DOFF (Directed Output of Forced Steam) is a specialist facade cleaning method used on buildings to safely remove biological growth, pollution staining, paint residues, and grime using superheated steam at low pressure. This is. without chemicals, damaging the surface, and saturating the substrate.
At All Clean London, our qualified rope access technicians carry out DOFF facade cleaning on high-rise and hard-to-reach commercial buildings throughout the city.
What Is DOFF Steam Cleaning?
DOFF is a superheated steam cleaning system developed by Stonehealth that heats water to temperatures of up to 150°C and delivers it at low pressure to the surface being cleaned.
The combination of extreme heat and controlled pressure is what makes it effective, the steam penetrates and lifts biological matter, staining, and residues at the root, rather than simply blasting the surface with water.
Unlike high-pressure washing, the low-pressure delivery means there is no risk of damaging delicate masonry, eroding pointing, or saturating the wall, making it one of the safest methods available for facade cleaning, particularly on older or heritage buildings.
What Does DOFF Machines Remove?
DOFF steam cleaning is effective at removing a wide range of contaminants commonly found on buildings:
- Algae, moss, and lichen: Biological growth that embeds into stone, brick, and concrete over time.
- Carbon pollution and traffic grime: Particularly common on buildings in central city areas, where decades of pollution leave deep grey staining.
- Paint residues and coatings: Previous applications of paint, sealants, or surface treatments.
- Graffiti: Including spray paint and marker on masonry surfaces.
- Biological staining: Bird droppings, fungi, and organic matter that discolours facades.
- General environmental build-up: Dust, dirt, and airborne particulates that accumulate on exposed surfaces.
Because the method uses heat rather than chemicals, biological matter is not just removed, it is killed at the source, significantly slowing regrowth compared to chemical treatments that leave residues behind.
Why Is DOFF Cleaning Suited to Buildings in London?
London’s commercial building stock presents a specific set of challenges that make DOFF steam cleaning particularly well suited to the city.
Many buildings in central London are constructed from stone, brick, and terracotta that has been exposed to decades of traffic pollution, weathering, and biological growth.
These materials require a cleaning method that is both thorough and gentle enough not to cause surface erosion or accelerate deterioration.
DOFF cleaning meets both requirements. The low-pressure delivery protects delicate or aged substrates, while the superheated steam achieves results that pressure washing and chemical cleaning often cannot match on porous materials.
It is also approved for use on listed and heritage buildings, making it one of the few methods suitable for London’s significant stock of protected and historically sensitive commercial properties.
Additionally, DOFF cleaning uses no chemicals, which is increasingly important for commercial landlords and property managers operating under sustainability frameworks or ESG commitments.
How Does All Clean London Carry Out DOFF Facade Cleaning?
For ground-level or low-rise facades, DOFF cleaning can be carried out from the ground using extended lances.
For multi-storey and high-rise commercial buildings, which make up a significant proportion of our work across London, our qualified rope access technicians abseil the facade, carrying the DOFF equipment with them and cleaning methodically from the top of the building downward.
This approach allows us to reach every section of a facade regardless of height or configuration, including areas above canopies, around architectural details, and on buildings where cherry picker or scaffolding access is impractical or cost-prohibitive.
Our technicians are fully trained and hold rope access qualifications to IRATA standards, and all work is carried out in full compliance with working-at-height regulations. See exactly how our team approaches a high-rise facade clean using the DOFF system in the video at the end of this post.
What Types of Buildings and Surfaces Is DOFF Cleaning Suitable For?
DOFF steam cleaning is suitable for a wide range of commercial building types and surface materials:
Suitable surfaces:
- Natural stone (limestone, sandstone, granite)
- Brick and terracotta
- Concrete and render
- Heritage masonry and listed building facades
- Monuments and decorative stonework
Building types:
- Office buildings and corporate headquarters
- Hotels and hospitality venues
- Retail and mixed-use developments
- Apartment blocks and residential towers
- Historic and listed commercial properties
Not recommended for:
- Surfaces where paint or coating removal is not desired
- Certain metals or coated panels where heat could cause damage
- Any surface where the existing condition requires a survey before treatment
If you’re unsure whether DOFF cleaning is right for your building, our team can carry out an assessment and recommend the most appropriate method.
How Much Does DOFF Facade Cleaning Cost in London?
DOFF facade cleaning costs vary depending on the size of the building, the area of facade to be cleaned, the level of soiling, and the access method required. Buildings requiring rope access or specialist equipment will carry higher costs than straightforward ground-level cleans.
As a general guide, commercial facade cleaning in London is typically priced per square metre or as a project rate following a site survey:
- Small retail unit or single-storey building: £300 – £600
- Medium commercial building (2–4 storeys): £600 – £1,200
- Large office block or multi-storey site: £1,200 – £2,500+
- High-rise or complex facade: £2,500 – £5,000+
Where DOFF steam cleaning is specified, particularly for heritage surfaces, listed buildings, or heavily soiled stonework, costs may sit at the higher end of these ranges due to the specialist equipment and expertise involved.
For a full breakdown of what influences facade cleaning costs in London, see our facade cleaning cost guide.
For an accurate quote tailored to your building, contact our London team today.
Frequently Asked Questions
Most commercial buildings benefit from a professional facade clean every two to five years, depending on their location, exposure, and the rate of biological growth or pollution build-up. Buildings in high-traffic or high-pollution areas of central London may require more frequent treatment.
See A DOFF Machine In Action
Our qualified rope access technician carried out specialist facade cleaning using a DOFF steam system on a high-rise commercial building in London; removing biological matter, pollution, and grime without chemicals or high-pressure water.
Watch more videos from All Clean London on our TikTok page.
Summary
DOFF steam cleaning is one of the most effective and surface-safe methods available for facade cleaning. Using superheated steam at low pressure, it removes algae, moss, pollution staining, and paint residues from stone, brick, concrete, and heritage masonry without chemicals or surface damage, and is fully approved for use on listed buildings.
Request a free quote today and keep your building’s facade clean, protected, and performing at its best.
