Client: Blue Coast Capital
Location: Fitzrovia, London
Completion Date: February 2019
Architect: Barr Gazetas
Key Evolve Contacts: Ian Craig & Andy Fuller-Lewis
M&E Engineers: Scotch Partners
Quantity Surveyors: Heasmans
Evolve was appointed by Blue Coast Capital to provide structural engineering services. The scope of works consisted of alterations to the existing slab above the reception areas, as well as roof extensions, slab infills and strengthening to the existing steel frame. Removal of the existing concrete encasement to the underside of the steel beams and internal columns was also included, with intumescent paint to be reinstated.
Originally built circa 1925, the expansion and refurbishment of the office building at 30 Cleveland Street in Fitzrovia was overseen by architects Barr Gazetas, who approached the redesign with careful consideration for the original style of the building.
Key design aspects of the renovation included the restoration of the historic Art Deco façades and use of 284 Crittall-style glazed bays. The new reception area alludes to the building’s heritage with timeless colours, geometrical elements and streamlined curves. The internal space also contains exposed dark grey steelwork and a central feature of white metal rods.
Terraces were added on the 4th and 6th floors, with a rooftop terrace on the latter floor providing uninterrupted views across Central London.
The refurbishment of the entire building involved a full strip out of all existing finishes and fit-out. Limited record information was available on the existing building, however some information on original load allowances was obtained which allowed a load takedown of the existing and proposed loads to be carried out. This along with intrusive investigations formed the basis of the assessment of the existing building.
In brief, the new structural works were to include the following:
- One- and two-storey extensions on the existing terraces on the 4th and 6th floors for new office space
- Plant rooms re-configured on the aforementioned floors with screens/acoustic roof and lift extension
- Various slab infills and formation of new openings for new risers
- New below ground drainage routes to utilise existing outfalls
The original steel-framed six-storey structure with single basement included concrete encasement to conceal the steel columns and beams to provide fire protection. The floors were one way spanning ribbed slab formed with concrete hollow pots between ribs, while the external walls were solid brick. The lateral stability of the building was provided by the concrete core and masonry spine walls. A series of deeper down-stand primary steel beams ran perpendicular to Cleveland Street with shallower secondary steel beams running parallel. Some alterations were carried out in the year 2000, including a lightweight one-storey roof extension and the addition of a new concrete lift shaft within the rear lightwell which provided stability to the building and allowed a number of internal brick walls to be demolished.
For the original building foundations, it was assumed that shallow pad foundations were provided under existing columns and strip foundations to walls. As part of the alteration works in 2000, a new piled foundation was installed to the new lift core. Load takedown checks were carried out to ensure existing foundations were not overloaded as part of the proposed alterations.
Under slab drainage runs were installed to suit new toilets and shower arrangement in the basement and connect to the existing foul drainage system, while new internal drainage connects into public sewers.
A new acoustic screen was installed to provide enclosure around the 6th floor plant while an acoustic roof covering was added on the 4th floor beneath the plant.
Where new slabs were installed, these were formed with metal decking as permanent formwork and concrete infill. New openings were be trimmed with steelwork to support the remaining slab load.