CLEANING TECHNIQUES

The system and specification for the cleaning of any surface should be carefully considered before embarking on any project. Too often we have seen irreparable damage caused by the use of an inappropriate system, too harsh a chemical or too abrasive blast media. Unfortunately we also still see poorly or even completely untrained operatives damaging the industry as well as the building and themselves.

RCR Ltd operates all the industry standard systems used to sympathetically but effectively clean the soiled masonry surfaces associated with our built environment. Each technique is carefully chosen for the individual situation, with due consideration of:

  • the type of surface to be cleaned
  • the type & degree of contaminant
  • environmental factors
  • speed
  • cost
  • access requirements

We will advise on the best system and produce a detailed specification if required for any proposed project free of charge. Early consultation will undoubtedly reduce costs overall and produce the best finish available. We operate all the systems to the highest standard using a suitably supervised fully trained and experienced workforce.
 
We have the facilities for all the following types of cleaning systems:

Nebulous Water Spray

Dirt is deposited on buildings mainly dissolved in rainwater. When this water evaporates the dirt is left behind. Reversing this process by dissolving the dirt by the application of mist sprays of water to the surface and then brushing or jetting away the resultant is one of the simplest ways of cleaning buildings. This operation still requires a high degree of skill to prevent over saturation of the fabric and consequent damage and is limited to a
light degree of soiling only.

Willett House on the south side of Sloane Square. This impressive Portland Stone building was cleaned using traditional water techniques. Carefully controlled and monitored mist sprays of clean cold water were used to soften the surface contaminants assisted with soft bristle brushes. Finally the façade was washed down with high-pressure water jetting equipment to remove all traces of dirt. This process was all carried out at night to avoid any undue inconvenience to the occupants and shoppers underneath.

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Chemical Cleaning

A wide variety of chemicals are available from light degreasers to highly aggressive acids and alkalis. A detailed knowledge of these chemicals and their properties is paramount before their use is recommended in any situation. RCR Ltd will evaluate the cleaning requirement and develop the correct system if chemicals are appropriate     

A large residential block of exclusive apartments in St Johns Wood. 10,000 sq m of external brick and stone was cleaned and restored on a fixed price lump sum contract. This type of contract has been exclusively developed by RCR to give its clients total assurance over the eventual total cost of their projects.

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Sand/Grit blasting

With this system, a blast media (sand, slag aggregate, glass beads etc) is applied to the surface to be cleaned through a pressurized vessel or pot. It is the impact of the aggregate with the surface that removes the contaminant. It is possibly the inappropriate use of this system which can produce the most devastating damage, so its recommendation and usage should be very carefully considered. When specified and operated correctly however it can produce exactly the required finish with minimal damage to the fabric or the surroundings.

The famous auctioneers Christies occupy a complete block of buildings in St James. When the time came to clean the outside RCR were consulted to offer the best solution. The problem was the priceless works of art stored in the basements underneath pavements which leaked water. Obviously a water based cleaning system was out of the question so a light sandblast used with minimal water to reduce dust. This system proved quick, effective and overcame any risk of damage to the artwork.

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JOS (soft abrasive)

A specialist form of wet sandblasting where the blast media is applied at low pressure through a special nozzle which directs the abrasive at the masonry in a swirling vortex.  The advantage of this system is that the media hits the wall at an oblique angle which softens the impact.  Whilst slow, and consequently relatively expensive, this system is approved by English Heritage for sensitive applications such as listed or historic buildings.

Latex Film

Where the use of water would be difficult, ie the interior of a church over a timber floor, and only light soiling is required to be removed, the application of a Latex is a very useful technique. Once applied the Latex draws out the soiling and becomes transparent to indicate the process has finished. The latex is then peeled off, removing the dirt at the same time. A number of different types of Latex are available with different properties and strengths so samples should be carried out to discover the most appropriate.

Steam

Whether on its own or in conjunction with chemicals, steam cleaning is very effective at removing heavy greasy staining and in particular paint stripping. Very high-pressure steam systems are now available such as DOFF.

It is essential to choose a cleaning contractor able to carry out all the above systems to a high standard as usually two or more techniques will be required on any one project to produce the desired result.