There are a lot of slate cleaning and sealing problems arising recently. Here below is a very helpful article by a good friend of mine. I hope it helps:
By Kind Permission of Ian Taylor
Cleaning Slate – Expert Advice on Cleaning Slate and Slate Floors
Cleaning, Problem Solving, Slate, Stain Removal
Cleaning slate isn’t too difficult. It’s vital, however,to know what kind of dirt or contaminant you are trying to remove before you can make a decision as to which cleaning product is best suitable.
Slate comes in many different colours and finishes. Some of these are smooth whereas others have a textured surface. Undoubtedly, slate is a very popular material for flooring right now.
Slate generally has good resistance to mild acids so this gives you a much wider choice of cleaning materials than you would have with more acid-sensitive stones like limestone or marble.
So, how do we go about cleaning our slate floor?
First, you need to check whether the contaminant is mineral based? e.g. grout staining, cement, rust or general dirt. If it is, you would be advised to use a mild acid cleaner such as Phosphoric Acid Cleaner.
In most other situations where you have, for example, general dirt and grime, wax, oil or a general build up of old polishes etc. I would recommend using a strong alkaline cleaner for periodic intensive cleaning. For everyday cleaning I’d recommend using a mild, neutral cleaner.
Here’s a Guide to Cleaning Slate:
1. Ensure your slate is protected with a high quality sealer such as Aqua Mix Sealer’s Choice Gold or for a wet look Aqua Mix Enrich n Seal. Sealers Choice Gold will give you a natural look with a matt finish and below surface stain protection. Enrich N Seal will give you the same protection but will give the slate a wet look. Alternatively you can use a topical sealer something like Seal & Finish Low Sheen for a pleasant low sheen gloss which really helps any ongoing cleaning.
2. You must eliminate all grit – this is the major cause of all wear to slate floors. Ideally, place a dust mat both inside and outside the room which will help remove grit from shoes and prevent it from spreading to the slate floor.
3. Sweep and vacuum the slate floor regularly. This will also help remove grit from the surface of the floor.
4. Mop up and soak up isolated spillages as they happen. You shouldn’t leave strong contaminants such as coffee or wine to dwell on a slate floor.
5. Wash the slate regularly intervals using a mild, neutral cleaner. This will clean the slate but it won’t damage the stone, grout or the sealer used.
6. Less frequently, carry out a deep clean. For this, I’d we recommend using a high alkaline content cleaner.
Some detailed instructions with regard to cleaning slate floors covered with cement or grout residue:
1. Use water to pre-wet the floor.
2. Apply some Aqua Mix Phosphoric Acid Cleaner solution to the floor – mixed with 1 part cleaner to 5 parts water to begin. (You can use a stronger mix if required). **PLEASE NOTE: Always conduct a small test on a relatively inconspicuous section of the floor first, before you begin.
3. Leave the cleaner to dwell on the floor for a few minutes
4. Agitate the floor and cleaning solution with a scrubbing brush (nylon bristle and not metal).
5. Soak up or wet vacuum the cleaning solution remaining on the floor. Rinse well with fresh water, agitating and rinsing again so you can get rid of any residual acid cleaner.
6. Make an assessment of the floor at this stage. You may need to apply an additional treatment of the cleaner.
If your slate floor only requires routine cleaning we would recommend Aqua Mix Concentrated Tile Cleaner – this is a mild cleaner and is safe and suitable for cleaning slate on a regular basis.
For more intensive slate cleaning, where the dirt is not mineral- based, we would recommend the use of a high alkaline Heavy Duty Tile & Grout Cleaner. This a powerful cleaner and decreasing solution. When applied to the floor, leave to dwell for between 5 and 15 minutes, depending on how bad the contamination. Then agitate by scrubbing with a nylon or natural bristle scrubbing brush. Clean up remaining the dirty solution and rinse well with clean water.
The critical elements here are the dwell time and the rinsing. Alkaline-cleaning solutions need time to work. Once you have “extracted” the dirt from the floor it will be suspended in the solution so you absolutely must remove it – on no account leave it to dry naturally.
Kev Martin
Marble Life Ltd
