Research article

Moisture control design has to respond to all relevant hygrothermal loads

Authors
  • Hartwig Künzel orcid logo (1Fraunhofer Institute for Building Physics, Holzkirchen, Germany)
  • Mark Dewsbury (2University of Tasmania, Launceston, Australia)

This is version 1 of this article, the published version can be found at: https://doi.org/10.14324/111.444/ucloe.000037

Abstract

Moisture-related damage is still a formidable cost factor in the building sector. Besides installation deficiencies, moisture control design failures are the most frequent reasons for moisture problems. Therefore, adequate moisture control analysis has become the key for sustainable buildings. However, by only focusing on vapour diffusion other important moisture loads such as driving rain, construction moisture or air infiltration are mostly neglected. Therefore, international moisture control standards often refer to simulation models for more realistic analysis, leaving many practitioners wondering how to handle these tools. To overcome this dilemma, the updated German moisture control standard has introduced a three-pathway approach for design evaluation: first, deemed to satisfy list, second, restricted Glaser calculation and third, fully fledged hygrothermal simulation. The third pathway includes the option to account for small leaks or imperfections in building envelope components. Guidelines in other countries are also embracing similar moisture control approaches which gives hope for more durable and sustainable building design. To reach this aim, moisture control should also become an integral part of the design process instead of a secondary chore.

Keywords: moisture control design standard, hygrothermal simulation, vapour diffusion calculation, deemed to satisfy, component leaks

Rights: © 2022 The Authors.

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Published on
15 Jul 2022
Peer Reviewed

 Open peer review from Hector Altamirano

Review

Review information

DOI:: 10.14293/S2199-1006.1.SOR-ARCH.AGNPAS.v1.RKXXZL
License:
This work has been published open access under Creative Commons Attribution License CC BY 4.0 , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Conditions, terms of use and publishing policy can be found at www.scienceopen.com .

ScienceOpen disciplines: Architecture
Keywords: Built environment , Sustainable development , Moisture control design standard; hygrothermal simulation; vapour diffusion calculation; deemed to satisfy; component leaks;

Review text

Many thanks to the authors for addressing the comments. Excellent work.



Note:
This review refers to round of peer review and may pertain to an earlier version of the document.

 Open peer review from Valentina Marincioni

Review

Review information

DOI:: 10.14293/S2199-1006.1.SOR-ARCH.AHLMEC.v1.RNMMUP
License:
This work has been published open access under Creative Commons Attribution License CC BY 4.0 , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Conditions, terms of use and publishing policy can be found at www.scienceopen.com .

ScienceOpen disciplines: Architecture
Keywords: Built environment , Sustainable development , Moisture control design standard; hygrothermal simulation; vapour diffusion calculation; deemed to satisfy; component leaks;

Review text

Dear Authors, thank you for the edits to the paper. The paper provides a timely overview of the development and challenges in the field of hygrothermal simulations and moisture risk. I recommend the paper to be accepted as is.



Note:
This review refers to round of peer review and may pertain to an earlier version of the document.

 Open peer review from Hector Altamirano

Review

Review information

DOI:: 10.14293/S2199-1006.1.SOR-ARCH.ADCI9V.v1.RBQJHU
License:
This work has been published open access under Creative Commons Attribution License CC BY 4.0 , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Conditions, terms of use and publishing policy can be found at www.scienceopen.com .

ScienceOpen disciplines: Architecture
Keywords: Built environment , Sustainable development , Moisture control design standard; hygrothermal simulation; vapour diffusion calculation; deemed to satisfy; component leaks;

Review text

A few specific comments are presented below:

  • This is an excellent paper
  • The paper looks at the importance of considering all moisture loads in a building when assessing the design and moisture risk.
  • The authors clearly described the different water sources that may affect or create risk conditions within the building, which should be adequately assessed.
  • It is excellent to see the links between the different sources of water, the issues that they may generate and how they are currently assessed.
  • In this way, it is also very interesting to see the limitation of the different and available tools highlighting what we could be missing.
  • The authors also provide several solutions for specific details and construction circumstances when discussing common issues.
  • Also great to see discussion on what is the current limitation of some of the tools but also an indication of what aspects of the current way of assessing moisture risk needs further work sample more grow sensitivity
  • Even though I could understand them, some figures need a bit of work and probably more explanation of what precisely the reader should look at. For example, in Figure 4, what is the relationship between the diagram and the picture; in Figure 5, the quality of the photo is not the best, so the staining on the render is not evident as it should be. The simulations shown in Figure 9 are unreadable, so unclear what is being presented


Note:
This review refers to round of peer review and may pertain to an earlier version of the document.

