Friday, March 5, 2010

Moisture- Stone Enemy Number One

MOISTURE-STONE ENEMY NUMBER ONE

Most of the problems associated with stone tile installation can be traced to moisture or water intrusion of some kind. Many stains are caused by the presents of water. Water is an essential ingredient for the setting cleaning and restoration of stone but it can also be its number one enemy.

What problems are associated with moisture and water. The following is a brief description of the problems, there prevention and remedies:


Efflorescence

Efflorescence appears as a white powdery residue on the surface of the stone. It is a common condition on new stone installations or when the stone is exposed to a large quantity of water, such as flooding. This powder is a mineral salt from the setting bed. To remove efflorescence do not use water, buff the stone with a clean polishing pad or #0000 steel wool pad. The stone will continue to effloresce until it is completely dry. This drying process can take several days to as long as one year.

Subflorescene

Subflorescene is what happens when the mineral salts migrate and do not make it all the way to the surface. In the efflorescence condition above, the slats are deposited on the surface of the stone. In subflorescene the salts crystallize just below the surface, causing stress within the pores of the stone. The result is a condition known as spalling which appears as pits in the surface of the stone. subflorescence is very common on green marbles and is very common on almost all stone surfaces where de-icing salts are used.

Iron Staining

Many light colored stone contain naturally occurring deposits of iron. Iron is a mineral found in stone and can occur randomly throughout the stone. If iron is present, it will begin to oxidize when exposed to water or other oxidizers such as acids and household bleach. Stone 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 stone is saturated with water. 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 stone. 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 stone 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 with a good alkaline based stripper. 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. There are several inexpensive test kits available that can be used to check the iron content in water. Check with your local plumbing supply store or store carrying water softening supplies. 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 stone is cleaned with this water.

3. If the water contains no iron and even if it does the stone should be checked for iron content. Remove a small sample of the stone and contact a testing lab and have them analyzed it for total iron. If there are spare tiles that have never been installed also have them tested for total iron. If iron is present naturally in this stone, it will probably be detected in the spare tile. If the results return with iron present then the following procedure should be tested.

4. Check the stone for moisture. A moisture meter is a useful instrument that can be employed to check the stone for moisture. If the stone contains water, it is very possible that iron is beginning to oxidize.

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(TM) from your plumbing supply or home center. Mix a solution in water and apply to the effected area. Allow solution to soak in and keep wet for several hours. Do not allow solution to dry. After several hours pick up excess solution with a wet vacuum and rinse throughly with water and a chelating agent such as EDTA. Be prepared to repolish any marble since these chemicals can cause etching.

2. If the above procedure fails than prepare a poultice with diatomaceous earth and the Iron Out(TM). Mix the poultice into a thick paste and apply to a small area. Cover the poultice with plastic and allow it to sit covered for 24 hours. After 24 hours remove the poultice paste and rinse the area with water and a chelating agent. If the stain is removed, the entire surface can be treated. If the stain still remains then replacement is the only solution.

Before the above procedure can be performed, it is important that the effected area be dry. If water or moisture are still present, oxidation of iron may continue

The yellowing of stone 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.


The above procedure has proven successful in some cases of iron staining however if the following test does not produce the desired results I would recommend replacement of the effected areas.

Marble and limestone in constant wet areas such as showers and pools, etc may be impossible to remove iron. The stone as well as adjacent materials such as grout etc will also be effected.







Warping

several type of thin stone tiles are very susceptible to warping. Many of the green marbles and a few agglomerate marbles are notorious for this warping condition. Many of an installer have had the surprise to find that there tile installation has become warped overnight. Why does this a happen and can it be prevented. Warping is caused by water. Green marble set with any water based material will have a tendency to warp. The mechanism of why the tile warps is somewhat a mystery. Some believe that the water fills the pores of the stone and when the water evaporates the orientation of the stones crystal change and cause it to warp. Whatever the reason, one thing is for sure, green marble can warp when set with water based materials.

Cure: Once a green marble tile warps it is difficult to repair. Attempts have been made to grind the tile flat , but this usually fails since additional water is introduced during the grinding process. The green simply warps again.

Prevention; The only way to prevent warping is to install it properly with a non-water based material such as epoxy. Some installers have also ben successful in sealing the back of the tile with epoxy and installing it in a water based system(see July Stone & tile Report). Do not attempt to seal the back of the tile with a silicone sealer. The silicone acts as a water repellant and will cause the setting material to fail resulting in a bond loss.


