McLaren restores an art deco dream

The views from the terrace on the ninth floor of Brettenham House are breathtaking. Located by the River Thames to the north of Waterloo Bridge, the 1932-built art deco building sits at an elbow of the river where it curves east towards the City, and south past Westminster.

This vista is one of the “wow” factors that developer Helical hopes will woo companies looking for location and character – as well as the pre-requisite BREEAM Outstanding, WELL Platinum, EPC A and NABERS 5* ratings.

“This is a beautiful historic building that has been brought back to its former glory, in a prominent location”, says Matt Redgrove, senior development executive at Helical. “The expectations of the market have heightened post-Covid because businesses need to attract their staff back into the office.”

Main contractor McLaren Construction and its specialist mechanical, electrical and plumbing (MEP) contractor Grant Walker Engineering are delivering the transformation. Where once Brettenham House’s roof housed all the building’s main plant, the redevelopment sees the new plant equipment shoehorned into the building’s cramped basement spaces, which includes stone vaults.

While the experience of standing on the roof terrace feels like riding the deck of a grand ocean liner, the multi-level collection of spaces in the basement – packed with plant at every turn – feels more like the engine room of a ship. 

“We have gone hell for leather down here and it’s been tricky,” says McLaren project director Robert Gibson. “It’s a proper warren.”

Finalising the design of the plant area is the main reason behind the completion date moving backwards, says Redgrove. Initially announced as March 2026, completion took place in August 2026. 

“The programme was provisional, knowing we still had design work to do collectively with the subcontractor,” says Redgrove. “The challenge of the job is fitting all that top-end kit in a basement that wasn’t originally designed for it. But it’s what unlocks this whole asset and the value that you see at the top.”

Brettenham House, which was built in 1932, is a steel-framed building with reinforced concrete ribbed slabs. Sitting between Lancaster Place to the east and the lower-level Savoy Street to the west, the building is not listed, but is a building of merit within the Savoy Conservation Area. 

The redeveloped building will provide 128,726 sq feet (net internal area) of office space and a retail unit on the ground floor. In addition to the nine stories above the ground floor level at Lancaster Place, there are three below that.

As well as the relocation of plant, and the installation of new building services and windows throughout, McLaren’s £90m cut-and-carve contract involves significant structural works including the construction of new pavilions and terraces on the
top floor; the removal of two lift shafts, added after the original construction; and the installation of four new cores, threaded through the existing steel frame, one for an escape stair, one with five lifts and two containing a lift each. 

The building’s two impressive marble staircases have been fully restored. Meanwhile, sections cut out of the ground and lower ground floor on the west side have created a three-storey atrium, installing a new oak-clad staircase and a glass-block clad feature wall around a lift shaft, which will be lit up. This intervention provides a connection between the entrances on Savoy Street and Lancaster Place.

Helical placed key packages before the main construction contract: GKR for scaffolding, early stone restoration works with PAYE, replacement of punched windows with Crittall – the building’s original window supplier – and Propak for larger format windows on the lower and upper floors. Incorporating a temporary roof over the whole building, GKR’s package was immense, requiring 8,200 sq m of scaffold and 4.2km of platforming.

The main contract was tendered competitively moving into a two-stage procurement process with McLaren, whom Helical engaged towards the end of RIBA Stage 3 of the design. “We typically do two-stage design-build because we feel it gives us the most certainty as a client in terms of what we’re aiming to deliver,” says Redgrove. “Also, it gives us the most opportunity to benefit from the contractor’s expertise and know-how.”

McLaren operations director Neil Smith picks out three areas where McLaren was able to significantly influence the design: the build-up of the ceilings, wall construction in the basement and the core walls. 

The original ceiling design was a Fermacell system which, as well as being quite deep with its two layers of fireboard, would have needed penetrations for fixings through it which would not have met the requirements for a tested solution for fire protection. “On the upper floors, most of the services are exposed, sprinklers for example need to be fixed back to the primary structure, so you end up with penetrations for sprinkler supports that would breach the solution,” explains Smith. 

McLaren’s alternative solution is a 12mm minimum thickness fire spray, pre-installing hangers for the services. This reduced the ceiling build-up depth from 300mm to 110mm, with a small void above through which the wiring runs, giving a better floor-to-ceiling height. 

The team used full-scale mock-ups of office bays to check the fire protection design, which was checked by BRE. “The mock-up process included how we finished it, with all the trades feeding into that at the same time,” says associate director Adrian Lindsay.

In the basement, blockwork walls dividing compartments would have required wide windposts which created problems in getting the plethora of services through them, says Smith. “We came up with a bespoke solution of introducing concrete spandrel panels on top of steel beams, which enabled us to move the services closer together, running through openings,” says Smith.

McLaren switched the material for the core walls from drywall to blockwork to increase its choice of tested solutions for fire protection. 

“This new world of fireproofing and fire-rated strategies has got us to a place where there are not enough tested solutions,” comments Smith. “By converting to blockwork, it increased our options.”

McLaren received a letter of intent in May 2024 and started work on site in September 2024. As the building was being stripped out, it had conducted 3D heat-map surveys, to work out what the exact position of walls and ceilings was and how that differed from those assumed in the design.

“Until we exposed everything, we couldn’t know exactly what was there,” says Smith. “It was about getting the building stripped back and then we could design the MEP to fit.” Down in the basement, 3D modelling showed that everything would not quite fit as intended. “We had to remove some of the concrete floor screeds. We were trying to find four inches in places,” reports Gibson.

Equipment that had to be accommodated in the basement includes two 20,000-gallon water tanks, one for the sprinkler system and another for grey water which will be re-used for flushing toilets. McLaren has also installed a new substation and two air source heat pumps, located in the lowest part of the basement, by the bottom
of Savoy Street.

When CM visited site in mid-July, the basement building services installation was still in progress. At ground floor level, glass blocks were being installed to create the feature wall by the new stairs while the door frames to the two entrances on Lancaster Place, refurbished on site, were waiting for the four 4m-high steel-cored, bronze-coated doors to arrive from D Wilson Architectural Metalwork in Birmingham. These will be eternally open, with revolving doors to be installed in the openings. 

Further up the building, McLaren has worked from floor 7 down to floor 1 on the fit-out, finishing floors 4 and 5 early for the marketing suite. Levels 4 and above have outside terrace space, while levels 1, 2 and 3 have bleacher staircases, designed to accommodate company gatherings.

Fit out on floors 8 and 9 started later since these levels required extensive structural modification, with partial demolition of the plant room, the construction of the steel-framed, stone-clad pavilions and addition of a mezzanine floor at level 9.

Smith says the long-standing relationship between Helical and McLaren has helped in navigating changes efficiently: “There has been a very open dialogue between all parties. If there’s a client requirement we can move into doing that very quickly. We don’t get involved in bureaucracy and it does not always cost money to change things.”

A case in point is the handrails on the two marble staircases, says Linden. McLaren’s subcontractor Steel Arts proposed that rather than replace the 180m of metal handrail with a wooden one, they could be refurbished, which led to cost savings.

One pleasing discovery, when the carpet was removed from the staircases, was the remnants of mosaic indents in the nosing of the stairs. These were beyond repair, so reclaimed marble from walls in the building was reused to create new indents.

It is details such as this that Helical hopes will help attract tenants to the renewed building when it is officially launched to prospective tenants. Redgrove is looking forward to stepping out onto the terrace, cocktail in hand, to celebrate that moment. “The CGIs don’t do that view justice,” he says. “When you actually stand there, it’s really spectacular.”