Evaluation of the Broumov parish house failure, its casuality, and some ideas of remedation
1. Introduction
This dissertation investigates the causes of the structural distress and visible cracking observed in the Broumov Parish House, a historical building located in Broumov, Czech Republic. Though modest in architectural appearance, the house holds invaluable 14th‑century frescoes, which greatly increase its cultural and historical significance. The aim of this research is to identify the mechanisms responsible for the cracking, assess the structural condition of the building, and propose remedial strategies that ensure both its stability and the preservation of its decorative features.
A multidisciplinary methodology combining historical research, on‑site observation, material evaluation, 3D digital modeling, and finite element numerical analysis (FEM) was applied. Various hypotheses were tested to explain the building’s behavior under environmental and mechanical actions. Despite the limitations imposed by the lack of detailed data on the foundations and soil, the study concludes that differential settlement and moisture infiltration are the primary causes of the observed deterioration. Recommendations for long‑term monitoring and for appropriate, minimally invasive remediation measures are provided to aid in the sustainable conservation of this important monument.
2. Historical Background
2.1 Bohemia
A historical overview of Bohemia’s evolution from the Přemyslid dynasty through the Habsburg Empire to modern-day Czech Republic. The region’s architectural heritage is influenced by centuries of political and religious change, including the Hussite Wars and the Thirty Years’ War.
Map of current European borders and the Bohemian crown border in the 1500s / Czech historical lands and current administrative regions
2.2 Broumov
Founded in 1213 by Benedictine monks, Broumov is notable for its monastery and Baroque architecture. The town’s prosperity, based on textile production, declined after WWII and the communist period, leading to poor maintenance of religious structures.
Location of Broumov in the Czech Republic
3. The Parish House
3.1 Historical Background
Located beside the Church of St. Peter and Paul, the house was likely built in stages, the earliest part dating to 1330–1340. It was extended in 1710 and used variously as a caretaker’s residence and later as the deanery. The Gothic frescoes were accidentally discovered in 1967. Restoration occurred between 1976 and 2014, with the latest reconstruction in 2019–2022.
Location of the building in the city of Broumov
3.2 The Frescos
The fresco room consists of a Gothic presbytery and a Baroque vaulted chamber. The paintings depict biblical and moral themes such as The Last Judgment and the Parable of the Wise and Foolish Virgins. They are considered unique 14th-century linear-style works with high artistic and cultural value.
Floor Plan
3.3 The Geometry of the Building
The Parish House is a two-story Baroque masonry structure with irregular geometry, reflecting multiple construction phases. Walls are built from stone and brick masonry, partially replaced with modern Porotherm bricks in later restorations. The roof, with timber Baroque trusses and slate covering, is typical of the region’s ecclesiastical architecture. The chapter details the building’s geometry to support later structural modeling.
The main façade of the building
4. Decay Overview
A detailed visual inspection was conducted in May 2023 using ICOMOS-ISCS guidelines to classify damage. The exterior walls show superficial degradation — plaster blistering, cracking, and detachment — mostly due to weathering and past restoration incompatibilities. The interior presents more concerning issues: deep cracks in the middle load-bearing wall, moisture-induced damage, and basement wall detachment.
The observed patterns suggest differential settlement as the primary cause, potentially aggravated by the building’s mixed masonry materials and nonuniform foundations. Moisture infiltration from the roof and capillary rise in walls have also accelerated plaster decay and salt efflorescence. This diagnostic chapter lays the foundation for the analytical modeling presented later.
a) Fracture crack near a window, b) craquelè effect
a) Delamination of Southwest facade, b) Blistering of Southeast facade
Cracks mapping on part of the middle wall
5. Photogrammetry of the Building
To document and monitor the condition of the Parish House, the author developed a 3D photogrammetric model using a RICOH THETA 360 camera and Matterport software. This “digital twin” captures both the geometry and damage state of the building, allowing precise spatial analysis. The 3D model includes annotated tags that locate visible cracks, plaster detachment zones, and fresco damage.
