The Burj Dubai just got bigger, solidifying its position as the world’s tallest building, without its developer having to lift a finger.

But how can a building gain an extra few metres without it actually getting any taller?

Well, the Council on Tall Buildings and Urban Habitat (CTBUH) - the body that has the final say in determining the world’s tallest building - on Tuesday changed how it measures buildings.

The Chicago-based CTBUH now measures a building’s height from the “lowest, significant, open-air, pedestrian entrance”.

Previously the council measured height from the sidewalk outside the main entrance.

The CTBUH said the change “allows for the recognition of the increasing numbers of multi-use tall buildings with often several different entrances at different levels”.

The change will impact the Burj Dubai in particular, the council said, with the building now measured from the lowest of its three main entrances.

The council did not say how much bigger the measurement change will make the Burj Dubai.

The tower’s developer Emaar Properties was not immediately available for comment.

The 160-storey Burj Dubai currently towers more than 800 metres above the Dubai.

Emaar has yet to reveal the final height of the tower, but it is believed to be around 808 metres high, or half a mile.

The Burj Dubai will be the tallest building in the world in all the criteria listed by the CTBUH, but will not be officially recognised until it opens.

GRAND OPENING

The Burj Dubai is set to open on Jan. 4 to mark the day when Dubai Ruler Sheikh Mohammed bin Rashid al-Maktoum took office four years ago.

The opening was pushed back by a month from Dec. 2, the latest setback for the mega-project, which was originally scheduled to be completed by the end of 2008.

Emaar had wanted the tower to be the tallest building in the world in all four criteria listed by the CTBUH, but will now have to settle with just three.

The council on Tuesday also discarded its previous “height to roof” category because it “doesn’t make sense anymore”.

“In the era of the flat-topped modernist tower, a clearly defined roof could usually be identified, but in today’s tall building world ... it is becoming difficult to determine a ‘roof’ at all, even less so to measure to it,” CTBUH Executive Director Antony Wood said in a statement.

The council will now rank buildings according to height to architectural top, height to highest occupied floor and height to tip.

The world’s tallest building height to architectural top is currently Taipei 101 in Taipei at 508 metres.

The world’s tallest building height to highest occupied floor is currently the Shanghai World Financial Centre in Shanghai at 474 metres.

The world’s tallest building height to tip is currently Willis Tower (formally Sears Tower) in Chicago at 527 metres. - Maktoob