Erosion

Erosion is a condition found when stone is exposed to constant amounts of water. This is especially true with marble that is used in water fountains. While marble is a very decorative material, it is one of the worst materials to use in or around water. Marble is composed of calcium carbonate. Calcium carbonate is a water soluble mineral. Quite simply this means it will dissolve in water. Want proof, visit the Grand Canyon. Erosion can be recognized by a slow deterioration of the stone surface. With polished stone the polish will be worn off. In older installations, the stone may become very soft, brittle and in extreme conditions, it will powder.
If any architects or designers are reading this article I beg you no to use marble for water fountains. If you do, plan on very high maintenance costs and plan on replacement in about five to ten years if not sooner.



Stabilizing erosion:

If your faced with trying to stabilize a marble fountain that is already deteriorated there are some treatment that can be applied that will extend the life of the marble. These treatments are general called consolidants and serve to replace the natural binders that are lost through erosion. Consolidants can be tricky and quite often will cause discoloration of the surface. Be sure to test the consolidant carefully before use.

Mineral crusts or Lime Putty

Mineral crusts or lime putty can be recognized by its white crust like formation on stone surfaces. These crusts are often found on outdoor stone stair, water fountains and other areas where stone is exposed to water. The crusts are a deposit of hard mineral salts consisting of calcium, magnesium. These minerals ordinate form the soil, setting bed or from the water itself. These salts are similar to efflorescence in that they are a mineral. They differ in that they form a hard crust that can be difficult to remove.

Crust Removal

there are only two ways to remove these mineral crusts. Abrasion or chemical. The mineral salts should be remove with an abrasive. I have found that a stiff non-ferrous wire brush can work well. Brushes can also be purchased that attach to an electric drill. Be careful and do not get to aggressive. Avoid damaging the stone surface.
Quite often abrasion alone will not remove all salt deposited. Strong Acidic chemicals will be required. These chemicals can be purchased from most chemical companies that supply stone cleaning products. Be careful when using these products around calcium based stone since the acid can also damage the stone itself.

Prevention.

The best prevention from mineral salts is to prevent moisture form entering the stone. On steps and fountains make sure all grout joints are caulked with a water proof material. When installing steps outdoors make sure a water proofing barrier is used. It is also a good idea to use a good stone impregnator on all surfaces to prevent water from entering the stone. Caution; Stone inpregnators will not waterproof stone. Do Not use them where hydrostatic pressure is a concern.


TESTING FOR MOISTURE


To properly test for moisture a protimeter is necessary. A protimeter is an instrument that reads moisture. The common protimeter has been designed for use with wood, drywall and other similar substances. The protimeter contains two sharp probes that are inserted into the wood or drywall to give a direct moisture reading in percent. Unfortunilty you can not push these probes into the stone, but the protimeter can give you important data oon stone moisture. By placing the pins so that the just touch the stone a relative reading can be obtained. For example, A reading of 0-6% is considerely relativly dry. A reading between 7-20% is wet. A reading of of 20% is very wet. These readings only tell you that the stone is wet, a little wet or dry. A direct percent reading can not be obtain with these instruments, but can provide useful information.

Another simple technique for determining moisture in stone is to take a piece of plastic about 12 inches square and place it on the suspected stone. Tape all four edges and allow it to stay overnight or 12 hours. After 12 hours, if there is any moisture present , you will see condensation collecting under the plastic.


TESTING FOR SALT

A protimeter can also be used to check for the presents of soluble salts. The following procedure will only tell you that salts are present. It will not tell you how much or what type. But in many cases the simple presents of salts can indicate potential spalling and/or pitting.

For this test you will need the following materials:

A rubber block
filter paper
distilled water
a protimeter
forceps

Any type of rubber will do as long as it is clean and does not contain any salts. A piece of hard plastic can also be used. Filter paper can be purchased from a scientific supply store and sometimes from the supplier who sells protimeters. Distilled water can be purchased from the grocery store.
The forceps are used to pick up the filter paper.

To check for soluble salts pick up a filter paper with the forceps. DO NOT touch the filter paper with your fingers. The human skin contains soluble salts which could be transferred to the paper giving a false reading. Place the filter paper on the rubber block. Add a drop of two of distilled water to the filter paper. Place the probes of the protimeter to the filter paper and record the reading. Next, take a new filter paper and place it on the stone to be tested. Add several drops of distilled water and take a reading. Record the reading on a piece of paper.

