The photos above detail the restoration of Black Caithness Slate pavers at an old cottage in the village of Gressingham on the outskirts of Lancaster. The building was in the process of being completely overhauled and the floor was next on the long renovation to do list.
Caithness Slate from the northern tip of Scotland and is known for its durability and strength however the years had certainly not been kind to this floor and it was in a very bad state.
To restore the appearance of the slate I recommended milling the floor with a set of very coarse pads that would remove a thin layer of stone off the top of the paving slab to reveal new stone underneath. The pointing was also cracked and loose in places so that would also need chopping out and replacing. After milling the stone would also be smoother and once sealed much easier to maintain going forward.
I estimated the process would take four days to complete. Happy to go ahead with the quote a date was booked for the work to start.
Resurfacing Caithness Black Slate
On the first two days there were two of us involved to get through milling the stone which is hard work. We used a set of milling pads applied to a weighted floor machine to cut through the stones surface using water for lubrication. This generates a lot of stone dust so a lot of rinsing and extracting needs to happen to remove it.
Milling carried on into day two but by the end we had started knocking out the old pointing which had already failed and wasn’t too difficult to remove. It was one big room with a partition at one end, the building itself was built in the 1870s or at least that’s as much information as the client could find as it was bought in an auction.
Due to its age, it had no water or electricity, so we had to work off generators whilst a rudimentary system supplied the water. This was not the easiest job for us as the generators were proving difficult to work with as the relays would overload and cut off the power; this happened more than a dozen times just in the first day alone, but we like a challenge.
As you will see from the pictures the stone flagstones were transformed. This was not a simple clean and seal job, this is milling back the surface using various diamond grits a heavy weighted buffing machine and patience, and some water. Using a wet system, the milling system won’t leave a house full of dust and the diamond grinding leaves the stone much smoother and a lot cleaner which makes it a lot easier to clean and maintain in the future.
Sealing a Caithness Black Slate Tiled Floor
Once the milling was complete and the new flexible breathable pointing was applied for which we like to use a product called VDW 800. We then called back the next day and finished the clean, the floor area was left for another day to dry.
Once dry, the floor was then sealing using a single coat of Tile Doctor X-Tra seal which is oil-based sealer that really brings out the colour of the Black slate. Additionally, this sealer is fully breathable so it will cope with the damp conditions you find with old floors that don’t have a damp proof membrane and so won’t peel off after a few weeks.
The client was very happy with the transformation and final finish and invited us back to cover more work in the outbuildings which eventually will join onto the main house. For aftercare cleaning I recommended Tile Doctor Neutral Clean which is an effective tile and grout cleaner that won’t upset the sealer.