Frost damage. Water expands by 10 per cent on freezing. Growth of ice crystals beneath a frozen surface produces internal pressure which spalls faces of stones. Use 'Jos' or 'Softkleen' type systems of low pressure (5-50psi) silica- free powder-blasting with minimal water. Use poultices for softening paints and drawing out iron stains. (See reference 4) Surface consolidation using limewater. Water that has been drained from a lime-slaking tank after lime has been slaked will be rich in calcium- hydroxide solution. Up to 30 coats are brushed on to the stone surface where they soak into the stone and combine with atmospheric CO2 to form calcium carbonate.

Clive Richardson is a technical director of civil and structural engineer R T James and Partners, and Engineer to the Dean & Chapter of Westminster Abbey. Practical Building Conservation: Volume 1: Stone Masonry. John and Nicola Ashurst. 1988. English Heritage. Consents may be required from English Heritage and local authorities prior to cleaning, especially if a facade is listed. Substances to remove can include soot, grime, paint, algae, ivy, pigeon gel, slurry coats and iron stains. spabbing. Following spab philosophy of repair, using tile creasing or dpc material to delineate repair from original. Modern Practical Masonry. E G Warland. Second edition 1953. Reprinted by the Stone Federation, tel 0171 580 5404. (The best book on inter-war and immediately post-war stone facades.)

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There can be few things better than snuggling under your duvet after a long, hard day at work. This already wonderfully cosy time can only be made better by the addition of the perfect bed set. Our bedding collection has everything you need to make sure night time is the right time for the perfect eight-hour slumber. Patterned and striped duvet covers Very lovely print looks fantastic on and really unique! Would definitely recommend,' says one shopper. If minimalism is your thing, then you’ll be interested in our diverse range of unadorned duvet sets. From crisp and classic waffle whites in cool cotton to subtle grey and dusky pinks in beautiful velvet, your calm and collected needs are more than catered for in our classic range. Kids tidying their own room? Whatever next! Natural Stone Database at the Centre for Window and Cladding Technology, tel 01225 826 541. Available late in 1998.

Expansive clay within stone, Smectite, for example, is a sandstone with 30 per cent shrinkable clay content. Keep the stone dry with Alkoxysilanes/Siloxanes (micro-porous water-repellents). Avoid silicones, which stay on the surface and go shiny or yellow with uv degradation.Photograph and test-clean sample areas of each stone type. Record and analyse the results before drafting the cleaning specification. The pending revision of bs 6270 will give guidance.