Residents of fashionable Hanover Quay in the south Docklands are wondering what's happening to one of the scheme's penthouses. The all-glass apartment - featured in the sales brochure for the 2003 development - has been replaced by what looks like a big concrete box, writes Emma Cullinan

The picture on the left appears on builder Sisk's website, as well as the website of selling agent HOK. The picture also appears in a Dublin Docklands Development Authority (DDDA) brochure.

So why the concrete panels (see right)? They were always part of the design, says John O'Mahony of O'Mahony Pike Architects. It hides a services core (vent pipes from a restaurant below, elevator and stairs), he says. This was confirmed by a DDDA spokesman.

O'Mahony says that the pictures of the building without the concrete panels must be an early photomontage.

Yet plan drawings from 2003 show the elevator set far back from the front elevation - although the large terrace in front of it was part of an old design, says O'Mahony. But surely the elevator and vents run right down the building, in which case why aren't the apartments below clad in concrete too?

It's also a strange place to put the services core: why would architects of the high calibre of O'Mahony Pike introduce a slab of concrete into a south-facing glass elevation?

A salesperson from HOK said the panels were part of a new conversion: someone had bought two penthouses and knocked them into one. However, when we asked Sisk its spokesman refused to comment.

What is known is that U2's The Edge has bought a penthouse adjoining the concrete panels - neighbours wonder if he's got anything to do with the new structure.