Integrated Building Retrofit for Seismic Resilience and Environmental Sustainability: A Critical Review

Abstract

Integrated seismic–environmental retrofit is gaining attention in research and practice, as it combines resilience and sustainability objectives in building retrofits. However, current research and practice remain fragmented. This paper presents a systematic literature review to analyse how retrofit is addressed across four key dimensions: structural, environmental, social, and governance. A thematic analysis in NVivo was combined with Python-based quantitative analysis of code frequency and co-occurrence. The integrated retrofit literature reframes environmental assessment, shifting towards whole-building lifecycle assessment and having seismic environmental impacts and energy efficiency as embedded components. Retrofit practices are mainly discussed in technical and compliance terms, but are not properly examined using unified quantitative metrics; the broad use of metrics and indicators limits comparability and replication. Social and governance dimensions remain peripheral, with weak connections to structural and environmental dimensions, which constrain cross-domain integration and challenge scaling up retrofit interventions. These gaps encompass the barriers facing integrated retrofit, with potential pathways to overcome, including aligned standards and datasets, capacity building, community engagement, and coordinated regulatory frameworks.

1. Introduction

The term ‘retrofit’ entails a range of processes and interventions designed to enhance the performance of existing buildings, with end goals that differ by discipline. Structural retrofitting is mainly concerned with the buildings’ seismic safety and resilience, e.g., [1,2,3,4], while environmental retrofitting is focused on improving thermal performance and reducing energy demand and carbon emissions, e.g., [5,6]. Both retrofits are essential for extending the safe and sustainable use of buildings; however, they are often researched, designed, and applied separately.

The need for effective retrofit strategies is pressing. In Europe, buildings account for around 40% of energy consumption and 36% of CO₂ emissions [7], and more than 40% of its building stock was constructed before the 1960s, lacking both seismic and energy efficiency regulations, which raises questions about their structural safety and energy performance [8]. Extensive research has advanced seismic retrofitting through strengthening techniques and lifecycle-based probabilistic risk assessment, e.g., [9,10]; likewise, the environmental retrofitting literature has highlighted the benefits of deep renovations [11,12], as well as economic, technical, and behavioural barriers that limit retrofit uptake [13,14,15]. However, these research domains remain isolated. Recently, there have been attempts to develop decision-making frameworks for integrated structural and environmental retrofits, but these efforts still vary. Practitioners and experts leading these retrofits have different sets of objectives and skills, and often the retrofit activities are performed in parallel with each other in response to current needs rather than using a holistic analysis and system design approach [16,17].

Both retrofit processes are labour-intensive, face similar implementation challenges, and target the same building stock; however, the intersection between the environmental and seismic retrofit remains underexplored. There is a lack of integrative reviews that examine how the key dimensions: structural, environmental, social, and governance, intersect to shape integrated retrofit strategies. This study addresses this gap and presents the first systematic synthesis, using thematic analysis of existing research on seismic–environmental integrated retrofits to examine how the key dimensions of structural, environmental, social and governance interact, identify patterns that reveal the extent and nature of their integration, and analyse the challenges and potential solutions influencing such retrofit interventions. In the process, it develops a structured synthesis that maps and clarifies the coverage, occurrence, and co-occurrence of key dimensions, supporting a more comprehensive, performance-driven retrofit framework for a safer, more resilient, and sustainable built environment.

2. Methodology

The data are gathered from scholarly, peer-reviewed articles on the types, tools, and approaches used and developed for the combined environmental and seismic retrofit of existing buildings. Key inclusion and exclusion criteria were developed prior to initiating the review. These were determined based on the study’s thematic focus (integrated seismic–environmental retrofit). The review excluded studies that addressed either seismic or environmental retrofit in isolation without examining their interaction or combination. The media used to map the literature were Scopus and Web of Science.

In line with systematic review practices (PRISMA 2020 [18]), the review process includes four stages: identification, screening, eligibility, and inclusion (Figure 1). The search strategy was performed using Boolean operators, e.g., {(“Seismic” OR “Structural”) AND (“Energy” OR “low carbon” OR “Climate change” OR “Carbon reduction” OR “decarbonization”) AND (“retrofit” OR “refurbish” OR “rehabilitation” OR “upgrade”) AND “buildings”)}. Searches were limited to articles in English published between 2010 and 2025. Furthermore, the types of literature considered were conference papers, journal articles, reviews, and indexed book chapters.

Review Steps:

• Identification: The queries, as a combination of selected keywords, were run on the selected indices (based on the title, abstract, and stated keywords of peer-reviewed conference papers, journal papers, reviews, and indexed book chapters). This step resulted in 355 returns, Figure 1. These returns formed the main database.
• Screening and eligibility: The abstracts of papers were reviewed according to the inclusion-exclusion criteria explained above. Papers that focus solely on seismic or energy retrofit without integration were excluded (Figure 1). A core database of 54 papers was selected and detailed in

  Table A1. The following are the identified shortlisted papers.

