CONSERV-TIMBER - Novel timber conservation method in old buildings

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Processes of timber conservation and consolidation

Publication . Neves, André; Henriques, Dulce Franco

In the present paper a solution is developed to deal with timber in old buildings, moderately degraded by rot fungi and although not fully sound, have enough load-bearing capacity and should be maintained. The solution involves traditional methodologies used in the area of conservation and restoration of wooden artworks and is especially relevant to timbers in heritage buildings. It consists in the sequential application of a biocide product and a consolidant by impregnation. The efficiency of the proposed solution is tested with destructive and non-destructive laboratory and in situ tests.

2017Conference object

Open access

Avaliação local da capacidade mecânica de elementos de madeira em edifícios antigos

Publication . Neves, André; Henriques, Dulce Franco

A manutenção e a reabilitação da madeira como material de construção dos edifícios antigos conduz necessariamente à sustentabilidade do património edificado. Além disso, reabilitar permite ainda conservar o valor histórico e artístico dos edifícios, um bem não recuperável. É neste sentido que importa avaliar o estado de integridade e capacidade mecânica da madeira existente nos edifícios e proceder à sua conservação / consolidação / reforço, em função do uso futuro do edifício, dando especial importância às palavras – Reduzir, Reutilizar e Reciclar. É necessário, portanto, encontrar formas de reconhecimento de características mecânicas da madeira em uso. O texto apresenta um estudo de correlação entre a resistência mecânica da madeira antiga de Casquinha, Pinus sylvestris L., obtida em laboratório por ensaios destrutivos e não destrutivos, com a mesma obtida in situ por ensaios não destrutivos. Através dos equipamentos Resistograph® e Pilodyn®, pretende-se estimar a capacidade mecânica local da madeira em uso, baseada nas correlações encontradas laboratorialmente para propriedades de referência da madeira, apresentando-se para o efeito um caso de estudo. Apesar da grande variabilidade de resultados obtidos, foi possível encontrar uma linha coerente de valores de propriedades para os elementos de madeira analisados.

2014-03Conference object

Open access

Mechanical evaluation of timber conservation processes by bending tests

Publication . Henriques, Dulce Franco; Nunes, Lina; Brito, Jorge de

This paper presents the laboratory work performed with the purpose of understanding the mechanical performance of 340x20x20 mm maritime pine wood samples degraded by rot fungi when treated with a biocide product followed by consolidation through impregnation with a polymeric product. Four commercially available products were used: a water-based biocide, BC, a solvent-based biocide, X, an acrylic consolidant, PB (PB 72), and an epoxy-based consolidant, E. Seven sets of specimens each one having a varied range of fungal degradation were prepared. Then the product combinations were applied by brush to six sets of specimens (E, X-E, BC-E, PB, X-PB, BC-PB) of which one was left untreated for control, 0-0. Finally all sets were subjected to static bending strength test until rupture. Results showed that the acrylic and epoxy-based products lead to increased mechanical capacity of the consolidated wood up to 100% in some cases in specimens with 70% of MOE loss. The results presented the same order of magnitude for both wood consolidants. The previous application of biocide did not have a significant impact in the behavioral pattern of the consolidant: a marked improvement of the bending strength of the degraded specimens after treatment and consolidation. These results demonstrated the feasibility of combining biocide/consolidation products, and provide indications of interest to the application of this technique to extend the lifespan of wood elements moderately degraded by fungi in old buildings.

