English gauged brickwork : historical development and future practices
Traditional brickwork, of quality materials, well detailed, and built by good craftsmen, requires little maintenance throughout its life. Inevitably, older buildings face varying degrees of maintenance and change, including repair of brick fabric. Many of these buildings might incorporate cut and rubbed brickwork, and gauged enrichments, of architectural, historic, and social significance. It is therefore vital that cut and rubbed and gauged work is carried out in a fully informed manner so as not to adversely affect the character, integrity, and structural stability of the building. This thesis investigates the development and the technical aspects of cut and rubbed, and gauged work, and re-examines historic materials, craft tools, and techniques that have fallen from use, and which played a significant role in the execution of post-fired worked brickwork. The design and construction of a small-scaled gauged niche masterpiece - historically considered to be the supreme test of a craftsman bricklayer - has been undertaken using traditional materials, tools and techniques. Historic and contemporary rubbing bricks have been tested and anlaysed. The cutting and rubbing performance of contemporary rubbing bricks was found to be inferior to their historic counterparts, being generally harder and more difficult to work. Microscopic examination has shown that historic rubbing bricks were fired at lower temperatures (7S0-900°C) than the modern rubbing bricks (-900°C). This has led to the bricks having very different physical properties, with the historic rubbing bricks, having significantly greater porosity and water absorption than the modern. Furthermore the historic rubbing bricks were shown to have a much finer texture, and contain significant quantities of reactive temper (chert and volcanic rock). This temper is believed to react with water to produce cements within the matrix, which may contribute to their overall durability. The information and experience gained from this exercise, combined with the interdisciplinary findings of this thesis, provides a contextual, historical, theoretical and practical understanding of cut and rubbed, and gauged brickwork for craft professionals to assess how it can be applied today, using the best of traditional and modern methods to achieve high-quality new work or succesfull conservation and repair.