Characterisation of Decorative Portuguese Gypsum Plasters from the Nineteenth and Twentieth Centuries: The Case of the Bolsa Palace in Oporto
The use of gypsum plaster for the interior coating of walls and ceilings in the Portuguese architecture was particularly expressive in the period between the eighteenth and the twentieth century. However, information about this important heritage is almost nonexistent, which is leading to a rapid loss of important patrimony. In this paper the results of the characterisation of five gypsum plaster samples from the second half of the nineteenth century belonging to the Arabian Room of the Bolsa Palace, located in Oporto, North of Portugal, are presented and discussed. XRD and TGA-DTA techniques were used to establish the mineralogical composition, and the relative proportions of the binders. Optical microscopy and FESEM-EDS observations were performed both in fractured and polished surfaces in order to determine the stratigraphy and the composition of individual layers. The results of this characterisation work showed that the plasters used were mainly composed of gypsum and hydrated lime in different proportions – a feature that was correlated with the application techniques of the decorative elements analysed – and allowed the determining of the restoration interventions they had already been submitted to. Some physical properties like the dynamic modulus of elasticity and capillary absorption were also determined, and a correlation between the results obtained was established with previous studies performed by the authors.
KeywordsDynamic Modulus Hydrated Lime Capillary Absorption Energy Dispersive Spectrometer Analysis Gypsum Plaster
Teresa Freire’s PhD research is being supported by the scholarship SFRH/BD/40128/2007 from Fundação para a Ciência e Tecnologia (FCT). The authors would like to thank technicians Susana Couto and Paula Menezes from the Materials Department and Ana Maria Francisco from the Buildings Department of LNEC, for their support in the execution of the experimental work.
- 1.Gourdin, W.H., Kingery, W.D.: The beginnings of pyrotechnology: Neolithic and Egyptian lime plaster. J. Field Archaeol. 2(1–2), 133–150 (1975)Google Scholar
- 3.http://www.igespar.pt/pt/patrimonio/legislacaosobrepatrimonio/. Accessed 9 June 2011
- 4.Starck, J., Wicht, B.: Zur historie des gipses. ZKG Int. 52(10), 527–533 (1999)Google Scholar
- 5.Middendorf, B., Knöfel, D.: Characterization of historic mortars from buildings in Germany and the Netherlands. In: Baer, N.S., Fitz, S., Livingston, R.A. (eds.) Conservation of Historic Brick Structures: Case Studies and Reports of Research. Donhead Publishing, Dorset (1998)Google Scholar
- 6.Gárate Rojas, I.: Artes de los yesos. yeserias y estucos, 381 p. Instituto Español de Arquitectura. Editorial Munilla-Lería, Madrid (1999). ISBN 84-89150-25-7Google Scholar
- 7.Vieira, E.: Traditional techniques of plasterwork and simulated plasterwork decorations in the north of Portugal. A contribution to their study and conservation. Master thesis, University of Évora, Évora, Portugal (in Portuguese) (2002)Google Scholar
- 8.Silva, H.: Giovani Grossi and the evolution of decorative plasterwork in Portugal in the 18th century. Master thesis, Lusíada University, Lisbon, Portugal (in Portuguese) (2005)Google Scholar
- 9.Freire, T., Santos Silva, A., Veiga, R., de Brito, J.: Characterisation of Old Portuguese plasters from walls and ceilings. In: Proceedings of the 3rd Portuguese Congress of Construction Mortars, Paper 11, 14 p. (in Portuguese) (2010)Google Scholar
- 13.Silveira, P., Veiga, R., de Brito, J.: Cracking of ancient gypsum plasters. In: Proceedings of the XXX IAHS World Congress on Housing, Coimbra, pp. 1779–1785, September 2002Google Scholar
- 14.The Palácio da Bolsa. ArtEditores, Porto (2009)Google Scholar
- 16.Veiga, M.R., Magalhães, A., Bosilijkov, V: Capillarity tests on historic mortar samples extracted from site. Methodology and compared results. In: Proceedings of the 13th International Brick and Block Masonry Conference, Lisbon (2004)Google Scholar
- 18.Freire, T., Santos Silva, A., Veiga, M.R., de Brito, J.: Characterization of Portuguese historical gypsum mortars. In: Proceedings of the 1st Historical Mortars Conference, Lisbon (2008). T_I_54_HMC008 (available in CD)Google Scholar