2013-09Journal article

Restricted access

Diagnóstico de estruturas de madeira em serviço num palacete do século XIX

Publication . Cândido, Ana; Henriques, Dulce Franco

No presente artigo são apresentadas e aplicadas metodologias de avaliação não destrutivas de elementos estruturais de madeira em serviço em edifícios antigos. Em Portugal existem muitos edifícios com elevado valor patrimonial, cuja estrutura é constituída em grande parte por elementos de madeira. Desta forma, para garantir a sua manutenção e conservação é fundamental aplicar técnicas comprovadas de inspecção e diagnóstico, a fim de ser possível o reconhecimento do seu estado e características reais. O caso de estudo que serve de base ao presente artigo é o Palacete Ribeiro da Cunha, construído em 1877, no centro de Lisboa. Ao longo do trabalho procedeu-se à inspecção e diagnóstico de três zonas do edifício: pavimento, cobertura dos arrumos e cobertura do lanternim. Cada local foi sujeito a um rigoroso plano de inspecção, recorrendo-se a métodos visuais e a ensaios não destrutivos com Resistógrafo, nos casos em que o elemento apresentava degradação biológica. Os elementos de madeira foram classificados visualmente pela aplicação das normas NP 4305:1995 - Madeira serrada de Pinheiro bravo para estruturas - Classificação visual [1] e UNI 11119:2004 - Load-bearing structures - On site inspections for the diagnosis of timber members [2]. O Eurocódigo 5 (EN 1995:2004 - Design of timber structures [3]) também é abordado na perspectiva de verificação de segurança tendo em conta o nível de degradação registado. A utilização de ensaios não destrutivos verificou-se vantajosa, não só por facilitar a compreensão e obtenção de propriedades mecânicas e resistentes da madeira, mas também pelo seu carácter pouco intrusivo dado que se trata de um edifício com enorme interesse e valor arquitectónico. Este estudo constitui uma parte de um relatório de inspecção e diagnóstico, que serve de base a tomadas de decisão sobre as acções a empreender, como sejam a implementação de medidas preventivas ou de tratamento ou então a aplicação de técnicas de reforço e reabilitação. This paper presents and applies a non-destructive evaluation method of wood structural elements in service in old buildings. Many buildings, with significant historical value, are located in Portuguese old towns. In most cases they have timber structures which need specific care to keep, at least, reasonable levels of conservation and security. Thus, the research and development of more efficient inspection and diagnosis methods are essential to verify the needs of rehabilitation. The case study is a palace located in a major historical area of Lisbon, named Palacete Ribeiro da Cunha. Its construction dates from 1877, thus being an important part of local heritage. Three different áreas of the timber structure were subject to a thorough inspection plan using visual inspection and nondestructive testing with Resistograph, where the elements were biological degraded. The wooden elements were visually classified by applying the NP 4305 standards: 1995 - Maritime pine for structures – visual classification [1] and UNI 11119: 2004 - Load-bearing structures – On site inspections for the diagnosis of timber members [2]. Eurocode 5 (EN 1995: 2004 - Design of timber structures [3]) is also addressed, in order to verify if the safety conditions are satisfied, despite the observed damage level. The visual inspection revealed itself very useful, supporting testing results. This study is part of an inspection and diagnostic report, which provides the basis for decision-making on actions to be taken, such as the implementation of preventive measures or treatment or the application of strengthening and rehabilitation techniques.

2015-09Journal article

Restricted access

Inspection and diagnosis of timber structures by non-destructive methods

Publication . Cândido, Ana; Henriques, Dulce Franco

Many buildings with significant historical value are located in Portuguese old towns. In most cases these types of buildings have timber structures which need specific care to keep, at least, reasonable levels of conservation and safety. Thus, research and development of more efficient inspection and diagnosis methods are essential to verify the needs of rehabilitation. The building studied is a palace named Ribeiro da Cunha located in a major historical área of Lisbon, Portugal. Its construction dates from 1877, thus being an important part of local heritage. The main objective of this study is the application of non-destructive tests in timber structure elements. To achieve this, three different areas of the timber structure were subjected to a thorough inspection plan, which included visual inspection and non-destructive testing. The biological wood degradation was also under analysis, through the identification of beetles, subterranean termites and fungi. The visual inspection proved very useful, supporting testing results for the assessment of timber structures. Nowadays, visual grading of timber structures is subject to regulation in many countries. Thus, the employment of some of these standards, and further explanation of the difficulties and limitations related with their application on-site, is one of the objectives of this study. In addition, Eurocode 5 (EN 1995:2004) is also addressed, in order to verify whether the safety conditions are satisfied, despite the observed damage level. The choice of non-destructive tests have proven useful, not only because it allows for a better mechanical characterization, but also because of its careful approach resulting in no damage, much needed in buildings with such architectural value. Therefore, this study can be useful in an initial inspection and diagnosis phase of the building`s timber structure elements rehabilitation needs.

2017Conference object

Open access