Kenny Tse is a director at Raymond Chan Surveyors. He talks about regulations relating to combining two flats into one I want to combine two flats on the same floor into one home. Is this possible? What planning issues would I have to consider? To convert two flats into a single dwelling, the first thing you would need to know is if the units are structurally safe to combine. You will need to appoint an authorised person, such as a building surveyor, structural engineer or architect, to look at the original plans and discern where the structural load-bearing walls are, where the water and gas lines are, and the like. If it is structurally feasible, then the building professional will draw up appropriate plans and handle all the applications with the Buildings Department and site works. If a structural wall is demolished or altered, strengthening works, such as installation of steel beams, might have to be carried out. Afterwards, the new building plan will have to be submitted to the Buildings Department for proper authorisation. In some newer complexes with green-building features, each flat is designed with a balcony. If two flats are combined, there will be two balconies attached to a flat. This modification will also have to be filed with and authorised by the Buildings Department. Is there any difference if I want to convert two floors into a duplex? Similarly, any alteration to the structure of the premises, such as opening a hole in the floor and installing a new staircase, would have to be authorised by the Buildings Department. But if the staircase planned leads up to the rooftop terrace, a roof hatch or shelter would have to be built as access and protection from rainwater. In this case, the landlord would not only have to seek the authorisation of the Buildings Department, but would also have to apply for an “occupation permit”. Also, the new structure should not violate fire safety and building codes. For example, it cannot block fire escape routes of other residents. What are the consequences if such alterations are carried out without prior approval and consent from the Buildings Department? Linking two or more floors by removing parts of the floor slab and/or adding internal staircases combining two or more units into one by removing the partition walls are classified as alterations and additions works, and one must obtain approval and consent from the Buildings Department. Without permission, the works would be unauthorised building structures or works, and subject to enforcement action under the Buildings Ordinance. Are there other legal restrictions? Before drawing up plans, the authorised person will first check if there are restrictive covenants in the title, deed of mutual covenant or land lease that prevent two flats in a building being converted into a single dwelling. It varies from building to building, complex to complex, depending on the rules. In many housing estates, the proportion of the number of parking lots to the number of residential units has to be maintained at a certain ratio. If the combination of two units causes changes to such ratio, then a land premium fee will be incurred and the amount will be calculated on a case by case basis. The owner may consult a general practice surveyor for details. Also, if one unit of this combined dwelling is sold to another buyer in the future, the landlord will have to appoint an authorised person to reinstate alterations made to the premises and submit the building plan for Buildings Department’s approval.