This Portland Limestone patio on Round Island in Poole Harbour had, together with a sun room indoors, been covered in a thick layer of carpet glue which had set hard in the warm sun over the years and the owner had found it impossible to remove themselves. There’s no bridge so the island is serviced via a boat from the mainland, which as you can imagine made it a bit of a task getting all my equipment over there.
Cleaning Portland Limestone Flagstones
I began by using 17″ Starke Silicone carbide discs which at 24 grit are much coarser that the burnishing pads we usually use. To get the right level of traction I used the disks on a Numatic buffing machine that had been weighted down and the combination worked well to cut through the glue and turn as much as possible of it to dust.
To remove the remaining glue I soaked the Limestone in a dilution of Tile Doctor Remove and Go and left on the glue overnight under sheets of plastic and dust sheets so it wouldn’t dry out it. It also ensures the product remains in contact with the glue and kept it away from any wildlife which might use the patio when I wasn’t there.
The next day the remaining glue had softened and I removed as much as I could using a black buffing pad attached to the buffing machine together with a strong dilution of Tile Doctor Pro-Clean before applying more Remove and Go again and steaming each tile in turn whilst brushing with a brass coated Spid wire brush.
This was quite a lot of work and as the stone was not dense and had wide pores the glue had sunk in deep when it was applied and I had to repeat this process several times before the stone was clean. Finally I used a pressure washer to thoroughly rinse and clean the stone before re-pointing where necessary.
Source: Professional Tile, Stone and Grout maintenance service in Dorset