Norma Smurfit has won her planning battle to demolish Hillbery - the house on St Thomas Road, Mount Merrion, Co Dublin she bought for €2.275 million at auction - and build a bigger house in its place.
Ms Smurfit appealed Dún Laoghaire-Rathdown County Council's decision to refuse permission on the grounds that, if allowed, it might set a precedent for similar development in the area.
According to her architect, De Blacam and Meagher, the existing house has a "confusing and undesirable layout".
An Bord Pleanála overturned Dún Laoghaire-Rathdown County Council's decision and allowed the development on the grounds of varied character of development in the area, the physical condition of the existing house and the fact that it does not have any protected status.