Home | About Us | Info | Buy | Sell | To Pay | Images | Library | Advice | Search | RSS Feeds | Site Map | Contact Us  

www.findstone.com   info@findstone.com

Ask any question, share your knowledge, or offer your services!

Sandstone Cure / Clean 

Areas: fireplace hearth, exterior walls, kitchen sink, paving, floor
Problems: dirty

Q 2344: We have a 1950's fireplace/hearth made of sandstone (beige and rose colors). We would like to restore it, as it looks old and dingy. We can't power wash inside, so what should we do? What chemicals are recommended? Should we have this professionally done? Marjie, July 30
R1: Dear Marjie: 
1. A solution of warm water and household bleach (3:1).
2. A natural fiber brush (tampico) like the one you use to do laundry.
3. Lots of patience and elbow-grease. Ciao and good luck, Maurizio, USA
Q 2296: I have an old cap stone from a church roof carved into a fleur de lis shape. It is approx 100 yrs old, and VERY crumbly/porous. The stone is about 2 feet tall, 1 foot wide, of sandstone, and all the original exposed surfaces are black with environmental staining. The stone is probably british, and is a pale yellow colour. Just by looking at it, its fairly obvious that any sort of grinding will really damage the surface as well as the ornamental work on the stone. I'd like to have the stone on display indoors, so can you recommend any kind of poultice that might strip the worst of the staining - I don't imagine for a second that I can remove all of it, as the poor stone has been perched on a roof in an industrial city surrounded by main roads for so many years! Any help most appreciated as I've got very attached to my little find now! PS: No, the stone wasn't pilfered! The church got demolished to make way for a business school! Rhian, July 25
R2: Dear Rhian: Now that you went through the trouble of letting us know that you are not thief, I will answer your question!! :-) 
Try to poultice it with a solution of water and regular household bleach (1:1). believe it or not, most of that "pollution dirt" is nothing but mildew! Once you remove most of the stain with the poultice, use a solution of hot water and bleach (3:1), and with the help of a natural bristle brush (tampico) and a lot of "elbow grease", take out as much as possible of whatever is left. Ciao and good luck, Maurizio, USA
R1: Dear Rhian: Try some bleach first, and gently rinse after letting the bleaching action take its course. This should at least get rid of some of the dark stain (a lot of which is organic in nature). Then with a soft brush and pH neutral soap, spot scrub the more resistant areas. (again, gently is the key word). If the stone is sandstone, and has been exposed to many years of weathering, it is going to be rather fragile, and even a blast from the garden hose could do considerable damage. Please try any of these suggestions on a small, inconspicuous area first before going after the entire piece. Good luck, JVC, USA
Q 2266: Someone recently applied a protective stone sealer to my exterior Colorado buff sandstone deck, and I am not at all happy with the way it looks now. before, it was natural looking, like the vertical stone on the exterior walls. Now, the deck has darkened a lot and has a blotchy appearance that is not consistent with the vertical stone surfaces. How can I restore the look of the natural stone, and what would you recommend to seal and protect it THAT WON'T CHANGE THE COLOR? (I live in Colorado mountains, and was advised that a sealer is important protect stone/grout joints from deterioration.) Thanks, GS, July 19 
R1: Dear GS: 
