What exactly are you buying? It depends on who does the sums

The way developers determine specifications such as ceiling height and 'saleable area' are a mystery to many flat buyers. Developers often include common areas, wall thickness and external facilities to calculate gross floor sizes - and floor thickness in storey hight.

Despite repeated calls for standard definitions from professional groups, including the Institute of Surveyors and the Consumer Council, the government argues self-regulation has been effective.

At present there is no clear standard definition of what constitutes a saleable area. It is very difficult for buyers to compare prices at new residential projects if developers adopt different methods to calculate areas.

Some developers cite gross floor area, which the government defines as all covered areas including common areas such as corridors, lobbies and the thickness of walls.

Others interpret saleable area as including a share of external facilities such as gardens and car parks.

New Territories Estate Agency Association president Liu Chi-ming said most people usually do not pay much attention to the height of a flat.

'This might not happen if a buyer is planning to purchase a second-hand flat because the buyer will certainly check the flat in person before making any decision,' he said.

Mr Liu said the dispute over 'low' ceilings occurred probably because the buyer bought a flat when it was still under construction.

'They can learn about the flats only through advertisements, price lists, sales brochures, promotional materials and information provided by the developer. There is no way to check if the area is the same as the developer claims,' he said.

Mr Liu, who has worked as a property agent since 1978, said he had seldom heard of consumers complaining about the height of a flat.

'This is the first time I heard of such a court case. Most of the complaints are about the useable area of a flat, but rarely the height.'

He pointed out that height requirements were imposed on the construction of village houses in the New Territories. 'Every floor of a three-storey village house should be about nine feet,' he said. 'This is a standard for village houses. But ... there is no such rule for apartments.'