C O N T E X T 1 2 5 : J U LY 2 0 1 2 7 – that have appeared in recent years on the North American market. These are set within the context of a general scarcity of laboratory-based literature by comparison with its availability in Europe. Testing of lime-water consolidation effects on poor lime mortars is the subject of a paper by Miloš Drdácky and Zuzana Slížková, in which the same issue of a lack of scientific data and published literature is highlighted. Laboratory testing suggests acceptable results of lime watering on a certain class of historic lime mortars from the technical and aesthetic perspective, but that the technique is not suitable for all situations. Consolidation appears to be effective only with applications running into three figures. This in turn may wash away sand grains and the binder in the original mortar surface layer, changing the appearance of the historic surface and, in historic plasters, risking mobilisation of water-soluble salts. Other articles look at specific building issues, two of which might resonate with UK readers. Mattias Legnér examines archival sources that have provided valuable information on the past indoor climate of a Swedish church from 1800 to 2000. The wider context here is changes to methods of heating in response to the symptoms of problems (humidity, surface soiling, dehydration of wood and beetle attack), not necessarily the causes. The archives have assisted in determining more clearly the past impact of wrongly chosen heating and ventilation systems; lack of maintenance; impact of building location (such as on wet ground); the building envelope; and the use of materials. Long-span documentation has been essential. It clearly needs to continue to avoid the kind of minimalist approach now favoured in England, where the least possible information that is ‘relevant, necessary and material’ is deemed to be necessary, without considering its longterm heritage management value. Thomas Boothby, Kevin Parfitt and Mark Ketchum have looked at the types of thin-shell concrete structures invented in Europe in the 1920s and 30s, and used by architect Milo S Ketchum and others in Colorado frequently enough for these structures to become a defining regional characteristic. Among those discussed are hyperbolic paraboloid roofs – one of the excellent 2009 shortlisted dissertation subjects submitted for the GASAs in 2009; and also structures of the kind recently the subject of some post-war listings. On the subject of buildings from the 1920s and 30s, the latest edition of C20, the magazine of the Twentieth Century Society (Spring 2012), features a number of 1930s town halls. These include Norwich, Swindon, Swansea and one facing the uncertainty of being vacated in 2013, Brent (originally Wembley Municipal Offices, built in 1939). Pevsner considered it one of the best of its kind. Its fate may rest in its potential conversion to hotel use. The building type appears to lend itself particularly well to this type of adaptive reuse. It has been successfully achieved at, for example, Bethnal Green (offices as bedrooms, council chamber as function spaces). The issue also has much else of interest: the campaign to restore features of the Paxton landscape at Crystal Palace now that the future of the Sport Centre (Sir Leslie Martin, 1954) is secure; the proposed rejuvenation of Sir Geoffrey Jellico’s Water Garden at Hemel Hempstead in his jubilee year (a post-war rarity on the National Register); celebrations of Powell and Moya’s Grade II* listed Chichester Theatre at 50; Arup’s spectacularly sited 1962–3 Durham University Student Union; and, last but not least, the 1957 house by J Roy Parker, featured in House and Garden in 1958 and recently acquired by Context’s book reviews editor Peter de Figueiredo. After recent conundrums in this column (when is a historic building not a historic building? A: when it’s a tree; and do you see a window as the frame or the glass? A: hopefully both), here is another: when is stone not stone – or, more precisely, natural stone? The columns of Natural Stone Specialist (February, March and April 2012) have carried a number of trenchant opinions about ‘reclaiming’ the words ‘natural’ and ‘stone’ that should be reserved for products that really are made from natural stone, not concrete. This elicited a good number of responses from readers and a debate on the LinkedIn professional networking site. A counter-argument was prompted from IHBC affiliate Simon Scott of Haddonstone, in relation to artificial stone as a substitute for natural stone. Further views expressed in the industry were that while some artificial products performed very well, many of them did not, or were at best roughly equivalent to stone at the very bottom of the quality spectrum. One writer stated that ‘the major constituent in cement may well be crushed limestone, but that doesn’t mean that we should call it stone’. Another pointed out that in relation to the need for more honesty about labelling stone products ‘we need to draw a line between legitimate selling of a product that desires to look similar to natural stone, and a product that pretends to be natural stone’. Given that, for example, some ‘Yorkstone’ comes from India, this debate is going to run and run. In the last issue, this column referred to the heritage legacy of Victorian railways. This has been picked up again by The Institution of Civil Engineers Proceedings on Engineering History and Heritage (Vol 165, Issue 2, May 2012) with a review of the work of the Railway Heritage Trust. It discusses some of the difficult decisions that have to be made when considering the conservation and restoration of historic railway structures, particularly bridges and viaducts. The trust’s budget is currently limited to around £2 million a year.
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