This documentation not only aids conservation planning but also provides data for structural simulations. It enables remote visualization and long-term monitoring, representing a modern approach to heritage diagnostics in line with HBIM (Historic Building Information Modeling) principles.
6. The Model Analysis
6.1 Geometry and 6.2 Material Properties
The structural behavior of the Parish House was analyzed using ATENA 2D finite element software. The wall geometry was reconstructed from measured sections, and material properties were estimated via the Masonry Quality Index (MQI), considering visual texture, bond patterns, and mortar quality. Calculations yielded an average compressive strength of 3.6 MPa and Young’s modulus around 1600 MPa, consistent with traditional mixed masonry.
6.3 Loads and 6.4 Boundary Conditions
Loads included self-weight, roof and vault thrusts, snow load (2 kN/m²), and live loads (2.5 kN/m²). Springs of variable stiffness (7–25 MPa) simulated the soil’s bearing behavior. These values provided realistic foundation constraints to reproduce ground–structure interaction.
6.5 Preliminary Analysis
The preliminary simulation showed that the structure remains within its load-bearing capacity, suggesting that overloading is not the cause of observed cracks. Instead, the stress concentration corresponds to the wall midsection, pointing to differential settlement or thermal/moisture effects as more plausible mechanisms.
6.6 Analysis of Different Decay Hypotheses
Several hypotheses were tested through parametric variations:
- Ground Settlement: Produced diagonal crack patterns similar to real observations but underestimated their extent.
- Freeze–Thaw Cycles: Modeled the expansion of water in foundation pores; results matched partial deterioration but lacked complete correlation.
- Material Heterogeneity: Mixed masonry zones and newer brick insertions may have created stiffness discontinuities amplifying local stresses.
Approximately 100 model configurations were evaluated, confirming that while no single hypothesis fully explains all cracks, foundation settlement remains the dominant factor.
6.7 Conclusion of the Model Analysis
The numerical study validated that settlement and moisture interactions best explain the damage pattern. However, the absence of in-situ tests limits quantitative precision. The analysis highlights the importance of integrating experimental data and 3D modeling in future studies.
7. Considerations for an Accurate Model
Recommendations for future testing include:
- Non-destructive tests (NDT): Schmidt hammer for surface hardness, ultrasonic tests for material continuity, and endoscopy to assess mortar quality.
- Geotechnical investigations: Boreholes, CPT/SPT testing, and Ground-Penetrating Radar (GPR) to evaluate soil layers and groundwater levels.
- Geometric and material documentation: High-resolution laser scanning and photogrammetry to produce an integrated HBIM model.
8. Conclusion
The research concludes that the Broumov Parish House is structurally stable but threatened by progressive settlement and humidity-related deterioration. The numerical analysis and on-site observations consistently indicate uneven foundation behavior as the most probable cause of the cracking. The creation of the 3D digital model is considered one of the key outcomes, providing a valuable monitoring tool for ongoing conservation efforts.
The study demonstrates how combining engineering analysis with heritage preservation principles can support evidence-based restoration decisions. It also emphasizes the cultural significance of the frescoes and calls for preventive maintenance to ensure their long-term survival.
9. Recommendations
- Implement a crack and soil monitoring system using mechanical gauges, inclinometers, and periodic photogrammetric surveys.
- Address moisture infiltration through roof inspection, gutter maintenance, and subfloor ventilation.
- Investigate fresco room microclimate using thermography and humidity sensors.
- Replace deteriorated external plaster with lime-based compatible materials to ensure breathability and salt migration control.
These measures aim to stabilize the structure while respecting the monument’s authenticity, in line with ICOMOS conservation principles.
10. References
The work cites 33 academic and technical sources, including studies by Borri, Corradi, and De Maria, Czech geological and meteorological data, and European standards (EN Eurocodes). The annexes include detailed damage maps, load calculations, and photographic documentation, consolidating the methodological transparency of the thesis.
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