Get the assurance of the Stonehealth Rosette

The Stonehealth Rosette and operator identity card mean you can be sure your stone is being cleaned by Stonehealth products used by experienced operators.

Working in the restoration and conservation industry is a responsibility as well as a privilege. Contractors can be required to work on a range of fragile and historic stonework from monuments to ancient churches – buildings that form a significant part of our heritage. It is absolutely vital, therefore, to be able to distinguish trustworthy and skilled tradesman from the ‘Jacks of all trades’. So how do you ensure that a contractor is easily recognised as one of the best? Stone cleaning product supplier Stonehealth has an asnwer.

For 25 years Stonehealth has supplied products and consultancy for sensitive stonework restoration and conservation. During this time the company’s contact with contractors in the field has enabled it to build up a list of those who it felt happy to approve as users of its machinery, which is regularly specified in conservation cleaning contracts. As you might imagine after 25 years, the list has become substantial. The company has approved contractors from the Black Isles down to Land’s End.

Since its inception, the Stonehealth approved contractors list has been used with much success by specifiers, although on occasions Stonehealth has been required by architects to investigate poor results and has discoverd contractors calling themselves Stonehealth approved when they are not even using the specified DOFF superheated water or TORC gentle abrasive machines from Stonehealth.

The company says it has seen machines used with nozzles and powders not approved by Stonehealth. Other machines have not been serviced in years and are, therefore, not working efficiently.

These issues posed concerns – jobs might not be completed satisfactorily and the reputation of both Stonehealth and everyone else on the approved contractors list could be put into question.

Stonehealth felt that it was its responsibility to do what it could to protect its reputation and that of its products and its approved contractors using it. It considered the best way to do that was to make it clear who had been approved and who had not.

After consulting with others in the trade, as well as architects and specifiers, the company came up with the following criteria, which have gone on to become the basis of what is now known as the Rosette Standard in cleaning:

• Individual operators should be trained by Stonehealth and have an ID card to prove it
• DOFF and TORC machines should be well maintained, serviced regularly and used only with approved parts and products
• Contractors should be able to provide at least two references from an architect or other specifier.

Companies with the Stonehealth Rosette are now being used regularly as reliable, knowledgeable contractors on jobs as varied as train stations to the oldest cathedrals.

John Lambert Historic Cleaning Services Ltd was one of the first companies to be awarded the new Stonehealth approved Rosette status and one of the projects it is currently working on is the Grade 1 listed St Bartholomew’s Church of Wilmslow.

There has been a church on this site since the 13th Century and some of the current restoration involves the most ancient parts of the building. Even the newer parts date back to the early 1500s.

The church is being lovingly and sympathetically restored using a variety of Stonehealth products, including the DOFF Recovery System (DRS) and Clean-film, Stonehealth’s latex paste used for drawing out dirt on internal walls.

The DRS resolves the problem of internal stone cleaning. The previous Stonehealth recovery unit was only suitable to be used with DOFF at low temperatures. The completely redesigned system is the latest development in the Stonehealth range and fits to all DOFF models simply by exchanging the lance for the DRS, which comes complete with vacuum.

The new version is not only ergonomically designed but is also more efficient and safe up to the 150ºC superheated cleaning setting. It includes a feature that stops the jet being distorted by the vacuum, so all vapour and water is extracted through the recovery head and removed cleanly and efficiently through separate pipes.

St Bartholomew’s is built of ashlar buff sandstone and has a Kerridge stone-slate roof. The works at Wilmslow include internal and external refurbishment and cleaning and conservation of the stonework of the chancel, nave, aisle and tower.

John Lambert Historic Cleaning Services understands that achieving the Stonehealth Rosette is an investment in the future of the business and Stephen Walsh, of Buttress Fuller Allsop Williams Architects, sent Stonehealth this testimonial: “Both myself and the client team at Wilmslow Parish Church are extremely happy with the masonry cleaning that has been undertaken by John Lambert Historic Cleaning Services using your company’s products.”

