How to clean an interior natural stone floor
This guide explains the basic points of how to clean and seal an interior natural stone floor. The same principles apply to cleaning and sealing vertical stone i.e walls & lintels etc. It can also be applied to treating tiles such as Victorian geometric tiles, quarry tiles, terracotta, and other clay-based materials such as brick.
The information contained within this article is not exhaustive. The method you follow when cleaning one kind of natural stone to another can be different.
So, how to clean an interior natural stone floor?
Our ‘how to’ guide will help you decide how to clean your natural stone floor safely. Feel free to contact us for additional advice.
You can use this guide when considering how to clean new and old sandstone, slate, limestone, travertine, and many other forms of natural stone.
Feel free to contact us for further information.
How to deep clean a natural stone floor
If you are cleaning a natural stone floor such as sandstone, slate, limestone, travertine etc the most effective way to clean it is to use an alkaline solution such as Floorseal Stone Floor Cleaner.
Floorseal Stone Floor Cleaner is effective when cleaning ingrained grime and dirt. If you have a dirty dull floor this is where we recommend using this product. It can be applied at a dilution rate of 1:10 (diluted with clean water) to a fully neat application.
Stone Floor Cleaner provides fantastic results when cleaning old floors which have blackened over time. It is safe to use on acid-sensitive floors like limestone, travertine, and marble. Also, highly effective on sandstone, York stone slabs and slate.
This product can be applied via brush, mop, and bucket or in conjunction with a slow speed rotary and wet pick-up vacuum. Apply to the floor and allow to dwell on the surface for approximately 15 minutes. Then agitate with a mop or stiff brush & rinse away with clean water.
Always rinse the surface heavily after use with clean water. You can use a tiny amount of neutralising agent to neutralise the floor after use. This means adding a very small amount of an acidic solution, such as a white wine vinegar or our Floorseal Cement & Grout Haze Remover. You only need a capful of solution to neutralise the floor.
When neutralising Stone Floor Cleaner on acid-sensitive surfaces like limestone, travertine, marble etc just heavily rinse the area with clean water.
Take care around painted, varnished surfaces, or metallic surfaces. Wipe down any surface which has come into contact with the product.
How to remove paint from natural stone floors
Floorseal Stone Floor Cleaner can also remove paint with adequate dwell time. We have found that soaking paint spots with just water and a small amount of Stone Floor Cleaner can work well.
If the stone is honed (smooth) and reasonably flat, a sharp scraper can be effective. For rough sandstones, a stiff brush can also help. It is possible with some natural stones, like sandstone, to carefully use a brass brush, which is a little softer than steel/wire brushes.
Dwell time (soaking for long periods of time) used in conjunction with Stone Floor Cleaner is the most effective method of removing paint. This method is also effective at generally deep cleaning the surface of natural stone floors.
It is possible to use solvent-based products for paint removal. We found that they are not that effective, they have a strong odour and can leave solvent staining in the stone.
Removing oil stains from natural stone
Oil marks are possible to remove with Floorseal Stone Floor Cleaner. You may need to use the product neat and allow lots of dwell time i.e. soaking.
Oil marks are notoriously hard to remove, they can be held deep within the stone and can also have oxidised. There are methods used to remove oil spots using poultices, but this is beyond the scope of this article. They often fail but can be applied and left overnight to draw deep stains out from within the stone. So this is more of a remedial measure to help with the overall process of cleaning an interior natural stone floor.
As a general idea, a powder is mixed with Floorseal Stone Floor Cleaner and applied to the stain. Cover the stain with plastic and tape it to the floor. Puncture the plastic so, that as the powder dries, the stain removing solution (after having sunk into the stain/stone) dries slowly pulling the stain up and out of the floor.
Be aware some oil stains will not respond; you can also leave/create a halo in the stone from where the poultice was applied!
Our preferred method would be to clean the floor as normal with Floorseal Stone Floor Cleaner. This would remove most of the marks, we would then consult with the customer over further works to remove individual stains (if any).
Removing cement or grout from natural stone floors
This must be carried out with care; please be aware some surfaces are acid sensitive. We recommend Floorseal Cement & Grout Haze Remover for the general removal of cement-based products.
Floorseal Cement & Grout Haze Remover can be applied to sandstone & slate. It should not be applied to limestone, travertine, concrete or marble.
When removing cement or grout hazes from sandstone or slate floors carry out a test to obtain the correct dilution rate. The product can be diluted from approximately 1:4 with water or applied neat. Try to avoid kitchen units and metal surfaces, wipe them down immediately if the solution encounters these surfaces.
