Street Cleaning/Graffiti Removal
Why natural stone facades should be cleaned
Barry J Hunt, chartered geologist and corporate building, conservation and specialist surveyor, reports.
TheRitz cleaned in just 16 days
Situated in Piccadilly, the Ritz is one of Lon- don’smost celebrated hotels. For over a century the hotel has been the benchmark by which other hotels aremeasured. A Lon- don landmark at 150 Piccadilly, the Ritz has been home to thousands of discerning guests since 1906, counting distinguished and renowned individuals amongst its clien- tele. Unfortunately, over time, the British
weather and pollution have taken their toll on the appearance of the stone façade, causing a worry to owners in wanting to up- hold the hotel’s reputation. To bring it back up to its impeccably high standards, the Ritz’smanagement teamselected Thomann-Hanry’s unique ‘façade gom- mage’ cleaning system. Requiring no scaffold, the façade gom-
mage systemis a uniquemasonry cleaning systemthat rejuvenates exteriors via an in- novative and slickmethod that is cost-effec- tive, super quick and does not interfere with the normal running of your business. The transformation would see the total project of 3600m2
of Portland stone and Cornish
grey granite, including intricatemoulding and decorative carving, cleaned in less than three weeks. The surface of the building itself was ex-
Stone is often thought to be timeless. Un- derground in the conditions of heat and pressure that created it, stone survives for millions of years. Brought to the surface it comes under attack both fromthe elements and fromman. Stone therefore needs to be protected andmaintained instead of being assumed to last forever. Nevertheless there is a potential conflict
between whether any adhering dirt or weathered veneer is in equilibriumwith the environment and should not be upset, and whether the build-up of dirt thatmay lead to breakdown of the stone should be prevented. It would appear, however, thatmuch of
the negativity surrounding the cleaning of natural stone facades is the result of poor research and improper selection of cleaning techniques. If cleaning is not undertaken at all or too late, stonemay have suffered a level of irreversible decay. The primary concern is to prevent dirt
build-up, principally fromairborne particu- lates thatmay contain a range of potentially problematicmaterials that can react with the stone and reduce its life. Regular clean- ing will help to identify areas where there is above normal build-up of dirt and salts that may be indicative ofmore far-reaching problems which, if rectified at an early stage,may have considerable cost benefits in the longer term. Damp areas are particularly likely to at-
tract dirt, especially in a wet climate, and can be identified as a result of a clean if not already apparent. Thick layers of grime can retain water against or withinmasonry re- sulting in increased salt cycling in thema- sonry and accelerated deterioration. Such
26 l C&M l SEPTEMBER 2014 l
www.cleaninghub.net
Above and below: the façade gommage system requires no scaffold, and rejuvenates exteriors via an innovative and slickmethod that is super quick and does not interfere with the normal running of a business. At the Ritz, 3600m2
of
Portland stone and Cornish grey granitewere cleaned in less than threeweeks - and the traffic kept flowing.
discoveriesmay also be indicative ofmore far-reaching problems that, if rectified at an early stage,may have considerable cost benefits in the longer term. The removal of a seedling, for example,may prevent later damage fromtree root growth and consid- erable disturbance tomasonry, while dirt and stainingmay obscure evidence of struc- tural failures in themasonry that could lead to eventual significant failures, for example stone falling onto adjacent public walkways. The key to cleaning natural stone facades
is a combination ofminimumimpact and great care and attention. Advances in un- derstanding stone and cleaning technolo- gies along with the greater ease of access, havemeant there are now generally far fewer issues arising fromthe various clean- ing techniques. Building owners should therefore be considering regular cleaning maintenance rather than leaving the fa- cades to the lottery of the elements.
tremely dirty. Having not been touched for over 20 years, the hotel experiences a high level of traffic outside it, a problemfrom being situated on one of London’s busiest streets. Defying traditional industry prac- tice, the cleaning was carried out scaffold- free, allowing the hotel to remain fully functional. And with high footfall from tourists, also decreased the dangers result- ing fromworking at height. Guests, too, benefited fromthe unnecessary blight of scaffolding, allowing the hotel to keep all of its 137 guest bedrooms and suites open, ensuring roomoccupancy wasn’t affected. Mark Styles,MD of Thomann-Hanry, said:
“Our unique façade gommage systemis perfect for hotels - when first impressions truly count, a dirty and unlooked after façade cast doubts in your guestsminds be- fore they’ve even set foot in your lobby. Our systemis unrivalled and, inmost cases, projects can only take amatter of days in comparison to the lengthy process of scaf- folding. Not only does this save time, but it means the building can function as normal while the work is taking place.” The Ritz saw a dramatic transformation,
as years of built up dirt on themasonry was broken down via the non-abrasive façade gommage process. Stephen Boxall,MD of the Ritz, said: “We
are delighted with the results of the clean to the exteriormasonry of the hotel.We were particularly conscious that the work did not cause any inconvenience or disturbance ei- ther to our hotel guests or to pedestrians and traffic in Piccadilly. The efficiency and speed with which Thomann-Hanry were able to complete the project has been quite astounding.”
www.cleanbuildings.co.uk
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