Lin Wang-gen, an official of the non-profit Consumers' Foundation, told a news conference that nearly 20 percent of the advertised area of apartments sold in 38 buildings surveyed in Taipei by his foundation was common space, balcony space or covered rooftop space.

This space, which Lin described as "fictitious space," Also includes elevator wells, machinery rooms, public corridors, public recreation halls, water tanks and air conditioner rooms. "These areas are not living spaces used exclusively by the owners, but are registered on official documents as part of the houses and are sold as such to the buyers." Lin said.

In some of the surveyed buildings, "fictitious space" accounts for up to 66.01 percent of the advertised space of the houses for sale, meaning that buyers have to pay for more than they can actually use, Lin said.

Almost all of the 38 buildings inspected have balconies and canopies which cannot be used as living space but those two parts made up an average of 19.84 percent of the houses' nominal size, Lin went on. In addition to warning potential house buyers to watch out for this unusable space, Lin urged the government to crack down on what he described as a "dishonest practice" employed by most house builders by excluding at least balcony and canopies from the registered size of houses.