  Filename	Paper Title
  P01	Analysis of Thermal Rehabilitation and Seismic Strengthening Solutions Suitable for Heritage Structures [40]
  P02	Application of Low-Invasive Techniques and Incremental Seismic Rehabilitation to Increase the Feasibility and Cost-Effectiveness of Seismic Interventions [44]
  P03	Assessing the Lifecycle Sustainability Costs and Benefits of Seismic Mitigation Designs for Buildings [22]
  P04	Assessing the Sustainability of a Resilient Built Environment: Research Challenges and Opportunities [47]
  P05	Beyond Direct Economic Losses: An Integrated Approach to Seismic Retrofit Considering Sustainability and Indirect Losses [53]
  P06	Combining Seismic Retrofit with Energy Refurbishment for the Sustainable Renovation of RC Buildings: A Proof of Concept [39]
  P07	Conceptual Design of Integrated Seismic and Energy Retrofit Interventions [50]
  P08	Concurrent Seismic and Energy Retrofitting of RC and Masonry Building Envelopes Using Inorganic Textile-Based Composites Combined with Insulation Materials: A New Concept [29]
  P09	Energy, Seismic, and Architectural Renovation of RC Framed Buildings with Prefabricated Timber Panels [31]
  P10	Evaluation of building retrofitting alternatives from sustainability perspectives [54]
  P11	Functional, Energy and Seismic Retrofitting in Existing Building: An Innovative System Based on Xlam Technology [30]
  P12	An Innovative, Lightweight, and Sustainable Solution for the Integrated Seismic Energy Retrofit of Existing Masonry Structures [38]
  P13	Integrated Rehabilitation of Reinforced Concrete Buildings: Combining Seismic Retrofit by Means of Low-Damage Exoskeleton and Energy Refurbishment Using Multi-Functional Prefabricated Façade [34]
  P14	Integrated Seismic and Energy Retrofit Interventions on a URM Masonry Building: The Case Study of the Former Courthouse in Fabriano [42]
  P15	Integrated Techniques for the Seismic Strengthening and Energy Efficiency of Existing Buildings: Pilot Project Workshop [55]
  P16	The Challenge of Integrating Seismic and Energy Retrofitting of Buildings: An Opportunity for Sustainable Materials? [36]
  P17	Integration of Resilience and Sustainability: From Theory to Application [48]
  P18	Iso-Performance Retrofit Solutions Adopting a Life Cycle Thinking Approach [56]
  P19	Life Cycle Assessment of Integrated Energy and Seismic Retrofits for Existing Buildings [41]
  P20	Life-cycle Assessment of Seismic Retrofit Strategies Applied to Existing Building Structures [43]
  P21	Life-cycle Performance Enhancement of Deteriorating Buildings under Recurrent Seismic Hazards [57]
  P22	Multidisciplinary Performance Assessment of an Eco-Sustainable RC-Framed Skin for the Integrated Upgrading of Existing Buildings [21]
  P23	Nested Buildings: An Innovative Strategy for the Integrated Seismic and Energy Retrofit of Existing Masonry Buildings with CLT Panels [35]
  P24	Optimal seismic retrofitting of existing buildings considering environmental impact [58]
  P25	Performance-Based Bi-Objective Retrofit Optimization of Building Portfolios Considering Uncertainties and Environmental Impacts [26]
  P26	Performance-Based Decision-Making of Buildings under Seismic Hazard Considering Long-Term Loss, Sustainability, and Resilience [25]
  P27	A probabilistic-based framework for the integrated assessment of seismic and energy economic losses of buildings [24]
  P28	Demolishing or Renovating? Life Cycle Analysis in the Design Process for Building Renovation: The ProGETonE Case [20]
  P29	Renovation of a School Building: Energy Retrofit and Seismic Upgrade in a School Building in Motta Di Livenza [59]
  P30	Retrofitting Historical Buildings with Innovative Techniques: Double-Skin Façade and Skylights for Courtyard Buildings [45]
  P31	Review of Methods for the Combined Assessment of Seismic Resilience and Energy Efficiency towards Sustainable Retrofitting of Existing European Buildings [17]
  P32	Seismic and Energy Integrated Retrofit of Buildings: A Critical Review [8]
  P33	Seismic and Energy Renovation Measures for Sustainable Cities: A Critical Analysis of the Italian Scenario [60]
  P34	Seismic–Energy Retrofit as Information-Value: Axiological Programming for the Ecological Transition [61]
  P35	Seismic Retrofit Measures for Masonry Walls of Historical Buildings, from an Energy Saving Perspective [23]
  P36	Seismic Strengthening and Energy Efficiency: Towards an Integrated Approach for the Rehabilitation of Existing RC Buildings [62]
  P37	Strategies for Structural and Energy Improvement in Mid-Rise Unreinforced Masonry Apartment Buildings. A Case Study in Mestre (Northeast Italy) [63]
  P38	Timber based systems for the seismic and energetic retrofit of existing buildings [64]
  P39	Simplified assessment of combined intervention for the seismic and energetic retrofit of a school building in Padua (Italy) [65]
  P40	Sustainable Urban Regeneration through Densification Strategies: The Kallithea District in Athens as a Pilot Case Study [27]
  P41	Design of Dissipative and Elastic High-Strength Exoskeleton Solutions for Sustainable Seismic Upgrades of Existing RC Buildings [66]
  P42	Interactions between Seismic Safety and Energy Efficiency for Masonry Infill Walls: A Shift of the Paradigm [67]
  P43	Seismic and Energy Integrated Retrofitting of Existing Buildings with an Innovative ICF-Based System: Design Principles and Case Studies [37]
  P44	Sustainable Renovation of Public Buildings through Seismic–Energy Upgrading: Methodology and Application to an RC School Building [68]
  P45	Innovative Seismic and Energy Retrofitting of Wall Envelopes Using Prefabricated Textile-Reinforced Concrete Panels with an Embedded Capillary Tube System [33]
  P46	Integrated Structural and Energy Retrofitting of Masonry Walls: Effect of In-Plane Damage on the Out-of-Plane Response [69]
  P47	An Innovative Structural and Energy Retrofitting System for URM Walls Using Textile Reinforced Mortars Combined with Thermal Insulation: Mechanical and Fire Behavior [28]
  P48	An Integrated Approach to Improve Seismic and Energetic Behaviour of RC Framed Buildings Using Timber Panels [32]
  P49	Seismic Retrofit of Stone Walls with Timber Panels and Steel Wire Ropes [70]
  P50	Cost–Benefit Evaluation of Seismic Risk Mitigation Alternatives for Older Concrete Frame Buildings [9]
  P51	Energy Efficiency and Seismic Resilience: A Common Approach [51]
  P52	Long-Term Sustainability and Resilience Enhancement of Building Portfolios [49]
  P53	Methodological approach for performance assessment of historical buildings based on seismic, energy and cost performance: A Mediterranean case [71]
  P54	Redefining the Concept of Sustainable Renovation of Buildings: State of the Art and an LCT-Based Design Framework [52]

  . Figure 2 and Figure 3 show the distribution of the documents across their sources and years of publication.
• Inclusion and analysis: The papers in the core database were thoroughly reviewed, and a thematic analysis was conducted to identify key dimensions and develop codes that capture recurring patterns within each dimension.
• The analysis results were collated to produce a mapping of the literature on the dimensions of integrated seismic–environmental retrofit, as well as the challenges that face such interventions with potential solutions.

