I am looking for advice on a peculiar situation. My friend's grandparents lived in a 1200 SQ FT single-storey house built on a 3600 SQ FT plot. The cost of acquiring the plot and constructing the house was largely borne by the eldest son (my friend's father). On the passing away of their parents, my friend's father and his two brothers reached a mutual agreement, based on which:
(a) The eldest brother would continue to own the 1200 ground floor house that the grandparents lived in
(b) The two younger brothers constructed a 1st floor divided into two 600 SQ FT portions, one for each of them
(c) a deed of settlement was made based on which UDS was allocated to each brother. The calculation used to arrive at the UDS was as follows. Of the 3600 SQ FT, there is a 1000 SQ FT garden area at the backyard. This was subtracted from 3600 to arrive at 2400 SQ FT. This 2400 SQ FT was divided in proportion to the built-up area of each brother's portion. Thus, the eldest brother would have a UDS of 1200 SQ FT, and each of the two younger brothers would have a UDS of 600 SQ FT. In addition, the eldest brother would completely own the 1000 SQ FT garden area at the back, and reserve the right to construct something on that area in future if needed. The deed of settlement does not explain the calculation of the UDS; all it documents is how much UDS is allocated to each brother.
Now, several years after this settlement was made, the eldest brother would like to construct an additional house for his son (my friend). He wants to preserve the garden area at the back, so the only option is to construct vertically, building an additional floor over the existing structure. He has the consent of his brothers. However, a question crops up about the effect of this expansion on the UDS calculation. Just because one brother decides to expand his built-up area, it should not result in a change in the UDS split. My friend believes that there should not be any impact, and the UDS allocation as per the previous deed of settlement should continue to hold good. But I would like to confirm his understanding with the legal fraternity. Even if the brothers agree that their UDS share remains the same, will this be viewed differently by the Municipal Corporation or concerned authorities? This property is in the Chennai municipal area.
Also, the new house on the 2nd floor will get its own door number and property tax ID. If there is no UDS associated with this house, will the property tax rates be different compared to the other portions?