Thomann-Hanry solves aquaduct’s water problem

Thomann-Hanry’s abrasive cleaning system carried out in an enclosed cabinet is just what is needed to prevent water pollution while cleaning High Bridge in New York.

Stone cleaning and restoration company Thomann-Hanry, with its facade gommage dry, gentle abrasive cleaning system that does not require scaffolding, is gaining itself quite a reputation in America.

Having been asked to quote to clean New York’s 3,500-year-old version of London’s Cleopatra’s Needle earlier in the year using its enclosed, heavyweight cherrypickers, Thomann-Hanry was back in New York last month (September) at the request of New York-based Schiavone Construction, a specialist in complex, heavy construction projects, to offer a solution to the cleaning of High Bridge in Harlem. The bridge is a 15,000m² granite aquaduct that once supplied Manhattan with drinking water.

The instruction was all the more urgent because elements of the $45million dollar project had been put on hold when water run-off from the cleaning system that had started to be used was proving impossible to control. There were concerns it would contaminate the river, as well as annoying drivers using the expressway below the bridge.

Thomann-Hanry sent a crew to conduct a feasibility study and carry out cleaning samples. Sample cleans in various locations were approved by the conservators. Thomann-Hanry’s proposal for containing dust while working from mast climbers above a river, expressway and rail line were also adopted. Schiavone is now moving on to larger scale trials and Thomann-Hanry is confident this complex project will move forward successfully.

Thomann-Hanry MD Mark Styles commented: “Once again our unique facade gommage system has been proven and accepted as a safe and non-abrasive technique on one of the oldest and most important historical structures in NYC.

“We are determined to do everything we can to assist our clients wherever they may be in the world and are encouraged by the growing numbers of enquiries we deal with worldwide…”

Originating in France, the Thomann-Hanry’s facade gommage patented formula has been in operation in the UK since 2006 and continues to grow year-on-year.

But Thomann-Hanry strongly advise clients that a building survey before work starts can save time, money and unnecessary work, as it demonstarted to a client in London earlier this year.

The Grade 2 listed 18 Wellington Street in Aldwych had not been cleaned or maintained externally for more than 20 years. A large number of cracks had appeared in the render facade and were causing concern to both owners and tenants.

Faced with worst case estimates of £300,000 or more, Thomann-Hanry was employed to carry out a full structural survey of the building, including a hammer test of the facade from an aerial platform.

The results were marked on to photogrammetric elevation drawings and a full schedule of works was prepared.

The hammer test, combined with render analysis, revealed that the cracks only extended through the render and were not affecting the structural integrity of the building.

Following instruction, Thomann-Hanry made a listed building application on behalf of the clients and the 12 weeks work started last month (September).

Thomann Henri Technical Director Stephen Syfret says: “The initial inspection suggested that the render had failed in most areas and that the entire facade should be stripped off and re-rendered. When we undertook a visual and hammer-test survey from the aerial platform, we found that much of the render had not actually failed and was still in a reasonable condition, only requiring localised repairs.

“The mortar analysis revealed that the surface layer was cement-based. The cracks were a result of differential shrinkage between marginally incompatible materials and should only need consolidation, rather than repair, as this had not failed but had only crazed.

“The detailed survey showed that much of the historic fabric (and our client’s budget) could be spared.”

Restorative Techniques is high achiever

New products (with more promised) and an export drive with the help of UK Trade & Investment has put Restorative Techniques on a fast-track to high growth.

Restorative Techniques has come a long way since the company was formed in 2009 and looks as if it is going even further in the future as its cleaning products increasingly find interest in overseas markets.

There are currently five of Restorative Techniques’ Thermatech superheated water cleaning systems and a Vortech gentle abrasive system being used by Croydon stone and conservation specialist Stonewest in a project expected to last five years to clean up an area of Kowloon, on the Chinese mainland facing the island of Hong Kong.