The papers in the core database were analysed to identify recurring codes and dimensions relevant to integrated seismic–environmental retrofit. Nvivo (v15.1) was used to explore and identify recurring concepts using iterative coding and abstraction [19]. Sample passages from the reviewed literature were highlighted and coded using nodes, which were given names relevant to their content. As the papers’ review process progressed, these nodes were later renamed/merged due to redundancy and overlapping content. The identified codes (‘child’ nodes) are grouped under higher-level dimensions (‘parent’ nodes). An example of such content analysis and coding is illustrated in

Table A2. Examples of code and theme identification from the shortlisted papers.

Quote (Paper)	Source	Code	Dimension
“The proposed seismic-plus-energy retrofitting hybrid concept… The integration of different insulation materials … to the textile reinforcement could result to various hybrid retrofitting solutions, such as TRM + PUR, TRM + XPS, TRM + Aerogels, TRM + NIM”	[29]	S1: Retrofit strategy or method	Structural
“As regards the anti-seismic function of the exoskeleton, operating from outside implies a major effort in the evaluation of the in-plane capacity of the existing floors, in the definition of possible innovative intrados, dry and lightweight diaphragms.”	[39]
“As to further increase the feasibility of retrofit interventions, another strategy consists in spreading realizations and costs over years by adopting an incremental rehabilitation strategy (FEMA P-420, 2009)”	[44]	S2: Standards, guidelines, codes
“…ductile mechanisms and brittle mechanisms (i.e., shear) capacities were evaluated for all elements according to EN1998-3.”	[21]
“A possible solution is represented by the introduction of an exoskeleton entirely carried out from outside. In this paper, a new sustainable technique is proposed, where the existing structure is connected to a self-supporting exoskeleton adopting demountable dry techniques, which may be assembled and activated in different phases of the building lifetime.”	[44]	S3: Low-invasive retrofit
“retrofit system consisted of a second skin with insulated timber panels … ensure minimum impact during the life cycle of the retrofitted building, … and their ability to be disassembled and completely recycled.”	[55]
“Thermal insulation layers are added on the other sides. Windows are substituted, and a shading system is installed on the new façade to enable better control the solar gain”	[39]	E1: Energy efficiency	Environmental
“In particular, thermal insulation of the roof and/or of the external walls is commonly improved with traditional materials (e.g., polystyrene, rock wool, etc.) or innovative systems (e.g., nano insulation materials or phase change materials) … to achieve the highest levels of energy efficiency.”	[17]
“the expected annual embodied carbon associated to seismic risk is estimated approximately equal to 4000 kg of CO2 if seismic interventions are not carried out, and about 400 kg of CO2 in the case of seismic retrofit.”	[39]	E2: Embodied carbon, Emissions in Material Selection
“The cost and emissions data for damaged buildings is determined by utilizing percentage of total material damaged given damage state”	[26]
“A life cycle thinking approach is applied by addressing the end-of-life scenario during the design of the retrofit intervention and by adopting dry, demountable and easily repairable techniques.”	[39]	E3: Lifecycle environmental impact
“life cycle thinking (LCT) approach for retrofit projects becomes an effective multi-performance methodology aimed at maximising structural and environmental/energy performances of a building during its entire life cycle from cradle to grave”	[55]
“post-earthquake repairing works can be limited to the replacement of a lower number of damaged components of the new structure, resulting in a more cost- and time-effective intervention”	[8]	E4: Seismic-induced environmental impact
“by coupling the seismic retrofit, the intervention reduces the risk of collapse of the building during an earthquake and, as a consequence, the amount of CO2 emission connected to the demolition of the damaged building, the waste disposal and the reconstruction of a new building”	[39]
“Pilot Project and engage main European stakeholders. 186 participants from 27 countries registered to the side event. The participants were from the European Institutions, European and international associations, national and local authorities, industry, universities, research institutions and engineering practice.”	[55]	So1: Community engagement in retrofit planning	Social and Governance
“Search and visualization tools will provide open access to interactive geo-referenced content and data (maps, graphs, etc.) considering pre- and post-mitigation states.”	[55]
“In this way, it is possible to apply the system either externally, avoiding excessive occupancy disruption, or internally, to preserve listed façades”	[8]	So2: Cultural and heritage-sensitive retrofit
“Additional aspects involved in the decision-making process are also represented by the low invasiveness and compatibility of materials, especially in the retrofit process of buildings with a historical value”	[17]
“Preparedness for post-earthquake recovery is one of the crucial aspects of resilience-based design, which aims to ensure continuous operation and liveable conditions immediately after an extreme event.”	[17]	So3: Post-disaster recovery and continuity
“… The serviceability of the retrofitted building is guaranteed also for lower-probability earthquakes to reduce, or even avoid, downtime and post-earthquake repair costs.”	[56]
“The government introduced the Sismabonus initiative… This initiative recognises substantial tax incentives (earning up to 85% of the total expenses …) for projects aimed at improving the seismic safety of buildings.”	[17]	G1: Governance mechanisms and incentives
“a simplification of the European standard EN ISO 13790 …, is applied herein for calculating the building energy needs.”	[29]
“The potential environmental impact was evaluated using the software SimaPro.”	[21]	M1: Digital tools in integrated approaches	Approach and Metrics
“The building is modeled as a three-dimensional structure with the software MidasGEN v.2017 (Midas GEN, 2017); the frame components are modeled as beam elements …”	[44]
“By proposing a common approach based on the expected annual loss… it is possible to evaluate the financial feasibility and benefits.”	[29]	M2: Indicators or measures
“… the TRM retrofitting scheme resulted in an enhanced global response… More than a 50% increase in the lateral strength was observed accompanied with more than a 50% higher deformation capacity…”	[29]
“The feasibility of the combined seismic and energy retrofitting is explored by comparing the break-even point (payback period in … for the building configuration considered in this case study.”	[29]	M3: Multi-criteria design and decision-making process
“Multi-performance methodology… On the one hand, the approach envisages the use of sustainable and eco-efficient materials for reducing the environmental burden at the early stage of the retrofit design, and on the other hand the promotion of external interventions and the use of prefabricated elements at the construction stage.”	[55]
“another challenge for the integrated intervention, given that the energy system must also be designed to accommodate possible localised displacements and to enable inspection, maintenance and substitution of structural components”	[39]	Barriers and challenges	Barriers and Challenges
“The quite low rate of EU buildings’ renovation derives from different barriers such as intervention cost, execution times, inhabitants’ relocation ...”	[55]

