The Potential of Uncoated Norway Spruce as a Façade Material—A Review

Round 1

Reviewer 1 Report

The authors have prepared an interesting overview of the use of spruce wood for façade applications. This topic is relevant and falls within the scope of the journal. The authors have provided a good overview of the various properties that might affect the performance of wooden facades. However, it would be nice if the authors could provide a few additional information regarding the use of spruce for the respective application:

-        What is the expected and actual service life of the spruce wood facades in different regions.

-        Protection by design considerably influences the service life of spruce facades.

-        What is the commercial perspective? Are spruce wood facades cheaper or more expensive solutions compared to alternatives.

-        There have been attempts to stimulate greying of wood with aqueous solutions based on iron. Another traditional surface treatment is based on charring? What is the potential of these solutions.

-        Which modification technique has the higher potential to be used on Norway spruce wood?

-        Addition of artwork could improve the manuscript.

 

Some additional comments are resolved bellow.

 

Introduction

L22, the term biological resistance could be replaced with the term durability.

L23, Does weathering influence service life? Aesthetics, yes; what about technical?

L21-30, an alternative method that improves the service life of the wood is full consideration of “protection by design” principles.

L44, please define “mature”. What was the appropriate age? Diameter? Do you have in mind the adult wood vs juvenile wood, the presence of heartwood at pine?

L48-60; Norway spruce was traditionally used in some other countries as well in the form of logs or cladding. A comparison of case studies from Sweden with other European countries might make sense.

The link between the proximity of the sea and decay hazard is not uniform and valid for all regions. I recommend the authors describe this relationship as regional characteristics.

L61-63, the authors should consider that the Spruce in most of continental Europe is under huge environmental pressure, which results in its decline.

The durability

L96-108, I agree that there is a difference between the durability of sapwood compared to heartwood. But how to perform the differentiation in sawmills? Is the presence of sapwood sufficient to make a differentiation?

L110-131, one of the possible reasons for the better durability of spruce heartwood, is linked to the pit aspiration, predominantly for above-ground applications.

L226-232, at bark beetle damaged wood, symbiotic fungi degrade the resin? This degradation could appear in stored wood logs as well.

In addition, there have been reports that killin’ drying of spruce improves the moisture performance of wood. There were no details provided, but this might be associated with resin allocation during the elevated temperatures.

L241; density

There have been some publications about the influence of density on spruce wood durability. There were no major differences. As far as I remember, this work was performed by a team in Oslo, As. The results have been published in the journal Wood industry.

 

 

 

 

 

 

 

 

Author Response

Dear reviewer,

Thank you kindly for your time and effort. Your input has been incredibly valuable to increase the quality of our manuscript.

Please find responses to the review report in the word file attached.

Kind regards,

Corresponding author Sebastian Svensson Meulmann

Author Response File: Author Response.docx

Reviewer 2 Report

Title: In general, Norway spruce is broad concept. The manuscript concerns to wood.

Key words: The façade is not mentioned.

Aim: The “potential” of spruce wood as construction material is discussed. Why this aim was selected is unclear, because the usage of spruce has been known for ages.

The durability of “spruce” relative to other wood species: The short durability of spruce wood is quite known. Five references in this field is not enough. I missed the references and information about mass lost, regarding the properties of decayed spruce wood and its usage.

The durability of spruce heartwood: I appreciated the explanation what does the heartwood of spruce wood mean. I expected the larger number of references from this field regarding the juvenile wood, the ratio of spruce sapwood to heartwood (or ripewood?).

The importance of water content in wood: The FSP was defined by Tiemann. Why authors did not quote him? Instead of it, they used their own definition. The name of FSP was stollen.

Line 192: Unclear sentence. What does the “better moisture performance” mean? Do you realize, the wood hydrophilicity? Wood contained water at the time of felling. How does wood gain the hydrophobicity?

The permeability of spruce: Please, solely use the SI units throughout the text.

The effect of density: As written in abstract, the “selection” of density is unclear. The unclear is regarding the density as factor or state variable. As factor, I missed the statistical analysis of literature data. As, state variable, I missed the connection between other properties, e.g. shrinkage, FSP, or others. Such information can be utilized in next chapter “The processing of wood”.

The processing of wood: Lines 316-320 are not quoted.

The quotation of used literature and authors own ideas are unclear throughout the text. Such writing leads to unclear ideas in sentences or ideas which are not promoted by quotation of literature nor own research.

The contribution does not inform the type of building construction for which wood will be used as a façade material.

Finally, I do not understand the aim of the contribution. The ancestors recognized wood as excellent construction material even for façade and for ages.

The quality of english was good.

Author Response

Dear reviewer,

Thank you kindly for your time and effort. Your input has been incredibly valuable to increase the quality of our manuscript.

Please find responses to the review report in the word file attached.

Kind regards,

Corresponding author Sebastian Svensson Meulmann

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors have revised the manuscript. They have addressed all of the open questions. Changes are clearly evident in the manuscript (track changes). I have no further recommendations.

 

Reviewer 2 Report

Dear authors,

thank you very much for reading my previous reviewing.

I admit your endeavor to enhance your manuscript.

The quality of manuscript will not be improved substantially, even after my reviewing.

Finally, I recommend to change the title to be the minireview of the spruce wood facade topic.

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