A framework for digital building logbooks: Drivers of affordable, circular and sustainable built environment

Sectoral policy coherence: energy, circularity, simplification and market competitiveness

Figure 1 shows the primary objectives of building-related data in relation to relevant EU legislation. It provides guidance on the purpose and role of DBLs, as well as the imperative for their implementation. This information is organised into four strategic themes, with examples of key policy instruments as shown below.

• Minimise the administrative burden and simplify regulatory compliance: DBLs can support the implementation of the EU Taxonomy by improving the availability, consistency, verifiability and longevity of the building-level data required for assessing alignment with the technical screening criteria (TSC). By linking existing data sources, such as EPCs and Environmental Product Declarations (EPDs), DBLs can reduce the administrative burden on financial market participants and facilitate data verification, in line with Articles 20 and 26. Similarly, DBLs facilitate CSRD and ESRS reporting by providing a single, digital repository that captures and updates building-related ESG data across the entire lifecycle of construction projects.

• Facilitate data-driven decision-making and renovation planning: EPBD requires Member States to establish machine readable building information tools, such as renovation passports (Art. 12), smart readiness indicators (Art. 15), and energy performance certificates (Art. 19), inspection schemes and digital verification tools to ensure compliance with designed energy performance and minimum building code requirements (Art. 23(8)). It further mentions the use and application of digital tools, such as digital twins (Art. 19(14)), BIM models, simplified EPC update tools (Art. 12(6)), and building automation and control systems (Art. 13(9)) to facilitate continuous performance tracking, reduce administrative burden, and support data-driven renovation decisions (Art. 19(4), Annex IV(1)).

• Promote the circular economy and material reuse: According to Article 75 of the CPR on CDPPs, stakeholders should be able to access, introduce or update information in DPPs, or create new ones. DBLs can help identify stakeholders and define their roles and responsibilities, as well as providing authorised access.

• Encourage transparency, market competitiveness and consumer empowerment: Under the IME, DBLs could facilitate customer empowerment and market efficiency by providing accessible, validated, and comparable information on energy use, dynamic pricing contracts, and demand response potential to consumers, citizen energy communities, and other market participants in line with Articles 14, 16, 18, 25.

Figure 1

Data, databases and information requirements in the EU policy framework

The current EU legislative landscape requires an extensive array of data points and information, creating a complex reporting environment for the construction and real estate sectors, as well as for public authorities and Member States. This covers the information that is required, generated, collected, stored, reported, exchanged or displayed during policy implementation. This often overlaps with existing market-driven data held by stakeholders, albeit in a fragmented way. In this context, DBLs can be positioned as an enabling instrument that aligns data and streamlines data flow, all the while preserving the level of policy ambition and regulatory objectives. Figure 2 shows the key data points, information requirements, and databases mentioned in the relevant EU legislation, grouped thematically.

Figure 2

Tools and policy instruments in the EU policy framework

The effective implementation of DBLs requires a structured approach that aligns with established building information tools and instruments. While EU policies provide the regulatory context, the operationalisation of these goals depends on a specific suite of technical tools, as mapped in Figure 3. These instruments, ranging from energy performance databases to digital permitting systems, act as the functional drivers of the DBL. By integrating these tools into a unified framework, Member States can accelerate the digitalisation, transparency, and sustainability of the built environment while ensuring that DBLs remain interoperable with existing national and regional systems.

Figure 3

Digital governance and enabling frameworks

Beyond sectoral requirements, a robust horizontal framework for data and digital governance is essential for the implementation of DBLs. DBLs can leverage current legislation to establish the necessary terminology, roles, responsibilities and principles for secure, interoperable data management. Table 5 summarises the relevant EU legislation that could inform the development of a digital governance framework for DBLs.

Governance and implementation models

The governance of DBLs varies significantly across the EU, reflecting different national priorities regarding data ownership, funding, and regulatory integration. These models can be broadly categorised into public-led ecosystems and mandated market-driven frameworks.

EPC and energy-related databases

EPCs represent the most well-established information tool under the EPBD. While most Member States have implemented central registers, the scope of data collected and levels of public access vary significantly; some registries capture only specific indicators, while others store all calculation inputs and outputs (Ruggieri et al., 2023). Similarly, access to the databases ranges from fully public to semi-public to restricted.

Under Article 20(8) of the EPBD, full EPCs, along with the input data required to calculate them must be uploaded to the database for the energy performance of buildings (Art. 20(8)). In turn, the databases must be interoperable and integrated with other administrative databases, such as building cadastres, land registries, and DBLs. This makes the information on building geometry, construction characteristics and technical systems already available in the databases. When linked with unique identifiers, this would enable the creation and implementation of DBLs at minimal additional cost. For example, in Portugal, when an energy expert issues a certificate, they must verify the building’s identification details by checking them against national databases, including cadastral information (Graf & Steuwer, 2025).

