The Building Magnesian Limestones of the British Isles: (BR 134)

This report is intended as a guide to the availability and nature of magnesian limestone for those wishing to use or specify it as a building stone. It is the fourth in a series of reports about the building stones used in the British Isles. Only nine quarries are currently producing magnesian limestones for building: the tenth, Park Nook, is a dormant quarry which the owner hopes will shortly be reworked. Each quarry is described individually and the following information is included where possible: the location, with an Ordnance Survey grid reference; the quarry size, including its depth or face height (where possible, estimations of the remaining reserves of building stone have been made); suitable uses of the stone available; the size of blocks obtainable, i.e. the average depth on bed; a list of reference buildings (one of the best indicators of a good stone is its appearance in a building. With a building of known age this is not only a guide to a stone's durability in the environment of its intended use, but also shows any inherent weathering characteristics. For example, stones may change colour to varying degrees on exposure); petrography is described for each stone, this being obtained by examining petrographic thin sections with a microscope; and the results of durability tests (these tests were crystallization tests and measurement of porosity and saturation coefficient. Chemical compositions were also determined and the results are included in the Appendix). In addition, colour photographs of each stone are reproduced in Plate 4 to give comparisons of their colours and textures. It must be emphasized that this report is intended only as a guide, and the user must therefore be critical and refer to all the information available, choosing stone not by the best durability classification alone. A list of reference buildings is included with each quarry indicating where and when the stone has previously been used. As with the other reports in this series, these historic precedents must not be ignored. Many magnesian limestone quarries are primarily aggregate quarries and do not supply large amounts of stone for building contracts. Some owners permit stone selection by private builders, but the quarries keep no record of the end use of their stone. The lists of reference buildings are therefore not particularly extensive. In addition, many of the well known magnesian limetsone buildings are constructed of stone from quarries that are no longer working. These quarries include Roche Abbey, Anston, Bolsover Moor, Huddlestone, and Smaws Quarry near Tadcaster. Useful guidelnes to follow when selecting new building stone are outlined below: identify the stone to be replaced or, for a new building, what is required to suit the design elements, and the traditional local use of the stone; look at the availability of matching stones, using the "Natural Stone Directory" and the relevant BRE reports - establish available sizes, workshop facilities and delivery times; look at the reference buildings and recent contracts and the durability ratings in this and the other BRE reports; where durability ratings conflict with field observations, cross check again the reference buildings and obtain advice from the Building Research Establishment or from English Heritage's Research and Technical Advisory Service; and ensure that all new stone in the building is given the best chance of long life by correct bedding, good detailing and sound work standards.

Table of Contents:
Geology; decay and durability; testing - petrography, porosity and saturation coefficient, crystallization test, chemical composition; the quarries and their stones - Abbey Quarry, Barnsdale Bar Quarry, Cadeby Quarry, Gebdykes Quarry, High Moor Quarry, Jackdaw Crag Quarry, Long Lane Quarry, Park Nook Quarry, Warmsworth Quarry, White Mansfield; acknowledgements; references; bibliography; appendix - details of test methods; glossary of geological terms; index; colour plates.

About the Author :
BRE, UK