The architect on the project is Purcell (previously Purcell Miller Tritton), with partner Brian Anderson being stationed in Hong Kong in an office that has now been opened there thanks to this project.

Another project using Restorative Techniques’ products is the cleaning of the famous sculptures of Jeddah – one of the largest collections of public sculpture in the world. Some are stone, others are in other media, such as steel. They are being renovated by Plowden & Smith, the London-based specialists in the conservation and restoration of fine and decorative arts. It was Plowden & Smith which was given the job of transporting the Tutankhamun exhibition when it came to the UK and the O2 arena in 2007.

For Restorative Techniques, projects like this have helped justify the time and effort that Directors Jamie and Julia Fairchild have devoted to UK Trade & Investment (UKTI), a Government scheme to help companies expand and grow abroad.

Much of the effort of UKTI – too much, some say – has gone to major corporations, but help is available to help smaller companies export as well and Julia Fairchild says she has been extremely pleased with the help she has received from the organisation.

She says UKTI has made experts available to Restorative Techniques to give advice on topics such as the pitfalls that can exist with exporting. “UKTI put us in touch with a really good shipping agent and we have been on courses for managing distributors and agents overseas,” she told NSS.

UKTI has put Restorative Techniques in touch with people in various regions of the World and advised on laws in other parts of the world regarding goods and trading. There is also always someone on the end of a telephone line to answer any queries – “And they don’t charge!” says Julia.

There is even money back on costs such as flights abroad. “You don’t get a huge discount but if you’re going to be doing it anyway it all helps.”

Restorative Techniques achieved such a high level of growth that it was put on a high growth programme (known as G3), only available to companies seeing more than 20% expansion.

The UKTI consultants have also offered advice on marketing and have emphasised the importance the internet now plays in reaching any market, which is something Restorative Techniques are now looking at. The cleaning product company has a website, of course, but UKTI has suggested some ways in which it could be developed further.

While exports are growing rapidly, most of Restorative Techniques’ business is still in the UK, of course, where sales are also growing nicely on projects such as the Houses of Parliament, Hampton Court Palace, The Tate art gallery and Battersea railway station.

New products (with more promised) have helped achieve that growth, which has necessitated recruiting two more engineers already with another on the cards.

Last year ThermaVac was introduced, which is a ThermaTech with vacuum recovery of the superheated water, which can be important on interiors where rooms can quickly fill with steam and water vapour.

Because ThermaTech uses water at 150ºC it requires a pretty special vacuum system to suck up the water. The ThermaVac system is currently being used by DBR in the House of Lords at Westminster and by Stone Edge on the Aloft Hotel conversion in Liverpool .

Now two customers have also asked Restorative Techniques to build ThermaTechs into Transit vans. The customers are supplying the vans, which Restorative Techniques are modifying to house diesel-powered ThermaTechs that can then be used without having to remove them from the vehicles.

Other new products have included Restorative Complex Paste, an EDTA-based sequestering / complexing agent for masonry cleaning presented as a paste, rather than a gel, so that it can be used more easily on open pored substrates.

There is a new impregnator called Restorative Surface Treatment that has particularly low visibility and will not add a shine to the stone, which is especially important for the heritage sector where it is expected to be particularly popular.

It is designed for floors in high traffic areas, where it can be re-applied as part of a regular maintenance regime without the need to remove previous applications.

It is specially formulated for Restorative Techniques and the company gave it a six month trial on Cotswold limestone before introducing it to the range. Whatever was thrown at it – including tomato sauce, wine and diesel – simply wiped off without a trace.

Even something as simple as pork or lamb chop brushes that many in the conservation sector like to use for cleaning joints or loosening particularly stubbord sulphation, for example, are now available from Restorative Techniques as the company aims to supply all the solutions for the stone cleaning and restoring sector.

Tensid celebrates 25 years with new Torik

Tensid celebrates its 25^th anniversary this year by introducing new superheated water and nebulous spray cleaning systems under the name of Torik.