If the reading obtained on the filter paper from the stone is higher, then there are slats present. If it is the same or lower, salts are absent. The protimeter works by reading ionic changes. When salts are dissolved in water, the ionic changes are higher, which gives a higher reading.

Sustainable Terrazzo Floor Care-Dispelling the Myths

Sustainable Terrazzo Floor Care-Dispelling the Myths

As the world moves towards more sustainable design and maintenance myths are starting to be propagated which only leads to confusion. School superintendents, custodians and teachers are being bombarded by false information. The following are some of these myths and the truth behind them as it applies to floor care

Myth #1- Coatings, waxes etc are used as a sacrificial layer to protect the floor.
FALSE- Coatings such as acrylics, epoxies, urethanes commonly found in floor finishes are soft compared to the natural hardness of terrazzo which is basically concrete and marble. Due to their inherit softness they tend to trap and hold dirt and debris which contributes to accelerated wear of the surface.
A simple test can be performed to prove this. Take a tile and coat one half of it with a standard floor finish and leave the other half polished using a sustainable method. Allow the tile to sit in a room for a week. After a week you will notice that the coated side has more dust than the uncoated side. Next take a rag and wipe it across both sides of the tile. You will note that the drag on the rag is much greater on the coated side vs. the uncoated side. Now imagine how hard it is to remove this dirt and debris with a dust mop on coated floor.

Myth #2- Terrazzo contains asbestos and should not be ground
Let’s take a look at what terrazzo consists of. It is composed of concrete and marble chips or epoxy and marble chips. None of these components contain asbestos. Some concrete mixes do contain fiberglass particles which under a microscope can easily be mistaken for asbestos. In addition we have taken core samples of terrazzo on several occasions and have had them tested for asbestos. In every case no asbestos was found.

Myth #3 -Using Green and sustainable methods cost more
False; In fact sustainable maintenance will reduce cost dramatically. Not only will less time be required to dust mop and wet mop, but you have totally eliminated all chemical costs. Several studies can be found at www.boylanstonerestoration that will show that on average the cost savings is around $1.85 per square foot per year. In addition the payback on the initial restoration cost can be less than 3 years.
Myth #4 –Going green will cost jobs
False: most floor care programs spend nearly 70 % of manpower on floor care. Due to budget cuts, other areas of maintenance are being neglected. In fact based on our informal surveys more and more work is being placed on maintenance staff. By reducing the maintenance costs and labor required on floor care, manpower can be directed to other neglected areas.

Myth #5- A natural polished terrazzo floor will stain without a protective coating.
False: The natural polishing process closes the pores of the terrazzo which reduces the absorption of liquids. In many of our terrazzo restoration projects coffee was spilled and dried on the floor. The dried coffee was scraped up leaving no visible stain.
Myth #6- Stripper, coating and cleaners are now available in Green Formulations
Caution must be excerised when looking at what constitutes a “green” product. Many chemical companies have reduced the percentage of hazdourous chemicals in their formulations. However this does not make the product any safer. Many articles have discussed this and have called it Green Washing. A great example of this is in a article by The Environmental Working Group(www.ewg.org/schoolcleaningsupplies , which uses the cleaner Simple Green as an example. There article states that Simple Green claims to be non-toxic and biodegradable but failes to mention that the principal cleaning ingredient it contains is a possible human carcinogen.The hazardous ingredient is still present along with all the dangerous it exhibits. To be totally sustainable it is best to use NO CHEMICALS at all.

The myths that are circulating must be investigated and common logic applied to them. Many of these myths are put forth by chemical companies who are trying to market there hazdourds , health threating products. A simple review of the MSDS will show many of the ill effects of these chemicals.

A New But Old Polishing Proceudre for Natural Stone Flooring

A New But Old Polishing Procedure for Natural Stone Flooring
By Frederick M. Hueston PhD
Putting New and Old in the same sentence is somewhat of an oxymoron. But in this case both of these adjective apply. What I am talking about is a polishing system for stone flooring that was used many years before chemicals came into existence and is now fast becoming the preferred method specified by architects and others. The word “Green” has entered our industry and I am finding that many projects across the US are now specifying that a green and sustainable restoration process be implemented in restoring both natural stone and terrazzo surfaces. This article will present not only what is sustainable but will give you an alternative to traditional polishing methods that is fast becoming the preferred method.

