Why does white marble turn yellow ?

Causes and cures (and why we recommend white or very light marble never be used in a shower)

Sitting in my office one morning I received a call from a very upset homebuilder. He told me he was building a two million-dollar home and had installed nearly 3500 square feet of a white statuary marble tile. Over the weekend one of the water pipes broke in a bathroom and completely flooded the home.

They managed to vacuum all the water and started to assess the damages. Beside warped wood, soaked drywall and an irate homeowner, the marble tile seemed fine except for some minor water spotting. After several weeks the replacement of warped wood and drywall was completed, but he noticed the white marble had turned yellow in many areas. At first he thought it might be some type of residue so they tried cleaning the marble with some bleach and water but the yellowing was still there.

Meanwhile, the homeowner was getting more and more irate and was threatening a lawsuit. It was at this point that he called me.

The problem of yellowed white marble is not uncommon. All over the United States I have encountered marble that has turned yellow, and even brown. Although flooding is a common cause there are several other reasons this color change will occur.

Improper Maintenance

As marble wears, the highly polished surface begins to become scratched and worn. The wearing of this polish causes the surface to become rough and become a magnet for dirt. If improper cleaners are used, this dirt begins to accumulate in the pores of the stone can will turn yellow. It is surprising how often I have seen this condition on marble. Upon investigation in these cases I have often found dirty mops being used. Mops used to clean the restrooms and/or kitchens were also used to clean the marble floors. Floors are mopped with strong cleaners or wax cleaner combinations or with no cleaners at all.

Cure: If you suspect yellowing due to improper maintenance the marble tile will have to be cleaned with an alkaline marble cleaner. I would suggest a heavy duty stone cleaner. Be sure the stone cleaner you buy needs to be alkaline and not an acid since acid cleaners will dull the polish. Apply the cleaner to the marble and scrub with a soft brush. Be sure to rinse the floor thoroughly. It may be necessary to repeat this procedure several times to remove all the imbedded dirt. If after cleaning the marble is dull I would suggest that you call us to professionally re-polish your floors then follow with an application of a good quality penetrating sealer (impregnator). If after several cleanings the yellowing is not removed then consider the next cause.

Wax Build-up or Coating

Many marble floors are coated with waxes, acrylics, urethane and other coatings. Most of these coatings are not specifically designed for use on marble floors. Some of these coatings are of poor quality and the coatings themselves will begin to yellow. It is not uncommon for coating to be applied in multiple coats. As the coating builds up it becomes soft and dirt is easily embedded in the soft layer. These coatings require frequent stripping which is often neglected.

Another possibility along these same lines is that process sometimes used for polishing marble floors is known as re-crystallazation. If this process is applied to a white marble floor that contains moisture it will turn the marble yellow.

Cure: To remove yellowing due to a wax or coating buildup the marble will need to stripped with a commercial wax stripper. I would strongly suggest having this done by a professional. These strippers often require the use of abrasive pads which can scratch and damage the marble surface. If you do try it yourself, before undertaking the entire project perform a small test to determine results.

If the marble tile has been recrystallized, it will be necessary to remove the recrystallized layer. This layer can often be removed by a professional polishing the tile with a powder marble polish containing oxalic acid. If this technique fails then the tile will have to be re-honed. It is strongly suggested that the polishing and honing procedure be performed by trained individuals. If these techniques fail to remove the yellowing then proceed to the next possible cause.

Iron Staining

Many white marble tiles contain naturally occurring deposits of iron. Iron is a mineral found in stone and can occur randomly throughout the stone. If iron is present in the marble tile, it will begin to oxidize when exposed to water or other oxidizers such as acids and household bleach.

It is for this reason that we recommend not using white marble in a shower.

White marble tiles can remain for years without yellowing then over time may slowly turn yellow, and in severe causes, may turn completely brown. This oxidation process is accelerated when the tile is saturated as in the flood in the above example. This process of oxidation is similar to the rusting of metal. If you expose a brand new nail to water and air it will turn brown and rust. The same process is occurring with the iron in the marble. If water and/ or air is eliminated the iron will not oxidize. This is the reason certain white marble suddenly turn yellow.

The process is difficult to reverse and replacement of the tile may be necessary. The following stain removal technique has proved successful in several cases. Before testing this procedure it is important to first determine if iron is the cause.

