Developer Frank Gilmer has been refused planning permission by Dún Laoghaire-Rathdown County Council to demolish the 1940s-built Buena Vista on Killiney Hill Road in Co Dublin and replace it with a much larger structure.

Gilmer, who is behind a number of high profile developments in the area, proposed a 743sq m (8,000sq ft) eight-bedroom house on the site with terraces on all sides to avail of spectacular sea views and a link to a pool house and spa. He also wanted to build a two-storey lodge house with a garage. Another house on the grounds, Santa Barbra, was to be retained.

The four-bedroom Buena Vista, formerly called Tower Hall, failed to sell at auction in June 2004 with a guide price of €4 million but was later sold to Gilmer for a figure believed to be around €5 million.

Although not a protected structure, the architect, John Devaney, who had an association with Michael Scott, incorporated features regarded as cutting-edge at the time, including a full height 180-degree curved glazed bay, porthole windows and original glass bricks and parquet floors. It was built on the site of two earlier 1860s houses owned by the Chaytor family but which burned down in 1940.

An Taisce objected to the development, saying the 743sq m (8,000sq ft) house would constitute unsustainable over-development and would undermine the archaeological heritage status of the nearby Martello Tower, a national monument. Another objector, Stephen Devaney, said the proposal seems more like "a potential nursing home or an overblown B&B" rather than a single residence. Referring to the proposed house as "a monstrous structure" and "approaching three times the size of any other structure in the immediate vicinity", he said the existing house was refurbished and added to by its previous owners in recent years.

The council ruled that the development would be contrary to its policy to rehabilitate, renovate and re-use existing buildings and would not preserve or enhance the character of a Conservation Area.

It said the massing, scale, location, roof design, removal of existing vegetation and proximity would affect Killiney Martello Tower, a protected structure, and would seriously injure the amenities of Santa Barbara "by reason of overlooking and visual intrusion resulting from an inadequate separation distance".