Refurbishment of St Anne's Court

published in The Independent

Until recently, anyone who took on the preservation of a old reinforced concrete building faced growing and often unpredictable maintenance bills. Now, new technologies are easing the burden. Mike Harrison looks at the refurbishment of a landmark building, St Anne's Court in Chertsey.

In the UK concrete repair contracts - mainly for Local Authority owners of high-rise housing - are now worth £139 Million per year, according to the Concrete Repair Association. This lucrative market has fuelled intensive research and produced new concrete treatments that take some of the guesswork out of ownership.

St Anne's Court at Chertsey in Surrey is a reinforced concrete private house that was finished in 1936 by the Australian born architect, Raymond McGrath, for a stockbroker friend, A.L. Schlesinger. The house stands in 25 acres of park land on the south slope of St Anne's Hill and has a Grade 2-star listing. Conservation work on the structure and interior was completed was completed in 1999 at a total cost around £1 Million.

Reinforced concrete attracted 1930s architects because it combined the compressive strength of concrete with the tensile strength of steel. It allowed radical departure from the pile 'em up forms of bricks or masonry.

McGrath took the opportunity to open up the building to light and to the landscape in the way that has become a cliché of the 'thirties. The house has a partly cylindrical plan, with a segment removed; so it resembles a large cheese. Enormous, thin-framed, flush-mounted steel windows and a third-floor roof terrace give spectacular views over the garden and the distant countryside. The surface of the concrete retains the marks of the pine boards used in the concrete moulds. When McGrath handed it over, pinkish grey masonry paint gave the final touch of in-yer-face modernism.

What McGrath didn't know was that, without further treatment, reinforced concrete is programmed to self-destruct. Jimi Fadayomi of the concrete protection company, Sika, says the problem is now well understood. When concrete is made, water in the mix reacts with limey chemicals in cement to produce a very alkaline artificial rock in any shape you want. Steel reinforcing in the concrete adds tensile strength and allows designers to use very slender shapes...

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