1. A sealer -- any sealer -- is as good as the operator who applies it. 
2. A sealer for stone will only protect your stone from staining, certainly not from deterioration. In fact -- although it's still to be proven that a sealer may actually "help" the deterioration process of natural stone (!) -- the application of something inside the stone is certainly not a a natural thing to do. At least in my book. Ciao and good luck, Maurizio, USA
Q 2227: I have a smooth surface sandstone fireplace that is dirty from age and creosote around the hearth opening. I would LOVE to restore it to it's natural state (the home is 80 years old and I'm sure it has never been cleaned). What would work best - especially since there are very large sections of the sandstone that make up the fireplace and I don't want it to get streaks since they would be so noticeable? Do commercial products work (of which I have not been able to find any specifically for sandstone - and no one that can tell me of any) - or is there something homemade I can use? I know it can be cleaned since my sister-in-law had a fire in her home and her sandstone fireplace that had roses carved in it - was cleaned beautifully. Unfortunately - NO ONE remembers "who" cleaned it - let alone what they used!!!!! So I know - after seeing the before and after of THAT fireplace that it can be done. Right now it's an eyesore in an otherwise beautiful living room. Any help you can give me would be GREATLY appreciated. Cathy July 15
R2: Cathy: Maurizio's is probably the best way to go about this. However, I do have another suggestion that you might want to try first. Get a hold of an old fashioned "art gum" eraser --the tan crumbly kind -- put a drop cloth or paper down on the hearth, and try erasing your discoloring. Not sure if this will work on your stone, but it sure does on the white limestone commonly used here in Texas. best to try it first on a discrete out of sight area if possible. Good luck, JVC, USA
R1: Dear Cathy, I'm wondering how many ways to spell your name there are in the 
English language!! Keep your windows wide open then use a solution of hot water and household bleach (3 of water and 1 of bleach) with a natural fiber (tampico) brush and a lot of ... Elbow-grease. You can find the latter ingredient on isle 12 at your local supermarket!! :-) Ciao, good luck and don't breath too deeply! Maurizio, USA
Q 2226: I just moved into a home with a rough / brick style sandstone fireplace. The problem is that around the fireplace at the walls, the stone has gotten paint on it. It appears as though the owners tired to wash it off or clean it and now it appears in some areas as a colored haze in the pores. I don't know if it's oil based or water based paint. I was thinking of trying a wire brush to remove it. From what I read on this site, a poultice is best used for smooth surfaces? Would it even make sense to try poulticing the paint off or the wire brush or some kind of chemical?, John, July 15
R1: Dear John: Neither. Poulticing is for deeply inbedded stains only. Paint is typically on the surface or just barely below it. The wire brush could be harsh a means. Soak your stone with a paint stripper based on Methylene Chloride (anything else won't cut it) and a natural fiber brush (tampico), like the ones used to do laundry. Maurizio, USA
A 2104: I have moved into a 50 yr. old sandstone exterior home and the sandstone needs to be clean. I live in north western Pennsylvania were they used a lot of wood or coal to heat homes in the area. I tried some different chemical and had no luck. I heard of cleaning it with a steam or hot water. Please tell me your opinion in cleaning sandstone exterior homes. J. C., June 23
R1: Dear J.C.: You could try to power wash your stone with a solution of water and bleach. 
There's no guarantee that it'll work, but the chances are quite in your favor. bleach won't hurt the stone (keep the PSI at no more than 900). Rinse with plain water, once you're done.,Maurizio, USA.
A 1963: Exterior entrance in front of my home is flanked by decorative sandstone that is beige & some with a blend of a rose tone. 45 years of weather has dirtied the stone somewhat with light black dirt in the sculpted valleys (gentle curves) particularly; the remainder of surface is just normal dirtiness. What would be the best method to use to clean the sandstone? Sanding, wire brushing, power washing, chemically w/ powerwash? If the last, what chemical & strength should be used? Sam, May 25.
R2: I once heard the surprising theory that you can clean sandstone with potato starch! I don't know how you would do this - maybe make a paste, then wash it off. Seabrook, USA. 
R1: Dear Sam: Power-washing with a specialty chemical is the best way to go in my opinion. Maurizio, USA,
A 1841: My husband spilled grease while bbQing on our flagstone patio. The patio has not been sealed. Help! How can I remove the grease stains? Pam AZ,May 14.
R2: Dear Pam: Yes, make a poultice with talc powder (baby powder) and acetone (available at any hardware store). Ciao and good luck, Maurizio, USA, Expert Panelist. 
R1: The flagstone is quite absorptive, as such the grease may not be completely removed. You could make a poultice from paper towels and acetone. Cut the paper towels somewhat larger than the spot. lay them on top of the spot, now soak in acetone. Cover with plastic wrap and tape down. 24 hours later remove the poultice, let the spot air dry and inspect. Redo until the spot is gone. Clean the area with a neutral pH cleaner. Regards, Steven, USA, Expert Panelist.
A 1834: We just bought a house, and there's a beautiful soapstone double sink in there that someone painted white. I was able to clean part of it that wasn't painted, but it's pretty scratched up, and the rest is covered with a thick paint. It's actually peeling away it's so thick in the bottom of one of the sinks. 1. What should I use to take the paint off? I know it's non-absorbent, but I didn't want to damage it in any way 2. Will sand paper take the scratches out? 3. After being painted, etc., will I be able to get it back to it's original beauty? Rosato, May 14.
