Evaluating Laboratory Measurements for Sound Insulation of Cross-Laminated Timber (CLT) Floors: Configurations in Lightweight Buildings

Round 1

Reviewer 1 Report

I've really enjoyed reading this article, look forward to the insitu measurments.

Author Response

To all reviewers:

Thank you for your remarks. The changes in this new version include additional material with Tables and the new Figure A4, as requested by some reviewers. Minor changes for clarifications in the manuscript are highlighted with yellow (Table 2, Figures A1, A2).

Reviewer 2 Report

The subject of the paper is very significant with interesting results. It would be preferrable, some extra figures that depict the cross-section of the examined  (CLT) floors to be added in order the reader to have a comprehensive view of the subject of paper. Of course, there are  table 2 (with some designs of the floors) and Figure 3A (top view of the floor), but they don't give the information that a completed figure  of cross-section provides.

Author Response

Thank you for your observation and the novel idea for clarifications. Figure A4 has been added with a perspective sketch of a representative configuration, such as Floor 9 with dimensions.

To all reviewers:

Thank you for your remarks. The changes in this new version include additional material with Tables and the new Figure A4, as requested by some reviewers. Minor changes for clarifications in the manuscript are highlighted with yellow (Table 2, Figures A1, A2).

Reviewer 3 Report

 

The paper describes a contemporary configuration of wooden floors for light-weight CLT-frame buildings, standardised laboratory measurements of sound insulation for cross-laminated timber (CLT) floors with additional layers. thickness and mass in a floor configuration provide enhanced sound insulation in both aspects of airborne and impact sound.

My remarks are :

1-     Please could you describe the line of equation 112 and 121 by the way you should add the numbers to those equations for all the manuscript

2-     Please could add more details in figure 3, I mean the floor 12 ??,?(??) =660 in comparison with figure 4

3-     Why it’s difficult to block low-frequency noise in structures below 200 Hz

4-     According to your results  the higher thickness and mass provide better sound insulation than others above the first eigenfrequency peaks, at what frequency value can we block ?

1-     In Table 2 the data for floor number 10 (Concrete screed 60 mm, Vibration mat, B 12mm Glass wool 20mm…) is not presented please could comment ?

a copyediting should be performed. Even though the manuscript is readable, the style is substandard at times: some symbols are wrong of some parameters are not the same, etc

 

 

Author Response

To all reviewers:

Thank you for your remarks. The changes in this new version include additional material with Tables and the new Figure A4, as requested by some reviewers. Minor changes for clarifications in the manuscript are highlighted with yellow (Table 2, Figures A1, A2).

Specific reply to reviewer:

"My remarks are :

• Please could you describe the line of equation 112 and 121 by the way you should add the numbers to those equations for all the manuscript."

Thank you for your observation. Those equations are defined in ISO 10140-2 (for airborne sound, line 112) and ISO 10140-3 (for impact sound, line 121) and our manuscript explains them in a very similar way. They are very common in building acoustics and no further details are usually provided in relevant scientific papers, such as the intermediate calculations. That is mostly for economy but also trust to the common ISO protocol of measurements.

 

We believe this would provide limited value to the data presentation (since all measured results are clear in Figures 1, 3, A1 and A2). However, we created additional material in Tables to provide the values you requested. To avoid two extra pages in the Appendix of the manuscript, we attach the tables to a supplementary  link instead.

 

• Please could add more details in figure 3, I mean the floor 12 ??,?(??) =660 in comparison with figure 4.

We have indeed provided all information we have in Figure 3 and did some extra calculations (Figure 4) and modeling for easier interpretations (Figures 5, 6). If you would like to see some specific information on the graphs, please specify your remarks.

• Why it’s difficult to block low-frequency noise in structures below 200 Hz.

Because most fundamental frequencies / early eigenfrequencies lie in the range of 10 – 200 Hz. That is the most dominant frequencies for such mechanical systems. Then those low frequencies have very big wavelengths (bigger than 1 m) which makes them very intrusive and difficult to stop with materials of limited thickness. Additionally, the very low frequencies 10-50 Hz are combined not related to airborne sound only, but also with vibrations with can propagate through many adjacent structural elements.

This problem is more evident in CLT structures (lower mass) as we explain in lines 40-43:

Measurements have shown that CLT components offer better sound insulation than traditional concrete structures at middle and high frequencies, but considerably worse at low frequencies below 100 Hz [10,12,14].

• According to your results the higher thickness and mass provide better sound insulation than others above the first eigenfrequency peaks, at what frequency value can we block ?

This depends on the case, since every configuration / combination of layers is a different mechanical system with different Eigenfrequencies.

• In Table 2 the data for floor number 10 (Concrete screed 60 mm, Vibration mat, B 12mm Glass wool 20mm…) is not presented please could comment?

The reason for this information missing is that such a configuration was never measured so we do not have the data. It was measured only once with parquet floor but not without.

We clarify that with a new explanatory sentence in the end of Table 2 with an asterisk:

* Some values are missing because Floor 10 was measured only once with parquet floor.

Similar remarks have been added in the captions of Figures A1 and A2.

• a copyediting should be performed. Even though the manuscript is readable, the style is substandard at times: some symbols are wrong of some parameters are not the same, etc

Thank you for your notification, we contact the Editor for such an editing round after reviewing.

Round 2

Reviewer 3 Report

Thanks to the author for their answer, all comments and remarks have been taken into consideration, as well as the corrections, but please again the English language needs to be revised thoroughly throughout the manuscript to avoid errors.

 

Author Response

Thank you for your observations, the text in the manuscript has been revised: several errors have been fixed or complicated phrases were clarified.

The changed text is highlighted with yellow in this version.

Please specify with a certain line number if you think of any further remarks.