In addition to leveraging the EPC databases to develop the core functionality of the DBLs, their wider implementation across Member States demonstrates how digitalisation, data interoperability, management and access, quality assurance and integration with financial and policy frameworks can inform DBL development and expand their functionalities (Gokarakonda & Diaconu, 2026).

• Quality assurance: Spain has adopted a multi-layered approach to ensure data reliability and quality, combining automation, document control, field inspections and enforcement to ensure EPC quality and compliance.

• Policy implementation: Portugal links its EPC database, which provides results on energy and CO₂ reductions, with grant-funded renovations in order to evaluate actual energy savings and adjust programme design.

• Automated verification: Many countries, including Denmark, Portugal, Austria and Greece, have enabled the automatic verification of EPC data.

• Stakeholder led design: In Italy, indicators in the SIAPE (Information System on EPCs) platform have been agreed with the regions and key stakeholders. The platform ensures interoperability with regional databases and provides differentiated user access to detailed and aggregated data.

Voluntary, research and industry initiatives for data sharing and alignment

The demand for building data has been driven by regulatory compliance, such as that relating to EU Taxonomy, sustainability and disclosures, and market frameworks for green building certifications. Promoting stakeholder-led convergence of building data helps to reduce the further fragmentation of data-related activities and prevent the creation of incompatible parallel systems.

• Voluntary and research initiatives are working to facilitate seamless ESG reporting, enhance resource efficiency, and benchmark whole-life carbon in the real estate and construction sectors, while ensuring building data is aligned, accessible, meaningful, and actionable across the value chain. These initiatives include the Building Passport Alignment Project (BPAP, 2024), the Centre for Built Environment Data Sharing (C-BEDS) (C-BEDS, n.d.), the Global Building Data Initiative (GBDI) (GBDI, 2026) and the Open Standards for Construction and Real Estate (OSCRE, 2026).

• Organisations and industry initiatives, such as the EU BIM Task Group and buildingSMART, have long been driving the digitalisation of the construction sector by encouraging the use of BIM and developing open BIM frameworks (buildingSMART International, 2026; EU BIM Taskgroup, 2018).

• National-level digitalisation initiatives and committees, as well as standardisation activities, provide further support for these efforts by offering governance and structural frameworks (European Commission, 2019).

• EU-level organisations and bodies, such as the European Construction Observatory (ECO), the European Data Innovation Board (EDIB) and the Interoperable Europe Board (IEB), could further strengthen these efforts by coordinating standards, promoting interoperability and supporting harmonised approaches across Member States.

Technical guidelines and frameworks for DBLs

For best practices in data technology and management, the sector draws upon established general frameworks and maturity models, such as those developed by DAMA International and capability-based data management maturity model approaches inspired by CMMI Institute (Pörtner et al., 2025). The ISO family of standards (e.g., ISO 8000, ISO/IEC 38505, ISO/IEC 11179) establishes formal, internationally agreed requirements for data quality, governance, and metadata management. For the building sector specifically, standards such as ISO 19650 and the open data formats, standards and services frameworks developed by buildingSMART International provide sector-specific foundations for information management, including BIM implementation, and lifecycle data governance (buildingSMART International, 2026; DIN, 2023).

In the context of DBLs, the EU technical study on DBLs provides the guidelines for establishing a common EU framework for DBLs (Ecorys et al., 2023). The study categorised DBL information into seven key aspects: 1) identification; 2) general aspects; 3) legal and financial aspects; 4) dimensions; 5) performance; 6) structure and materials; and 7) building services. Key aspects of the technical implementation include defining principles for DBL implementation, ensuring semantic and technical interoperability, and creating a data management plan. The study also identifies five key principles for technical implementation, including simplicity, FAIRness, data quality, levels of information need (LOIN) and keeping data at its source. The study also suggests a semantic data model comprising a data dictionary and ontology, as well as an interoperability framework based on existing standards (Böhms et al., 2023). Semantic interoperability ensures the reusability and interoperability of the data, while technical interoperability ensures its accessibility and findability.

While the EU study only provides the high-level principles, there are few other frameworks tailed for budlings data. Achieving this requires a more granular, multi-layered structural architecture. To meet this need, the DWELT framework offers a “system-of-systems” approach specifically designed for the architecture, engineering, and construction (AEC) domain (Farghaly et al., 2026). This framework provides a clear pathway for technical implementation through five distinct layers:

• Define (D): Establishing a federated data model through combined top-down and bottom-up requirements.

• Wire (W): Ensuring data structuring, validation, and interoperability across heterogeneous sources.

