Heyne Tillett Steel
Great Portland Estates
The extensive refurbishment of a 1970s reinforced concrete office building comprising of four interconnected buildings.
The project included a complete refurbishment, a new extended façade, and the construction of roof extensions providing three additional floors.
This significant renovation and extension of an existing reinforced concrete building used extensive pre-contract survey and monitoring of foundations to achieve a considerable increase in floor area while retaining and reusing as much of the original frame as possible.
This research enabled large increases in load to be safely supported on the existing superstructure and foundations without requiring strengthening.
Three floors were added to the building and lightwells infilled with a steel frame supporting lightweight concrete filled metal decking. 3D analysis of the existing structure enabled the design team to optimise the 10.000 fixings and thereby remove this high-risk element of the construction programme from the critical path.
Standardising the 360 new steel prefabricated frames into only eight different types also contributed to the overall success of the project.
Due to the rigorous initial analysis a significant amount of original embodied carbon was able to be retained, and optimisation of the new structure minimised its own carbon footprint, thereby creating a highly sustainable modern commercial property.