. In addition to the emerging dimensions in the reviewed literature, approaches, metrics and barriers for integrated retrofit were examined using the same procedure. The codes were then used to formulate the review’s findings and evaluate the extent of current knowledge coverage, identifying remaining gaps to highlight challenges and opportunities for the uptake of integrated retrofit.

Table 1. Developed thematic map used to analyse the collected literature.

Dimensions	Developed Codes
Structural dimension	“S1”, “Retrofit strategy or method”: “The retrofit strategy integrated seismic strengthening with thermal insulation.”; “Both structural safety and energy efficiency were addressed in the retrofit approach.”; “Retrofit methods were selected to improve energy performance.”; “Combined structural and energy retrofitting was a key design goal.”; “A dual-purpose retrofit addressed both thermal and seismic demands.” “S2”, “Standards, guidelines, codes”: “The retrofit complied with Eurocode 8 and national energy efficiency regulations.”; “Certification systems like LEED or BREEAM guided retrofit planning.”; “Local construction codes were followed for integrated retrofitting.”; “Standards influenced the selection of materials and retrofit techniques.”; “Code requirements shaped the scope of both structural and energy upgrades.” “S3”, “Low-invasive retrofit”: “Minimal intervention techniques preserved the building’s original appearance.”; “Low-invasive retrofitting was used to avoid disrupting interior spaces.”; “Strengthening was achieved with external supports to reduce invasiveness.”; “Retrofits were planned to minimise visual and structural changes.”; “The intervention allowed continued occupancy during application.”
Environmental dimension	“E1”, “Energy efficiency”: “Energy demand was reduced through passive design measures.”; “High-performance insulation was added to improve thermal performance.”; “Solar energy systems and renewable energy enhanced building energy profile.”; “The retrofit focused on reducing operational energy use.”; “Energy-saving strategies were integrated with structural strengthening.” “E2”, “Embodied Carbon and Emissions in Material Selection”: “Low-carbon materials were prioritised to reduce embodied emissions.”; “The retrofit assessed greenhouse gas (GHG) emissions from material production.”; “Recycled materials reduced the embodied carbon of the intervention.”; “Circular economy principles guided material selection.”; “GHG calculations informed environmentally responsible design choices.”; “E3”, “Lifecycle environmental impact”: “Life cycle assessment was used to compare retrofit options.”; “Environmental impacts of maintenance and disposal were considered.”; “The design accounted for emissions over the building’s lifespan.”; “Lifecycle thinking guided sustainable material and process choices.”; “Long-term performance was prioritised over short-term gains.” “E4”, “Seismic-induced environmental impact”: “Post-earthquake repairs contribute significantly to GHG emissions.”; “Retrofit design aimed to reduce environmental cost of future earthquakes.”; “Material waste and reconstruction emissions were evaluated.”; “Seismic damage scenarios included environmental impact projections.”; “Strategies were chosen to minimise emissions from potential repairs.”
Social and governance dimension:	“So1”, “Community engagement in retrofit planning”: “The community participated in retrofit planning workshops.”; “Public consultations shaped retrofit design decisions.”; “Stakeholders contributed to identifying retrofit priorities.”; “Local input was sought to ensure retrofit acceptance.”; “Engagement processes improved project transparency and trust.” “So2”, “Cultural and heritage-sensitive retrofit”: “Historical elements were preserved during the retrofit.”; “Retrofit design respected cultural values and identity.”; “Visual integrity of heritage features was maintained.”; “The building’s character guided retrofit material choices.”; “Interventions avoided disrupting architectural heritage.” “So3”, “Post-disaster recovery and continuity”: “Critical functions were maintained after seismic events.”; “Retrofit ensured continuity of essential building operations.”; “Design included post-disaster recovery provisions.”; “The upgrade improved resilience for rapid recovery.”; “Continuity planning was integrated into retrofit decisions.” “G1”, “Governance mechanisms and incentives”: “Government incentives supported retrofit implementation.”; “Policy frameworks influenced retrofit timing.”; “Public funding enabled integrated retrofit solutions.”; “Regulatory schemes prioritised high-risk buildings.”; “Governance structures facilitated coordinated retrofitting.”
Approach and metrics:	“M1”, “Digital tools in integrated approaches”: “BIM was used to model and coordinate retrofit design.”; “Finite element tools informed structural decisions.”; “Energy and LCA simulations were combined in planning.”; “Digital workflows integrated multi-domain assessments.”; “Tools supported collaboration across disciplines.” “M2”, “Indicators and measures”: “Retrofit outcomes were measured using performance indicators.”; “Metrics included emissions, repair cost, and downtime.”; “Standard indicators were used for benchmarking alternatives.”; “Indicators captured both environmental and structural effects.”; “Quantitative measures supported transparent evaluation.” “M3”, “Multi-criteria design and decision-making”: “Retrofit alternatives were ranked using weighted scoring.”; “Design considered cost, resilience, and emissions criteria.”; “Decisions reflected social, technical, and environmental goals.”; “Multi-criteria tools helped evaluate complex trade-offs.”; “Stakeholder priorities were integrated into final decisions.”
Barriers and challenges	“C1”, “Barriers and challenges”: “High costs limited retrofit implementation.”; “Conflicting priorities made consensus difficult.”; “Lack of skilled labour slowed construction.”; “Technical constraints complicated integrated retrofitting.”; “Funding gaps and coordination issues were major barriers.

illustrates the identified dimensions and their codes.

