Maintaining the external fabric of an old building generally involves repairs to the masonry, roof and openings. In most cases, this will mean routinely repointing the brickwork, re-slating the roof and painting the window frames. Actually cleaning the fa莽ade and removing years of built-up grime is done on a far less frequent basis 鈥� and with good reason.
Cleaning the Portland stone fa莽ade of a large landmark building traditionally requires an extensive scaffold to provide full access so that a combination of steam, water and chemical cleaning products can be applied. It鈥檚 slow, it鈥檚 messy, it鈥檚 expensive and it鈥檚 highly intrusive for the users of the building.
There is one technique, however, that avoids all this hassle and gets the job done in no time at all. It鈥檚 called 鈥榝a莽ade gommage鈥� and there鈥檚 only one company in the UK that offers it.
Thomann-Hanry, headquartered in Park Royal, north London, is the UK representative of the eponymous Paris-based contractor that developed the fa莽ade gommage method during the 1980s.
Managing director Mark Styles was running his own small building company when he first encountered fa莽ade gommage about 15 years ago.
鈥淚 was a general builder, doing mainly residential and commercial projects in London when by chance I met someone who鈥檇 been working out in France and had seen this technique being used,鈥� explains Styles.
His contact described a technique that required no scaffolding, created no mess and was incredibly quick. Styles immediately realised that such a system could prove very popular among the owners of the many Portland stone-clad buildings in London鈥檚 West End. So he contacted Thomann-Hanry in Paris and paid them a visit.
A relatively small and highly-specialised company, founded in 1945, Thomann-Hanry is family-owned and had no ambitions for international growth. But Styles persuaded the firm to license its technique to him so that he could set up what is essentially a franchise based in London.
鈥淚 started the business in 2005 but it was 2008 before I got my first project,鈥� says Styles. The job was to clean the fa莽ade of the Grange Hotel in Holborn 鈥� a relatively small job, but a foot in the door. It was followed shortly afterwards by a contract to clean the fa莽ade of Marks & Spencer鈥檚 Oxford Street store.
It was this job that really got the ball rolling, says Styles. 鈥淢&S didn鈥檛 want scaffolding all over their building, covering up their window displays and obstructing the pavement,鈥� he says. 鈥淭hat store does 拢1m-worth of business every day and they couldn鈥檛 risk disrupting it.鈥�
Retail has proved to be a major client sector for Thomann-Hanry. 鈥淔or them, the main concern is loss of trade,鈥� says Styles. Traditional cleaning methods can mean scaffolding the fa莽ade for weeks or even months; it鈥檚 unsightly, disruptive and a deterrent for potential shoppers.
Fa莽ade gommage offers a much quicker alternative. Working from a lorry-mounted hydraulic boom, inert, fine powders are projected under low pressure across the surface of the building, erasing layers of accumulated dirt to reveal stonework and masonry as it first appeared.
鈥淲e use a very fine powder to rub 鈥� not blast 鈥� dirt from the surface,鈥� says Styles. The composition of the powder varies according to the type and texture of the substrate, but the main component is aluminium silicate 鈥� very similar in texture and chemistry to magnesium silicate, or talc.
The enclosed cabin from which the Thomann-Hanry operatives work is designed to prevent the powder residue from escaping into the environment. 鈥淭he equipment should recover 100% of the material,鈥� explains Styles. The cabin contains a powerful extraction unit that captures the dust, passes it through a wet mesh and turns it into a slurry. This is then de-watered and can be recycled and mixed with Type 1 aggregate for use as fill.
Because fa莽ade gommage is gentle and non-abrasive, the process is ideally suited to historic buildings. Among the UK landmarks that have received the Thomann-Hanry treatment are the Bank of England, the Ritz hotel and King鈥檚 College, Cambridge.
Over the past couple of years, Thomann-Hanry has been active in London鈥檚 Regent Street, first sprucing up Roxburghe House, a major retail property owned by the Crown Estate, followed by two more Crown Estate properties: Alitalia House, on the south west corner of Oxford Circus, and Hamley鈥檚, the world-famous toy shop.
