Cork County Hall will be officially re-opened on Monday week. Frank McDonald, Environment Editor, looks at its transformation.

The souvenir brochure for Cork County Hall's official opening in April 1968 is suffused with regional pride over the completion of a landmark office tower that rose to a height of 211ft (63.94 metres). That made it 11ft taller than Dublin's Liberty Hall and thus the State's highest building - a badge it still retains, at least for the present.

This icon of Cork on the western approach to the city had been designed by the then county architect, Patrick McSweeney. He was particularly pleased with one of the building's most distinctive features - the modelling of its façade in concrete tracery, saying its "precise detail design ... plays a major part in the overall effect".

But this outer skin would become its Achilles' heel. As early as 1981, extensive repairs were needed to deal with a serious erosion problem. By 1994, wire canopies had to be erected over the entrance to protect staff and visitors from pieces of masonry falling off the building. It was also very uncomfortable to work in, due to excessive solar gain.

In 1999, Cork County Council held an architectural competition in association with the RIAI to renovate and extend County Hall. It was won by Dublin-based Shay Cleary Architects, whose design solution aimed to upgrade the existing building in a sympathetic way while reorganise the site layout to provide it with a new context.

The winning scheme proposed an L-shaped arrangement of tower block and sixstorey extension to the east, including a tripleheight entrance concourse containing a new council chamber; previously, the building could only be entered laterally from the east or west because it gabled onto Carrigrohane Road - a very peculiar arrangement.

But Shay Cleary's plan to strip County Hall of its concrete tracery, replacing it with a mullioned and louvred glass façade, was opposed by An Taisce, Docomomo (the international organisation dedicated to protecting 20thcentury architecture) and D P Curtin, a nephew of Patrick McSweeney, who was intent on defending his uncle's work.

The issue came to a head in 2001 when the then Cork city architect, Neil Hegarty, recommended that planning permission should be  refused. "Cork is somewhat like Chicago - we are the second city, but can boast the tallest building," he said. "I believe it is our duty . . . to protect the building . . . because it is unique and has a rare quality."

In appeals to An Bord Pleanála, An Taisce described County Hall - one of the State's relatively few 20th century protected structures - as "a striking monumental landmark [and] a design classic of its era" on a par with Centre Point in London's Oxford Street, which is also listed for preservation; it, too, has external concrete tracery.

Shane O'Toole, on behalf of Docomomo, argued that advances in concrete technology in recent years meant that the decaying tracery could be repaired rather than removed. He also dismissed the new design as "a simple glass box with straight edges and a plain outline", saying "it bears no relation whatsoever to the original".

The appeals board took a different view, however. In its decision to grant permission, it said the proposed development "would be in accordance with the interests of conservation and sustainability [and] would be compatible with the requirement to protect and enhance the status and function of the building as Cork County Hall".

The board was right. Architecturally and environmentally, the tower has been enhanced rather than debased by Cleary's scheme - which, as he emphasises, was not just a renovation, but a redevelopment of County Hall. "What we did was to take on McSweeney's legacy and reinterpret it, and I'm very pleased about that," he says.

Architecturally, the tower still has two "skins" - an inner layer of gold anodised aluminium windows, true to the originals, and an outer layer of louvred glass with vertical mullions.

It also remains the dominant element, dwarfing the six-storey block alongside, which is barely perceptible behind the canopy over the entrance concourse.

The slender circular columns in front are very elegant and continued inside. Iranian red marble was used for the floor of the concourse to contrast with an otherwise white interior.

The elliptical council chamber oversails it in a raised pod - a device first used by Cleary in his 1993 renovation of the Department of Agriculture's foyer in Dublin.

The timber-clad chamber has a big letterbox window looking out over the concourse and towards the plaza in front, where Oisín Kelly's sculpture of two men looking upwards in awe at the tower has been reinstated.

Affectionately known in Cork as "Cha and Mia", they were originally intended to stand outside the capital's Liberty Hall.

A reception desk is placed in a more intimate space beneath the undercroft. Debates in the chamber are relayed to closed circuit screens in the concourse, and there is also public access to the see-through canteen to the rear. For the official opening on June 26th, more than 700 guests will dine in the concourse area.

The most extraordinary feature of the original building is that, although the council chamber was located at the very top of the tower, it had no views out. With its highlevel clerestory, ambulatory and cruciform columns, it still has the aura of a post-Vatican II chapel. It is to be used now for conferences along with the extra storey above.

This glazed pavilion is a major addition to the tower. Given that the heavy concrete band had marked the summit since 1968, with some partly visible plant rooms above, the new element sits somewhat uneasily in its context. The major plus is that it will be a restaurant offering diners an unrivalled 360-degree panorama of Cork.

"We want to make this a public use building to the greatest possible extent. The public are entitled to that, having paid for it twice," said Tim Lucey, assistant county manager in charge of the €65 million renovation and redevelopment project. The next phase is to be a library headquarters, to be built to the west of the tower.

Sadly, the setting of County Hall has deteriorated markedly since it was first built. Then, it had an open relationship with the Lee Fields and river to the north. Now it faces the truly awful Kingsley Hotel, which recently acquired two flanking wings to the front; its jumble of roof plant is also visible from practically all of the office floors.

The offices are all naturally ventilated and a pleasure to work in, according to staff - and there are 600 of them. Everyone above a certain rank got his or her own cellular office, but several departments have an attractive open-plan. All of the public counters for planning, motor tax and so on, are conveniently accessible from the main concourse.

Cork county architect Billy Houlihan believes it has all been "money well spent in the context of maintaining the stature and importance of the building. Shay Cleary, for whom this has been his  practice's largest ever project, said people in Cork are "bowled over" by how it has turned out. And he puts that down to having "fantastic clients".