Leinster House 2000 is a development project, which created a major new office wing for the houses of Ireland’s Parliament at Kildare Street. It extended the northern end of Leinster House by connecting to it below ground at basement level.

Leinster House was designed by Richard Castle in 1745 and built shortly afterwards as a grand town house for the Duke of Leinster although in reality its scale and layout were of a country, rather than a town house.

In 1922, it was purchased by the first Irish Free State government to serve as a parliament house. This complex of buildings of national importance was originally designed by Sir Thomas Deane in the late nineteenth century as part of the larger scheme which placed the National Gallery, the Natural History Museum, the National Library and the National Museum as wings on the four corners of Leinster House.

The conservation project is a skilful blend of restoration with the addition of substantial new facilities in a highly sensitive historic environment. As the new building connects to Leinster House at basement level only, the use of the main spine corridor at that level as the link between different parts of the complex reinforced the importance of the Leinster House main stairs. These have been widened and care was taken to minimise the loss of the historic fabric and to preserve the architectural integrity of the whole. The additional significance given to the stairs was entirely appropriate.

The façade construction has included vertical elements of stone, evocative of the columns on the screen wall and fenestration patterns generally on the adjoining buildings. This mitigates the presence of the new work while still using a contemporary idiom.

The internal elevation of the 1823 façade forms one edge to the new atrium, in which the new opposes the old to create a space of considerable drama. The atrium announces the new building and its extraordinary landscaped courtyard, inserted between the two nearly parallel blocks, which house the offices. The basement area under the garden is a well-laid out complex of committee rooms, providing sophisticated facilities for members. The architectural quality of the building is notable, and accomplished. It offers a language of modernity that achieves a timeless, almost classical quality, and which relates sensitively to the earlier buildings around.

The project set out to create a high quality modern building of 8,000 m2, which harmonised entirely with its surroundings. A new classical style screen wall formed the public entrance and the 1823 façade within the new public atrium was restored. The new internal stairway was created in the style of the 18th century in order to form a graceful internal link and the vaulted basement corridor of the same style was restored. Historic sculptures were also restored to decorate the interior spaces. A careful reconstruction of an 18th century curved wall which had been temporarily dismantled for construction site access purposes now serves as a link between the old and the new and as the northern quadrant of the garden wing to Leinster lawn.

Leinster House 2000 is a confident, yet respectful project that inserts a new building into a historic and symbolic environment of great national significance.