Significance of a combined approach for replacement stones in the heritage buildings' conservation frame

TL;DR

This paper proposes a combined approach using aesthetic and physical property criteria to select suitable replacement stones for heritage building conservation, improving long-term compatibility and appearance.

Contribution

It introduces a methodology that integrates aesthetic and physical property assessments for selecting compatible substitution stones in heritage conservation.

Findings

Aesthetic criteria alone are insufficient for stone selection.

Physical property analysis can identify compatible substitution stones.

Combined criteria improve long-term aesthetic and structural compatibility.

Abstract

Stone substitution is a conventional operation during heritage buildings' restoration, but becomes problematic for architects and restorers when the quarry is mined out. The compatibility of the substitution stones with the original ones has been for long mainly based on the aesthetical aspect, this resulting too often in a patchwork of original and substitution stones with different patina after several years because of differences of properties. In this study, the objective is to show how substitution stones can be selected by combining aesthetic criteria and stones properties that are relevant for analyzing their compatibility. A couple of French limestones with their potential substitution stones were selected for the study. Our results showed that potential substitution stones selected on their aesthetic criteria require to be rejected because of their differences of physical properties. On the other hand, our results showed also the possibility to select substitution stones with satisfactory aesthetic aspect and properties that enable to expect a satisfactory compatibility with the original stone.