How To Clean Limestone Floors and Tiles
By Ian Taylor on Apr 2, 2008 in Cleaning, Limestone, Problem Solving
If you want to clean limestone and care for your limestone floors it can be a relatively simple task. However, you do need to take care with stone like limestone as it is prone to damage by acid and acidic-based products since it is a calcium-based product.Limestone, in general terms, is relatively soft when compared to say granite or indeed marble. This means that it is always sensible to consider wear prevention. Here is a simple 6 – Part guide to cleaning limestone and maintaining limestone floors:
1. Ensure that your limestone is sealed with a high quality product to help protect wear and tear. We suggest a product like Sealer’s Choice Gold.
2. Make sure you try and eliminate grit from the limestone floor as this is the main cause of wear and tear to a limestone floor. Place dust mats inside and outside the room to remove grit from shoes and to help prevent the transfer onto the floor.
3. Vacuum and sweep the limestone floor on a regular basis. This also helps to remove grit and other contaminants.
4. Clean up any spillages as quickly as possible and don’t allow them to dwell and hence stain the stone.
5. Clean the limestone floor regularly using a mild and neutral cleaner. This will help clean the stone without harming the grout or the sealer.
6. Once a quarter conduct a deep clean using a high quality alkaline cleaner.
For more routine cleaning use a product like Concentrated Tile Cleaner. For deeper less periodic cleans, we’d suggest using Heavy Duty Tile & Grout Cleaner. This is a very powerful degreaser and deep cleaning solution.
DENISE COSTELLO | Mar 24, 2011 | Reply
Can you please advise cleaning grout off newly laid limestone floor tile.
Ian Taylor | Mar 29, 2011 | Reply
Hi,
I suppose it all depends on how bad the grout film is. First of all, we need to remember that grout is basically fine sand, plus cement with some additives to improve the flow and workability. The large amount of cement present means that it is very similar in its chemistry to the limestone, in fact it is the cement, which is largely calcium based, that is bonding it to the stone.
IN this case, we cannot use the standard, acid-based cleaners that are normally used for cleaning grout residues – if it can damage the grout residue- it can, and will, damage the stone. What I would recommend is a non-acidic, mildly abrasive cleaner such as nanoscrub this is also based on calcium and will not scratch the stone, but will help to safely rub off thin films of grout residue.
If, as is often the case these days, the grout has a lot of polymer added, then you could also try a safe solvent type cleaner/stripper such as sealer and adhesive remover. This will attack the polymer and not the cement (or stone). It may be that the polymer is the main issue and so this approach may give the best result, you could add the nanoscrub to the Sealer & Coating Remover for an added boost.
If none of this works, and the residue is substantial, you may have to consider seeking professional advice, it might be a relatively simple job to lightly re-hone the surface, taking the grout problem with it. This would necessitate the use of professional equipment and also resealing afterwards.
Hope this helps
Ian
Dallas | Aug 5, 2011 | Reply
I need to strip and reseal my limestone floor, what chemical is best to do this with. I will be stripping, regrouting, resealing and polishing the floor. Can you recomend a polishing machine also and any other product or tutorials I might be able to follow. I am not a tile man, I have tiled and done a lot of construction finish work and worked with stone, but any help you can offer would be much appreciated. I am not able to have this hired and have time on my hands due to the economy. Thank you for the help.
Ian Taylor | Aug 8, 2011 | Reply
Hi Dallas,
Stripping and resealing is the easy (or rather straightforward) part. Polishing, well that depends on what you mean by polishing and what type of limestone you have. For example, not all limestone can be polished to a high shine, (some cannot even reach what we call a ‘smooth hone’ and wil always look chalky/dusty) this is a function of the stone’s hardness, the softer the stone, the lower the maxmium ‘polish’ that can be achieved. If you have had the floor for some time, and know it was highly polished to begin with, and it has over time, slowly dulled down, then ok, it ought to be able to be repolished. However if you have just inherited the floor when moving into a property for example, then you do not have the history and will need to conduct a test to determine what level of polish can be achieved.
Also, how flat is the floor? – if there are any raised edges – even a mm or so, (we call this lippage in the UK) then really, this ought to be ground flat first – this means the whole floor generally as it all has to be brought down to the same level. this pricess usually involves diamond griding using several different gradesof diamond from coarse to the finer grades and ultimately finishing with the polishing grades – so can need 3 or more passes.