R2: Dear Rosato: Use a paint stripper based on Methylene Chloride. Anything else won't do. 
Follow precautionary direction in the back label of the can. You can try to sand the scratches up with sand paper, but don't hold your breath about the results. Soapstone is treated by applying mineral oil onto it and rubbing in it.Maurizio, USA
R1: You should be able to restore the sink. It is important to remove all the paint first. I would suggest you make sure that it is not lead based paint first. If it is, I encourage you to just throw the sink away. 
Now, soapstone is a very forgiving stone. Your goal is to sand the spots down with a rough grit sand paper to get rid of the scratches. The lower the grit the more aggressive the sand paper. Only use as low as you have too. Start with a 120 first, if this is not sufficient then go to 80, etc. Once you have it smooth and even you want to thoroughly clean the sink to make sure all paint and whatnot is gone. From there, reverse the process with the sandpaper sanding with each grit successively higher. You are done when you reach the 300 grit sandpaper. Now mineral oil and use the sink as you like. Remember, the sink will need attention frequently. The sink can be cleaned by scrubbing with powder abrasive cleaners and a brush. Do this when you want to deep clean the sink. After each deep cleaning re-oil the sink. Steven, USA
A 1762: What is the best way to clean sandstone paving? Martin, April 26.
R3: Hi Martin; firstly we need to know the type of sandstone you are trying to clean. Do you know which quarry it came from, or which country? and do you have any technical details on the stone you can share? These are the basic questions that need addressing before advice on cleaning can be given safely and effectively. Libi, Australia
R2: Hello Martin, Well you know you will not get a good answer without stating what sized area, what type of sand stone, what surface finish and is it external or internal. 
Well, If it's external and a little mess won't matter, try to:  
1. Saturate the paving with clean water first, this will help prevent loosened dirt from soaking in. ( Very Important )
2. Apply a suitable domestic cleaner (if it's safe for your hands it's safe for the stone) a little white vinegar may also help. Then scrub and scrub till your arm aches.
3. Spread clean dry saw dust (absolvent material) over the entire surface and wait for the soiled water to be absorbed.
4. Sweep up the mess. Go and have a nice cup of tea.
best wishes, Roy, UK.
R1: Probably I would recommend using a biogradable detergent and a pressure washer.
Regards, Steven, USA
A 1697: Where a cleaning company company based in Sydney Australia. We've been asked to clean a Heritage sandstone building in the City, which is approx 90 years old. I've tried to get some advice from stone cleaning professionals in the city and am getting conflicting advice from chemicals to water washdown (slow spray with brush down after). I'm going to pass the job over to someone else, as I don't want to put our companies reputation at risk, however I've done a fair bit of research on this through the net, and I'm intrigued as to your response to the cleaning solution. The stone shows signs of algae and copper  contamination. Regards, Richard. April 13.
R3: Make use of German technology as they clean and restore their centuries old cathedrals on an ongoing basis. I can let you know a company to contact. Regards Thomas, South Africa.
R2: Dear Richard: You made the smartest move possible by letting the job go. The  wash down technique is the safest, but there are also chemicals that, when properly selected and used, can do the job faster and better. but then again, they're not easy to locate, nor to get precise directions on their use. Ciao and good luck, Maurizio, USA
R1: Dear Richard, have you done the most fundamental of all research into your heritage sandstone building problem? Have you properly researched what the soiling is? Unless you know what you are dealing with (and keep in mind that there could be a number of soiling agents) how can you think of tackling this job? Have you researched the properties of the sandstone to see what it is made of, what cements it together, what structures it might have that might have a bearing on its integrity? Different sandstones react differently to different treatments. So, unless you know exactly what is soiling the stone, what the products of the soiling agents are and what the stone is made from how can you choose the best method of cleaning??? (Dr. Hans), Australia
A 1578 a: Good Morning! I would appreciate your help immensely. We have a sandstone kitchen, laundry and bathroom floor. When we moved in our house we sealed the floors but the sealant did not work. The kitchen especially needs cleaning as any oil or stain goes right into the sandstone. We have been told that before resealing we can clean the sandstone with chlorine or bleach and this will fix the stains. Is this okay to do and can you recommend a sealant that WILL WORK and has not to be re applied every 2 years. The people we got the the sealant from are unable to be contacted now. I am hoping for a simple answer or perhaps an old time solution that may have been used in ancient times for sealing Sandstone. We built our own home and have recorded it.Trijntje, Australia, March 21.
