From decay to decadence: The rebirth of Cambridge House

 

Central London's architectural tapestry is woven with a rich history of iconic structures that stand as testaments to the city's heritage. Among these treasured gems, Cambridge House, a distinguished listed building, holds a special place as a window into the past. Speaking to Studio PDP’s Conservation Architect, Jokin Asiain, we explore how to transform our heritage assets in a way that not only preserves their historical essence but also embraces innovative techniques to ensure their relevance for generations to come.

Originally known as Egremont House, Cambridge House is a Grade I listed former townhouse which was built in 1756 for Sir Charles Wyndham, the Second Earl of Egremont. It is a rare example of an ‘Hôtel Particulier’; a formal architectural set-piece arrangement typical of 17th century French design, where the house is set back from the street and is fronted by a private courtyard (or cour d’honneur). This creates a dramatic arrival sequence and layering of space, from the street, through the forecourt to the porticoed entrance. The composition uses symmetry, space and classical Palladian style to convey grandeur and status.

It was residence to the youngest son of George III, Duke of Cambridge, from 1829 to 1850, then the home of Henry John Temple, 3rd Viscount Palmerston whilst he served as Prime Minister, before operating as the Naval & Military Club from 1865 to 1999. During this time, it became known colloquially as the “In & Out Club” due to the prominent gatepost signs directing vehicles (and originally, horse drawn carriages) through the courtyard at the front of the building. During the latter Club years a lack of investment, subsequently compounded with vacancy, meant the ageing building fell into disrepair

Now, the building at 94 Piccadilly is the centrepiece of – what will be – Cambridge House Hotel and Residences; a 102-key, five star hotel with seven private residences and extensive amenities. Adjoining this important building, which is being carefully restored, are two Grade II listed buildings at 90-93 and 95 Piccadilly, and complementary new build elements on Half Moon Street and White Horse Street.

With the Piccadilly, Victoria and Jubilee Lines plus several sewers in close proximity, squeezing in the space and functionality needed for the hotel, residences, restaurants and bars has been a challenge. Almost iceberg like, the development stretches both up and down with additional floors and a four storey basement.

Projects don’t get much more complex than this, combining conservation, restoration and new build. When you factor in its location in the heart of the West End and the sympathetic touch needed to balance the historical value of these heritage assets with the lavish spaces a luxury hotel demands, the true enormity of the task can be appreciated.

So, how do you approach addressing this delicate balance? The first and most important step, according to Jokin, is to understand the building, its significance and value (both aesthetically and historically speaking) and to understand how it was built. This is not something that can wholly be done prior to construction. The team found that, as the stripping out works commenced, more of the original fabric (in addition to altered fabric) was uncovered, allowing them to better read the building and the layers that have been built up over time; almost an archaeological approach to discovering the building’s timeline.

Existing photography showing some of the ornate detailing; decorative plasterwork and mouldings

What is your restoration philosophy and approach?

Once you understand the building, you can find the parts that add real significance; its heart and soul. Those parts you fight to preserve. In turn this lets you see the areas where compromise is possible, allowing for the integration of modern services and environmental upgrades. A hierarchy of steps then emerges with conservation and repair at the pinnacle, moving through replication and ending with removal if the other two are unachievable. It’s all about balance.

By way of an example, the building was bombed in 1940 and all the roofs were rebuilt, post-war. These, therefore, have much less historical significance since they were not original. Additionally, the quality of the rebuilt spaces housed beneath was not reflective of the original design intent for the internal spaces, resulting in something rather labyrinthine. This was identified as an acceptable area for modern intervention; one which would not impinge on the historical significance. Here, the roofs are being rebuilt to include insulation, upgrading the building envelope to provide better thermal performance.

In contrast, where we would not compromise is in the proportions of the historically important rooms, says Jokin. We ensured that we would not alter the proportions or impact on the decorative elements within those spaces. This meant that insulation could not be installed to those external walls. Again, it’s about the balance.

By following this process, decisions were made about what to restore, retain and replace.

At 94 Piccadilly, the ground and first floors contained the most significant spaces (including a grand ballroom), with original and 19th century decorations, so a conservation approach has been applied to the features on these floors. When the 3rd Earl of Egremont sold the house, all the fixtures and fittings, including the original balustrade to the main stairs were stripped out and taken away, so the current balustrade is unfortunately an unsympathetic 19th Century replacement. The original architect, Matthew Brettingham’s design of the 18th-century iron staircase balustrade was similar to the balustrade he designed at Norfolk House at 31 St James’s Square, Westminster. Norfolk House was completed in the same year as 94 Piccadilly and has a very similar plan, so, given the historic significance, it was proposed that the existing balustrade should be replaced with a scholarly reproduction, using the balustrade at Norfolk House as a reference.

To allow for construction of the basement levels, the front portico and annex have been dismantled stone by stone and stored off-site ready to be reinstated once the basement areas complete, and the dome above the main stair has been carefully propped to prevent damage to the decorative plasterwork during works to replace the rotten supporting structure.

The existing dome above the main stairs

Looking through the dome, which has been carefully propped to prevent damage during the works.

Moving to 90-93 Piccadilly, the Grade II listed staircase and façade have been retained, with remaining structures carefully dismantled around them. The Grade II listed 95 Piccadilly is being retained and restored, with the ground and first floors containing the most significant rooms with the most valuable features. There is, rather unusually, an original 19th century secondary glazing system, which will be restored. The unlisted properties, which make up the remainder of the site, have been taken down and replaced with new build elements which are sympathetic to the conservation area.