If you floor is true and flat, and all you are looking to do is bring back a bit of the shine, you could do this with the polishing grades of diamonds, or there are also alternative systems that use powders, pastes and even pads. The Dimaond systems susually require professionals, both for their skill and experieince and the fact that it is not cost effective to purchase or hire the heavy griding machines and the diamonds blocks.
The powders, pastes and pads (synthetic felt type pads impregnated with diamonds- there are several brands on the market) can all be used with regular low rpm (150 to 350 rpm) single rotatary cleaning machines (again plenty to choose from and available to hire). There is a lot of debate about the effectiveness of the pads at the moment but in general terms they are ok, at mainitaing a shine that is already there, not so good at taking a dull floor back to a shine.
It is hard to be precse with out knowing more about your stone and it’s condition.
Re stripping, well if you have to grind the the old sealer will largely be removed in the process (along with any surface dirt) so no stripping required. If you are not going to do anything more than use a pad or pad&powder/paste system then you may have to strip. I would recommend a safe stripper like Sealer & Coating Remover by Aqua Mix. Re re sealing – use a good quality, probably water based impregnating sealer. I am guessing you are in California, so would recommend giveing the help desk at Aqua Mix a call, they will talk you throught the sealing process.
As far as tutorials go, there are a few more articles on this blog on sealing etc but I can also recomend thisbook:
http://www.lulu.com/product/paperback/stone-restoration-basics/693497?productTrackingContext=search_results/search_shelf/center/1
it is a bit expensinve, and it is clearly aimed at people wanting to set up in the stone restoration business, but it si a good basic book that covers pretty much everything.
Hope that helps.
Ian
Marianne | Aug 25, 2011 | Reply
I have brand new limestone floors going in and the installer has asked if we want to just seal the limestone or to polish it with a diamond polisher and then seal it. They are 24″X24″ tiles and look amazing. Any advice on whether it is worth the additional amount (which is a lot!) to diamond polish it?
Ian Taylor | Aug 30, 2011 | Reply
Hi Mariane,
It is very hard to advise on this unseen but on the face of it I would question the polishing on a number of counts:
1. You have just bought them, so are they polished or matt/honed? – Whatever the factory finish you have, is the intended finish for that stone – (I guess that is a polite way of saying that if you had intended to have a polished limestone, you would have purchased one – in other words, you bought them because you liked them or the display you saw etc so why would you now want them more highly poished?
2. You say they ‘look amazing’ – so, either they are already polished (sufficiently) or they are honed but look great – I suggest leaving well alone.
3. In my experience, tile installers and stone polishers are distinctly different animals – two very different sets of skills (and equipment) so, while it is not impossible that your installer is also an expert stone polisher – it is highly unlikely. Recently there has been an increase in the number of people offering stone grinding and polishing services with little knowledge, training and equipment, plus new products (nylon pads imprengated with diamonds) have meant that tile/stone installers no longer need to invest tens of thousands of pounds in equipment and hundreds of hours of work to be able to offer these services. However the ‘pads’ are only going to give a light surface polish to the stone and this will not last as long as a true diamond grind. I may well be doing your installer a great diss-service, but I would be careful, ask him for his reasons as to why he thinks the floor needs polishing, ask to see references and a portfolio of work (true stone polishers are so passionate about their work that they keep photos!). If he does intend to just give the floor a quick once-over with this new breed of pads – then ok, but he should not be charging you a lot in that case – but, unless you are not happy with the finish of the stone, I would pass.
4. Can your stone even take a polish? – limestone is a very varied stone and so it is hard to generlaize but it can be very hard, medium or it can be very soft. Without knowing your stone, it is impossible to give an opinion but many limstones are simply too soft to take a polish, and often those that do, are too soft to hold that polish for any legnth of time – I would want to know for sure that it is hard enough to be polsihed.
Hope this helps
Ian
shirley | Sep 4, 2011 | Reply
I have a shower which is tiled with honed limestone. It has gradually become patchy with black staining. how do I clean this up and clean off all the existing sealer and re-seal with something that wont allow moisture to get into the tiles
Ian Taylor | Sep 6, 2011 | Reply
Hi Shirly,
There are a couple of things that we need to look at, one is the cause of the black staining and the other is the ‘waterproofing’ that you desire.
It is a fair and safe bet to assume that the black patchy staining is mould/mildew – don’t be worried by this – it happens to the best of us. I have often said that if we wanted to breed mould deliberately then a domestic shower cubicle/enclosure would be a great place to do it. I have covered dealing with mould and mildew before but it is worth revisiting. First of all I will stick my neck out and say that if your origional sealer was a reasonable one, then it will have done it’s job, and the staining you are seeing is actually ontop of the sealer and so the sealer is not ‘to blame’. Futhermore, replacing the sealer with a ‘better’ one could make no difference.
