I was contacted by a very unhappy customer from the village of Exminster who had recently had a new Limestone Patio laid in the Garden of their house in near Exeter. After the builders had finished laying the patio, they must have used some sort of brick acid to clean the stone and remove excess mortar. With limestone being Acid Sensitive, it etched the stone leaving it in a mess. Also, you need to consider the effects of acid rain so leaving an acid sensitive stone un-protected in the UK is a big no no and will result in its degradation over time.
Exminster is a village on the southern edge of the City of Exeter, and I often find myself working there, so it was no problem to pop down and visit the property to investigate the problem fully.
Whilst at the property and discussing the Patio with the owner I carried out a couple of tests using various products. The testing went well, and my customer could immediately see the potential of the Patio and how the problems could be rectified. The process I had worked out would involve treating the damaged white areas using a series of Tile Doctor Diamond pads to polish out the damage and then restore the colour and protect the Limestone with Tile Doctor X-Tra seal which is an ideal sealer for external stone. Happy to accept our quote a suitable weather window was chosen, and the date was set for the work to be done.
Renovating an Acid Damaged Limestone Patio
I started by adding weight to a Viper rotary floor buffer and then ran over each slab several times with a very coarse a 100-grit milling pad using water for lubrication. The process was repeated using a finer 200-grit milling pad and then a 400-grit burnishing pad again with water to lubricate the process. After each pad the patio was rinsed with water running at high-pressure using a cleaning and extraction system that is fitted into our van.
After the stones had been renovated, I gave them a full deep clean to remove any remaining dirt and staining using Tile Doctor Remove and Go which was worked into the Limestone with a black scrubbing pad. After a final rinse and extract with the van mounted cleaning system I left the Limestone patio to dry out overnight.
Sealing a Limestone Tiled Patio
With the weather still in our favour I returned the next day to seal and protect the patio with two coats of Tile Doctor X-Tra seal. This is a truly remarkable product which is fully breathable and can be used both internally and externally. It’s an oil-based sealer so its puts back the essential oils that have been leached out of the stone by the use of brick acid, thereby restoring colour and structure to the stone.
My customer was very happy with the transformation and with the summer just around the corner can now enjoy their freshly laid Limestone patio in all its glory. More importantly it is now sealed and protected against future elements.
PS… For aftercare of an acid sensitive and sealed patio like this one you need to be careful what you clean it with. In this case I recommend Tile Doctor Neutral Cleaner which has a neutral pH that won’t damage the stone or the sealer. Many of the cleaning products you will find in supermarkets etc. are simply too strong and will weaken the sealer over time.