Furthermore, a quantitative analysis was performed to illustrate the occurrence of the codes, assessing their frequency, similarity, co-occurrence, and interactions. A Python script (Python v3.13.7) was developed to match the thematic codes identified in NVivo (Table 1) within the shortlisted papers. The Python script reads and processes each paper’s PDF file, extracts sentences, and applies basic text preprocessing (e.g., removing references). Semantic embeddings of each sentence were generated using the “AllenAI SPECTER” model, chosen for its suitability for the scientific literature. Each sentence embedding was then compared with the embeddings of the predefined thematic codes using cosine similarity. Sentences with a similarity score ≥ 0.85 were recorded together with their matched codes and dimensions, and the matched sentences were then aggregated by paper, matched code and dimension.

3. Analysis

The following sections are organised to present and discuss the findings of the thematic analysis across the structural, environmental, social, and governance dimensions, as well as approaches, metrics, and barriers for integrated retrofit.

3.1. Structural Dimension

Figure 4 shows the frequency of matched codes illustrated in Table 1 across the shortlisted literature presented in Table A1. The noticed pattern for the structural dimension is that the literature is intensely focused on addressing technical strategies and methods (S1: “retrofit strategy and method”), which is supported by the importance of compliance to “standards, guidelines and codes” (S2) and is less concerned with low invasive techniques (S3). This highlights the importance of the structural dimension in the reviewed literature; however, the focus on it is through a traditional lens, related to compliance and technical strategies. Retrofit innovations that result in fewer disruptions and disturbances to residents, addressing the social impacts of retrofit processes, remain underrepresented. Furthermore, the similarity scores for the identified codes in the literature are illustrated in Figure 5; these scores record the quality of the code match. A score closer to 1.0 means that sentences are very semantically close to search phrases. Figure 5 shows that structural codes S1 and S2 have relatively high similarity scores, indicating that these codes are well consolidated within the reviewed literature compared to code S3. The research is yet to converge on techniques and terminology related to low-invasive retrofit interventions.

Building on these observations, the literature shows consensus around two broad intervention strategies to reduce seismic vulnerabilities and energy deficits in existing buildings: actual retrofitting, or total or partial demolition and reconstruction. The first option is preferred as it implies lower embodied energy and lower interruption of use; however, when retrofitting alternatives are not economically and technically feasible, then the second option, demolition and reconstruction, is selected [20,21].

Recent research has attempted to address the environmental sustainability of seismic retrofit strategies (S1) and performed a multidimensional comparison across these strategies, evaluating structural behaviour, environmental performance, and feasibility, e.g., [22,23]. These example studies illustrate why S1 dominates, as they represent the mainstream focus on retrofit methods and trade-offs. The collected literature also emphasises that mapping a building’s baseline structural vulnerabilities before determining the retrofit plan is a crucial step in any retrofit intervention, e.g., [24,25]. However, standard-compliant retrofitting measures (S2) often come with higher embodied carbon emissions as they rely heavily on conventional materials, e.g., reinforced concrete or steel. Therefore, it is necessary to determine the retrofit level combinations that achieve optimal performance and provide the most sustainable solution, which is also economically feasible [26]. This reflects the consistent presence of S2 as standards and performance compliance are well-defined and used in the literature as part of the feasibility and acceptance of the retrofit solutions.

Furthermore, there has been growing attention toward low-invasive retrofitting strategies (S3), as highlighted in [27], where these strategies are described as densification models that avoid interior disruption by focusing interventions on external load-bearing and thermal skin systems. Examples of such low-invasive interventions: Textile Reinforced Mortar (TRM) jacketing combined effectively with thermal insulation [28,29], cross-laminated timber (CLT) panels [30,31,32], exoskeletons and Prefabricated Systems [33,34]. However, not all intervention solutions classified as CLT or exoskeletons are low-invasive. Valluzzi et al. [35] proposed creating a new internal CLT structure, ‘nested buildings’, which is considered an invasive intervention because it involves demolishing the building’s internal slabs and partitions. Such inconsistency in the classification of these technologies may have narrowed the scope of S3 in the literature, partly explaining its lower frequency of matches.

Table 2. Integrated retrofit approaches using example case studies.