The sealer should have helped to prevent the mould from getting too deep a hold – or ‘root’ in the stone and therefore cleaning it will be easier than had it not been sealed. Quite how easy it is will be dependent upon how much mould there is and how long it has been left. Mould staining is an example of where prevention is better than cure, in that it is easier in the long run to keep a surface free of mould, by never letting it get a hold, than it is to remove large areas of established mould. I will discuss prevention in a moment, so first lets look at how you can clean it.
This is an area where there is a certain amount of debate, there are many people on cleaning forums and the like who do not advocate using a bleach (particularly so in the USA). There is in fact a debate as to whether mould should be ‘killed’ or ‘cleaned’. My view is that if there is a lot of black staining, it may be better to do both – that is clean away the mould build up and try to kill off the spores at the same time, and like it or not, bleach is an effective way of doing this. There are also other proprietary alternatives to bleach that purport to do the same thing – fine, the point is we need to totally remove it.
My method would be to use a household bleach, diluted with water to make quite a weak solution. Spray this onto the affected areas and leave for an hour. This works great for low to medium instances, if there are thick layers of mould I would scrub them away first with an alkaline detergent, then rinse and then apply my diluted bleach solution. After an hour, I come back and throughly rinse with clean water. The scrubbing removes much of the solids and the bleaching kilss the organism and just as importantly, kills the colour and the stain. Other methods include using a mildly acidic cleaner (not in conjunction with an alkaline or bleach this time) – the idea being that the mild acid (often citric) will take a thin layer of grout away (not enough to notice), taking the anchored-on mould with it. This can be successful but not in your case as the acid would be detrimental to the acid sensitive stone.
So, in your case, I would use a detergent with a scrub pad then rinse, the a very light spray with the dilute bleach as described above. Then rinse and dry.
Regarding a new sealer – I am not sure it warrants it – you have a honed limestone so it is not meant to be shiny, therefore you really have only a choice of impregnating sealers (those that soak in and sit just below the surface) A coating sealer may offer slightly easier clean off – but, it will look wrong on your stone, it won’t last as long in a shower and it really will do nothing to prevent the mould from forming. My advice would be to simply top up the existing sealer. If you feel the sealer is inferior, then use a safe stripper to remove it and then use a premium quality impregnating sealer (for that stone, probably best with a good water-based one). Note, none of the available selaers will offer 100% water-rpoofing – that is not what theyare designed for.
With the stone clean (and importantly dry) and the sealer reinstated now the really important thing to do is take measures to prevent a future build-up, by trying to do as many of the following things as possible
1. increase the airflow – fit an extractor fan in the shower area – to extract as much moisture as possible, as quickly after showering as possible. If there is a fan installed, get it serviced, see if it is rated high enough, set the timer if it has one, for longer (so that it stays on for a few minutes more after showering)
2. leave the curtain open or the cubicle door ajar – again to assist the flow though of air
3. leave a window open for longer
4. dry the walls down! – ok this is the really easy one, after showering, does not even have to be every time the shower is used, but frequently, take an old towel and dry the walls, this removes the moisture whithout which the mould cannot thrive.
5. occasionally, or at the very first sign of mould (a few black spots, or a brown/red slime) spray with very dilute bleach or alternative and then rinse as above.
Mould thrives on moist, stagnant warm porous surfaces that allow it to grip. Take one or more of these conditions away and it will no longer be able to thrive. Grout joints are both textured and porous so it stands to reason they will become stained first – as they hold more moisture than tiled surfaces. Your stone is of course more like the grout, so it will allow the mould to develop more easily on it’s surface than say a glazed ceramic tile would, but often even tiles become covered with mould if they are alowed to build up limescale and soap scum, which makes the surface more textured and porous – so keeping the tile/stone and grout joints clean and dry regularly is the best way forward.
hope this helps
Ian
Marie Anne | Sep 11, 2011 | Reply
Hi There,
I’ve used bathroom cleaner on what I think is limestone flooring in the bathroom (rented apartment) and now it’s turned white with numerous white spots everywhere.
Is there a way to fix this and restore the original colour?
