compliance.” In areas with dense high-rise buildings, the construction period is directly related to rental loss, and schedule advantage is a key variable in material decision-making.
The logic of North American facade retrofit is “safety-driven, mandatory inspection, rectification within a time limit.” For flexible stone to enter North America, fire certification is the first threshold—a high threshold means great opportunity; once certification is passed, the competitive landscape will change accordingly.
1.4 China: The World’s Largest Urban Renewal Program
China is the country with the largest facade retrofit market and the strongest policy promotion in the world.
1.4.1 Policy Framework
China’s urban renewal policy has evolved from “shantytown renovation” to “old residential area renovation” and then to “urban renewal action.”
Table 1-5 Evolution of China’s Urban Renewal Policies
| Stage | Policy | Time | Core Content |
|---|---|---|---|
| Shantytown renovation | Shantytown renovation policy | 2010–2020 | Large-scale demolition and reconstruction |
| Old residential area renovation | 14th Five-Year Plan[9] | 2021–2025 | Renovate 219,000 old residential areas |
| Urban renewal action | 15th Five-Year Plan[10] | 2026–2030 | Renovate 115,000 old residential areas |
During the “14th Five-Year Plan” period, the national plan was to renovate 219,000 old residential areas, involving a construction area of about 3 billion square meters[9]; during the “15th Five-Year Plan” period, the plan is to renovate 115,000 old residential areas, involving a construction area of more than 2 billion square meters[10]. Since 2024, urban renewal has been promoted as a national strategy, covering multiple dimensions such as old residential area renovation, old factory area renewal, old street revitalization, and urban village renovation[11].
Table 1-6 China’s Facade Retrofit Market Scale
| Indicator | Data | Source |
|---|---|---|
| 14th Five-Year Plan renovation target | 219,000 communities | [9] |
| 15th Five-Year Plan renovation target | 115,000 communities | [10] |
| Construction area involved | More than 2 billion m² | [10] |
| Total old residential areas | About 170,000 | [9] |
| Residents involved | More than 42 million households | [9] |
1.4.2 Scale and Structure of the Facade Retrofit Market
The scale of China’s facade retrofit market can be estimated from three dimensions: about 170,000 old residential areas nationwide, involving more than 42 million households and a construction area of about 4 billion square meters; the national urban existing building area exceeds 60 billion square meters, of which about 60% was built before 2000; estimating at a comprehensive exterior wall renewal cost of 150 to 300 RMB per square meter, the market scale for old residential area exterior wall renewal alone reaches hundreds of billions of RMB[12].
Table 1-7 China’s Facade Retrofit Market Scale Estimation
| Estimation Dimension | Data | Estimation Basis |
|---|---|---|
| Old residential area area | About 4 billion m² | [12] |
| Exterior wall area proportion | About 30% | Empirical value of building exterior wall area |
| Exterior wall area | About 1.2 billion m² | 4 billion × 30% |
| Comprehensive cost | 150–300 RMB/m² | Project settlement data |
| Market scale | 180–360 billion RMB | 1.2 billion × (150–300) |
1.4.3 Unique Challenges of China’s Facade Retrofit
China’s facade retrofit market has four unique challenges: high building density—high-rise building density leads the world, construction space is limited, and disturbance control requirements are high; concentrated material aging—a large number of residential exterior wall ceramic tile detachment problems built from the 1990s to the early 2000s are prominent; diverse resident demands—facade retrofit involves the vital interests of a large number of residents, with extremely high requirements for schedule, noise, dust, and safety; difficult funding balance—funding sources cover government subsidies, resident self-funding, and social capital, with high cost control requirements.
Engineering Case: Renovation of a Residential Community Built in 1998 in Guangzhou
A residential community built in 1998 with 8 buildings had ceramic tile facing on exterior walls. In 2023, it was included in the old residential area renovation plan. Pre-renovation investigation showed: average hollowing rate 15%, local water seepage, flatness deviation 5 to 8 mm. Scheme comparison: traditional ceramic tile renovation, cost about 180 RMB/m², construction period 6 months; flexible stone renovation, cost about 150 RMB/m², construction period 3 months. The flexible stone scheme was ultimately selected, and resident satisfaction reached 92%.
