Blog, Building Repair, Cleaning

Complete Guide to Steam DOFF Cleaning – Dust and Organic Film Removal

Steam DOFF (Dust and Organic Film Removal) is an advanced cleaning method used for the restoration of various surfaces, particularly historic buildings and delicate structures. This guide provides a step-by-step process for effectively implementing Steam DOFF cleaning.

What is Steam DOFF Cleaning?

Steam DOFF cleaning involves the use of superheated steam to remove dirt, grime, and other contaminants from surfaces without causing damage. This method is especially suitable for sensitive materials and historical structures.

Where is Steam DOFF (Dust and Organic Film Removal) Cleaning Used

Steam DOFF cleaning is a specialized cleaning method that utilizes superheated steam to remove dirt, grime, and contaminants from various surfaces. It is particularly suitable for delicate or historically significant structures where traditional abrasive cleaning methods might cause damage. Here are some common applications and locations where Steam DOFF cleaning is used:


  • Historic Buildings:
    Steam DOFF cleaning is widely used to clean and restore historic structures, including architectural details, facades, and ornamental elements. Often features part of a holistic heritage FM package.
  • Monuments and Statues:
    It is employed to clean and revitalize monuments and statues made from sensitive materials like stone or metal.
  • Churches and Cathedrals:
    Steam DOFF is chosen for cleaning intricate details on church exteriors, stained glass windows, and other delicate surfaces.
  • Public Art Installations:
    Sculptures and public art installations made from materials that require gentle cleaning benefit from the precision of Steam DOFF.
  • Government Buildings:
    Many government buildings with historical significance use Steam DOFF to maintain the appearance of their facades and architectural features.
  • Residential Properties:
    In certain cases, Steam DOFF may be applied to residential properties, especially those with historic or delicate architectural elements.


  • Urban Environments:
    Steam DOFF cleaning is often used in urban areas where pollution and environmental contaminants can accumulate on building surfaces.
  • Countryside and Rural Areas:
    Historic structures in rural or countryside locations, away from urban pollution, can also benefit from Steam DOFF cleaning.
  • Tourist Attractions:
    Landmarks and tourist attractions with historic structures frequently use Steam DOFF to maintain the visual appeal without causing damage.
  • Heritage Sites:
    Sites with cultural or heritage significance, such as ancient ruins or archaeological structures, may employ Steam DOFF for cleaning.
  • Museums and Galleries:
    Steam DOFF is considered in museums and galleries where preserving the integrity of artefacts or building elements is crucial.
  • Commercial Buildings:
    Some commercial buildings with intricate facades or architectural details opt for Steam DOFF cleaning for a gentle and effective restoration.
Steam DOFF cleaning

RFM Group recently used Steam DOFF cleaning as part of a full facade upgrade and renovation at King Edward VI (KEVI), Handsworth School.

How Steam DOFF Cleaning Works

Steam DOFF cleaning operates on the principle of using superheated steam to remove contaminants from surfaces. Here’s a breakdown of the process:

  1. Superheated Steam Generation:
    • The DOFF machine generates superheated steam by heating water to high temperatures under pressure.
    • Steam is produced at temperatures exceeding 150°C (302°F) and is delivered through a nozzle.
  2. Thermal Shock:
    • The high-temperature steam causes a thermal shock when it comes into contact with the surface to be cleaned.
    • This shock breaks the bond between the contaminants and the surface.
  3. Low Pressure:
    • Steam DOFF operates at low pressure to prevent damage to delicate surfaces.
    • The low-pressure steam effectively penetrates and lifts dirt without causing harm.
  4. No Chemicals:
    • Unlike some cleaning methods, Steam DOFF does not rely on chemicals for cleaning.
    • It is an environmentally friendly process, using only water.
  5. Precision Control:
    • Operators have control over the steam pressure and nozzle distance, allowing for precise cleaning tailored to different surfaces.

What Steam DOFF Can Remove

  • Organic Growth:
    • Steam DOFF is effective against organic growth such as moss, algae, and lichens.
    • The high temperature kills and dislodges these growths from surfaces.
  • Dirt and Grime:
    • It can remove accumulated dirt, dust, and atmospheric pollutants from various surfaces.
  • Paint and Graffiti:
    • While not primarily designed for paint removal, Steam DOFF can soften and facilitate the removal of certain types of paint or graffiti.
  • Microorganisms:
    • The high-temperature steam helps eliminate bacteria and other microorganisms on the treated surface.
  • Stains:
    • Steam DOFF is effective against various types of stains, including water stains and mineral deposits.
  • Oil and Grease:
    • It can break down and remove oil and grease deposits on surfaces.
  • Airborne Pollution Residue:
    • The method is successful in removing residue from airborne pollutants and environmental contaminants.
  • Architectural Soot:
    • Steam DOFF can be used to clean architectural soot from surfaces, restoring the original appearance.

It’s important to note that the effectiveness of Steam DOFF cleaning depends on factors such as the type of surface, the nature of the contaminants, and the expertise of the operator. Professional assessment before implementing Steam DOFF cleaning is crucial to ensure the method’s suitability for the specific cleaning requirements.

