These photographs from the hallway of a house in Banbury where old thick slate tiled floor had been laid and the customer was unable to get them clean or restore any colour back into the stone.
Cleaning Slate Flagstone Tiles
I prepped the skirting boards with masking tape to protect them and then cleaned the floor with a strong dilution of Tile Doctor Pro-Clean which was left to dwell on the floor for a while before being worked into the flagstones by hand using a stiff bristle brush. Normally I use a rotary machine fitted with a scrubbing pad for this but given it was a small area it made sense to get on my hands and knees and apply some elbow grease. This process soon saw the dirt coming out of the tile and the dirty solution was removed using a wet vacuum before rinsing the floor down with clean water. This allowed me to see the stubborn areas where more Pro-Clean and elbow grease were applied, again this was removed and the floor given a thorough rinse using a wet vacuum to remove the liquids and get the floor dry.
Sealing Slate Flagstone Tiles
The floor soon dried so it wasn’t long before I could seal it for which I used two coats of Tile Doctor Colour Grow Sealer which as its name suggest enhances the natural colours in the stone. Once this was dry I continued with a couple of coats of Tile Doctor Seal and Go which adds a nice low sheen to the stone as well as adding to the protection provided by the sealer. As you can see it brought all the dark slate colour back and the sealer should ensure the floor is easy to clean in future.
Source: Sealing Slate flagstones in Oxfordshire