Testing for Iron:

  1. Before assuming the marble is yellowed due to iron, be sure to attempt cleaning and stripping as outlined in the first two possible causes above. If these procedures fail then testing for iron will be necessary.
  2. If a flood has occurred or excessive water was used first check the water for iron. If any amount of iron is detected then it is possible iron has entered the stone through the water supply. To eliminate the iron there are chelating chemicals that can be added to the water to prevent the iron from staining. This is very important if the tile is cleaned with this water.
  3. Even if the water contains no iron the tile can be checked for iron content. We can remove one tile and have it analyzed total iron. If there are spare tiles that have never been installed it would be a good idea to also have them tested for total iron. If iron is present naturally in this stone, it will probably be detected in the spare tiles. If the results return with iron present then the following procedure should be tested.
  4. We can check the tile for moisture using a moisture meter. If the tile contains water, it is very possible that iron is beginning to oxidize.

The Process for Removing Iron Staining:

  1. Prepare a solution of water and the following chemical: Sodium Hydro sulfite and Sodium Metabisulfite. These chemicals are available in a product called Iron-Out® you may have seen at your plumbing supply or home center.
  2. We will mix a solution in water and apply to the effected tile, and allow the solution to soak into tile and kept wet for several hours. It is important that the solution not be allowed to dry. After several hours pick up excess solution with a wet vacuum and rinse thoroughly with water and a chelating agent such as EDTA.
  3. Be prepared to expect that the marble may need to be repolished since these chemicals can etch marble.

If the above procedure fails we can then prepare a poultice with diatomaceous earth and the Iron Out™. The poultice mixture will be applied to a small area and covered with plastic wrap. After 24 hours remove the poultice paste and rinse the area with water and a chelating agent. If the stain is removed, the entire floor can be treated. If the stain still remains then replacement is the only solution.

NOTE: There are also some new chemicals that are available which contain Ammonium Thioglycolate which look promising for removing iron oxidation.

The yellowing of white marble is a common problem. New installations should be sealed with a good quality penetrating sealer (impregnator) which will help prevent oxidation of the iron by eliminating moisture.

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Testimonials

JMC did an outstanding job sealing the grout for the floor tiles and shower tiles. JMC also sealed the granite counter tops. The price was competitive and reasonable. The owner, Justin, personally performed the work. The good experience started with him showing up at the scheduled time. He was diligently focused on performing a good job. He applied several coats of sealer to the granite tops to insure a quality job. He spent hours sealing the grout for over 2,000 sq ft of floor tile. His enthusiasm and attention to quality never waivered. I highly recommend using their services.

Steve Temecula CA

Justin helped my husband and I repair a large crack in our granite slab. He not only repaired the crack but resealed all of our other countertops too. His price was very competitive and he kept his word on when he was available and showed up on time. What more could you have asked for! Thank you Justin!!

Misty Temecula CA

Justin did an amazing job color enhancing and sealing our slate floors. I called and met with several tile cleaning companies, but chose Justin because I felt he was the most honest, knowledgeable, and experienced. He took the time to explain different options and even showed me a small area before he continued with the entire floor. He spent hours prepping, cleaning, enhancing, and sealing our slate. His work paid off...our floors are finally gorgeous! He changed our dull, chalky looking slate by giving it a brilliant luster that enhances our home. I could not be more thrilled with the results. Bottom line, Justin did exactly what he said he would at the cost we agreed to and even changed his personal schedule to accommodate my schedule. He went above and beyond. In a time when I feel it is difficult to find good, honest, hardworking people to hire, Justin at JMC Tile and Grout has changed my mind. Thank you Justin!

Laura Temecula CA

Justin is very professional. He has done 2 separate marble polishing jobs for us and each time we have been very pleased. He is very thorough and careful, doing a great prep job to prevent any damage. His prices are very fair. So glad we found Justin. There are very few marble and stone care professionals in this area. Highly recommend Justin!

Diane Murrieta CA

Justin came in and cleaned and resealed the grout on our floors. He was a very professional and easy person to talk to. He was also very helpful with other things around the house. Great guy and great job. Well done!!! Thank you!!!

Helene Temecula CA

Justin did an excellent job of repairing a large crack in our kitchen granite. It was quite deep and covered a large area. Needless to say it was very noticeable and would have caused us to replace an entire slab of granite if we had not had it repaired. He spent almost an entire morning in the restoration. He was meticulous in his work, was able to match the color of the granite and it looks 100% better. In addition he resealed and polished all the rest of our granite countertops. We certainly would recommend him. He was professional, very neat and thorough. He arrived exactly on time, even though he had to drive an hour to reach us. He will certainly be someone we contact again if we need any more restoration or maintenance on our granite. We were delighted with his work. Cyndi M. Coronado

