Paper contribution

Performance Evaluation of a Ventilated Stone Façade after 48 Years of Service Life

Alenka Mauko Pranjić; Peter Zapušek; Janez Sevšek; Ana Mladenovič; Primož Oprčkal; Sandi Čeferin

Proceedings
EUROCK 2026
Pages
1265-1270
Submitted
28 January 2026
Accepted
15 June 2026
Published
12 August 2026

Summary

Abstract

As part of the renovation of a building constructed approximately 40 years ago, designed by a renowned architect, the investor seeks to preserve as many original building components as possible. Particular attention is given to the ventilated stone façade, which is both an architectural and structural element of the building envelope. The façade consists of natural stone panels mechanically fixed to a substructure with dowel-type anchors. The is stone commercially known as “Plavi tok” (Serbia), with a thickness of 30 mm and dimensions of 125 × 60 cm. A detailed field survey showed that around 30% of the panels exhibit measurable bowing, most notably on the west-oriented façade. Dark staining was observed at all anchoring points, linked to silicone sealant. A smaller number of panels display local damage at anchoring zones or defects related to primary geological discontinuities in the stone. Part of the deformation and damage is attributed to improper anchoring, where the weight of upper panels imposed additional loads on the anchors of lower panels, leading to stress concentration and long-term bowing. Laboratory testing focused on rock-mechanical properties and anchoring behaviour. Results confirm that the intrinsic quality of the stone remains suitable for use in a ventilated façade system: low water absorption (0.2%), good flexural strength (10 MPa), and minimal degradation under freeze–thaw cycles. Failure mechanisms observed during dowel-hole load tests were comparable to those in fresh reference samples, and flexural strength showed only minor reduction compared to initial properties. Overall, the study indicates that panel deformation primarily results from environmental exposure, façade orientation, moisture–temperature interaction, and long-term stress redistribution related to panel mass and anchoring details, rather than from general deterioration of stone. These findings provide reliable basis for conservation planning and for decisions regarding partial replacement or reuse of existing stone in façade refurbishment.

Contributors

Authors

  1. Alenka Mauko Pranjić Slovenian National Building and Civil Engineering Institute, Slovenia
  2. Peter Zapušek Slovenian National Building and Civil Engineering Institute, Slovenia
  3. Janez Sevšek Slovenian National Building and Civil Engineering Institute, Slovenia
  4. Ana Mladenovič Slovenian National Building and Civil Engineering Institute, Slovenia
  5. Primož Oprčkal Slovenian National Building and Civil Engineering Institute, Slovenia ORCID 0000-0002-6930-2571
  6. Sandi Čeferin Marmor H Hotavlje, d.o.o.

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References

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