Deep Cleaning Dirty Slate Flagstone Flooring in Oxfordshire

Every so often we come across exceptionally old tiles that are in desperate need of restoration. These Slate flagstones at a property in Banbury, Oxfordshire had to be a couple of hundred years old, the grout had come loose and I wagered that it’d been covered by bitumen (also known as asphalt), plaster, and concrete for a significant portion of its life. The property owner was keen to try and restore them and had tried to clean them, only to realise that it was a bigger task than initially thought. Flagstones are known to be hard wearing and durable, but no floor can be easily restored when subject to this kind of treatment. However, at Tile Doctor we are experienced with cleaning tiles in this kind of condition – and I was more t

Cleaning Old Slate Flagstones

Upon arrival at the property, the first thing I did was to cover the walls to protect them from splashes of cleaning products I would be using. I then started the process by mixing two products – Tile Doctor NanoTech HBU and Tile Doctor Remove & Go – in a bucket and spread it over the entire floor. These two products are both very powerful cleaners on their own and work even better together: NanoTech HBU utilises nano-sized particles to penetrate areas that normal cleaners simply can’t reach, while Remove & Go is specifically designed for the removal of coatings such as old sealers. For added impact and so the blend of cleaning products would not dry out, I covered the floor with a plastic sheeting, leaving the solution to dwell and work to break down the bitumen, plaster and concrete overnight. The following day, after removing the plastic sheeting I used my rotary floor machine fitted with a silicone carbon brush to slowly scrub the floor, beginning to loosen the soil. After this, I thoroughly rinsed the floor with water. I then used Tile Doctor Grout Clean Up, which is a concentrated phosphoric acid cleaner to remove the plaster and thin layers of concrete, before again rinsing the floor with water. Next, I had to remove the particularly thick chunks of concrete carefully using a chisel, before scrubbing the floor with Grout Clean Up once more. To complete the cleaning process, I then mixed a solution of our strong alkaline cleaner, Tile Doctor Pro Clean, with water and scrubbed and rinsed the flagstones with water.

Sealing Old Slate Flagstones

The next day I returned to the property to grout the floor, before leaving it again for another day to fully cure. On the final day, I sealed the floor using Tile Doctor Seal & Go, which is a topical water-based blend of acrylic polymers that provides a stain resistant surface seal combined with a long-lasting low-sheen finish. This eliminates traditional two-step sealing methods. I applied eight coats of this to give the floor the strong sheen (seen in the below photo), that the customer requested.


The floor had been in awful condition, for decades or perhaps even hundreds of years, yet using the right methods and products I successfully completed the full restoration within a single week. The customer was absolutely over the moon with the result.


Source: Slate, Stone and Grout Cleaning and Restoration Service in Oxfordshire