To enhance the thermal and acoustic performance of the windows without compromising the significance of the listed buildings, there is a studied balance between installation of secondary glazing to the most significant areas and double glazing to new or low significance areas.

What were the main challenges you encountered?

The influence of age coupled with an extended period of vacation, meant the condition of the existing fabric was poor and quite heavily decayed in places. There was dry rot everywhere which has meant the necessary removal of more fabric than we would have initially hoped for.

In one of the principal rooms the original plaster had survived the bombing and was therefore from the original decorative scheme, however, the battens supporting the lath and plaster were completely rotten and so it all had to be removed. There’s really nothing that can be done in those circumstances and that is the most challenging thing in Jokin’s eyes. In this case, whatever can be removed and stored, is, in the hope that it can be reused, and as a backup, the team have ‘squeezed’ (the creation of a mould by first paint stripping the decorative feature to reveal the correct original detail, then applying layers of liquid rubber) all the decorative plasterwork so that an exact replica can be created if needed.

Between 1851 and 1865, this was Lord Palmerston’s study, with its original, ornate plaster ceiling

Another major challenge is always how to incorporate services within the historic fabric. Following the same principles of identifying the areas of the most historical significance, the team have been able to locate the plant room and the majority of the services within new build areas of the redevelopment. In some instances, intervention is unavoidable, for example where rooms are completely surrounded by other historical rooms. The integration of mechanical services in particular, has been challenging as the fan coil units are large. So again, the team needed to understand how the building was built to know where these elements could be discreetly located. For example, in the sitting room, there are some existing niches which are inherently weak structural points. Proposals are therefore to raise the existing lintel to create a taller niche where services can be installed, discreetly hidden behind new finishes across the upper sections of the niches. Elsewhere, grilles will be fitted either within the mouldings (with new decorative elements on top) or integrated with the interior design approach with just a discreet mesh the same colour as the finished walls.

Which areas required the most innovative approach?

The biggest innovation in this project has been how to design out noise and vibration from the nearby underground lines which run in close proximity to the buildings. Here, a number of options were explored before a way forward was agreed. One idea was to essentially build a box in a box; an acoustically designed container within each room. This would have resolved the issues of sound and vibration transfer but would impinge on all the things the team didn’t want to compromise on – namely the proportions of the room and the layout. It would also mean hiding the original decorative fabric. Not acceptable.

Another option looked at removing all of the existing finishes so that they could be locally isolated – in essence placing all the new timber and plaster elements on battens that were acoustically separated. Floor joists would also need to be acoustically isolated. It was felt this would have been a very aggressive form of intervention, particularly to apply to those rooms of real historical significance.

So, in collaboration with the conservation officer, English Heritage and structural engineers, AKT II,  the decision was made to apply the largest interventions in the least significant spaces – the basement level. In, what we believe to be a first for a Grade I listed building, the existing structure of the main building at No. 94 Piccadilly (and additionally at 95 and 90-93 Piccadilly) was cut and placed on rubber pads, acoustically separating the whole structure, mitigating noise and vibration.

During construction: the installation of the acoustic isolation

What strategies are in place to prevent any future deterioration, ensuring the continued preservation of the building?

The single most important aspect is that the building is going to be used – not just by guests and residents but by the public who will be able to access the ground floor tea lounges, ballroom, gallery and central courtyard. Once a year there will be an open house when the main – most historically significant - rooms at first floor level will also be open to the public. The building will therefore be in constant use and that means that it’ll be heated, it’ll be maintained and that is, hopefully, what will take it off the heritage at risk register, which is Jokin’s primary concern.

The restoration of the collection of buildings which make up Cambridge House Hotel stands as a testament to the harmonious coexistence of heritage and innovation. As we continue to cherish the history embedded within its walls, we are reminded that by embracing innovation, we can ensure that the legacy of this architectural marvel lives on for generations to come.

Project team:
Tower Properties Management – Client
AARRKK – Development Manager and Client Representative
Studio PDP - Architect, Lead Designer, Principal Designer and CDM Coordinator
Jean-Louis Deniot - Interior Designer
Laura Gonzalez – Interior Designer
Studio Clementine – Interior Designer
Gardiner & Theobald – Project Manager
Donald Insall - Historic Building Consultant
AKT II - Structural Engineer
Hoare Lea – Services, Acoustic, Environmental, Lift and Fire Consultant
Deconstruct UK – Enabling Works Contractor
Ardmore – Main Contractor
Walter Lilly – Heritage Specialist Contractor
Robert Myers Associates - Landscape Consultant
Core Five - Cost Consultant
DP9 Limited - Planning Consultant
Malcolm Turner – Hotel Consultant
Arup - Traffic Consultant
Anstey Horne & Co - Rights of Light, Daylight and Sunlight Consultant
Point2 Surveyors - Party wall and Neighbourly Matters Consultant
Tim Moya Associates - Arboriculturalist
Sweco Building Control Limited - Building Control
MOLA - Archaeological Consultant
BIMTech - BIM Consultant
Reef Associates – Façade Access and Maintenance Consultant

Specialist conservation subcontractors:
Locker & Riley – Plaster
Vogue – Timber repairs
Melluish & Davis – Chimney pieces

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