Thank you
Marie Anne
Majid Saili | Sep 14, 2011 | Reply
Hi Ian, three months ago I fitted a limestone fireplace for a customer, I fix the back panel of fireplace to the wall using universal adhesive which is normally used for dabbing plasterboard to walls which is off white in colour, the next day four damp patches 5″ in diameter appeared on the face of the back panel obviuosly from the dabbing plaster at the back but I was not worry because I thought once they dry the damped patches would disappear but unfortunately 3 months on I am left with four yellowish marks on this lovely off white limestone fire place. can you help?
Many Thanks, Maj.
Ian Taylor | Sep 20, 2011 | Reply
Hi Marie Anne, it sounds like you have used a product that contains an acidic ingredient, This has then etched (burned the surface) of the limestone. In doing so it has dulled the surface, thus causing it to scatter (rather than reflect) light – this creates the dull, white mark. I assume that if you wet it, it will temporarily show the colour, until the water dries away.
The stone needs resurfacing, depending on the degree of etching, if the floor was shiny before you may be able to do this with a hand repolishig paste like Reshine.
Or you may have to use diamond hand pads, or even call a stone profesional to re grined the stone if it is really badly damaged. Suggest you contact Aqua Seal STC ( I think you are in Sydney?) they will be able to advise you.
Hope this helps
Ian
Ian Taylor | Sep 20, 2011 | Reply
Hi Majid,
I am not sure there is anything that can be done here. A couple of things could have happened: The adhesive has acted like a bridge or a conduit between the back wall and the back of the limestone. This can allow the transport of soluble minerals to permeate through to the front. Or the wetting action of the adheisve has set has caused some thing to be disolved and travel through to the stone as the water dried – for example ther can be soluble forms of iron (Iron sulphide? – I am not a chemist!) the point is this iron then oxidizes (rusts) inside the stone. Or it could just be contamination from components in the adhesive that have travelled through the stone. If the stain was still mobile, (like damp, dirty water) it may be possible to pull it through the face with a poultice but I think this highly unlikely as I think that it is one of the reasons I have mentioned. If it is, then whatever the cause, it has now ‘set’ inside the stone and become a pretty permanent feature.
If it is as a result of iron, there is a chance that over time, with exposure to UV light, it will fade back (happens a lot with white marble) but this can take lot of time.
It is no help to you now, but you may be able to prevent this from happening agin in the future by first pre-sealing the back of the stone with a good impregnating before using the adhesive.
Hope this helps
Ian
janan plush | Sep 26, 2011 | Reply
New bathroom limestone both on the floor and the shower. Can a steam cleaner help keep the flooring clean or will this damage. What should we use on a weekly basis to keep the floor in good clean condition. It has been sealed.
Ian Taylor | Sep 26, 2011 | Reply
Hi Janan,
team cleaners are ok, especially when used with a good detergent – but only for infrequent, deep cleans – not for every day cleaning. I doubt they will damage the floor but they will damage or degrade the sealer, and thus reduce it’s life expectancy.
For every day cleaning use a soft brush or a flat mop, dry or with a static spray cleaner if you can get one. When you have to wash it, use a neutral cleaner (ph7)
Hope this helps
Ian
Virginia | Feb 6, 2012 | Reply
I have a Bath stone floor which has degraded somewhat over the 5 years since it was laid. The original polish has worn off despite my mopping with a shine-maintenance solution, and the pores and grouting have gradually filled up with the local ‘mud’. Do I steam-clean to get this out, or apply a proprietary stripper then scrub or suck the sludge off with a wet-and-dry vacuum. I have been advised gradually to build up the polish finish with a mopping solution, but I feel the mud would again clog the pores before it had built up enough to fill them. What would be your advice?
Ian Taylor | Feb 8, 2012 | Reply
Hi Virginia,
OK, personally I have found that deep cleaning with the right cleaner tends to outperform a steam cleaner – and I have done head to head tests in a comercial\environment; in the time it took the cleaner to steam clean the grout around one 10 inch tile, I had deep cleaned about 12 tiles and grout with an alkaline detergent. His reults were pretty good, not better than the chemical though and the time was totally impractical.
Sure steam cleaners have improved since then, but unless you can get your hands on a ‘turbo-spinner’ type I would not bother and even with one of those I would be inclined to use it in conjunction with a chemical.
My advice is this:
remove loose dust and debris with a soft broom or swifer type cloth
then, as the stone is a very porous limestone, pre-wet the floor with warm water – just mop it over
Then use a proprietary alkaline cleaner such as Xtreme Clean (contact All for Stone) mix as per instructions, say about 1 part cleaner to 3 or 4 parts water, then apply to the floor. Leave it to dwell for about 10 to 15 minutes (pre wetting the floor helps with this stage as the stone is already saturated and will therefore not suck the cleaner in too deep or dry out to fast.