 Open peer review from Valentina Marincioni

Review

Review information

DOI:: 10.14293/S2199-1006.1.SOR-ARCH.AXGIXS.v1.RKTXUG
License:
This work has been published open access under Creative Commons Attribution License CC BY 4.0 , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Conditions, terms of use and publishing policy can be found at www.scienceopen.com .

ScienceOpen disciplines: Architecture
Keywords: Built environment , Sustainable development , Moisture control design standard; hygrothermal simulation; vapour diffusion calculation; deemed to satisfy; component leaks;

Review text

This article presents a timely overview on the development of hygrothermal simulations and protocols for the consideration of appropriate moisture mechanisms and sources. It presents some of the challenges associated with the most common assessment method, the "Glaser" method, and justifies the need for an approach that assesses moisture risk under as-built, in service conditions. It also presents some useful examples of international and national standardisation, showing how the building physics community worldwide is advancing towards a more appropriate assessment method, and presenting some of the challenges. This is a must-read article for everyone who is using hygrothermal simulations in their practice or research work.

Please find below some comments and points that need clarification.

In section 1, can you please be more specific regarding "renewable insulation materials"? Are you referring to natural (or bio-based) materials ?

Typos in 2.2: "less o e r requirement"; "most cladding systems are generally direct ly fixed"; "are also very common , only few damage cases had been reported". Section 2.2 would be better renamed as "Wind-driven rain" - the section on solar vapour drive is in 2.3.

In 2.3, the statement "the cavity of masonry walls should net be ventilated", could be rephrased to "Considering all aspects, it is preferred for the cavity ...". Also, in some areas (e.g., high wind-driven rain exposure) a slight ventilation might still be important; in these areas, it is also likely that cavity wall insulation cannot be installed. Can you comment on this?

Section 2.3 does not mention solar vapour drive in solid masonry walls. Can you please expand on this? There is evidence that solar vapour drive occurs in solid masonry walls, and - if appropriate insulation is installed - moisture can reach the indoor environment and leave the building (via appropriate ventilation) without accumulating in the wall or indoors.

In section 2.4, you could mention the different heating methods in buildings such as churches (e.g. IR heating?), which lead to a non-uniform indoor temperature.

In section 2.5, CSB is Calcium silica te Brick. What do you mean with "green" wood? Also, it would be good to know in which country the fire safety regulations require window head insulation to be mineral wool. Is it Germany? Australia?

In section 2.6, why is moisture from the ground a problem only for structures with crawl spaces? Can you please elaborate on this or add a reference? The last word of the paragraph could be "options" rather than "settings".

Section 3 could be renamed "considering construction imperfections in the evaluation of moisture risk", as the chapter is not on moisture sources, but on how they are considered in simulations.

In section 3.1, is the drainage at window connections the only provision for a successful EWIS? In the UK, the failure of a EWI project highlighted other areas such as the eaves detail (see https://passivehouseplus.ie/news/health/disastrous-preston-retrofit-scheme-remains-unresolved).

In section 3.2 (towards the end), please change "juristic" to "legal". It is unclear where the legal implications are: are you referring to the choice of air permeance in the design? Or in the model, for diagnostics of failure? Can you explain this in a bit more detail?

In section 4, do you have any references on failures with lightweight blocks?

In 4.1, I haven't heard of "mineral foam insulation"; can you rephrase to " mineral insulation boards" or "mineral-based insulation panels", and provide an example (e.g. Calcium-silicate)? Also, what do you mean with "respectively in the calculation tool"? Can you please rephrase this sentence?

In 4.3, can you provide some examples on the restrictions that have to be observed?

In 4.4, it is great to see that BS 5250 is in line with other national standards. The recent update of BS 5250 includes the requirement of hygrothermal simulations according to EN 15026 for traditional solid masonry walls located in areas of high exposure to wind-driven rain.



Note:
This review refers to round of peer review and may pertain to an earlier version of the document.