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Restored to former glory15th of September 2010
ECJ editor Michelle Marshall visits the world famous Ritz Hotel in the heart of London, whose Portland stone façade has recently been restored to its former glory in just three weeks thanks to an innovative masonry cleaning system from Thomann-Hanry.
Situated in Piccadilly, The Ritz is one of London's grandest and most famous hotels. Opened in 1906 it has long been a destination for the elite traveller and has seen some truly historic figures go through its doors - Churchill, de Gaulle and Eisenhower held summit meetings there during the Second World War, while King Edward VII, King Alfonso of Spain, Russian ballerina Anna Pavlova, the Aga Khan and Charlie Chaplin have all visited. The grandeur and opulence of both the interior and exterior are legendary.
Over the years, however, weather and pollution had taken their toll on the appearance of the external façade and the Portland stone was in need of some urgent attention. After exploring the systems available, the management decided on Facade Gommage, which has been developed and provided by Thomann-Hanry. First launched 25 years ago, this low pressure dry masonry cleaning system has been refined over the years and been used to restore many of the world's most iconic buildings - the Kremlin in Moscow, MetLife Skyscraper in New York, Louvre Museum in Paris and Canberra's Australia War Memorial to name just a few.
The main differences between Façade Gommage and other stone cleaning solutions are that it is extremely quick, and the building requires no scaffolding while the cleaning process is taking place. At The Ritz 3,600 square metres of stone was cleaned in just three weeks - more conventional methods could have taken up to six months.
Mark Styles heads up the UK operation that was responsible for The Ritz project, which he set up as a partnership with the French parent company in 2005. He explained how the Façade Gommage actually works. "The operator sits in a cabin which is elevated and moved around using a crane. He works a hose which blows a fine powder of 20-30 microns onto the masonry. Although it is very sharp, the powder is softer than the limestone it is cleaning.
"The powder is abraded by the limestone, while also breaking down the dirt. Inside the cabin is a box which acts as a huge vacuum to suck in the dust created as a result of this process. The water curtain inside converts this to a slurry which is pumped down to ground level. The water is filtered, cleansed and re-used, while the powder residue is perfectly safe and suitable for landfill disposal."
Styles explained more about the powder itself. "The powder is made from aluminium silicate, the slag from smelting aluminium. This is imploded to the size required and produced to Thomann Hanry’s own specification in France. No chemicals are involved in the process of cleaning, the powder is non-toxic and non-hazardous – bringing obvious environmental benefits. It takes 2,500 litres to charge the system and that can last the entire job. Three kilos of powder are used per square metre of stone."
All types of location
The speed at which cleaning can be completed makes the system suitable for use in all types of city location. "In the City of London, for example, there are restrictions on when building maintenance work can be done and it generally has to be carried out over a weekend," Styles continued. "This is just not possible with conventional cleaning methods but we have worked on such projects very successfully."
The fact buildings do not have to be scaffolded for cleaning is a major advantage in terms of both convenience and cost. "Scaffolding can be a major cost on a cleaning project," Styles said, "particularly on tall buildings. Obviously economies of scale mean the bigger the building is, the more cost effective the Façade Gommage clean." Cleaning is charged by the square metre, which also means the client can budget accurately for the job.
The most important consideration, of course, is the quality of the work, and here Styles is entirely confident. "We expect to see better results using this method than with water cleaning, which can actually often stain stonework. Façade Gommage gives a natural, clean finish, and because it is mild and non-abrasive it will not damage the fabric of a building."
The Ritz project was started in January of this year, the surface was extremely dirty and in desperate need of cleaning - it had not been done for over 20 years. The hotel is constructed in Norwegian granite up to the plinth then Portland stone from the first floor. The reasons for this go back to the days when London was populated with horse-and-carts. The roads were dirty and much of that dirt was thrown against buildings. Granite was easy to clean whereas the stone would have absorbed more dirt. “As far as the cleaning is concerned”, said Styles, “they behave in the same way.”
There are usually three or four people in the team and all operators have been fully trained in the use of the Façade Gommage system. At The Ritz work usually started at 8am and continued until 6pm. Operators work for between four and five hours at a time up in the cabin, which seems like an unbearably long time but Styles insisted: "You really do lose all perception of time – before you know it hours have flown by.” The operator in the cabin wears a fully pressurised suit and all the air he breathes in is filtered. Dust is being blown out of the helmet because of the positive pressure – making this is a completely safe process for the operator too.
Hotel occupancy unaffected
The Ritz is situated on one of London's busiest streets - Piccadilly - which could have resulted in traffic chaos but the Façade Gommage system requires little space so only one traffic lane was needed. And because there was no scaffolding room occupancy could remain unaffected, saving the hotel thousands in otherwise lost revenue.
All good news for The Ritz management, as managing director Stephen Boxall explained. "We are delighted with the results of the clean to the exterior masonry of the hotel. We were particularly conscious that the work did not cause any inconvenience or disturbance either to our hotel guests or to pedestrians and traffic in Piccadilly.
"The efficiency and speed with which Thomann-Hanry was able to complete the project has been quite astounding. The continuing refurbishment of the hotel building is a testament to the commitment we have made to ensure that The Ritz is looking her best at all times."
Development director Nicholas Jackson was responsible for liaising with Thomann-Hanry throughout the job. He explained: "The relationship with Mark Styles was excellent throughout despite the project being difficult due to the unexpected severe winter weather, increased pedestrian footfall due to a major international conference being held in Green Park and reacting to the often short notice requirements, restrictions and whims of the Ritz, which operates very differently from other hotels due to the nature of the clientele."
Works in all weathers
Work can be done in all weathers, problems only arise if it becomes extremely cold. And Façade Gommage has also been used indoors on a number of projects, including cathedrals. On sites such as these the entire building becomes a vacuum and a long hose is taken inside, with the machinery being situated outside.
Thomann-Hanry is now enjoying success with Façade Gommage across London and the rest of the world, but for Mark Styles it was a struggle to establish the business in the UK. "Many local authorities liked it and there were not many legal or administrative obstacles to it being used," he explained. "The major challenge was persuading people to try a new system (although it was not actually new, it was here in the UK). This is understandable when you’re talking about buildings of significant importance, plus the fact that the construction and maintenance industry is a very risk-averse one.”
Now it's a very different story. The system is actually being recommended by authorities in the City of London and local councils are accepting it too. Thomann-Hanry is appointed by the client directly in 75 per cent of cases, usually being brought in by the chief engineer or contract administrator.
Façade Gommage has won awards and received accolades from prestigious organisations around the world, and has even been granted approval by UNESCO for work on three buildings on the World Heritage List. Its convenience, cost effectiveness and environmental credentials make it a
reliable cleaning solution for stone, masonry, brick, terracotta, alabaster and polychrome surfaces.