Environmental Impact of a Mono-Material Timber Building Envelope with Enhanced Energy Performance
Round 1
Reviewer 1 Report
The paper has been carefully reviewed. This paper proposes a novel, solid timber, building envelope that uses computational design and digital fabrication to improve buildings' energy performance. The theme of this proposal is sensational. I am passionate about wooden constructions, and I applaud all the efforts to improve this type of construction sector.
A few small adjustments should be made to the paper:
- Improve the standardization of figures. Some are big, some are smaller. Some have some kind of word side correction.
- Standardize the font of figures and tables, some are different from the text.
In general, the paper has merit for publication after these adjustments.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
This paper studied the Environmental Impact of MMWW construction system on Energy Performance, the research is interesting and fit the scope of the journal. The followings are the suggestion for this paper, in order to improve the readability for the readers.
In Figure 5, is the MMWW construction system connected with CLT panel with shear connectors, is the structural capacity of these connection system been examined?
Texts in Table 6 are too small, need to be enlarged.
In Figure 13, please specify the unit of time.
In Figure 14, it is difficult to understand the ratio of each material shown in legend, which conclude materials with different colors. I suggested find a better way to demonstrate and make it easier for readers to understand.
The discussion seems to be the final part of this study and looks like the conclusion of the study. In the scientific paper, the final conclusion of this study is suggested to be added.
Reference in line 757,758 need to be justified.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Dear Authors of ”Environmental Impact of a Mono-Material Timber Building Envelope With Enhanced Energy Performance”
The reviewer would like to express the appreciation to authors’ initiative and efforts for the development and assessment of the performance of MMWW. It is a very interesting concept and the authors have made a tremendous effort to demonstrate it in reality and in its performance evaluation.
In the following comments, the reviewer gives following remarks to the manuscript.
1. It seems the manuscript is duplicating results from a paper which has been already published by the authors themselves (doi: 10.1016/j.enbuild.2021.111597). Especially some key figures and the analysis on the thermal performance and the airtightness performance seems identical between the published paper and the present manuscript. It is recommended to NOT duplicate results from an existing publication. The manuscript needs to delete the duplications and restructure the whole manuscript by citing the existing publication properly.
2. There are a lot of grammatical errors and unusual expressions in most of sections (the reviewer does not point it out one by one as there are too many). There is a sentence which is incomplete (L615). The numbering of figures is not consistent (there are expressions of figures like “Figure X” (L469), “Figure Y” (L430), “Figure Z” (L444), etc.), and it is clear that the authors did not make a thorough proofread by themselves. The manuscript should be checked on such basic mistakes before the submission.
3. The description on thermal resistance R in L125-128 is incorrect. This is strange because the description on R in the previous paper (doi: 10.1016/j.enbuild.2021.111597) seems appropriate. It seems the own proofread was missing.
4. In L250, it is claimed that the MMWW system has the improvement in structural, thermal, moisture management, and airtightness performance. Although the mechanism of structural, thermal, and airtightness improvement mechanisms are addressed in the rest of the paragraph, the moisture safety improvement is not explained. This must be motivated with a proper qualitative description.
5. The section “2.3.2.Design-to-Fabrication Workflow” does not seem to be essential to make the findings of the study. In other words, the same discussion in “4. Discussion” could be made even without section 2.3.2.
6. The description in “2.4.3.Moisture Content” is extremely poor. WUFI Pro provides only 1D models while the section of the MMWW is highly complex and it is unclear how it was modelled in the 1D setup. The model inputs (initial condition, indoor climate, surface transfer, exposure to rain, orientation, material data, handling of the air layers, etc.) are all missing. And thus, the results on the moisture analysis presented in “3. Result” is not to be verified.
7. Even if the methodology in the WUFI analysis would have been presented properly (see comment 6), the discussion in “3.1.3.Moisture Content” is weak. It necessary to define the critical moisture content of the timber and motivate it properly considering the potential risks and relation of different parameters (moisture content, temperature, relative humidity, and time duration.)
8. The manuscript ends with “4. Discussion”. The reviewer recommends to add a “Conclusion” section.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Dear,
The paper is ready to be published.
Best Regards.
Author Response
Thank you very much for your feedback and support.
Reviewer 2 Report
This paper is now ready for publication.
Author Response
Thank you very much for your feedback and support.
Reviewer 3 Report
Dear Authors of ”Environmental Impact of a Mono-Material Timber Building Envelope With Enhanced Energy Performance”
The reviewer would like to very much appreciate the efforts and the significant improvement that the authors made on the manuscript. It now has a much clearer structure and a more focused storyline. The reviewer agrees with the approach of the authors to make the focus on the LCA of the newly developed system and leave the moisture safety analysis for another paper. Although the manuscript has a good quality, there still are minor improvements to be made.
· - A motivation for using only one indicator (GWP) should be given. The title and some parts of the body text say “environmental impact” analysis, which could cover not only GWP but other environmental indicators.
· - The section numbering seems very odd. There are only 2 headlines which are numbered (“1.1.1. Timber Frame Construction” in L111 and “3. Results” in 464.) Please give a consistent numbering system.
· - L15 says “moisture diffusion behavior” is evaluated, which is not the case. Please correct.
· - In L117, it should say “glulam” instead of “Glulam”.
· - L147, “permeability” can mean not only air permeability but also vapor permeability. Please specify.
· - L417, the functional unit of “m2” is not fully clear. It is supposedly the are of the wall, but it needs to be clearly defined to avoid confusion/misunderstanding. (Ex. The total floor area is often used as a FU of a building LCA.)
· - L426, please motivate the reason for excluding B-module while stating the LCA to be cradle-to-grave. It is understandable to exclude it as the U-values of all scenarios are set as the same. But it does not fully motivate to count the operational anergy as zero in the LCA. And the conclusion about the proposed system being “carbon negative” should also consider the reality of the operational energy for heating/cooling.
· - In Table 4, is it appropriate to use Brettsperrholz data for X-Fix connectors? Please motivate or clarify the potential data discrepancy (CLT being softwood with a few glue lines vs X-Fix being hardwood with a lot of glue lines).
· - In Table 4, is it appropriate to use Buch Holz generisch data for Lignoloc beech nails? Please motivate or the potential data discrepancy (generic beech data might not consider the processing in the factory other than regular sawing vs Lignoloc having some extra processing (compression etc. if the reviewer remembers correctly)).
· - Table 5 is given in an odd size and the end on the right side is missing.
· - Figure 9 and 10, the reviewer recommends to use the same color for the same material.
· - L545-550, it is unusual to state that another paper is being written. The reviewer recommends that the moisture study is mentioned simply as a primary topic of a further study and do not mention the new paper in the making.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
