Cleaning & Hygiene


Cleaning stone façades – don’t ignore the buildings’ exterior this summer


Don’t ignore your buildings’ exterior this summer. If stone buildings aren’t cleaned as part of the maintenance cycle, the stone may suffer a level of irreversible delay. These, often historic buildings, must be maintained properly before permanent damage is inflicted.


M


ark Styles, managing director of leading stone cleaning and restoration experts, Thomann-Hanry,


is concerned that a buildings’ exterior is often not prioritised as it should be. “The façade of a building is too often left to battle with the elements, with most building owners and facilities managers opting to look after the interiors of their building rather than the exterior. We’ve worked on a vast array of projects where the build-up of dirt has caused a building’s material to become almost unrecognisable, most commonly found to be caused by a 24/7 city lifestyle and the heavy pollution this environment creates.” The primary concern is to prevent dirt build-up, principally from airborne particulates that may contain a range of potentially problematic substrates that can react with the stone and reduce its life. Regular cleaning helps to identify areas where there is above normal build-up of dirt and salts that may be indicative of more 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 attract 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 within masonry resulting in increased salt cycling in the masonry and accelerated deterioration. “Most stone façades are normally quite easy to treat, and with the nature of our scaffold-free system it’s possible to arrive on site and get up and running within two hours.” continues Mark Styles of Thomann-Hanry. “The main difficulties come when dirt or soiling includes disfiguring pollutant or sulphate crusts, which usually build up in sheltered or protected areas not regularly washed by the natural action of rain. They are


Building & Facilities Management – May 2015


particularly common under


cornices, window sills, or


other projecting decorative features – common with buildings in London – and if left for some time untreated, the removal process can sometimes involve a loss of a small amount of stone resulting in further costs and issues to building owners alike.” Thomann-Hanry’s unique ‘Façade Gommage’® technique cleans the exterior of buildings avoiding scaffold which is a huge benefit. Lack of scaffold also ensures vastly improved security during the operational period – a particular benefit to sectors where security is paramount such as banks or hotels. Mark Styles of Thomann-Hanry concludes, “When considering an exterior clean, using a unique system that does not require the use of scaffold, such as the non-abrasive ‘Façade Gommage’® system from Thomann- Hanry, can make the works significantly easier. Business can run as usual minimising loss of trade, maximising profit potential and maintaining an ‘as normal’ functionality, whatever the business. Not only do we have a number of high profile banks and hotels as clients but interestingly many leading property companies – Land Securities, Grosvenor Estates to name a couple – have chosen the scaffold-free technique when cleaning their own buildings, which has to be the best endorsement ‘going scaffold-free’ can get.”


Cleaning and restoration is undertaken from a cabin fixed to a hydraulic boom which methodically travels up and down the building. The ‘Façade Gommage’®


patented formula uses an ultra-fine, nonabrasive cleaning powder, softer than the masonry surfaces being cleaned but strong enough to weaken dirt without causing damage. Once removed, the dirt is collected and recycled on completion. The key to cleaning natural stone façades is a combination of minimum impact and great care and attention. Advances in understanding stone and cleaning technologies along with the greater ease of access, have meant there are now generally far fewer issues arising from the various cleaning techniques. Building owners should therefore be considering regular cleaning maintenance and surface protection products rather than leaving the façades to the lottery of the elements this summer. “Stone is often thought to be timeless. Underground 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 from the elements and from man. Stone therefore needs to be protected and maintained instead of being assumed to last forever


.” Barry J


Hunt, Chartered Geologist and Corporate Building, Conservation and Specialist Surveyor www.cleanbuildings.co.uk


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