15 Alice Lane Annex
15 Alice Lane Annex – Description from Paragon Architects.
The context of this project had a profound impact on its design. This is the sixth building on the Alice Lane Precinct and sits in the southern corner. An early decision was made to rehabilitate the structure rather than demolish it. There were compelling reasons for doing so, including cost and time benefits. However, it did complicate structural issues somewhat both vertically and horizontally.
The original plan was stepped and this subsequently required the accommodation of 3 different grid systems across the building, into the interstitial spaces around it and the adjoining buildings. Three of the existing five levels were retained and converted to parking. This has subsequently joined the existing super-basement below the precinct, which will provide a total of 3500 parking bays.
An additional parking level and transfer structure were added and 5 storeys of office plates, each measuring between 3500 to 4200 sqm. The length and width of these plates initiated the need for a single internal atrium running the length of the building that brings natural light and reduces the plates to a more manageable size. The transfer structure sits above P zero level and acts as a junction for the transfer of forces from one grid system to another.
The long narrow atrium opens the east and west cores to accentuate the vertical circulation provided by two scenic elevators. The ends of the building are softened with the curved glazed ends generating an inverted trapezoidal form. This contrasts with the concrete which flanks the main entrance, whose construction was also complicated. Together it complements the plan which is in itself, a parallelogram, necessary to accommodate all the geometric conflicts.
The building form is further softened and layered with the addition of aluminium screens, suspended off the full height glazing on the east and west elevations; to shade the building from the morning and afternoon sun. In addition to their functional role, the screens provide a powerful aesthetic to the building, and are expressed as circular perforations on a regular grid to form tree motif. The concept of the tree motif continues into the building and informed the interior design.
Tree patterns in various materials, were added to the lobbies and ablutions to give an illusion of space. Back lit forest screens in both the mens’ and womens’ bathrooms, illuminate the areas. Playful mirrors dot the walls and emphasise these panels and introduce movement throughout the space. External planting and cascading levels reduce the elevated scale of the entrance which provides a softer and more tangible environment. The building has achieved a Four Star Green Star Design V1 rating, while the construction period was a tight 19 months, but finished on schedule.