on anti-carbonation treatment applied to the surface of the concrete. However, if chemical attack and corrosion on reinforcements is more general it causes substantial spalling of the concrete, as can be seen in the illustration. There are two solutions to the problem when it becomes as significant as this. Either the concrete section needs to be replaced or concrete needs to be cut back around the reinforcement, the reinforcement treated and the surface made good with a mortar mix that will resist further water penetration and, thus, chemical reaction and further corrosion. The difficulty from a conservation point of view with reinforced concrete structures is that a repair will not generally be guaranteed for longer than 20 years and, thus, by implication unless the whole building is treated to give further protection the structure has a vety limited life. The Conservation Officer has a very real problem in considering how to deal with a deteriorating reinforced concrete building because the building will have limited value because of its future reduced life. It is almost certain that it is not cost-effective to carry out substantial repairs to a seriously damaged building. If the building is of some imporGovernmentHouse,Tartola,BritishVirgin Islands. tance, it is possible to put forward an approach which, although not necessarily cost-effective, does mean that the building can be retained. Towards the end of 1998 I was asked to carry out a survey of the OId Government House in Tortola, British Virgin Islands. It had been decided that the house should be demolished due to the condition of the reinforced concrete elements which were repairs and addons to the structure which was originally 19th century. My inspection of the building indicated to me that reinforcement corrosion was a problem which was not insurmountable but that the main reason for the proposition to demolish was that it was considered that the building had been weakened by the cracking and corrosion and would not resist earthquakes. It was felt that it was unsafe for the building to be used by the Governor because of its inherent defects. My report suggested that the danger to life if there was an earthquake was much reduced if the building was not permanently occupied but was used, perhaps, as a visitor centre. The building occupied a very prominent position overlooking one of the most prominent bays on the Island and was certainly significant aesthetically and historically. I was able to put forward suggestions for repair of the structure which, fortunately, had not deteriorated to the point where it would be very expensive to repair, and I have just been advised that the building has been saved. I believe the significance of the saving of this building is that it indicates that, if a building is of sufficient historic interest, then there are techniques for repair to give the building a reasonable life. If a system of ongoing maintenance is developed and adhered to, there is no need to consider demolition as an option. Brian Morton CEng MICE DipConseruation (AA) !HBC is Consultant to The Morton Partnership Ltd. This article was prepared in association with Timothy Eley, Structural Engineer within The Morton Partnership Lid. scott beaven ltd FARROW&BALL Manufacturers o/Traditional Papersand Paint The National Trust Range of Paints Exclusive manufacturers of ~ and Britain's only paint manufacturer to offer a complete range of traditional finishes DEAD FLAT OIL National Trust & Archive colours in an oil rich resin DISTEMPER Both a soft distemper and an oil bound distemper in white and 17 colours LEAD PAINT A traditional flake white, linseed oil & pure turpentine only recipe LIME WASH Traditionally slaked lime putty ready for dilmion SCUMBLE & VARNISH Finest quality oil scumble, dead flat and eggshell varnish Also A full range of both water and oil stainers and a comprehensive range of early formulation emulsion, oil gloss and eggshells in all National Trust and Archive colours All your conservation and restorationpaint requirements met directftom the factory Tel: 01202 876141 Fax: 01202 873793 website: farrow-ball.corn For colour cards & product information or visit our showroom at 249 Fulham Rd London SW3 Context65March2000 Architectural ironmongers The key to excellence Few companies have the expertise to refurbish or replace fine fittings from old doors. Scott Beaven have. We can painstakingly renovate or make by hand the locks, keys, knobs and hinges which add that special value and character. 5 Octavian Way Team Valley Gateshead Tyne & Wear NEll 0HZ Telephone: (0191) 491 5000 Fax: (0191) 491 5999 Email: radim@scottbeaven.co.uk 29
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