Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The primary concern lies in the limited methodological novelty and insufficient validation of the proposed BIM framework. While the integration of BIM for construction waste quantification is commendable, the approach essentially automates existing waste calculation principles without introducing significant theoretical or technical innovations beyond current state-of-the-art applications in this domain.

Substantial methodological gaps undermine the framework's reliability and generalizability. The material database and allocation factors central to the automated calculations lack transparent derivation, with critical parameters like the 80% hazardous waste assumption for lead-painted components appearing arbitrary without proper validation. The single Budapest case study provides inadequate evidence for the claimed European-level applicability, failing to demonstrate robustness across different building typologies or regulatory environments. Furthermore, the framework's dependency on LOD 300 BIM models significantly limits practical implementation, as most existing historical buildings lack such detailed digital documentation, creating a substantial barrier to real-world adoption that remains unaddressed. 

Author Response

Dear Reviewer,

Thank you for your valuable and constructive comments. We appreciate your critical insights regarding the methodological novelty and the practical applicability of the framework. We have carefully addressed your concerns and revised the manuscript accordingly. Please find our point-by-point responses below.

Comment 1: The primary concern lies in the limited methodological novelty... the approach essentially automates existing waste calculation principles without introducing significant theoretical or technical innovations.

Response: We acknowledge your point. We have clarified in the Introduction that the primary novelty of our research lies in the specific adaptation and automation of these principles for a challenging historic building typology (late 19th-century Central European housing stock), where standard BIM tools often fail due to complex, non-standard material compositions. We emphasized that bridging the gap between theoretical circularity principles and practical heritage management is a key contribution.

Comment 2: Critical parameters like the 80% hazardous waste assumption for lead-painted components appear arbitrary without proper validation.

Response: Thank you for highlighting this. We have revised the relevant section in the Methodology (Section 3.4,2) to clarify that the 80% ratio is a conservative estimate derived from the historical prevalence of lead-based primers (minium) in the Austro-Hungarian region. We opted for a "safety-first" approach to avoid underestimating hazardous waste volumes in the absence of chemical testing for every single element.

Comment 3: The single Budapest case study provides inadequate evidence for the claimed European-level applicability.

Response: We have expanded the Discussion section to explain that the "Budapest typology" is, in fact, representative of the standardized architecture of the former Austro-Hungarian Empire. Consequently, the material database and structural logic presented in our framework are directly applicable to the historic building stocks of other major Central European cities, such as Vienna, Prague, and Krakow.

Comment 4: The framework's dependency on LOD 300 BIM models significantly limits practical implementation...

Response: We agree that creating LOD 300 models is resource-intensive. However, we have added a discussion point arguing that pointcloud-based survey methods (like TLS) are insufficient for waste quantification because they cannot identify internal structural layers (e.g., floor fills). We argue that for accurate circularity planning, the investment in LOD 300 modeling (based on archival plans and probes) is necessary to distinguish between reusable and non-reusable materials.

We hope that these revisions satisfactorily address your concerns.

Reviewer 2 Report

Comments and Suggestions for Authors

The abstract looks like a summary and lacks a quantitative outcome for example the % waste reduction, comparative metrics etc and at same time missing a clear mention of method validation or applicability limits.

The introduction is informative but its focusing only on budapest’s buildings rather than the research gap itself and still missing a clear objective statement and research questions especially at the end of the introduction.

The citations 13,20,29,31,35 looks inconsistent please recheck if order follows appearance.

The algorithmic logic flow such as the pseudocode or computational workflow diagram is not clear and missing and the Fig 2 is general.

 The case study lacks numerical analysis such as the mass of total waste and % reuse, recycle rates per scenario an also missing the environmental impact quantification such as co2 savings and energy equivalent.

clear limitations and future work is still missing.

figures 2, 4, 7  captions are too briefy and need explanatory legends and tables 2 and 4 are so dense you might try to splitting or highlighting key values only.

I suggest to have a summary figure showing the entire workflow and the case study outputs in one diagram.

Regarding the references please be aware that you have used more than 40 references but many are pre 2020 and Q1 journals expect more than 40% recent references between 2021–2025.

Add 4 to 5 references from recent BIM circular economy studies (Automation in Construction, Journal of Cleaner Production, Buildings, Waste Management) and please verify all DOI links and conform to journal style (MDPI format in this case).

For example in literature Review you can cite Hussien, A.; Zubaidi, R.A.; Jannat, N.; Ghanim, A.; et al. The effects of tea waste additive on the physical and mechanical characteristics of structural unfired clay bricks. Alexandria Engineering Journal 2024, 83, 10390–10405. https://doi.org/10.1016/j.aej.2024.05.090, when discussing wast valorization and reuse of waste materials in construction  especially as an example of circular economy practices and material recycling showing your engagement with sustainable material research beyond digital frameworks.