R3: Dear Trijntje: It may come as a shock to you, but up until 15 years ago or so, nobody ever sealed any stone with anything. Nobody ever used sandstone as flooring material in a kitchen, either! 
To remove oily stains, you need to poultice them with acetone, or other mineral solvent (bleach won't do the first thing about oil). Finally, as far as the sealer is concerned, you may want to try several options available on the market. Just leave my own out of the picture, please! You may want to consider using boiled lynseed oil: two or three applications (24 hours in between) and see what happen. It will darken the stone. Maurizio
, USA,
R2: In really ancient times, sandstone was not sealed. It is so absorptive that I think sealing it is a waste of time and money. As to chlorine bleach, I think it is too caustic for a soft material like sandstone. I would suggest a poultice or sanding the floor in the area of the stain. Try waxing the floor so that the sacrificial coating (wax) is compromised first. Regards, Steven, USA
R1: To remove stains you need to implement a procedure called poulticing. For now, suffice it to know that the chemical you have to use is related to the nature of the stain (i.e.: Hydrogen Peroxide 30/40 volume for organic stains, Acetone for oily stains, etc.) As far as the "perfect" sealer for sandstone is concerned, to the best of my knowledge it just does not exist (and I believe I tested just about any sealer under the sun). I really wouldn't be thrilled to sell you a bottle of mine, if you have any expectation of a decent sealing job. Sandstone is just too absorbent and, very definitely, does not belong in a kitchen. Even if you could find the "perfect" sealer, its effectiveness would be short lived. What I mean is that you wish you could get away by applying it once ever couple of years. Once very couple of months would be more likely! An old remedy? Try boiled linseed oil on a spare tile (you may have to apply it three or four times). It's a good sealer (although, being organic, it will yellow with time). What's more, it actually stains the stone (it's an oil, right!), consequently any future staining agent that will go through won't be so noticeable any more. Maurizio
A 1387: Dear Maurizio, Thank you so much for the advice with the smooth Arizona sandstone hearth. I have some follow-up questions and hope I can make myself clear. The following questions pertain to the stains on the smooth Arizona sandstone hearth. What is the % concentration or strength of the hydrogen peroxide I should use on the smooth hearth? (beauty shops which I have called no longer use it. However, I may be able to obtain it through my place of employment) How should it be applied? How long should I leave it on? Should I agitate periodically with a soft brush? How do I take it up after the allotted time?, wet vac? or wipe up? The following question pertains to the stains on the rough-cut Arizona sandstone fireplace where wax has dripped. I have since removed the wax, but stains (from the coloring in the wax?) still exist. Since this is a vertical face and nothing sets on it what do I use to take out stains on this (there is still a slight stain left after I use vinegar)? Thank you very much for your time. bob in Seattle. Jan 30.
R1: Dear bob: 30 / 40 volume. Wear rubber gloves. Put some baby powder in a glass or stainless steel bowl, pour some HP on it and mix to form a paste more or less of the consistency of peanut-butter (this is a poultice). Apply the poultice onto the stain (approx. 1/4" thick) and leave it there until is totally dry. After that, remove the talc (baby powder), clean with a damp rag or a wet brush, and check if the stains came out. Repeat it if necessary., Maurizio
Dear Maurizio, I finally found some 40% hydrogen peroxide solution (which has phosphoric acid in it as a stabilizer). There are two parts to my problem. The first deals with the fireplace hearth (smooth finish). How do I use the peroxide? With the poultice I purchased (I've used it about a dozen times with slow results) it is applied and agitated for a period of 40 minutes and then removed using a wet vac. Do I dilute the peroxide or use it full strength? How do I prepare the surface before applying the peroxide? How long do I leave it on? Do I agitate during application? How do I remove it afterwards? The second problem pertains to the sandstone vertical face (rough cut and  brick-like). How do I remove the stains from this surface? Thanks for being patient with bob in Seattle.