This year Tensid is celebrating 25 years of supplying equipment and cleaning products to restoration cleaning contractors and conservators, as well as stone, brick and concrete manufacturers and suppliers. And it is still developing its product range. The company’s most recent launch is the Tensid Torik superheated water cleaning system.

This method of cleaning and its recognised benefits are not new. In fact, Tensid has been supplying cleaning equipment like this for many years. But products can always be improved and the new Torik system has been developed with both the user and specifier in mind.

It is available as standard in 110 volts to meet site requirements, although a 240V version is available on request.

Manufactured using high quality components, it comes with a set of three, quickly interchangeable lances. This, says Tensid, offers the contractor a reliable, high performance system at an affordable price with low maintenance costs, while the specifier gets ease of inclusion into superheated water cleaning projects.

Torik Nebulous is another addition to the Tensid family. Again, not a new way of cleaning but Torik nebulous has been developed to meet the high demands of the cleaning industry, which requires reliable equipment capable of meeting specification requirements.

It is built to provide a flexible cleaning system, with manifolds manufactured in 1.4m long, marine grade stainless steel. They can be linked together easily to clean large areas with the adjustable nozzles mounted on tough, flexible arms.

These nozzles can deliver anything from water droplets to ultra fine mist and are fitted with individual on/off valves for precise and detailed cleaning.

An easy mounting system to scaffolding is included and there is a built-in pressure gauge and timer.

This system was used by PAYE Stone to clean the Old War Office in Whitehall (see contribution below from Adrian Paye).

Cleaning masonry with poultices and latex material is one of the most gentle and safest ways of cleaning stonework yet can produce extraordinarily effective results.

One example where these Tensid products were used is at the Cenotaph in Whitehall when it was given a once-in-a-generation clean in readiness for the 100th anniversary of the start of the First World War next year, when it will be required to look its best as the country’s main focus for the remembrance.

Part of the monument was cleaned with superheated water, but the top, where heavier and deeper-seated contamination was disfiguring the stone, required an alternative approach.

What was used was Tensid’s Monumentique, a latex paste. It was applied with trowels, left for 24 hours to dry and form a film, then gently pulled off, taking the trapped soiling with it. The result is an effective deep-clean.

Monumentique is based on synthetic latex and cleans deeper seated stains as well as surface contamination.

Here, too, Tensid offers a new version of an established product. It is a new natural latex made by Prosoco and called Dri Klean, which is generally better suited for cleaning superficial surface soiling and especially for internal cleaning when the use of water is not possible or practical.

Clay poultices work in a similar way to latex. The appropriate poultice is applied to the soiled or stained area, left for an appropriate period depending on the level of contamination. Sometimes it helps if the poultice is covered with a plastic film to prevent it drying out prematurely.

The poultice will dissolve and mobilise the stains and soiling. At the end of the process, the remaining dry clay can easily and safely be removed and disposed off.

Tensid supplies a range of poultices that all work in a similar way but are individually formulated to deal with various types of staining – atmospheric, paint, copper, iron, oil or water.

Cleaning the statue of Shakespeare at Leicester Square and the Old War Office

by Adrian Paye

In the centre of Leicester Square is a Carrara marble statue of William Shakespeare, erected during the remodelling of the square in 1874.

Over the decades it has suffered from soiling from atmospheric pollutants and staining from chemicals used in the fountain water. PAYE was employed by Westminster Council to provide technical advice and to clean and restore the monument.

Following an initial clean using superheated water to remove loosely adhered surface staining, various poultices were trialled to establish the most appropriate cleaning solution. These included Monumentique Paste, 1260 Poultice and Marble Poultice. Two applications of Tensid 1260 with a dwell time of 72 hours per coat was proven to be most effective, and this was also undertaken on the marble dolphins, bowl and surrounding plinth.

The cleaned and restored statue now stands proudly in the centre of the recently refurbished square.

At the Old War Office the Portland stone facades were cleaned using carefully controlled volumes of water delivered as fine nebulous sprays.