Master's Thesis

Thermal and moisture behaviour of earthen structures

Final Thesis 2.64 MB Appendix 1.77 MB

Author of thesis: Ing. Šimon Madzik

Acad. year: 2025/2026

Supervisor: Ing. Jan Müller, Ph.D.

Reviewer: doc. Ing. David Bečkovský, Ph.D.

Abstract:

This thesis explores the thermal and moisture performance of earthen wall constructions in the context of sustainable and low-energy building design. With growing interest in ecological materials and passive construction techniques, earthen materials—such as adobe, rammed earth, and straw-clay composites—offer significant environmental and hygrothermal advantages. However, their behavior under Central European climatic conditions requires deeper scientific analysis to inform design decisions and construction practices.
Using WUFI software, six wall assemblies were modeled and evaluated based on thermal performance, relative humidity distribution, moisture content evolution, and risk of mold development. The case studies include both traditional and modernized variants of earthen walls, as well as a conventional aerated concrete wall for comparison. The simulations assessed performance across annual climatic cycles and under realistic boundary conditions specific to the Czech Republic.
The results highlight the strong moisture-buffering capabilities of unbaked clay and straw-based composites, as well as their ability to regulate indoor humidity and temperature variations. While thermal insulation is essential for meeting modern U-value requirements, certain earthen configurations—especially when combined with internal and external clay plasters—demonstrate comparable performance to industrial alternatives. The study also discusses the role of diffusion-open layers, mold prevention thresholds, and the significance of internal surface behavior.
Beyond simulation, the thesis evaluates the construction, fire safety, acoustic performance, and environmental benefits of earthen materials. The findings support the viability of earthen structures for contemporary sustainable architecture and identify opportunities for further research in structural modeling, microbiological safety, and material prefabrication.

Keywords:

Adobe, Rammed Earth, Cob, Sustainability, Humidity, Thermal Properties, Moisture

Date of defence

03.02.2026

Result of the defence

Defended (thesis was successfully defended)

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Grading

C

Process of defence

The student presented his work Thermal and Moisture Behaviour of Earthen Structures, using a PowerPoint presentation. During the defence of the thesis, he stated: - Motivation, - Thesis Objectives, - Applications of earthen structures, - Wall Assemblies Analyzed, - Simulation Tools, - Interior Temperature Results, - Relative Humidity Results, - Mold Risk (Isopleths), - Water Content, - WUFI Showcase, - Conclusion. The student further clarified and answered the questions and comments of the supervisor and the opponent of the thesis: Opponent questions: Choice and uncertainty of material parameters: How sensitive are your results to the chosen material parameters (thermal conductivity, vapour diffusion resistance, sorption curves) of the earthen materials? Did you test any “wetter” or “drier” variants of adobe or rammed earth, and would such parameter changes influence your main conclusions? Validation of simulations: You rely entirely on numerical simulations. Did you consider at least a simple validation step using temperature and humidity measurements on a real earthen wall (for example surface temperature and RH in winter and summer)? How would you estimate the accuracy and reliability of your simulation results without any experimental verification? Practical design recommendations: If a designer asked you to propose a specific external wall build-up made of unfired earth for a family house in Czech climatic conditions, what exact composition (materials and thicknesses, type of insulation, type of plasters) would you recommend based on your thesis, and why? Please justify using your simulation results. Construction detailing and robustness: The assignment mentions design of constructions. Can you discuss how typical details (base of the wall, window reveals, roof-wall junction) should be designed for the earthen walls you analysed, especially in terms of moisture safety and protection against driving rain and splash water? Why are such details critical when implementing earthen constructions in practice? Finally, further questions were submitted by the members of the Examination Committee: - Proč jste zvolil tento typ hlíny? - Kdy jste zahajoval měření v rámci roku? - Zkoušel jste navrhnout experimentální testy? - Co jsou klíčová témata při návrhu objektu z hlíny? Student se snažil vcelku velmi dobře reagovat na připomínky oponenta a zdůvodňovat svoje navrhovaná řešení, rovněž na většinu otázek členů komise k předložené práci reagoval velmi dobře.

Language of thesis

English

Faculty

Fakulta stavební

Department

Institute of Building Structures

Study programme

Civil Engineering – Building Construction (NPC-SIS)

Composition of Committee

doc. Ing. David Bečkovský, Ph.D. (místopředseda)
doc. Ing. František Vajkay, Ph.D. (člen)
Ing. Jan Müller, Ph.D. (člen)
Ing. Lubor Kalousek, Ph.D. (člen)
Ing. Martin Mohapl, Ph.D. (člen)
Ing. Petr Šimůnek, Ph.D. (člen)
doc. Ing. Roman Fojtík, Ph.D. (předseda)

Supervisor’s report
Ing. Jan Müller, Ph.D.

Grade proposed by supervisor: A

File inserted by supervisor Size
Posudek vedoucího práce [.pdf] 160,76 kB

Reviewer’s report
doc. Ing. David Bečkovský, Ph.D.

Grade proposed by reviewer: D

File inserted by the reviewer Size
Posudek_oponenta-Madzik.pdf 127,80 kB

Responsibility: Mgr. et Mgr. Hana Odstrčilová