Section 55(2) in West Bengal Municipal (Building) Rules, 2007
(2)In the case of existing building(a)excepting storage buildings, where the open spaces required have not been provided, an addition in the number of stories, if otherwise permissible, may be allowed with a set back, provided such building continues with the same occupancyProvided that no formal set back may be necessary up to a height of eight metres for adding only one floor over an existing single storied residential building;(b)the extent of the set back from the property boundary shall be such as to make the addition to the building conform to the provisions of rules 46 and 50;(c)if any car parking space is required to be provided under these rules and no such car parking space can be provided, the covered area allowable under the provisions of these rules shall be reduced by the area required for such car parking space which cannot be provided in the said building.Explanation.For the purpose of calculation, the area required for one car parking space shall be taken as 20.00 sq. metres;(d)the height of the building shall conform to the rules as indicated in rule 49 and in no case after addition the height shall exceed 14.50 metres;(e)the addition to an existing building with residential occupancy shall not exceed 200.00 sq. metres in covered area;(f)the addition to an existing building with educational occupancy shall not exceed the total covered area of the existing building;(g)the addition to an existing building with other occupancies including mixed use building but excepting storage building shall not exceed 100.00 sq. metres in covered areas.(h)in case of partition of existing building common walls may be allowed as the partition line.