Case insight: The demand of China’s facade retrofit for materials is a comprehensive demand of “safety + economy + fast installation + low disturbance.” In old residential area renovation, the schedule directly affects resident cooperation, and materials with fast installation advantages will significantly reduce project implementation resistance.
The logic of China’s facade retrofit is “policy-driven, huge scale, diverse challenges.” If flexible stone enters China’s facade retrofit market, it needs to respond to the three core concerns of “safety, disturbance, and cost.”
1.5 Southeast Asia, South Asia, and the Middle East: Renovation Demand in Urbanization
1.5.1 Southeast Asia
Southeast Asia is in a rapid urbanization process, and a large number of early commercial and residential buildings have entered the renovation cycle. The core challenge facing the region is the tropical climate—high temperature, high humidity, strong ultraviolet radiation, and salt spray erosion, imposing severe requirements on the durability of exterior wall materials.
Market characteristics: large demand for commercial building renovation; hotels and tourism facilities usually undergo exterior wall renovation every 5 to 8 years to maintain competitiveness; high cost sensitivity, and cost-effectiveness is a key factor in material selection.
Table 1-8 Building Stock and Climate Challenges in Major Southeast Asian Countries
| Country | Urbanization Rate | Building Stock | Climate Challenges |
|---|---|---|---|
| Malaysia | About 78% | Large number of 1990s commercial buildings | High temperature, high humidity, salt spray |
| Thailand | About 52% | Large number of commercial and residential buildings | High temperature, high humidity, strong ultraviolet |
| Indonesia | About 57% | Large number of early buildings | High temperature, high humidity, salt spray |
1.5.2 South Asia
Countries such as India and Bangladesh are in the process of large-scale urbanization, and early buildings are beginning to age, but the renovation market is still in its infancy. With sustained economic growth and gradual improvement of building safety regulations, the South Asian facade retrofit market is expected to usher in rapid growth in the next 10 to 15 years.
1.5.3 Middle East
The Middle East has a concentration of high-end building projects, with extremely high requirements for material quality, while facing the test of extreme high temperature and salt spray environments. Traditional stone and ceramic tile facing have high self-weight and complex construction; lightweight and durable flexible facing materials are becoming a new choice. In cities such as Dubai, Abu Dhabi, and Riyadh, summer surface temperatures can exceed 60°C, imposing strict requirements on material heat resistance and UV resistance.
Engineering Case: Renovation of a Hotel Built in 2005 in Dubai
A 12-story hotel built in 2005 had aluminum panel facing on exterior walls. In 2023, the renovation required “construction without closing, upgrading grade, shortening schedule.” The scheme selected stone-imitation texture flexible facing material for reasons: lightweight, no increase in structural load; fast construction, not affecting hotel operations; good stone-imitation effect, enhancing hotel grade. After project completion, the hotel appearance was completely renewed, and the occupancy rate increased by 8%.
Case insight: The demand of Middle East facade retrofit for materials is a comprehensive demand of “high-end + lightweight + fast installation.” “Construction without closing” is a hard constraint; if materials cannot meet it, they do not have bidding qualification.
The logic of Southeast Asia and the Middle East markets is “climate-driven, cost-sensitive, high-end differentiation,” while the South Asian market is still in the cultivation stage. For lightweight flexible facing materials to enter these markets, they must solve the three problems of “weather resistance, cost, and high-end.”
1.6 Common Demand of the Global Facade Retrofit Market for Materials
Based on the analysis of facade retrofit markets in various regions, six common demands for facade retrofit exterior wall materials can be extracted:
Safety first—fire protection, detachment prevention, and fall prevention are bottom-line requirements. The UK Building Safety Act[3], the New York FISP program[4], and China’s high-rise building exterior wall detachment control all place safety first.
Lightweight priority—facade retrofit projects usually cannot carry out large-scale reinforcement of existing building structures; material self-weight directly relates to structural safety and construction feasibility.
Long-term durability—facade retrofit projects involve large capital investment and great construction disturbance; owners and residents hope for one renovation and long-term benefit, and material durability directly determines the cost-effectiveness of renovation.
Low construction disturbance—facade retrofit projects are mostly located in densely populated areas, and construction noise, dust, and traffic impact are strictly restricted; materials with convenient construction and low disturbance are more welcomed by the market.
Controllable cost—facade retrofit projects have diverse funding sources, and cost control is a common demand. The cost here refers not only to material unit price but also to the full life cycle cost covering construction, maintenance, and renovation.
