Specialist DOFF Steam
Cleaning for Heritage
& Sensitive Surfaces

What Is DOFF Cleaning and When Is It Required?

DOFF cleaning is a specialist steam cleaning system that delivers superheated water at temperatures up to 150°C at very low pressure. This unique combination makes it the industry standard for cleaning delicate, historic, and listed building surfaces where conventional pressure washing would cause irreversible damage.

The system is specifically designed for natural stone facades, terracotta, faience, brick, render, and masonry surfaces that cannot withstand high-pressure mechanical cleaning. Conservation officers, architects, and heritage bodies regularly specify DOFF cleaning as the approved method for restoring protected structures.

DOFF cleaning is also highly effective on modern buildings where delicate cladding, coated render, or polished stone requires cleaning without any risk of etching, pitting, or coating removal. If your building has surfaces that demand a careful approach, DOFF is the correct system.

Marsh Exterior Cleaning operates DOFF equipment across Liverpool, Manchester, Wirral, Cheshire, and the wider North West, serving property owners, managing agents, local authorities, and construction firms requiring post-build or remedial cleaning.

The Real Cost of Incorrect Cleaning Methods

Using standard high-pressure washing on heritage or sensitive surfaces is one of the most common and costly mistakes property owners make. Excessive pressure strips protective patina from natural stone, drives water deep into masonry cores, and can dislodge pointing from centuries-old mortar joints.

Chemical cleaning agents pose equally serious risks. Acidic solutions etch limestone and marble surfaces permanently, while alkaline treatments can cause efflorescence — persistent white salt deposits that are extremely difficult to reverse.

Biological growth left untreated accelerates material decay. Black biological crusts on sandstone and limestone trap moisture against the surface, promoting freeze-thaw damage in winter. Over time, this leads to surface delamination that cannot be repaired — only replaced at significant cost.

For listed buildings and properties within conservation areas, unauthorised or damaging cleaning methods can result in enforcement action and legal liability. DOFF cleaning provides a method that satisfies conservation requirements while delivering exceptional results.

We Use the DOFF Integra System

Marsh Exterior Cleaning operates the DOFF Integra — the market-leading superheated steam cleaning system engineered by Stonehealth Ltd. The DOFF Integra is the industry's most advanced system for removing paint coatings, graffiti, bird fouling, algae, moss, fungi, wax coatings, chewing gum, bitumen, oil, and grease — all without causing any damage or disfiguring the substrate.

The system feeds a normal water supply through a pump into a hotbox where it is rapidly heated to temperatures of up to 150°C. The low volume of superheated water and steam — just 3 to 5 litres per minute — is then delivered through heat-resistant hoses to specialist nozzles. The surface being cleaned suffers no damaging pressure, thermal shock, or deep saturation, and dries within minutes.

We recommend the DOFF Integra for brick, stone, concrete, glazed and encaustic tiles, wood, faience, and terracotta surfaces. It is also effective as a sterilisation tool for commercial kitchens, hospitals, factories, and food production environments.

DOFF Cleaning: Technical Specifications & Applications

The DOFF system was originally developed for the heritage and conservation sector, where no other cleaning method could safely remove decades of atmospheric soiling from delicate stonework. It operates using a diesel-fired boiler unit that heats mains water to temperatures between 60°C and 150°C, delivered through a lance at pressures as low as 0.5 bar — less than a garden hose.

This combination of extreme heat and minimal pressure is what makes DOFF uniquely suitable for surfaces that would be damaged by conventional methods. The heat breaks molecular bonds in biological growth, paint films, and atmospheric deposits, allowing them to be flushed away without any mechanical force acting on the substrate.

On sandstone facades, DOFF removes black biological crust — the hard, dark layer formed by centuries of pollution and biological activity — revealing the original warm tones of the stone beneath. This process is standard practice on Georgian, Victorian, and Edwardian buildings across Liverpool and the North West.

Limestone and Portland stone respond exceptionally well to DOFF treatment. These calcium-based stones are particularly vulnerable to acid rain and chemical cleaning, making DOFF the only safe mechanical option for thorough cleaning.

For brick facades, DOFF removes paint layers, limewash, bituminous coatings, and mortar smears without disturbing the fired surface of the brick or the integrity of the pointing.

Terracotta and faience — glazed architectural ceramics common on Victorian and Edwardian commercial buildings — require extremely careful treatment. DOFF's low-pressure delivery avoids chipping or crazing glazed surfaces while effectively removing surface contamination.

Modern applications include cleaning polished granite, coated aluminium cladding, GRC panels, and reconstituted stone. We also use DOFF for removing chewing gum from commercial paving.

For large-scale projects, we work alongside scaffolding contractors and access specialists to ensure complete coverage of multi-storey elevations. Our team holds IPAF, PASMA, and working-at-height certifications as standard.

Protect Your Building's Character

Get a free assessment and method statement for conservation-grade DOFF cleaning. We respond within 24 hours.

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