Thomann-Hanry® occupy a unique position in the crowded building conservation sector

Unlike competitors in the façade cleaning and refurbishment market, the company offers a non-scaffold solution known as façade gommage®. This patented process projects fine powders under low pressure across masonry and stonework, gently erasing decades of accumulated grime to reveal the building as it first appeared.

There are some particularities about this unique and innovative approach to façade cleaning and building restoration. Many of your questions can quickly be answered by exploring our comprehensive collection of frequently asked questions.

façade gommage® façade cleaning system

What is façade gommage®?

façade gommage® is a patented scaffold-free facade cleaning system created and developed by Thomann-Hanry® in Paris. ‘Gommage’ is a French term that refers to the process of gently cleaning masonry.

How does it works?

Projected under low pressure from a cabin mounted on a hydraulic boom, ultra fine dry particles flow across all surfaces, gently rubbing away decades of accumulated dirt and grime in a matter of days. It is Chemical-free and uses minimal water. The process also offers impeccable environmental credentials as the inert cleaning powder we use is a recycled by-product of aluminium smelting and, at the end of the process, all cleaning residues are again recycled.

What is the façade gommage® powder?

The powder used is 25-50-micron aluminium silicate crystals.

How is it formed?

It is a waste product from the aluminium smelting process which we then grind down to a fine powder.

façade gommage® is not the same as shot blasting/sandblasting. What is it that makes the system non-abrasive?

façade gommage® powders are very light but sharp and do not have the mass or energy to abrade the stone in any way. Furthermore, the system operates at a very low pressure of around 4 bar.

The powder removes dirt from surfaces under low pressure with a gentle rubbing action rather than by blasting.

How is it compared to other systems such as JOS/Torc, for example?

The Mohs for JOS/Torc is 6.5/7 which is a great deal higher than the rating of 1 for the gommage powder.

Under what pressure is the system operate?

The system operates at a very low pressure of around 4 bar.

Can the pressure use to project powder vary?

It can, but the operative is doing this by eye all the time by moving closer or further from the substrate and also by the speed at which he is moving.

Describe the cleaning action:

The powder rubs and lifts dirt from the masonry then, in turn, powerful fans extract the spent cleaning powder and dirt.

Some façade materials suitable for cleaning by façade gommage®:

Terracotta, Portland stone, Yorkstone, Ketton stone, Bath stone, sandstone, limestone, marble, granite, concrete, render, pre-cast panels, brickwork (red, yellow and glazed brickwork), among other surfaces.

Will the powder remove mortar joints?

The powder will not remove the mortar joints – even loose and friable ones – only clean them.

Does façade gommage® remove paint from stonework?

No – the façade gommage® system is sympathetic towards stonework as it provides a gentle clean and therefore is not abrasive enough to remove paint; sandblasting would remove paint. However, as it is an aggressive means of cleaning it would also remove a layer of the substrate sitting below the paintwork.

Are there any a) chemicals and b) any water used?

There are no chemicals or water used in the cleaning process itself. Water is only used within the cabin to capture the dust.

How much water is normally used?

façade gommage® requires approximately 1000 litres to charge the system which is then continually filtered and reused during the project.

How is dirt removed from the cabin and what happens to it subsequently?

The dust is extracted by powerful fans which drive it through a water curtain, capturing the dust and allowing pumping to ground level as a slurry.

Is the façade gommage® raw material recycled after use?

As the powder itself is a raw material, at the end of life the wastage from the project is taken to landfill.

How fast the façade gommage® clean can go?

We have the capability to clean 300 sq. m to 500 sq. m. flat surfaces a day.

Is there a need for the building owner to provide any services or facilities in order to clean a building by façade gommage®?

No – façade gommage® is a self-contained system and we do not require and services. We can also bring our welfare vans meaning we do not need to even use your welfare areas.

Is there a need to access internal premises?

We would want to ensure all windows are closed to avoid any dust ingress.

Is there any protection for pedestrians?

We provide a custom made pedestrian walkway or ensure a sterile area below.

What equipment is carried in the cabin?

There is no loose equipment carried on the cabin, only the fixed fans, the operative who is harnessed in and the cleaning hose.

Can façade gommage® system be used from scaffolding?

Whilst Thomann-Hanry® can work from scaffolding, this negates many of the advantages of this system. This still achieves the same quality of clean, but it is much slower. Another pitfall: the dust collects on the scaffold and needs cleaning up by hand.

How high can your machines reach?  Do you have different sized machines for narrow streets and pavements with weight restrictions?

The boom can reach up to 42m from ground level and smaller machines are available for buildings in narrow streets or with other limited access.

Can third-party suppliers buy this powder and hire your equipment for use?

No – the façade gommage® system is patented and only Thomann-Hanry® operators are trained for use of the equipment in the UK.

For the façade gommage® material safety datasheet, click here.

See our façade gommage® projects