Environmental compliance—global environmental requirements for building materials are increasingly strict; the EU REACH regulation[5], China’s green building materials certification[13], and the US LEED standard[6] all impose clear requirements on environmental performance.
1.7 Flexible Stone’s Entry: A Material “at the Right Time”
Against the above background, flexible stone’s entry has a clear era fit. There is a clear correspondence between its material characteristics and facade retrofit demands.
Safety dimension—self-weight only 3 to 5 kg/m², detachment risk far lower than ceramic tiles and stone; fire performance can meet different grade requirements through formula adjustment, with flexibility in compliance.
Lightweight dimension—exterior wall renewal can be completed without increasing structural load, especially suitable for high-rise buildings and old buildings with severe structural aging.
Durability dimension—weather resistance, water resistance, and chemical corrosion resistance are all superior to coatings, with a service life of more than 20 years, matching the building cycle.
Construction dimension—using thin-set process, under the premise that the substrate meets requirements, there is no need to remove the original substrate; construction is fast, noise is low, dust is little, and the impact on residents’ lives is small.
Cost dimension—material unit price is higher than coatings, but life cycle cost (including construction, maintenance, and renovation) is lower than coatings and ceramic tiles in most scenarios.
Environmental dimension—production energy consumption is significantly lower than ceramic tiles and stone, and it can be recycled, conforming to the development direction of green building materials.
Table 1-9 Matching Degree Between Flexible Stone and Facade Retrofit Demands
| Demand Dimension | Flexible Stone Matching Degree | Core Advantage | Data Support |
|---|---|---|---|
| Safety first | ★★★★★ | Self-weight 3–5 kg/m², low detachment risk | Test report |
| Lightweight priority | ★★★★★ | About 1/10 of ceramic tiles, 1/20 of stone | Test report |
| Long-term durability | ★★★★★ | Service life 20+ years, matching building cycle | Aging test |
| Low construction disturbance | ★★★★★ | Thin-set process, low noise, little dust | Project data |
| Controllable cost | ★★★★ | Life cycle cost lower than ceramic tiles and stone | Cost estimation |
| Environmental compliance | ★★★★★ | Low-temperature forming, low energy consumption, recyclable | Carbon footprint accounting[13] |
Summarized from the perspective of material generational replacement: traditional exterior wall materials have entered maturity or decline, and their technical potential is approaching its limit; the new demands proposed by the facade retrofit market are difficult for traditional materials to satisfy simultaneously; flexible stone is in the growth stage, its technical potential is still being released, and it is highly matched with facade retrofit demands. Generational replacement is happening, but it is a gradual process, and flexible stone’s market share will gradually increase.
The tide of global urban renewal is surging with unprecedented force. Europe’s Renovation Wave, North America’s safety regulations, China’s old residential area renovation plan, and the urbanization processes of Southeast Asia, South Asia, and the Middle East together constitute a global facade retrofit market worth trillions. In this market, the renewal and replacement of exterior wall materials is one of the most basic, most common, and most urgent demands. Traditional materials each have their own insurmountable difficulties, while flexible stone, with its comprehensive advantages of lightweight, thin and flexible, durable, environmentally friendly, and convenient construction, is becoming a new choice for facade retrofit exterior wall materials.
This is not an accidental coincidence but an inevitable trend—when facade retrofit becomes the main theme of global urban development, a material born for facade retrofit will naturally step onto the stage of history.
Decision Reference for Facade Retrofit Offices
Decision Matter
Whether the material selection for existing building exterior wall renewal and renovation projects should adjust the current technical route.
Situation Assessment
Facade retrofit has changed from “optional” to “mandatory,” and three forces have pushed it to the forefront: land and space constraints are approaching their limits, and cities can only tap potential inward; buildings concentratedly built from the 1950s to the 1990s have envelope systems that are concentratedly aging; regulations and policies in the EU, North America, and China have formed mandatory requirements. The driving logic differs by region—Europe relies on regulatory mandates, North America relies on inspection mandates, China relies on policy promotion, and Southeast Asia, South Asia, and the Middle East are under the dual pressure of climate and urbanization—but demand converges in the same direction: safety, lightweight, durability, low disturbance, controllable cost, and environmental compliance. Traditional materials collectively fail in the face of this demand: ceramic tiles are heavy and prone to detachment, coatings have short life, stone is expensive, and aluminum composite panels are difficult to pass fire requirements.
