Question - "Hi, I am a cleaning contractor and have a customer who has a limestone floor in a reception of a hotel which has been maintained by some one else. It is only 6 months old and has gone streaky. I have dealt with marble and other stone before but not limestone. What would you recommend?"

Our Answer - "Limestone is a calcium based stone, just like marble (in fact, marble was once a limestone, before nature subjected it to many years of heat and pressure). Limestone is typically much softer than marble and this results in it wearing faster and not being able to take quite the same degree of polishing (so not as shiny). Some high density marbles can get close to the performance of marble and are often mistakenly sold as a marble as a result (Crema Marfil and Rojo Alicante for example).

The main thing to know, is to avoid anything acidic - just do not use any acid based cleaners.

The streaks that the floor has will undoubtedly have been caused by the cleaning process. Basically wet or damp mopping, or even machine cleaning but no rinsing, thus there is always a small residue left behind. This residue will contain not only some dirt, but also residue of the cleaning chemical, however mild it may have been. Over time this builds up to give a streaky appearance. If left to accumulate it will eventually have a dulling effect on the floor.

Smooth surfaces like fine honed and polished stone are a little like glass, and even plain water can leave water marks. When washing windows it is common knowledge that if they are not rinsed, or squeegee-dried there will be streaks - it is the same for floors.

I would recommend a deep clean with something like Heavy Duty Tile & Grout Cleaner. Mix the solution 1:4 with water, apply to the floor, leave to dwell for 10 to 15 minutes, make sure it stays wet). Then scrub with a white pad. Now wet vac the dirty solution, then rinse with fresh clean water to remove all traces of cleaner and dirt, wet vac that water up also. Finally, buff dry with absorbent/cotton cloths or cotton bonnet on a machine.

For regular cleaning thereafter, use a neutral detergent designed for the material, such as Concentrated Stone & Tile Cleaner. I realise that the above 'procedure' may not be practical on a daily basis, but it is advisable to schedule in such a clean at regular intervals, this can be once per week, per fortnight etc - depending on the circumstances, and how long it takes to build up to a streaky finish again. The fact is that no-rinse cleaning = streaks, end of story.