A 1330: Great Site! Thanks, I hope someone can help. Recently moved into a house with a rough Arizona sandstone fireplace and smooth hearth. Through the years, the hearth has acquired stains. Knowing enough geology to get me in trouble, I do not want to use anything acidic on this material. I have used differing ratios of vinegar and water to remove surface stains and dirt. However, deeper stains will not come out. Knowing that stone is porous my best guess is that I will need to grind / sand the stone until the stains are removed and then refinish by polishing and/or sealing the surface. Can someone please advise on best method(s), materials and tools to use? Thank you. bob, Jan 15.
R2: Dear bob: We're a little bit ... confused, aren't we! 1. You say that you know enough geology not to use any acidic substance to clean the stone, then you use vinegar (Acetic Acid, that is)! 2. You say that your best guess to remove deep stains is to grind the stone. I'm wondering what your not so good guess is going to be! Stains, if they are not too old, can be only removed by poultice. A poultice is the combination of an absorbent medium (Kaolin, diatomaceous earth, talc, cotton balls, paper towels, etc.) with a chemical, which should be specific to deal with the particular nature of the stain (organic stain, or oily, or biological, etc.). Considering that's a fireplace, the typical stains occurring on the hearth are usually organic. You can try to poultice them out using Hydrogen Peroxide 30 / 40 volume (available at a beauty salon near you). If you will turn out to be successful, then you will proceed to seal the stone with a good quality stone impregnator (several applications will be needed). No offence meant, I was just teasing you a little bit! Ciao and good luck, Maurizio
R1: bob.. you might want to try a poultice type stain remover. Directions and instructions can be found elsewhere on this site. Grinding and or sanding probably won't do much good on this stone as the stain has most likely penetrated deep into the stone. Also, sandstones do not polish very well , but it is important to seal the stone, and periodically reseal it. JVC
Thank you to Maurizio and JVC for their replies. Sorry for the mix-up with the vinegar (acetic acid). I was thinking one thing and typing another. (So much for multi-tasking :-) I have called around the area where I live and that led me to a company in Seattle, Washingtion which recommended the use of a poultice. I've since purchased and used it (3 applications) with little or no results --- can't see a difference, but I will continue to use it. I was told mult-applications would be necessary. The facing of the fireplace is also Arizona sandstone which is done in rough-cut, brick-like shapes. Through the years candles have dripped wax down the front of the stone and have left stains and wax build-up. Last night I had an idea on how to remove these. First, I used a heat gun to melt the wax. As the wax melted I dabbed it with a soft cloth. I did this until there was little or no wax left. However, this left a stain. (The only reason I can think of for this is the coloring in the wax was left behind.) After this step I tried with vinegar using both a wire brush and a soft brush. I kept applying vinegar, using both brushes, until the sandstone looked fairly clean. I then rinsed with water using the soft brush. This method was very successful. Questions: What type of liquids should I not use on sandstone? Would peroxide work better? back to the subject of the smooth hearth. I will try peroxide on this per recommendation. However, I have more questions. 1. What chemical and mechanical treatments should I not use and why? 2. How can I remove surface scratches? 3. Is it possible to fill chips in the surface? What can be used for these? Thank you very much for your help. It is really appreciated. bob in Seattle, Jan 18
Dear bob: I don't quite understand. You want to know what to use to make the surface of the stone smooth and mention that you're going to use Hydrogen Peroxide. That is something you should be using to poultice the stain out, not to smooth the surface (by the way, in most instances, "professional poulticing kits" turn out, in my opinion, to be just marketing gimmiks that only help their manufacturers to put their kids through college!!). To remove the scratches you have to sand them with a rather coarse sandpaper (better if you use that sand-cloth used for metals) and then, to smooth the surface, you should sand it with finer and finer grits, until you reach the desired result. To fill the chips, if they are deep enough, you can try with matching grout. Ciao and good luck, Maurizio

Comments? Complaints? Compliments? info@findstone.com
The views expressed in this section are not of FindStone.
I've just spent about ten minutes looking at your site, but from what I did see I am very impressed. It looks very helpful and user friendly I will use your site for various things in the future, Thank you for this resource. Randy, CLEANING CO. , FL, USA.