Cornwell House, London – Projects
Project Details
Type
- Workplace
Architect
- Emrys Architects
Client
- GMS Estates
Location
- London
Occupying one of the most prominent sites on Clerkenwell Road, Grade-II listed Cornwell House was built by the speculative developer Charles Powell in c.1878-80 as the Sessions House Hotel. The architect of Cornwell House is unknown, but the building was designed with a curved polychromatic brick frontage turning the junction between Clerkenwell Road and Clerkenwell Green, with ten bays of polished granite shopfronts at ground floor level, inserted slightly later in c.1897.
The primary significance of the building, and particularly sensitive to change, is the robust late Victorian elevation, which also makes a strong contribution to the local townscape and the Clerkenwell Green Conservation Area.
Externally the building features a curved façade that is finished in white brick, with dressings of red brick, stucco and polished granite. The building is traditionally constructed, with masonry walls on corbelled foundations supporting timber floors and roof. Inside, the building was originally divided up into a roughly sectoral arrangement.
The interior of the building was originally constructed with a public house and dining rooms on the ground floor, with cellular hotel rooms on the floors above, and in the 1920s it was converted into a spectacle factory and offices for the General Optical Company. In 1979 the ground-to-third floors of the interior appear to have been gutted, aside from the northern staircase, and new partitions inserted to provide individual craft workshops on each floor, which form the present layout of the building.
The transformed building is intended to house commercial facilities, such as a café, on the ground floor, open plan offices on the higher floors and bike storage / commercial space in the basement. The proposed plans to do this included the demolition of the internal elements of the building while retaining the external walls to create open plan spaces, lowering the basement level by 700mm to create new spaces with generous head-height, the addition of a new storey on the top floor, which will consist of a lightweight steel frame with large glazed windows and an open terrace along the front façade, and the construction of a new lift from the basement to the 4th floor within the rear lightwell, which will consist of a steel lift shaft founded on an RC lift pit.
The desired timber floors are to be supported on steel beams spanning from the external brick walls to 2 No. of new internal steel columns. The columns are to be founded on RC pad foundations. The basement is a ground bearing reinforced concrete slab. The roof extension consists of a steel frame with timber infill and glass façade.
The building posed a number of structural challenges and opportunities. Being nearly 140 years old it has undergone numerous alterations, such as installation of steel beams and columns without altering the floor plates which resulted in unique connection details. Those complex details had to be considered and worked around when planning the new construction sequence as well as temporary supports.
One of the biggest challenges related to the lowering of the ground floor to the level below the ground water. Although the soil conditions were not untypical for a London site in the front of the building, the soil inside the rear lightwell, where a new lift was to be installed, turned out to be exceptionally bad, consisting almost entirely of fine particles suspended in water. The soil resembled quick sand and had hardly any bearing capacity. Based on historical studies, it has been established that in the 12th century there were several wells in that area from which Clerkenwell took its name. It appears that one of those wells may have been later infilled and built around, challenging engineers eight centuries later.
Cornwell House has been built with attention to detail resulting in a high quality building of a unique character. We are delighted to have worked on its renovation to give it a new lease of life and to allow the future generations to enjoy its charm.