Now scrub with a scrubbing brush, medium bristles should be fine, you can do this by hand or get hold of a rotary machine.
Use a wet vac to pick up the dirty solution
Now mop over with fresh, clean water, wet vac again.
Finish off by drying the floor with towels, or buff with the machine.
This should really clean the stone and the grout.
As far as reinstating the polish, well it depends how much of the polish was created mechanically in the stone, versus chemical ‘polish’ deposited ‘on’ the stone.
Not all limestones are hard enough to polish, I suspect yours is kind of in the middle, could get very smooth and flat, but not reach a very high shine, the rest of the shine coming from the build up of the dressing/shine-maintenance cleaner product.
My guess is that the floor has worn beyond the ability of the shine-cleaner to restore, so I suspect you would need the services of a professional stone company to ‘re-finish’ it before recommencing the use of your cleaner. However, once you have deep cleaned the floor you can have a good look at it.
Once you are happy with the ‘mechanical’ finish of the floor, before proceding with your shine/cleaner build up – I would seal the floor with a good water based impregnator (clear/colourless).
Hope this helps
Ian
Virginia | Feb 8, 2012 | Reply
Ian –
Very many thanks for taking the trouble to understand the problem and to give me your expert advice! I can now set about the floor at least knowing which route to take . . .
Virginia
chrism | Mar 4, 2012 | Reply
I need help, just purchased and installed an egyptian limestone foyer and fireplace it is honed but has a light film on it how do I remove the film.
Ian Taylor | Mar 8, 2012 | Reply
Hi, as you cannot use an acidic cleaner on thisstone, your only other option is mild abrasion. If you are in the US, look for a product called nanoscrub. it is a mild, calcium derived cream abrasive that has just enough abrasive power to help shift stubborn films without dmagaing the stone. Outside of the US, look for Microscrub. If your film is worse than that, then you could consider some fine honing powder and a white pad.
Hope this helps
Ian
Andrew | Mar 14, 2012 | Reply
I have just bought two limstones slabs which my new multifuel stove sits on and am not sure how to clean the limestone and whether it is safe to put a sealant on, is it safe to use sealant on tiles exposed to such high tempretures?
Ian Taylor | Mar 16, 2012 | Reply
Hi Andrew,
Just use a high alkaline cleaner like this: follow the instruactions, pre-wet the stone before applying the diluted cleaner, let it sit, then scrub and rinse. Repeat if necessary.
A good water based premium sealer will be fine, it will not get hot enough to damage it
hope this helps
Ian
peter tornkvist | Apr 29, 2012 | Reply
Hi Ian
We recently had a limestone floor put in our kitchen. Our builders (it was part of a house renovation job) were incompetent and did not take care with the tiles. As a result they are very dirty and require deep cleaning.
So far I have tried applying an undiluted alkaline solution agitating it with a sanding machine. But this seems to have little or no effect.
As a next step I had thought to repeat this process but with ‘microscrub’ (EU version of nanoscrub.
I am a bit concerned about doing too much as the tiles are only half an inch thick and I am concerned I might scrub myself through them!
What advice would you give?
If it isn’t possible to clean the tiles is it possible to bleach them? At the moment they have unbecoming rust coloured patches on them.
Cheers
Pete
Ian Taylor | Apr 29, 2012 | Reply
Hi Peter, a couple of things here:
First of all Using an alkline cleaner undiluted is not actually always going to help, many, if not most, actually NEED water for them to work, so ironically NOT diluting them does not make them stronger or more potent.
Also, I suspect from your description that the dirt is ‘builders’ dirt – i.e cement based and most likely grout residue/haze. If it is an alkalie will do little in any case.
You cannot use an acid cleaner though as that will damage the stone for sure.
I would agree with you that the next step should be a microabrasive like Microscrub. – use this with a little water and if you can get one (hire) a mono brush machine – rotating machine, slow rpm (175 to 350) with either natrual fibre pads or medium brush head.
If this does not work, you have to up the abraive a little bit – but now you will be removing stone, only microns but still removing stone, where as with the Microscrub you will not be.
So, next try a honeing powder – for this you most definately need a machine and a wet vac again yoiu can hire them. This proicess is a little more involved so I suggest you email me if you ned further infomration
Hope this helps
Ian
Peter tornkvist | Apr 29, 2012 | Reply
Thanks Ian, I will try this
Regards, Peter