Completed in 1991 at a cost of £32m, St Mary's was designed as a trailblazing low-energy hospital after an architectural competition won by Ahrends Burton & Koralek. Virtually all the external cladding and roofing was deemed to be defective and is to be replaced.
The remedial work forms part of a £25.7m package of building works being carried out by Isle of Wight NHS Trust. The project will be entirely funded by NHS Estates, which granted final approval for the works last December. The project also involves the construction of a £5m mental health unit, a £3.5m day procedure unit and an elderly rehabilitation unit.
Roger Manison, the trust's project director, said: "The trickiest part will be to carry out a complex refurbishment while enabling the building to continue functioning as a working hospital.
"As the island has inherited the problem, it should not be penalised. We are committed not to reduce hospital activity or beds throughout the contract." The three new buildings will play their part in a complex decanting sequence of hospital wards and operating theatres. The remedial works to the hospital will be carried out in five phases between autumn 1999 and the end of 2002.
The trickiest part will be to carry out a complex refurbishment while enabling the building to function as a working hospital
Roger Manison, Director, Isle of wight NHS trust
The building's distinctive stainless steel cladding was expected to have a life-expectancy of 60 years. But corrosion where the thin sheets overlap and around fixings has eaten away as much as two-thirds of the sheets' 0.6 mm thickness in places.
The sheets will be replaced by flat zinc-alloy sheeting that Manison claims has a life-expectancy "far in excess" of 60 years and will weather to a blue patina.
The architect for the remedial works and the day procedure unit is Frederick Gibberd Partnership, which investigated the defects. Nightingale Associates has been appointed architect for the mental health unit.