What is the DOFF System?
The DOFF is a superheated steam cleaning system manufactured by Stonehealth Ltd, widely regarded as the most effective and safest method of cleaning historic and sensitive masonry. Water is heated to temperatures of up to 150°C and delivered at very low pressures — typically as low as 15 bar — meaning the cleaning power comes from heat rather than force. This makes it ideal for fragile stonework, soft sandstone, brick, terracotta, render and other materials that would be damaged or eroded by conventional pressure washing.
What can it clean?
The DOFF system removes paint (including layers of historic painted finishes), graffiti, biological growth including moss, algae, lichen and mould, atmospheric carbon soiling and grime, oil and grease deposits, and general weathering staining. Because the steam penetrates deep into the pores of the stone, it kills biological spores at source — meaning surfaces stay cleaner for significantly longer compared to other methods.
Safe for listed buildings and sensitive structures
The DOFF system is the only method approved by Historic Environment Scotland for use on Scotland's most sensitive and protected buildings. It leaves no chemical residue, produces no run-off that could cause environmental harm, and does not alter or damage the surface profile of the material being cleaned. For building owners, this means full compliance with planning and listed building consent conditions.
Every job starts with a test panel
Before any full clean, we carry out a test area on your building to confirm the correct temperature, pressure and nozzle settings for your specific material. This ensures a perfect result every time and gives you visible proof of what to expect before the full work begins.
Stonework Restoration section (replaces/expands the current brief text):
The DOFF machine uses low pressure superheated steam to clean historic and fragile masonry without causing any damage to the substrate. The high temperature instantly kills all moss, algae and lichen spores as it works, which means your stonework stays cleaner for significantly longer than with pressure washing or chemical treatments. Ideal for sandstone, granite, brick and render, it restores buildings to their natural finish while protecting the integrity of the stone for years to come.