Author Response

Dear Reviewer,

We would like to express our gratitude for your thorough and detailed review. Your comments regarding the quantitative presentation of results, the bibliographic updates, and the methodological clarifications have significantly improved the quality of our manuscript. We have addressed all your points as detailed below.

Comment 1: The abstract looks like a summary and lacks a quantitative outcome... missing a clear mention of method validation or applicability limits.

Response: We have revised the Abstract to include specific quantitative findings from the case study (e.g., the increase of high-value reuse from 19.6% to 56.8% with selective demolition). We also added a sentence clarifying the applicability limits (Central European historic building typology).

Comment 2: The introduction is informative but its focusing only on budapest's buildings rather than the research gap itself...

Response: We have refined the Introduction to better articulate the research gap. We clarified that while general BIM waste tools exist, a specific gap remains in automating this process for historic buildings with complex, non-standard material compositions (like the Austro-Hungarian typology), where standard tools often fail.

Comment 3: Missing a clear objective statement and research questions especially at the end of the introduction.

Response: We have rewritten the end of the Introduction section to explicitly state the research objectives and have formulated two specific research questions regarding the automation of waste quantification and the impact of demolition technologies.

Comment 4: The citations 13, 20, 29, 31, 35 looks inconsistent please recheck if order follows appearance.

Response: We have thoroughly checked the entire manuscript and corrected the citation order to ensure that all references appear sequentially in the text, as required.

Comment 5: The algorithmic logic flow... is not clear and Fig 2 is general.

Response: While we retained the overview nature of Figure 2, we have added a detailed step-by-step explanation of the algorithmic logic (ID matching, decomposition, volume-to-mass conversion, allocation) in the Methodology section to clarify the computational workflow.

Comment 6: The case study lacks numerical analysis... and missing the environmental impact quantification such as CO2 savings.

Response: Regarding the numerical analysis, we emphasize that Tables 6 and 7 already contain the mass values (in tonnes) and percentages. We have made references to these tables more explicit in the text. Regarding CO2 and environmental impact: We have added a new paragraph to the Limitations section explaining that CO2 quantification was excluded from this specific study due to the lack of reliable Environmental Product Declarations (EPD) for historic, 19th-century building materials. We acknowledged this as a direction for future research.

Comment 7: Clear limitations and future work is still missing.

Response: We have significantly expanded Section 5.3 (Limitations and Future Research). We added two new specific points: one regarding the limitations of survey technologies (why TLS is insufficient without probes) and another regarding the current lack of historical material EPDs for carbon calculation.

Comment 8: Figures 2, 4, 7 captions are too briefy and need explanatory legends and tables 2 and 4 are so dense you might try to splitting or highlighting key values only.

 Response: We have expanded the captions for Figures 2, 4, and 7 to provide better context. For Tables 2 and 4, instead of splitting them, we added explanatory "Notes" directly below the tables to guide the reader on how to interpret the dense allocation and bulking factor data.

Comment 9: I suggest to have a summary figure showing the entire workflow and the case study outputs in one diagram.

Response: We believe that the combination of the now-clarified algorithmic description (Response 5) and the detailed result graphs (Figure 10) effectively communicates the workflow and outputs. Adding another complex diagram might overcrowd the paper; however, we ensured that the connection between the workflow and the results is made clearer in the text.

Comment 10: Regarding the references please be aware that you have used more than 40 references but many are pre 2020 and Q1 journals expect more than 40% recent references between 2021-2025. Add 4 to 5 references from recent BIM circular economy studies... For example... Hussien, A...

Response: We have updated the reference list by replacing selected older citations with recent studies from 2021–2025 to meet the currency requirement. Furthermore, we have included the suggested reference by Hussien et al. (2024) in the discussion on material recycling (Section 2.2) to broaden the context of circular economy practices.

We hope that these revisions meet your expectations.

Reviewer 3 Report

Comments and Suggestions for Authors

Dear authors, I would like to congratulate you for the submitted manuscript. Your article deals with a generous topic that has been studied in the literature since 2017, with the development of the BIM concept in demolitions. The correlation of BIM with LOD 300 is welcome for the proposed objective. BIM is a suitable choice for the study carried out. The workflow reflects the authors' thorough knowledge in the field studied.

The paper is carefully written, the methods used are well presented and the results are replicable.

