BEIJING, April 3 (Xinhua) -- Authorities in Beijing on Monday expanded the housing purchase limit to cover the single-storey houses as they seek to cool down the property market.

Now the purchase restriction covers all commercial houses, said Zhao Xiuchi, a professor with the Capital University of Economic and Business.

As of Monday, single adults with Beijing hukou, or residence permit, and married people without Beijing hukou, are temporarily banned from buying a single-storey house if they already own at least one apartment in Beijing, said the municipal commission of housing and urban-rural development.

Local families that already owned two homes or more and non locals who have no record of paying social insurance or income tax for five years are also banned from buying a single-storey house.

The single-storey houses are mainly in the downtown districts and children of the owners are usually enrolled in good primary and middle schools, thus sparking speculation and fast rises in housing prices, said Zhao.

Zhao added that restriction aims to curb market speculation.

Over the past more than half a month, authorities in Beijing introduced a spate of measures, including higher down payment, high mortgage rates and tougher purchase restrictions, to cool the red-hot property market.