It uses low pressure ultra-high temperature, The ultra-hot steam quickly removes algae, moss & other unsightly organisms, whilst the steam also kills off the growth of spores, reducing the need for chemical cleaners & retarding re-growth. The use of steam allows the surface to dry quickly & is ideal for avoiding high pressure jetting, which drives water droplets into porous surfaces, causing spalling of brick masonry or stone when the water freezes in harsh winter periods. It is also used to remove some paints from historic render, brick, masonry, stone & many other surfaces.