Alitalia House is soon to become Microsoft鈥檚 flagship London store. Along with other works, including stone restoration, asphalting of balconies and slating, Thomann-Hanry was commissioned by the Crown Estate to clean the Grade II listed building鈥檚 frontage, comprising 4,000m2 of Portland stone.
Designed by William Tanner almost a century ago, the building鈥檚 elevations feature ornate Beaux Arts details which the gentle action of the fa莽ade gommage process was able to scour without damaging the fragile masonry. The work was carried out at night to avoid interactions with shoppers and minimise disruption to traffic, and it was completed in 12 night-time visits.
The 600m2 frontage of Hamleys, built in 1881, was cleaned in just two nights. Over the following four weeks, the company also completed other refurbishment works, from stone and window restoration to replacement of lead dormers and slating.
Doing away with the scaffolding is probably the main selling-point of fa莽ade gommage, says Styles. 鈥淎 lot of clients don鈥檛 want their building scaffolded, either because it hides the building, doesn鈥檛 look good or for security reasons. Banks don鈥檛 really want scaffolding all over their buildings,鈥� he explains.
The speed and efficiency of the fa莽ade gommage process is the other big plus for clients. Thomann-Hanry arrives at night, or at weekends, and after each visit, the only sign that it鈥檚 been there is that another part of the building looks cleaner.
According to Styles, 鈥渢here鈥檚 nothing remotely similar鈥� on the UK market to compete with Thomann-Hanry. That鈥檚 partly due to the patent protection, but the main barrier to entry is cost. 鈥淭he equipment is massively expensive,鈥� he says.
Thomann-Hanry operates a fleet of machines, mainly comprising access platforms and compressors, but the most important machine is the fa莽ade gommage 鈥�crane鈥� itself. This is a custom-built boom-lift carrying the working platform or cabin and supplying the powder matrix and the extraction system.
鈥淚t鈥檚 based on a Terex crane chassis, but it鈥檚 so heavily modified that you probably wouldn鈥檛 recognise it,鈥� says Styles. 鈥淭here are only nine of these machines in existence and we have two of them 鈥� though we have had as many as four at work at once鈥�.
Each machine costs 拢10m, and they are expensive to maintain, explains Styles. 鈥淎 lot of the parts are bespoke and must be made to order鈥 new bumper cost us 拢50,000,鈥� he adds. 鈥淥ur overheads are massive.鈥�
The fa莽ade gommage process is 鈥� not surprisingly 鈥� expensive compared with traditional cleaning carried out from a scaffold. But Styles stresses that the relative speed, convenience and environmental benefits make fa莽ade gommage not only competitive but also highly desirable from the client鈥檚 point of view. He also admits that many of his clients have deep pockets.
When Styles began marketing the fa莽ade gommage method the focus was purely on cleaning 鈥� he was not proposing to carry out repairs or restoration work. That soon changed, though:
鈥淲e didn鈥檛 originally plan to offer a full restoration service, but it was more or less forced upon us. We鈥檇 speak to a potential client about cleaning their fa莽ade and they鈥檇 say 鈥榳hat鈥檚 the point of paying you to clean the fa莽ade when we鈥檙e going to have to put scaffolding up to do the repairs anyway?鈥欌�� explains Styles.
Thomann-Hanry therefore now offers a full restoration service, with cleaning being the main element. Once the cleaning has been done, the company carries out a full inspection and prepares a detailed report of all the defects that need repair. It鈥檚 then up to the client to decide whether or not to proceed. If repairs are carried out, Thomann-Hanry employs its own team of stonemasons, painters and leadwork specialists who can tackle most jobs.
Styles says that, at present, there鈥檚 enough work in London to keep the company busy, although he has made the occasional foray outside the capital 鈥� notably to work on King鈥檚 College, Cambridge. 鈥淲e have an incredibly strong presence in London 鈥� most people know about us,鈥� says Styles.
鈥淚t鈥檚 a bit different outside London; it鈥檚 a matter of getting the word out,鈥� he adds. 鈥淏ut we recently did a series of CPD presentations in the north of England and completed a three-day tour of Liverpool, Manchester and Birmingham, so we鈥檙e getting out there.鈥�
This article was first published in the聽
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