The photographs below are of an 80m2 Black Limestone Patio that was laid in rear garden of a property in Sandbach. All was going well until the installer decided to clean up the stone and remove the excess grout (aka grout haze) using brick acid. This is common practice in the trade after laying a patio however what they failed to realise is that Limestone can be marked by acids and in fact can be dissolved over time. This left the patio looking drained and in quite a state as you can imagine.
In an attempt to restore the black colour of the stone, the tiler painted on a restoration product however with the grout haze still present on the stone all this did was to add to the problems. Frustrated the customer decided to call Tile Doctor and so I went over to see what could be done.
I quickly deducted that the brick acid will have damaged the surface of the stone so to restore it I ran some tests on a small part of the patio that I been badly affected using a series of diamond encrusted burnishing pads of different grits. The pads successfully demonstrated that the appearance could be restored and impressed with the difference I was given the job of renovating all 80m2.
Restoring an Acid Damaged and Painted Limestone Patio
Being outside weather was an issue and I had to reschedule until a dry weather window appeared. Cleaning during damp weather isn’t a problem, it’s the sealer which needs to be applied when the sone is dry to get the right result.
Made with industrial diamonds and available in different sizes and grits, burnishing pads are ideal for restoring the appearance of polished stone floors. The first step was to work on the most badly damaged tiles with a coarse 100 and then 200-grit diamond milling pad fitted to a weighted rotary machine and lubricated with water. This took off the ruined top layer of the limestone bringing up the virgin stone underneath.
Next the patio was worked on with a 400-grit diamond burnishing pad, followed by 800-grit, and then 1500-grit pad. Each pad further renovates the appearance of the stone (Honing) and had to be rinsed after each pad to remove the slurry that is generated.
With 80m2 of Limestone paving to cover it took four days to completely restore all the stone using this method. It was tough work, but it made an incredible difference and naturally was far more cost effective than replacing the patio.
Sealing Limestone Patio Tiles to Restore Colour
With the stone cleaned up the last step was to restore the natural black colour in the Limestone with an application of Tile Doctor Stone-Oil which restores the deep black colour and adds texture to the stone, it’s also an impregnating sealer in its own right that adds protection and improves mechanical strength once cured.
I allowed this to dry overnight then returned the next day to finish the patio restoration with a further coat of Tile Doctor Ultra-Seal, a no-sheen natural-looking sealer formulated to provide maximum stain protection without altering the colour of the stone.
The customer was delighted with the transformation, what was one an uninviting ugly area now looks fantastic and welcoming. Impressed with the result they left the following glowing feedback: