The expertly renovated One Building on Dublin’s Lower Grand Canal Street suggests that jaded office blocks with some architectural quality – even from the bleak 1970s – can be given a new lease of life rather than consigned to the scrapheap.

Designed by Stephenson Gibney and Associates – headed by Sam Stephenson and Arthur Gibney – the six-storey office block looked like an alien intrusion into the urban landscape when it was completed in 1972 and let to the Local Appointments Commission.

Surrounded almost entirely by two-storey terraced houses on Grattan Street, Grattan Place and Albert Court, the block was built by McInerney Properties and seemed to have been “plonked on the site from the sky”, as estate agent Mark FitzGerald puts it.

“Now it rises out of the ground, as if it’s meant to be there,” he says.

Indeed, the fortress-like exterior that the block had is now replaced by a much more welcoming set of steps, done in smooth concrete made from an aggregate rich in sea-shells.

The addition of a glazed penthouse, fringed with sun shades, has also lightened up the building and given it a better profile than it had previously. Developer Chris Jones says not one of the nearby householders objected to the scheme after being briefed on it.

Demolition was never an option, not least because it would have taken much longer to get planning permission for a new office block on the site – and that would have run the risk of missing out on the current demand for good working space in Dublin.

Architect Neil Burke-Kennedy stripped the quasi-Brutalist building back to its concrete frame, introducing an open-plan at every level with a new “garage style” of architecture – exposing ducts and pipes to compensate for the rather low 1970s floor-to-ceiling heights.

Smooth Italian concrete wall panels, a custom-made terrazzo floor at the entrance level and hotel-quality toilets and lifts have been installed to enhance the exceptional finish. And views from the penthouse level in every direction are as breathtaking as you can get in Dublin.

With nearly 4,200sq m of lettable space on seven levels and a substantial concrete service core, the building manages to achieve an overall B2 energy rating despite being air-conditioned rather than naturally ventilated. This is much higher than it was in the past.

Because of its vintage, the One Building has ample parking – 44 spaces in the basement and another seven at podium level, where they clash with a basketball playing area.

Jones however hopes this space will be used for staff play rather than executive car parking.

From the rear, you can see the former Bank of Ireland headquarters in Lower Baggot Street, also dating from the early 1970s.

Its Delta manganese bronze facades have all been stripped off, to be put back again with better-performing windows as part of its renovation.

Not all office blocks of this vintage should be reconditioned, as so many lack architectural merit, and several have already been demolished – notably Canada House, on the southeast corner of St Stephen’s Green, which is now being replaced by deBlacam and Meagher.

There is no case for retaining much of Lower Mount Street; the sooner most of the buildings thrown up there in the 1970s and 1980s are demolished, the better. The only real exception would be the excellent Grattan House, which was also designed by Stephenson Gibney.

At the time, it was believed that new office buildings would have a lifespan of 25 years or so, after which they would be demolished and replaced.

What the One Building shows is that this lifespan can be extended almost indefinitely by renovating buildings of merit.

Ironically, its completion coincides with the recent decision by An Bord Pleanála to permit the ESB to demolish its controversial headquarters in Fitzwilliam Street – another Stephenson Gibney project – because it did not believe that the unlisted building warranted preservation.

What all of this indicates is an urgent need for Dublin City Council to publish its inventory of 20th-century buildings in Dublin, identifying those that should be retained into the future. This inventory has already been done by consultants but has yet to see the light of day.