I believe that the following aspects are not fully clarified and would contribute to increasing the impact of the study:

1. The authors' justifications regarding environmental protection are understandable, but the study omits the cumulative impact of demolition and reconstruction with new, innovative materials, which consume considerable resources and last little in terms of years vs. renovation and consolidation. Another aspect that needs to be clarified is how much energy a double-height building will consume and how much waste the new tenants will generate. At least as a bibliographic reference, not as elements that would modify the objectives of your study. Since you justify the study in the context of the circular economy and the carbon footprint generated, I believe that the carbon footprint necessary for the reconstruction of a new and large building should be mentioned. Or mentioned that the space will become green space. All the arguments are in favor of demolition, but it does not explain what will be done in place of the building, parks or other buildings? From the point of view of the circular economy, not the recycling process of materials from demolitions. The above questions derive from the main objective stated by the authors in lines 100-103.
2. Regarding the statement in line 390 “For example, the foundation level is typically unknown, as excavation is generally not carried out.” Why don’t they use building plans? In European capitals there are building plans dating back to the 19th century? Or if they don’t, at least justify their absence taking into account the rigors of construction imposed in the former Austro-Hungarian empire.
3. Why aren’t modern technologies used to scan the interiors of buildings that are to be demolished and implement BIM afterwards? Technologies such as: TLS – Terrestrial Laser Scanning, Thermal Imaging, EM scanning, GPR – Ground Penetrating Radar, etc., with the pros and cons of each method?
4. I believe that there are missing elements that would attest that the estimates are correct. The validation part of the proposed model in a real case of demolition is not just the use of hypothetical scenarios such as those described in lines 804-813. The answer is obvious according to the proposed scenarios.

I strongly recommend revising the manuscript to enhance its clarity and to more clearly articulate the superiority of the proposed method

Author Response

Dear Reviewer,

Thank you for your encouraging words and for recognizing the relevance of our topic and the suitability of the BIM/LOD 300 approach. We greatly appreciate your insightful comments regarding the broader environmental context and the technological alternatives. We have addressed your suggestions as follows:

Comment 1: The study omits the cumulative impact of demolition and reconstruction... future energy consumption... carbon footprint.

 Response: We agree that the cumulative impact is crucial. We have added a paragraph to the Discussion section explicitly stating that from a circular economy perspective, renovation is generally preferred over demolition due to the high embodied carbon of new construction. We clarified that our framework is a "damage mitigation" tool for unavoidable demolition scenarios, and we flagged the comparative LCA of "demolition vs. renovation" as a key direction for future research.

Comment 2: Why don't they use building plans? In European capitals there are building plans dating back to the 19th century.

Response: We have clarified in the Methodology section that although original 19th-century plans are often available in archives, they rarely accurately document the current foundation depth. Therefore, our standardized calculation formula provides a more consistent and safer estimation for waste quantification than relying on potentially obsolete historical drawings

Comment 3: Why aren't modern technologies used... (TLS, GPR, etc.)?

Response: We have added a discussion in the Limitations section comparing our method with TLS. We argue that while TLS is excellent for geometry, it is surface-based and cannot identify internal material compositions (e.g., the slag fill within a Prussian vault or the specific layering of a floor). Our database-driven approach, derived from typology knowledge, provides the material-specific data required for waste estimation that geometric scanning alone cannot offer.

Comment 4: The validation part... the answer is obvious according to the proposed scenarios.

Response: We acknowledge that the benefit of selective demolition is intuitively expected. However, we emphasized in the Conclusion that the novelty and value of our framework lie in the precise quantification (e.g., forecasting exactly 1,178 tonnes of reusable brick vs. 142 tonnes). This granular data is what transforms a general "green principle" into actionable data for logistics, tendering, and business modeling.

We believe these clarifications strengthen the manuscript significantly.

Reviewer 4 Report

Comments and Suggestions for Authors

The case study is well described, and the results have clear practical implications.
The authors state that the framework is applicable at the European level.
However, the database is extremely specific to the Budapest building typology. I don't know if it's necessary, but would it be helpful to specify alternative databases?
I'm accepting a minor revision only because I believe there's a typo. The entire paper refers to Archicad 27, except for Section 5, where Archicad 28 is introduced.

Author Response

Dear Reviewer,

Thank you for your positive feedback and for identifying the inconsistency regarding the software version. We appreciate your attention to detail, which has helped us ensure the accuracy of the manuscript. We have addressed your comments as follows:

Comment 1: The entire paper refers to Archicad 27, except for Section 5, where Archicad 28 is introduced.

Response: Thank you for spotting this typographical error. We have corrected the text in Section 5.1 to consistently refer to Archicad 27, which was the software version used for the case study.

Comment 2: The database is extremely specific to the Budapest building typology... would it be helpful to specify alternative databases?

Response: We agree that the current dataset is specific to the region. To address this, we have added a clarification in the Evaluation of the Framework section (Section 5.1). We emphasized that while the data is local, the framework structure is universal. The system was designed to allow users from other European regions to easily substitute the input parameters (such as material density or component ratios) with their own local historical data without needing to modify the core algorithm.

We are grateful for your support in refining our paper.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Accept in present form.

Reviewer 3 Report

Comments and Suggestions for Authors

The authors clarify all aspects that I emphasized. They improve the bibliographic references. I recommend that this manuscript be published in its current form (Version 2).