Hazes and smears of grout are easy to remove, lumps may need chipping/scraping off before the haze is removed.
As with all cleaning products test before use! Particularly if there is a possibility the floor is limestone, marble, travertine, or another form of acid-sensitive material.
Some floors described as just ‘natural stone’ or even sandstone are acid sensitive. A classic example is the local stone found in the Cotswolds. This natural stone is sometimes described as sandstone, it is in fact Oolitic limestone, so acid-sensitive!
Always rinse this product away with plenty of clean water and allow the floor to dry.
How to remove efflorescence from natural stone
The removal of efflorescence is quite simple and can often be carried out with just a brush – if the efflorescence has appeared recently. You will need to observe and decide whether your natural stone floor is being affected – you should consider the following.
Efflorescence is a salt left on the surface after moisture has evaporated, it can be removed by brushing or applying Floorseal Efflorescence Remover.
Brushing & chemical treatments can both remove the salting, but it can return if the underlying issue is not resolved. This may be because the floor is inherently damp or just at certain times of the year. If so, the salting can become a ‘crust’ and is difficult to remove.
Crusts are quite common on Victorian geometric tiled floors in York where there is a high water table. This is coupled with the fact the floor might be laid on compacted dirt, lime, or cinders.
You may need to remove the worst of the crust via mechanical action, chipping or brushing and then apply Efflorescence Remover. Take care not to damage the stone when chipping, scraping or brushing the stone.
Once the efflorescence is removed check for any re-occurrence. If efflorescence reoccurs, we recommend sealing with a breathable sealer such as Floorseal Natural Stone Sealer Breathe.
How to remove rust marks from natural stone floors
Removing rust can be carried out with Floorseal Rust Remover for Stone. It is a non-acidic solution which can be applied to acid sensitive surfaces.
This product is to be applied neat (it turns purple when reacting with rust) and should be rinsed away within 10 minutes of application. Do not allow the product to dry on the surface.
Floorseal Rust Remover for Stone will remove surface contaminations and ingrained rusting from most common interior natural stone floors, particularly when applied more than once.
Stripping old sealers before sealing internal natural stone floors
The removal of old topcoat water-based acrylics is possible with Floorseal Stone Floor Cleaner. This product can also break the surface tension left by old impregnating sealers.
The removal of old sealers from internal natural stone flooring is problematic and not always economically possible. Solvent-based acrylics are very difficult to remove and often require a solvent-based stripper to be successful.
Polyurethane sealers are very difficult to strip and require a very powerful stripping agent. These stripping agents are noxious and sometimes people will, in preference, sandblast the surface (where possible). This is often carried on old Yorkshire sandstone slabs as a property is being renovated.
It is not possible to fully remove old impregnators or colour enhancing impregnators. Cleaning will only break surface tension and allow more impregnator to be applied. Over time old impregnators will eventually break down but it is a slow process.
Cleaning the remains of screeds & bitumen
Screeds and bitumen often can be removed in sheets so appear to be easy. What we have found is that bitumens usually also soak into the surface of the stone. This is common on old Yorkshire sandstone flags.
Screeds, if cement-based, can cause the surface of the stone to become soft. This can also happen if old sandstones have been under laminate for a long time.
Old floors laid with natural stone discovered under bitumen and screeds can be in poor condition. If bitumen has been applied sandblasting is often the only solution. This is due to deep bitumen staining which cannot be cleaned from the surface.
If the floor has become soft, white, flaky, and de-laminating – Again often sandblasting is the only solution.
You can remove any cement-based screed residues with Floorseal Cement & Grout Haze Remover.
There is no effective way of using a cleaning agent to remove ingrained bitumen residues that we have found to date.
In conclusion: best ways to clean an interior natural stone floor
Floorseal Stone Floor Cleaner is used to remove most ingrained dirt/marks and oil marks. This product can also be used to remove paints and old acrylic sealers and breaks the surface tension created by old impregnating sealers.
Floorseal Cement & Grout Haze Remover should be used for the removal of cement-based grouts, screeds, and general cement. Can also be used to remove the haze from lime pointing. Do not apply to acid-sensitive materials.
Floorseal Efflorescence Remover will remove salting left on the slab from moisture passing through from the base or left by evaporating water. Do not apply to acid sensitive materials.
Floorseal Rust Remover for Stone is a non-acidic rust remover suitable for use on most kinds of stone. Can be used on acid sensitive surfaces but proceed with caution on coloured concretes.
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The information included in this article is not exhaustive. If you need further information please contact Floorseal on (01484) 861461 or email us firstname.lastname@example.org our web address is www.floorseal.co.uk
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