Strategy	Structural Indicators	Environmental/Economic Indicators	Typology and Implementation	Scalability/Stakeholders	References
Steel Exoskeleton Systems	Lateral load capacity ↑ 50–100%; seismic damage reduced, base shear ↑ by 1.5	Cost EUR ~250–710/m2; high embodied CO2 than timber; but external application avoids demolition	RC frames, mid-rise residential; external installation, minimal disruption	Scalable in suburbs/low-density; limited by urban space constraints	Penazzato et al., 2024 [36]
RC Exoskeleton Systems	RC shell retrofits: stiffness ↑, deformation ↓, seismic capacity ↑	Higher CO2 than steel/timber; longer intervention time; reduced reversibility	RC residential blocks (e.g., in Italy); may require new foundations	Less scalable due to time/cost; more possible for large blocks than small-scale projects	Pertile et al., 2021 [37]
CLT Panel Systems	lateral load capacity ↑ 25–50%; mitigates brittle RC failures (e.g., soft stories, short columns)	Cost EUR ~350–500/m2; lower embodied CO2 than steel; moderate thermal insulation (may need additional layers)	RC/masonry retrofits; can be external or internal (“nested buildings”)	Prefab, fast install, but less compatible with incremental retrofits or reparable retrofits	Penazzato et al., 2024 [36]
TRM Jacketing Systems	In-plane/out-of-plane wall strength ↑; lateral strength ↑ ~50%	Cost EUR ~80–115/m2, lower embodied CO2 than FRP; fire resistant, lower labour cost	RC and masonry envelopes; applied externally or internally	Demonstrated on EU residential buildings	Bournas 2018 [29]
Aluminium Insulation Panel Systems	Out-of-plane wall capacity ↑ ~49% after retrofit	Recyclable aluminium (low weight, corrosion resistant); insulation panels reduce thermal dispersion	Sandwich panels bolted with anchors for masonry walls	Prefabricated and fast to install; external application avoids disruption	Longobardi et al., 2024 [38]
Hybrid composites (Textile-Reinforced Concrete Panels (TCPs) and TRM Panels)	lateral strength ↑ ~30%; initial stiffness ↑ ~22%; improved displacement and energy dissipation	Prefabricated panels shorten downtime; embodied CO2 lower than RC jacketing	RC frames and masonry walls (tested in Korea-EU projects); prefabricated panels with textile reinforcement and capillary tubes	Prefab-ready; minimise onsite work/downtime	Baek et al., 2022 [33]

presents representative case studies from the reviewed literature to illustrate seismic retrofit approaches and their potential performance ranges. These are example case studies, and systematic benchmarking across all strategies remains limited due to a lack of comprehensive data on the different performance and feasibility indicators.

3.2. Environmental Dimension

Examining the distribution of the codes within the environmental dimensions in Figure 4 shows how the integration of seismic and environmental retrofit reshapes research priorities, with “lifecycle environmental impact” (E3) and “seismic-induced environmental impact” (E4) being more frequent than “energy efficiency” (E1) and “embodied carbon in material selection” (E2). The reviewed literature emphasises “lifecycle environmental impact” (E3), treating efficiency measures (E1) as components of whole-building lifecycle assessment. “Seismic-induced environmental impact” (E4) is a distinctive contribution of integrated retrofit-focused research linking seismic safety with sustainability by accounting for waste and emissions generated by earthquake damage and repair, which explains its frequent occurrence in integrated literature. “Embodied carbon in material selection” (E2) remains less frequent than E3 and E4, reflecting a gap in material data and methods across the reviewed literature on material selection and the calculation of its environmental impact in retrofit interventions. These patterns suggest that the integrated retrofit literature is shifting toward a system-level assessment of retrofit approaches but struggles to connect design decisions with material environmental impact and circularity. The findings of Figure 4 are also reflected in Figure 5; the similarity scores display high semantic consistency for environmental codes, especially E3 and E4, indicating that these codes are well-defined in integrated retrofit research. However, E2 shows a relatively lower similarity score, suggesting that research on integrated retrofit has to converge on shared terminology and methods for material-level impacts when designing retrofit interventions.

The collected literature emphasises the importance of adopting lifecycle thinking (E3) that extends beyond operational energy to address material use, waste generation and end-of-life scenarios [39]. The reviewed literature assessed embodied and operational carbon using LCA; for example, Bocan et al. (2024) [40] analysed climate zone-dependent energy gains from seismic–environmental interventions, Kulthanaphanich et al. 2025 [41] assessed embodied carbon and operational carbon through LCA comparisons of various retrofit options, highlighting trade-offs between lower- and higher-impact solutions, and Caprino et al. (2021) [42] assessed the embodied impacts of retrofitting buildings’ based on element types and orientation. It is also essential to consider a comprehensive LCA that considers the material impacts of retrofit interventions across categories such as human health, ecosystem quality and resource use [43], as material decisions made to enhance structural performance can unintentionally generate toxic byproducts or non-recyclable waste. These examples help clarify what Figure 4 illustrates: energy efficiency (E1) and embodied carbon (E2) emerge as components within E3 in the integrated retrofit literature.

Recent studies have used the concept of “seismic-induced environmental impact” (E4), defined as the carbon emissions arising from post-earthquake damage and repair, for example, Zhou et al. (2022) [26] used carbon emissions associated with repair activities to demonstrate how preventive retrofitting can reduce long-term environmental impacts, and Labò et al. (2018) [44] addressed low-invasive retrofit techniques to minimise occupant disruption and reduce the waste stream associated with the demolition of finishes. These insights reinforce the system-level shift identified in the findings of Figure 4, where environmental retrofits are no longer confined to energy efficiency but also extend to lifecycle and seismic-induced impacts, and suggest a link between retrofit interventions and their social implications.

Figure 6 illustrates the distribution and presentation of the matched codes across the literature. The coding distribution shows a clear divide between what is widely found across the literature and what is concentrated in specific niches. “Retrofit strategy or method”, “lifecycle environmental impact”, “indicators and measures”, and “seismic-induced environmental impact” are broadly spread across the reviewed literature, reflecting their centrality across most studies on integrated retrofit. However, “low-invasive retrofit”, “energy efficiency”, “multi-criteria decision-making”, “heritage-sensitive retrofit”, “community engagement”, and “governance mechanisms” are concentrated in a smaller subset, often tied to specific contexts or case studies, for example, lifecycle studies, heritage retrofit, or performance-based analysis. These patterns (distribution of blue-dark blue cells in Figure 6) indicate that some papers cover multiple codes across all dimensions, while others remain focused on a narrow set of codes, suggesting uneven development or a lack of consistency in the frameworks guiding integrated retrofit, which leads to limited comparability between the different integrated approaches.