Optional Paths
Path one: Continue using the traditional exterior wall material route—mature technology, but difficult to simultaneously meet the six core requirements, with safety and schedule risks.
Path two: Adopt flexible stone and other lightweight flexible facing materials—balanced comprehensive performance, conforming to the direction of facade retrofit demand, but requiring pilot verification.
Path three: Implement classified strategies by project—high-risk buildings prioritize lightweight flexible schemes, general projects maintain traditional schemes and strengthen inspection frequency.
Decision Recommendations
Exterior wall renewal is the most basic, most common, and most urgent demand in the trillions of facade retrofit stock, and material generational replacement is an inevitable direction. Flexible stone is one of the few materials that can simultaneously meet the six core requirements. It is recommended to include it in the facade retrofit exterior wall material selection catalog, carry out pilot applications in projects with suitable conditions, and gradually promote it after accumulating engineering data. The compiling team will expand on the technical principles, engineering applications, and market paths of flexible stone in subsequent chapters, answering “why flexible stone can” and “how to do flexible stone.”
Risk Warnings
Flexible stone still has shortcomings in certification systems, market awareness, and engineering case accumulation. Before large-scale promotion, pilot verification and standard connection should be completed. Material generational replacement is a gradual process; in the short term, it is not advisable to comprehensively replace traditional schemes with a single material. It is necessary to combine actual project conditions to do substrate testing, scheme comparison, and life cycle cost accounting, avoiding blind material selection.
Reflections on Stone, Insights on Fortune
Facade retrofit is not a “passing fad” but a “long-term track.” China’s urbanization has entered the stock era, and facade retrofit is the most certain construction market in the next decade. The value of judging trends lies not in seeing the future, but in laying out in advance.
Europe relies on regulations, North America relies on inspections, and China relies on policies. The paths differ, but all point to the same thing—facade retrofit is not about replacing surfaces, but about reshaping the value of existing space. When facade retrofit becomes the main theme of global urban development, the material logic also changes: structural life is up to a century, while envelope systems have only 20 to 30 years of life. The mismatch of “structure not old, cladding fails first” is the most real starting point of facade retrofit.
Flexible stone happens to grow on the demand of facade retrofit. But we are more clear-headed: material substitution is not the endpoint; system capability is. For flexible stone to truly stand firm, it relies not on promotion, but on the accumulation of standards, systems, carbon data, and engineering cases. As the compiling team, we choose to record this era with an engineering approach and work with the industry to complete this generational replacement.
References
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[2] European Parliament and Council. Directive (EU) 2024/1275 on the energy performance of buildings[S]. Official Journal of the European Union, 2024.
[3] UK Parliament. Building Safety Act 2022[S]. UK Public General Acts 2022 c.30, London, 2022.
[4] New York City Department of Buildings. Facade Inspection & Safety Program (FISP)[S]. NYC Administrative Code § 28-301.1, New York, 2020.
[5] European Parliament and Council. Regulation (EC) No 1907/2006 concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH)[S]. Official Journal of the European Union, 2006.
[6] U.S. Green Building Council. LEED v4.1 for Building Design and Construction[S]. Washington, DC: USGBC, 2019.
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[8] Governo Italiano. Decreto Rilancio (DL n. 34/2020): Superbonus 110%[S]. Gazzetta Ufficiale, Roma, 2020.
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[10] State Council. Notice on Issuing the “15th Five-Year Plan for Urban Renewal”[Z]. Guofa [2026] No. 12, 2026-05-28.
[11] General Office of the CPC Central Committee, General Office of the State Council. Opinions on Continuously Promoting Urban Renewal Actions[Z]. 2025-05-15.
[12] Ministry of Housing and Urban-Rural Development. China Urban Construction Statistical Yearbook 2023[M]. Beijing: China Architecture & Building Press, 2024.
[13] State Administration for Market Regulation, Standardization Administration of China. Greenhouse Gases—Carbon Footprint of Products—Quantification Methods and Requirements[S]. GB/T 24067-2024. Beijing: Standards Press of China, 2024.
[14] KfW Bankengruppe. KfW Klimaschutz und Sanierungsreport 2023[R]. Frankfurt am Main, 2024.