• Engineer (E): Providing a secure, federated data ecosystem for real-time data exchange via APIs and publish–subscribe mechanisms.

• Leverage (L): Applying advanced analytics, such as machine learning and predictive modelling, to support data-driven optimisation.

• Transfer (T): Delivering insights to stakeholders through intuitive dashboards and 3D visualisations, ensuring effective communication and usability.

Another adaptation of this framework proposes a data governance model for the built environment, focusing on delivering a vision for data in the built environment based on five key characteristics: the data should be 1) aligned, 2) transparent, 3) interoperable, 4) trustworthy, and 5) clear, consistent, and unambiguous (Jones et al., 2025). These principles align with the digital governance and enabling frameworks in the EU, which were discussed earlier.

By applying this structured approach, DBLs can deliver a vision for the built environment where data is aligned, transparent, interoperable, trustworthy, and consistent. This technical rigour is particularly necessary given that most existing private DBLs currently rely on proprietary technologies, leaving their methods for governing data quality and interoperability largely opaque. Transitioning toward these open, standardised frameworks is therefore essential to prevent further data fragmentation and ensure DBLs provide measurable market value.

Impact pathways from DBL functionalities to policy outcomes

As shown in Figure 4, DBL functionalities generate multiple quantifiable benefits that are systematically linked to specific policy outcomes. Establishing these systems involves three primary cost components: 1) human resources, 2) capital, and 3) operational costs (Ecorys et al., 2023). The capital costs required to enable the core DBL functionality of data collection, storage and access involve the following: collecting and verifying data; creating an online platform and semantic model; reaching an agreement on data standards with stakeholders; acquiring licensed data; and compiling a dictionary. DBLs also incur operational costs relating to maintenance, scaling up the number of DBLs and adding additional functionalities. The resulting benefits of DBLs are primarily realised as avoided costs, most notably through significantly reduced labour for information gathering and a decrease in the time required for regulatory permits and approvals.

Figure 4

Social cost-benefit analysis (SCBA)

In all three scenarios, the results demonstrate a positive Net Present Value (NPV) and a Benefit-to-Cost Ratio (BCR) greater than one, indicating that the cumulative benefits of DBL implementation clearly outweigh the costs of setting up and operating the platform (Table 6). The CBR increases with the number of additional functionalities.

The SCBA model estimates a cost per DBL of approximately €1,000 in the first year, rising to approximately €1,100 by year 25, with only a marginal difference in the three scenarios. While this is higher than certain existing public DBLs or DBLs largely based on statistical models, it aligns with private-sector initiatives that rely on rigorous, on-site data collection. For comparison, the costs obtained from interviews with DBL providers vary significantly depending on their data collection methods and business models (Gokarakonda & Zsolt, 2025):

• Public and mandatory: Approximately €1.17 per building by consolidating existing public databases.

• Mandated private: A privately operated DBL in a country with a DBL mandate that gathers building-related information from existing data sources and on-site visits costs about €10 for a year of subscription.

• Private and voluntary (statistical): DBL with focus on material passports that largely uses statistical methods to develop DBLs at a cost of approximately €7.5 per DBL.

• Private and voluntary (on-site data collection): A DBL provider for large housing portfolios that collects and verifies data based on on-site visits costs between €500 and €1,000 for buildings requiring first-hand verification. However, the same DBL provider also considers that a licensing model for owners of large portfolios of between €0.13 and €0.25 per dwelling per month to be a feasible business model.

The high variability in the costs of DBLs is largely due to differences in governance and business models and the data collection methods. It underscores that DBL financial models are highly sensitive to the costs of data collection and verification methods. Although the total annual cost increases with the number of DBLs, capital expenditure (‘basic costs’) accounts for the largest proportion in the early years. From year five onwards, operational (recurring costs) and functionality-related costs become more significant. The cost per DBL stabilises at €1,160–€1,250, indicating that the DBL platform has reached maturity and the technical costs have levelled off due to economies of scale.

Another interesting finding of the SCBA is the disproportionate value generated by the functionalities. Table 7 enables the direct comparison of the proportion of total costs for setting up and maintaining the DBLs, and the proportion corresponding to the core and the additional functionalities in scenario 3. Although, the functionalities account for only around 12% of total costs, they represent over 60% of the total benefits.

Overall, the analysis shows that although initial investments are intensive, the benefits grow exponentially as the number of users increases. Because the savings from automated updates and reduced administrative effort are ongoing throughout a building’s lifecycle, the system achieves a swift transition from an investment-heavy phase to one where the societal and market benefits clearly dominate the costs. These benefits become even more significant as additional functionalities are added, as the cost of these is often negligible compared to the capital costs of setting up DBLs.