3.3. Social and Governance Dimension

Figure 4 indicates that both social and governance dimensions remain peripheral in integrated seismic–environmental retrofit research, with low counts in matches. “Community engagement in retrofit planning” (So1) is the least among social codes in terms of matches within the reviewed literature. “Cultural and heritage-sensitive retrofit” (So2) and “post-disaster recovery” (So3) occur more frequently (Figure 4). Although So2 and So3 are not central to the reviewed literature, they are conceptually consolidated with clear terminology. Governance mechanisms and incentives (G1) are the least frequent of all codes, with a weak, scattered similarity index (Figure 4 and Figure 5). This reveals that governance has not yet been systematically incorporated into integrated retrofit research.

Technically sound retrofit solutions may face limited adoption as decision making involves conflicting and disproportionate criteria, and stakeholders’ priorities often outweigh awareness of seismic risk [25,44]. People tend to support interventions that address both seismic and environmental performance when framed around their livelihood, for example, operational savings, a healthier indoor environment, living comfort, and real estate value [39]. Furthermore, case studies suggest that engaging stakeholders and presenting retrofit trade-offs in an accessible way can demystify interventions and encourage wider acceptance [26,45]. The reviewed literature tends to address community engagement as a factor in a ‘successful retrofit’; however, it does not address it as a core aspect in the design of the retrofit, for example, using participatory approaches, which may explain why So1 is not central or frequently mentioned in the reviewed literature.

Many older or heritage structures, especially in seismically active regions, are deeply embedded in cultural heritage and collective memory, which makes heritage-sensitive retrofitting particularly critical; it must respect principles of minimal intervention and authenticity to safeguard heritage values [46]. Aruta et al. (2024) [45] discussed the balance between improving resilience and preserving heritage value to maintain architectural integrity, allow continued use, and sustain local identity. Thus, “preservation of community heritage and identity” (So2) represents a recognisable but specialised niche, conceptually consolidated around heritage-sensitive approaches, even if less central than structural or environmental strategies.

Governance mechanisms (G1) remain the least matched code with the lowest similarity score across the reviewed literature, Figure 4 and Figure 5. Governance is central when discussing the alignment between engineering technical needs and local authorities/policymakers’ objectives [47]. However, current practice remains fragmented, and resilience and sustainability are often treated as separate issues [48]. Community retrofit programmes operate under clear cost burdens and stakeholder budget limits; in many cases, building portfolios are pre- or low-code and highly vulnerable, which further constrains integrated seismic–environmental retrofits [49]. The literature reviewed implicitly discusses governance using adjacent concepts, such as coordination, incentives, and budgets, rather than explicitly addressing governance mechanisms.

3.4. Approach for Integrated Seismic–Environmental Retrofit

This section examines the strength of association between thematic codes related to the methodological framework (approach and metrics) and the codes related to dimensions: structural, environmental, social and governance. The pointwise mutual information (PMI) score was used to measure this association. The number of matched codes in the collected literature was used to calculate PMI scores using Equation (1).

$$PMI\left(x,y\right)=\mathrm{l}\mathrm{n}\left[{\displaystyle \raisebox{1ex}{$count(x,y)·N$}\!\left/ \!\raisebox{-1ex}{$\left(count(x)·count(y)\right)$}\right.}\right]$$

(1)

where count(x, y) = number of observations where x and y occur together, count(x) = number of observations where x occurs, count(y) = number of observations where y occurs, N = total number of observations (e.g., total number of sentences).

PMI indicates how tightly a code is represented by showing whether it appears with particular other codes more often than would be expected by chance. High PMI values signal strong links, while lower values suggest broader use. Figure 7 shows the calculated PMI values for “digital tools” (M1), “indicators and measures” (M2), and “Multi-criteria design and decision-making” (M3), along with the codes of the identified dimensions, and will be examined row-wise. Examining PMI scores, M1 has high PMI values (red to dark orange cells in Figure 7) across multiple dimensions’ codes, which indicates that they occur in a specific and ‘tightly’ representative context with these codes, reflecting the clear and targeted use of BIM, FEM, and other simulation workflows in retrofit interventions. PMI scores for M3 (dark orange cells in Figure 7) show association with social codes, lifecycle environmental impact, embodied carbon, and standards and guidelines. “Indicators and measures” (M2), on the other hand, have relatively low PMI scores compared to M1 and M3 despite being among the most frequent matched codes. The low PMI scores indicate the broad use of M2 across various contexts, supporting multiple themes without forming a strong, exclusive association. These insights highlight the fact that integrated retrofit is not just about the presence of dimensions’ codes, but also about how tightly they are connected through methods. M1 and M3 act as drivers of integration, while M2 (metrics) reflects a broad but scattered presence that needs to be clearly linked to the methodological frameworks and their digital tools.

Retrofit decisions have often been driven by single-criterion approaches, most commonly structural safety or cost minimisation, and often neglecting post-disaster downtime or lifecycle carbon emissions [26]. The relatively high PMI scores for M3 illustrate how integrated retrofit literature is now moving toward multi-criteria frameworks that capture broader system implications. Researchers have advocated the use of multi-criteria decision-making (MCDM) frameworks; the retrofit approach needs to capture broader system implications, including seismic damage, operational-energy performance, and economic losses under earthquakes, as well as weather/climate uncertainties [24]. This transition from single-criterion to multi-criteria approaches lays the foundation for more balanced integrated retrofit approaches; however, they require rigorous data collection and complex computational analyses.

Decision making supported by digital workflows was developed using a combined cost–benefit and energy indicators [50]. Conventional seismic assessment techniques, e.g., nonlinear dynamic analysis or performance-based design, are now coupled with lifecycle assessment (LCA), social impact evaluations, and, in some cases, climate modelling using different digital workflows [17,51,52]. Tanguay and Amor (2024) [47] suggested early-stage integrated workflows incorporating structural performance, LCA, and cost modelling to support multi-criteria (structural, environmental, economic and social) decisions. These examples highlight the strong presence of M1 in the reviewed literature.