What is Green?
Everywhere you look individuals, government agencies, universities and schools and even private businesses are going green. As we hear news about global warming and how we are polluting our own environment, it is of utmost importance that we all do our part in saving our planet not only for our present generation but for generations to following.
What Does Going Green Mean?
The term Green or Going Green has entered our vocabulary but few really know what the term means. Going Green is principles that minimize the use of nonrenewable resources and seek to prevent air, water and ground contamination and other activities that degrade the environment. According to The US Green Building Council worldwide buildings account for 17% of fresh water withdrawal, 25% Wood Harvest, 33% CO2 emissions and 40% material and energy use.
Going Green is simply changing the way we build, operate and maintain buildings to reduce the negative impact it is having on our environment.
Many small businesses feel that they are too small to make an impact on the environment. Even individuals feel the same. Take a look at the following facts and you will see this is simply not true.
• A single quart of motor oil, if disposed of improperly, can contaminate up to two million gallons of fresh water.
• A 1/32" leak in a faucet can waste up to 6,000 gallons of water a month, or 72,000 gallons a year.
• Americans throw away 25 billion Styrofoam coffee cups every year, and 2.5 million plastic beverage bottles every hour.
• The amount of wood and paper we throw away each year is enough to heat 50 million homes for 20 years.

And the list goes on and on.


Stone Restoration and Green
Traditionally the restoration, repair and maintenance of stone and terrazzo surfaces use chemicals that are harmful to the environment and to people in general. Chemicals such as polishing compounds contain harmful acids. Solvent based cleaners and sealers emit harmful VOC’s. Not to mention the carcinogens and toxic effects many of these chemicals have on humans. The procedures used to restore stone surfaces also produce a copious amount of waste and use large amounts of fresh water.
I am currently working with a stone restoration company that is taking steps to eliminate all these harmful chemicals and processes. This company has developed methods to restore , repair and maintain stone surfaces using no harmful chemicals. As matter of fact the restoration and polishing of marble, granite, limestone and terrazzo uses no chemicals at all. Here is a summary of their process
The floor is ground and resurfaced using a fixed diamond abrasive and water. These abrasives are similar to sandpaper but differ in that there is no grit removed or left behind on the floor. The diamond abrasive is fixed to a pad. There are no chemicals used at all.
The water used will be recycled and reused in a specially designed system.
To polish the stone or terrazzo super fine abrasives are used. These abrasives contain no harmful chemicals.
Many stone restoration and janitorial companies are also using floor finishes to achieve a high luster on the stone or terrazzo surface. In addition to these finishes containing chemicals that are harmful to the environment. They also have a negative impact on the esthetics of the surface in the following ways:
-Most finishes used on stone and terrazzo are soft and tend to show wear and scuff marks in a very short time. This increase the amount of maintenance as well as cost for daily maintenance
-All floor finishes at some point will need to be stripped off. The chemical strippers used are caustic and can cause damage to the stone or terrazzo, not to mention the environmental impact.
-The old finish once it is removed will need to be disposed of. Most of these waste finishes are considered a hazardous waste.
-Most finishes do the opposite of what they are designed to accomplish. That is they become a dirt magnet. I have conducted experiments that show a coated surface will attract more dirt than a surface restored using a green system.
Even today’s stone restoration companies are using polishing compounds that contain dangerous oxalic acid.
A Green stone and terrazzo restoration process have no negative impact on the building environment or the occupants since no chemicals or finishes are used. The maintenance requirement after the stone or terrazzo is restored is reduced by as much as 50% or more saving on labor and chemicals.

Can Natural Stone be polished without the use of chemicals?
Many stone restoration companies will argue that it is impossible to achieve a deep high reflection on natural stone without the use of chemical polishes. This in fact is not true. Mechanical polishing using diamond abrasives alone with the proper equipment can achieve results that are as good as or superior to chemical polishes. These methods will be discussed and presented my next article.

Be Wary of Green Washing
Caution must be excerised when looking at what constitutes a “green” product. Many chemical companies have reduced the percentage of hazdourous chemicals in their formulations. However this does not make the product any safer. Many articles have discussed this and have called it Green Washing. A great example of this is in a article by The Environmental Working Group(www.ewg.org/schoolcleaningsupplies , which uses the cleaner Simple Green as an example. There article states that Simple Green claims to be non-toxic and biodegradable but failes to mention that the principal cleaning ingredient it contains is a possible human carcinogen. The hazardous ingredient is still present along with all the dangerous it exhibits. To be totally sustainable it is best to use NO CHEMICALS at all.