18 Marcus Clarke Street represents a major design departure for Canberra buildings in that it has a visually permeable facade and large floor plates of typically 2,350m², with the opportunity to create campus-style environments via interconnecting stairs.

This high quality development incorporates 12 levels of commercial "A" Grade office accommodation of 29,400m² GFA. It includes three levels of underground car parking together with bicycle parking spaces, plant and services areas, a ground floor with commercial support areas, plus 11 levels of commercial office space and a plant room on level 12.

The Commonweatlth Department of Agriculture, Fisheries & Forestry has taken a 15-year lease on all of the commercial area in the building as well as leasing up to 4,250m² of space in the adjoining building at 7 London Circuit, which was also being built by Thiess.

The site is on the western side of Canberra's central business destrict and is bounded by Marcus Clarke, William Clemens, Murden and Wilden Streets. The contract included provisions of roads, power, water, stormwater and sewer services across the overall site.

Construction was a conventional reinforced concrete core, formed using a jumpform system, reinforced concrete beams and post-tensioned slabs on bondek sheeting.

The building achieved a 4.5 star Australian Building Green-house Rating and Ecologially Sustainable Development initiatives were incorporated into the design to ensure it became a benchmark ESD building in the ACT.