Within the collected literature, the following metrics (M2) can be found in the decision-making frameworks for the integrated retrofit:

• Structural Performance Indices: Probabilities of collapse, drift thresholds, or downtime estimates. These remain fundamental for life-safety and resilience objectives.
• Lifecycle Environmental Indicators: Embodied carbon (kg CO₂e), energy use (MJ or kWh), water footprint (L), and total material mass are among the most commonly cited.
• Socioeconomic Metrics: Repair costs, business interruption, displacement duration, and social vulnerability indices.
• Cost–Benefit Measures: Net present value (NPV) and cost–benefit ratios are frequently used for financial comparisons.
• Intangible or hard-to-quantify benefits, such as preserving cultural heritage or local identity. These remain unevenly quantified.

Overall, the approaches and metrics’ codes provide the methodological backbone of integrated retrofit research, structural and environmental dimensions codes define what needs to be achieved, and social and governance dimensions codes outline the conditions for acceptance and application.

3.5. Barriers and Opportunities

The mapping of co-occurrence between the different dimensions and codes helps guide the discussion of the barriers and challenges facing seismic–environmental retrofit. Thus, the matched codes were cross-examined against the extracted text from the papers, and the co-occurrence of the codes is presented in Figure 8. It can be seen that the strongest co-occurrence between the codes is between “indicators and measures” and “multi-criteria design and decision-making” (320). Both also frequently appear with “lifecycle environmental impact” (243 and 187, respectively), which suggests that indicators, multi-criteria frameworks, and lifecycle analysis form a dense set of analytical tools in the literature. “Standards, guidelines, and codes” are strongly paired with “energy efficiency” (226) and also occur with “lifecycle environmental impact” (124) and “cultural and heritage-sensitive retrofit” (122). Their weak association with analytical tools (e.g., 43 with “indicators and measures”) reflects the standards’ role as a compliance reference rather than an assessment tool. A resilience thread is evident in the pairing of “cultural and heritage-sensitive retrofit” with “post-disaster recovery and continuity” (207). “Post-disaster recovery” also connects with “retrofit strategy or method” (129) and “lifecycle environmental impact” (135), highlighting a heritage–resilience thread that focuses on recovery and continuity alongside technical aspects. “Retrofit strategy or method” shows strong co-occurrence with “digital tools” (150), “cultural and heritage-sensitive retrofit” (172), “seismic-induced environmental impact” (129), and “lifecycle environmental impact” (119). Its weaker presence with “indicators and measures” (39) reinforces our earlier finding that indicators are broadly represented across the literature but lack a unified use. Governance-related codes are weakly integrated, co-occurring with “lifecycle environmental impact” (64) and “multi-criteria design and decision-making” (59). This observation again indicates that governance dimensions remain peripheral and not adequately integrated with structural and environmental dimensions, or with approaches and metrics.

Building on these insights and the mapping of the identified dimensions across reviewed literature,

Table 3. Barriers and pathways to the seismic–environmental retrofit.

Barrier	Pathway to Address
Technical complexity and lack of standardised methods: Integration requires multidisciplinary expertise (structural + sustainability), no unified framework to link resilience and sustainability; existing standards (LEED, BREEAM, building codes) are discipline-oriented. Methods often rely on project-specific tools and specialised inputs.	Standardising metrics and tools: unified indicators and open-access toolkits, and collaboration among standards bodies, academia, and professional associations to provide replicable guidelines and develop cross-referenced standards.
Organisational silos and limited awareness: Structural/seismic experts, energy consultants, and policymakers rarely collaborate outside large projects. Local authorities lack capacity to evaluate integrated approaches. Owners remain unaware of long-term benefits.	Capacity building and awareness: Training programmes, cross-disciplinary curricula, and knowledge-sharing platforms to bridge silos. Targeted communication campaigns to inform owners and local authorities of long-term environmental, economic and safety gains.
Socio-cultural resistance and disruption concerns: Retrofit projects can cause displacement and financial concerns, especially in low-income or heritage sites. Communities fear loss of character, hidden costs, and disruptions to their lives.	Community engagement: Transparent communication, participatory design, and demonstration projects promoting heritage-sensitive retrofit strategies that balance safety with cultural preservation.
Fragmented policy and regulatory frameworks: Seismic codes and sustainability standards are governed by separate authorities, with misaligned policies and technical aspects. The roadmap of integrated retrofits for communities is unclear or not referenced.	Policy harmonisation and targeted financing: Unified permitting processes and bundled incentives. Expansion of programmes such as the European Green Deal and Italy’s EcoBonus to support integrated retrofit.
Data gaps and uncertainties: Many regions lack building inventories, lifecycle databases, or updated hazard models. Long-term uncertainties (climate, seismic frequency, energy costs).	Improved datasets and scenario planning: Investment in open-access building and material databases, updated hazard assessments, and integration of uncertainty modelling into retrofit decision making.

summarises the barriers facing seismic–environmental retrofit and potential pathways to address them.

4. Conclusions

This paper establishes a structured analysis to understand integrated seismic–environmental retrofit by identifying four key dimensions: structural, environmental, social and governance. Current research has concentrated on structural and environmental dimensions, while social and governance dimensions remain comparatively less explored, limiting the potential of real cross-domain retrofit integration. The integrated retrofit literature reframes environmental dimension, shifting toward a whole-building lifecycle assessment that incorporates seismic environmental impacts and energy efficiency as embedded components. Retrofit practices are primarily discussed in technical and compliance terms, but are not thoroughly examined using unified quantitative metrics. Social and governance dimensions remain peripheral, with weak connections to structural and environmental dimensions, which limit scaling up retrofit interventions. These insights highlight the challenges to integrated retrofit, including fragmented standards and policies, technical complexity, a lack of standardised metrics, and limited stakeholder engagement. Overcoming these challenges and advancing integrated retrofit requires alignment of standards, financial and regulatory support, professional capacity building and active community participation. By highlighting these gaps and opportunities, this paper advances a structured synthesis to support a more comprehensive and performance-driven retrofit framework for a safer, more resilient, and sustainable built environment.