Cleaning hard surfaces with high pressure by using a truckmount or portable can be profitable, but not knowing the type of floor and how to clean it correctly can result in costly claims.

It’s hard to fathom that in the past 10 years hard stone products have experienced an incredible 2,000 percent growth in sales.

Even if you as a carpet cleaner do not want to get heavily involved in hard floor cleaning, it’s smart to know how to clean some of the surfaces for your current clients.

Slate is one such surface you may encounter, in areas such as commercial building entryways and even in many homes.

Why is understanding formation important?
In order to fully understand the cleaning principles involved with this type of stone, the cleaner first needs to know a little about how slate is formed.

Slate is formed from clay-rich mud through tectonic stress and is believed to have started forming 570 million years ago.

It was created when sediments of organisms on the seabed formed mud deposits.

Pressure and temperature in the Earth’s crust squeezed the mud into layers of shale that eventually caused it to move upward.

Slate can be found in construction of walls, floors, roofs, and even high quality pool tables.

But what is it that — as floor care technicians — we need to do differently when cleaning slate?

Cleaning challenges
Slate gives us three challenges that make it a little more complex to deal with than most other stone.

First is its formation.

The thin layers of rocks stuck together come out from very high pressure cleaning.

When cleaning slate, turn your pressure down.

To compensate for low pressure, you need to add a little more agitation, but no more then 800 pounds per square inch (PSI).

Second, its absorbent nature causes it to absorb staining material, thus creating stains.

Most cleaners find that products made to clean hard surfaces that contain oxygen get absorbed in the stone and cause safe “bleaching action” to remove the absorbed stains.

Lastly, to prevent staining and layers of slate from chipping off, manufacturers and installers often put a coating of wax on the slate to make it more durable.

This poses another problem for cleaners.

Sometimes the wax may have been removed in certain areas or it could be removed from high-pressure cleaning.

Inform your customer that this may not be a cleaning issue but, instead, a restoration issue.

Proper stripper and wax made for use on natural stones should be used.

But, remember: Test in an inconspicuous spot in case of an adverse reaction.

Understanding a bit more about the floor you are cleaning can help you better answer when asked what procedures and products will work best on that floor.