Cyndi Coronado CA

Justin is the man. My wife and I recently moved into our new home in Lake Elsinore, we thought that we would seal the grout on our floors and shower by ourselves. After realizing the size and scope of the grout sealing project we decided to contact an expert to get an estimate. I had read online that most tile companies charge about $1.00 per square foot so I had an idea how much the estimate would be. Justin came out the same day and gave my wife the estimate. Since we did not have any furniture in the house yet we asked if he could start the same day. It was already 2pm at that point and Justin was not sure if he had enough sealer with him to do the whole job. He agreed to start sealing the grout near the walls where the heavy furniture would be placed and come back later to finish the job another day. After he started sealing our grout he found more sealer in his work van and decided that he would just power through and finish the job for us the same day! We were thrilled with the entire experience. Justin is truly a tile and stone professional. When he was finished sealing the grout he also sealed our new granite counter tops. All I can say is, if we ever have a tile or stone job in the future, Justin is "our guy." Great service with top quality products and fair pricing, what more could you ask for? Also, at no point during the job did he attempt to up-sell us anything, as a matter of fact, he tried to lower his price once the job was finished but we wouldn't hear of it. We agreed to a set price and that is what he deserved. Thanks Justin, you saved us a lot of time and energy. I can sleep better at night knowing that our expensive new flooring is protected for many years to come. I would highly recommend JMC Stone & Tile to friends and family.

Lake Elsinore CA

Justin thank you so much for the wonderful job you did restoring my marble floor. Very professional and I will recommend your service to all our friends. Thank you Elizabeth, Riverside County

Elizabeth , Riverside County

Thank you Justin at JMC Stone and Tile Care. He re colored our grout with color seal and it looks amazing. His attention to detail to customer service is top notch and I have no problem referring your services. If your in Temecula CA JMC Stone and Tile Care is my recommendation for all your tile, stone, and color sealing needs. Thank you so much

Cathi Cameron, Temecula CA

We are so happy with the service from Justin at JMC stone and tile care. He re colored are old nasty stained grout on our countertops with color seal. The grout looks brand new he will be referred to all our friends in Murrieta CA.

Julie Johnson Murrieta CA

Justin (JMC Stone and Tile Care) cleaned the tile and grout of my floors in April 2013. On the day he was at my home to provide a quote and also on the day of service, Justin was prompt, courteous and professional. Once involved in the job and realizing that part of my floors was not as badly in need of cleaning as the rest of the tile, he reduced the cost of the service. I very much appreciated his fairness and integrity! Not only did my floors looks sparkling clean when he was done, but I also knew much more about how to keep my floors clean on my own. He was quick to share secrets of his trade! I recommend Justin’s service without reservation. His service is unparalleled, and he is a friendly and honest professional! Gail Miller Temecula CA

Gail Miller Temecula CA

Justin, I would like to thank you again for the excellent job you did repairing and retiling our marble tile table. I would definitely use your services again and recommend you to anyone needing stone or tile work done in Murrieta CA. Thank you, Heather Lumsden

Heather Lumsden Murrieta CA

We have been very pleased with the service that Justin has given us. The overall quality of his work was excellent. In one small area we had a slightly rough feel to the sealant he had applied to our granite countertops. Justin returned on the very day that we called him and quickly repaired it. This is a very courteous, professional, and above all, competent service in Murrieta CA. Thanks so much John Welniak

John Welniak. Murrieta CA

February 14, 2013 Justin We are absolutely thrilled with our new floor!!!! Yes, I say new floor because that is the way the whole house looks! It looks like brand new tile. Justin, you did a fabulous job! Thank You, Judy Nitti

Judy Nitti Temecula CA

I accidentally spilled some cleaner on our marble vanity and made those awful etch marks. I called Justin at JMC Stone and Tile Care and he assured me that I didn't ruin my bathroom vanity. Thanks so much for removing those etch marks, we will definitely refer you to anyone in Wildomar CA.

J. Escarsega, Wildomar CA

I would like to thank Justin of JMC Stone and Tile care for bringing back the beautiful shine to our granite countertops. Very professsional and courteous and on time. It's hard to find all those qualities in one place. Thanks Justin again and we are clients for life and we will definitely refer you to anyone in Oeanside Ca.

Lacey Linek, Oceanside CA

We had a last minute emergency and we had a surprise visit from an important client. We called a few tile and stone companies and not one would help us. We called JMC Stone and Tile Care and Justin rescued us. He was very professional and accommodating to our last minute request to have the tile cleaned. For that we can't thank you enough and will refer you to anyone in Carlsbad CA.

Kyle Batsford, Palomar Reprographics, Carlsbad CA
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