Study of a multilayer treatment for the consolidation and protection of stone materials from Portuguese monuments

Inês Chaves Lopes de Almeida

Key information

Authors:

Inês Chaves Lopes de Almeida (Inês Chaves Lopes de Almeida)

Supervisors:

Ana Paula Patrício Teixeira Ferreira Pinto França de Santana (Ana Paula Patrício Teixeira Ferreira Pinto França de Santana); Bruno Monteiro Sena da Fonseca (Bruno Monteiro Sena da Fonseca)

Published in

June 17, 2025

Abstract

Porous stone materials, such as limestone and sandstone, are commonly found in Portuguese heritage, holding significant cultural, artistic, and historical value. However, due to their intrinsic characteristics and environmental exposure, these materials are vulnerable to degradation, which threatens their preservation. Conservation efforts often require the use of multifunctional products that offer both consolidation and protection, either separately or combined. This study aimed to evaluate the potential effectiveness and compatibility of a multilayer treatment on two porous stones with distinct mineralogical compositions: Ançã Stone (limestone) and Silves Sandstone. Both are widely used in Portuguese architectural heritage. The treatment involved the sequential application of two commercial products: ESTEL 1000, a consolidant, and MasterProtect H305, a water- and oil-repellent. The performance of ESTEL 1000 alone and in combination with MasterProtect H305 was assessed. Both products proved effective for their intended purposes. ESTEL 1000 increased the drilling resistance, indicating improved mechanical strength, while MasterProtect H305 provided surface protection by inducing hydrophobicity and reducing water absorption in both stones. However, the use of ESTEL 1000 raised compatibility concerns, especially with Ançã Stone, as it significantly altered its water transport properties. In contrast, the additional application of MasterProtect H305 did not exacerbate these issues, since the changes observed in the evaluated parameters were minimal. Overall, the multilayer treatment showed promising results for the conservation of porous stones, though special attention must be paid to potential material-specific incompatibilities, particularly in the case of limestone such as Ançã Stone.