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The Benefits of Steam DOFF Cleaning

The use of Steam DOFF cleaning offers several benefits, making it a popular choice for various applications, especially in situations where delicate or historically significant surfaces need to be cleaned. Here are some key benefits of Steam DOFF cleaning:

  • Gentle and Non-Abrasive:

    • Steam DOFF cleaning is non-abrasive and gentle on surfaces. It does not involve harsh chemicals or abrasive materials, making it suitable for delicate materials like historic stone, brick, and wood.
  • Preservation of Historic Structures:

    • It is particularly effective for the cleaning and restoration of historic buildings and monuments, helping preserve architectural details without causing damage.
  • Environmentally Friendly:

    • Steam DOFF cleaning relies solely on superheated steam and does not require the use of chemicals. This makes it an environmentally friendly and sustainable cleaning method.
  • Efficient Removal of Contaminants:

    • The high-temperature steam effectively breaks the bond between contaminants and surfaces, making it highly efficient for the removal of dirt, grime, organic growth, and other pollutants.
  • Safe for Sensitive Materials:

    • Because it operates at low pressure, Steam DOFF is safe for use on sensitive materials such as historic stonework, delicate carvings, and friezes.
  • Versatility:

    • Steam DOFF can be used on a variety of surfaces, including stone, brick, concrete, metal, and more. Its versatility makes it suitable for diverse cleaning applications.
  • No Residue Left Behind:

    • Since Steam DOFF uses only water, there are no chemical residues left behind after the cleaning process. This is especially important for surfaces where residue could be detrimental.
  • Effective against Biological Growth:

    • It is highly effective in removing and killing organic growth such as moss, algae, and lichens, contributing to the long-term maintenance of surfaces.
  • Precision Control:

    • Operators have precise control over the steam pressure and nozzle distance, allowing for tailored cleaning based on the specific needs of different surfaces.
  • Reduced Water Consumption:

    • Compared to traditional cleaning methods, Steam DOFF generally requires less water, contributing to water conservation efforts.
  • Enhanced Safety:

    • The low-pressure steam and absence of chemicals make Steam DOFF a safer cleaning method for both operators and the environment.
  • Minimal Disruption:

    • Steam DOFF cleaning often requires less downtime for the cleaned area, minimizing disruption to the surrounding environment. 
water droplets on gray surface

Complete Guide to Steam DOFF Cleaning Process

Equipment and Safety Precautions

Equipment Required

  1. DOFF Machine: This is the primary equipment that generates superheated steam.
  2. Hoses and Nozzles: Different nozzles can be used for various surfaces.
  3. Water Supply: A clean water source is essential for the DOFF machine.
  4. Protective Gear: Personal protective equipment (PPE) includes gloves, safety glasses, and appropriate clothing.

Safety Precautions

  1. Training: Ensure operators are trained on the proper use of the DOFF machine.
  2. Protective Gear: Wear appropriate PPE to prevent burns and injuries.
  3. Environmental Considerations: Consider the environmental impact and take necessary precautions.
  4. Surface Assessment: Assess the surface to be cleaned for any vulnerabilities.

Step-by-Step Steam DOFF Cleaning Process

Step 1: Site Assessment

Before starting the cleaning process, assess the condition of the surface to be cleaned. Identify any fragile areas or sensitive materials that may require special attention.

Step 2: Setup and Preparation

  1. Connect the DOFF Machine: Attach the hoses and select the appropriate nozzle for the surface.
  2. Water Supply: Ensure a steady water supply to the DOFF machine.
  3. Test Run: Conduct a test run in an inconspicuous area to determine the ideal steam pressure and nozzle distance.

Step 3: Pre-Cleaning

  1. Remove Loose Debris: Use a soft brush or compressed air to remove loose debris from the surface.
  2. Pre-Wet the Surface: Pre-wet the surface with water to enhance the effectiveness of steam cleaning.

Step 4: Steam Cleaning

  1. Adjust Steam Pressure: Set the DOFF machine to the recommended pressure for the specific surface.
  2. Maintain Consistent Distance: Keep a consistent distance between the nozzle and the surface to avoid damage.
  3. Overlap Cleaning Passes: Ensure overlapping passes to achieve thorough cleaning.
  4. Monitor Progress: Constantly assess the cleaning progress and adjust settings if necessary.

Step 5: Post-Cleaning

  1. Inspect the Cleaned Surface: Examine the cleaned surface for any remaining contaminants or damage.
  2. Rinse if Necessary: Rinse the surface with clean water if residue is present.
  3. Dry the Surface: Allow the surface to air dry naturally.

Step 6: Final Inspection

  1. Assess Results: Evaluate the overall success of the cleaning process.
  2. Document Findings: Document any specific challenges encountered or special considerations.

Restore and Preserve

Steam DOFF cleaning is a powerful and versatile method for restoring surfaces while preserving their integrity. Following this comprehensive guide will help ensure a safe and effective cleaning process, yielding outstanding results without compromising the structural integrity of the treated surfaces.

A full glossary of cleaning terms can be found in RFM Group’s Industry Terms in Cleaning Glossary.

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