Concrete polishing can only be done if you are intending to ..

1. Prepare a new area, hence laying of new concrete to the floor finish level. Upon proper curing, polish it.
2. On existing floors, hack away the tiles/screed, and increase the floor height by laying new concrete. Typically, people do not hack away the old concrete.

If you think that removing the tiles and screed and polish the existing concrete, your floor height will drop by 50mm to 70mm, depending on screed and tiles thickness. You will then need to change your doors. Bear in mind though, polishing on existing concrete isn't a good idea. If you intend to go that way, do coring test to determine the thickness of the concrete slab.

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