Removing Urine Stains and Odors from Stone Surfaces

Removing Urine Stains and Odors from Stone Surfaces

Frederick M. Hueston, Stoneforensics.com

 

Your new puppy made a mess on your new marble floor. The granite floor in front of the urinals in the men’s room is stained and smells of urine. These are just a few of the issues with odors emitting from your stone surfaces.  Weather it’s your puppy or your husbands poor aim the following should remove the stain and the odor.

The Chemistry of Urine

Urine is unique in that it is a substance that comes our of the body as an acid and when it starts to dry becomes an alkaline crystal. For you amateur chemist it starts at a pH of 5-6 and converts to a pH of 10-12. These alkaline crystals are hydrophilic which simply means they absorb moisture. As these crystals absorb surrounding moisture the stain can grow in size. If the stone is a polished marble or limestone it can become dull due to the initial acid reaction but can also dull from the strong alkali. If this is the case the stone may need to be repolished.

Removing the Stain

Removing urine stains can be tricky and timing is everything. The quicker you can get to the stain the easier it will be to remove.

As soon as you can blot the urine up with some dry paper towels. Do Not wipe since this will only spread the stain.  Clean the stain with some dish soap and water. Mix about one teaspoon of dish soap in a gallon of water. Apply this solution on the wet area and allow it to sit for a minute or two. Blot the solution up and rinse with clean water. If there is still a stain, then you will need to apply a poultice.

 

The following is a basic procedure for stain removal More detailed stain removal instructions can be found here. http://stoneforensics.blogspot.com/ or www.SurPHaces.com

 

What you’ll need:

1.     Flour(use only white flour)

2.     Hydrogen Peroxide 20 Volume(You can purchase 20 volume peroxide at most beauty supply stores)

3.     Plastic wrap (saran wrap or equivalent)

4.     Plastic putty knife

5.     Low contact painters’ tape

6.     Mixing bowl or cup

7.     Plastic or wooden spoon

 

 

1. Wet the stained area with distilled water. Pre-wetting fills the pores of the stone with water isolating the stain and accelerating the removal by the chemical.

2. Prepare the poultice.  Take a small amount of flour and pour the peroxide into the flour and stir until you reach a creamy consistency.

3, Apply the poultice to the stain being careful not to spill any on the non stained areas. Apply approximately 1/4-inch thick over-lapping the stain area by about one inch.

4. Cover the poultice with plastic (food wrap works great). Tape the plastic down to seal the edges. It also helps to poke several small holes in the plastic so that the powder will dry out. Failure to do this may result in the poultice staying wet.

5. Allow the poultice to dry thoroughly. This is a very important step. The drying of the poultice is what pulls the stain from the stone into the poultice material. If the poultice is not allowed to dry, the stain may not be removed. Drying usually takes from 24 to 48 hours.

6. Remove the poultice with a plastic putty knife. Rinse with distilled water and buff dry with a soft cloth. If the stain is not removed, apply the poultice again. It may take up to five applications for difficult stains.

Step 2 Odor removal

 

Once the stain is removed the urine smell may still be present. The following is how to neutralize the odor:

The nasty smell you experience is the result of bacteria using the urine as a food source. So, in order to eliminate the odor we need to kill the bacteria. There are numerous products out there that are designed for eliminating the odor in carpets. These same chemicals can be used for stone.  If you use these products make sure they are enzymatic. Many products are only mask the odor, you want to eliminate it, so an enzymatic product is necessary.

 

Instructions for applying an enzymatic cleaner

 

• Spray the affected surface liberally with the cleaner using a pump sprayer or spray bottle.
• Cover with plastic  for 1 to 2 hours to slow the evaporation rate and allow time for the first application to soak deeply into the stone.
• Note that as the first application of cleaner goes to work, the urine odor may intensify at first. This is typical with old or heavy urine deposits and indicates that the urine being loosened and is rising to the surface.
• Remove the plastic and blot the floor dry with paper towels or cloths. Expect the blotting towels or cloths to be colored yellow and smell heavily of urine. Dispose of the soiled towels or cloths.
• Reapply the cleaner. Allow to dry 1 to 2 hours. (In humid climates lacking AC, drying may take longer.)
• Reapply as needed, with 1 to 2 hours drying time between applications, until odor is removed.

 

The above processes are time consuming but will be well worth the effort if done properly.

 

 

 

 

The Care and Feeding of Slate Flooring( Wiping the Slate Clean)

By Frederick M. Hueston, Technical Editor

Slate flooring is become increasing popular in the US today. Years ago slate was basically gray and pale and there weren’t many varieties to choose from. Today there are literally hundreds of slate colours. In India alone there are several hundreds running every imaginable color and well as texture.  The problem with slate for flooring is that it differs somewhat from the typical highly polished marble, limestone and granite. This article will explore the proper care and feeding of slate flooring. Sections of this article can also be used to give your customers so they know the proper care of their new slate flooring.

 WHAT IS SLATE

 Slate is a stone, which has been metamorphosed from shale—that is, it consists of clay-like materials that have undergone change under heat and pressure.  In other words, slate can be recognized by its sheet-like structure.  The material is usually thin and if broken in half, will flake off into sheets.  Slate is seldom highly reflective unless a coating is placed on it, and its surface is usually uneven unless machine- sanded.

Although slate can be purchased in 12" x 12" tiles, the most popular size is random patterns of varying shapes.

 For those of you who would like to know more. Slate is made up of minerals of quartz and illite. You will also find minor amounts of mica, calcite and other mineral.  Red colored slates contains hematite, which gives it is red color. Greens contain chlorite and blacks and grays contain carbon and or graphite.  The reddish tans are the result of iron oxides.

 BASIC SLATE FLOOR CLEANING

           OK, lets get down to what this article is all about—the actual care and maintenance of your slate flooring. It is not a complicated subject.  In fact, most of the mistakes that are made, and the main reason slate flooring gets dirty or ruined can be traced to simple neglect.

          Let’s suppose you’ve just purchased a brand-new car—and you never wash it. Soon enough the paint will fade, the body will rust, and the car will cost you a small fortune to restore.  On the other hand, if you make the effort to wash it on a regular basis and throw a coat of wax on it every now and then, it will look as good as new for years.  This is exactly what you need to do for your slate flooring.  Keep it clean and protected, and it will last till the kids move out—and may even be around when they move back in. The following maintenance tips will tell you what you need to know to make this possible.

     

 DAILY CLEANING

 

          To keep your slate flooring in tip-top condition, a few simple maintenance procedures are necessary.  For best results, they should be followed very closely.

 DUST-MOPPING

          Of all the procedures used to maintain slate flooring, dust mopping is probably the most important.  Dust, dirt and grit are what cause most surfaces to scratch & mar; if we could somehow eliminate them, this would cease to be a problem.  Several studies have indicated that floors, which are dust-mopped often, stay cleaner and shinier longer.

           Do dust mop your floor daily.  If traffic is heavy, or the floor is located in a commercial building, do it several times a day. Remember do not use oil-treated dust mops on slate flooring.

           When dust mopping, be sure to run the dust mop in one direction only. Do not move it back and forth.  Think of it as pushing the dirt in only one direction.  When you have accumulated enough dirt and debris, pick it up with a dustpan and brush and take the dust mop outside to shake any remaining dust.  When storing the dust mop, be sure to keep its head off the ground. Hardware store sell various hangers, which are excellent for storing mops and  brooms.

           Designate only one dust mop for each type of surface.  For example, you should use one dust mop for your slate flooring and a separate one for other tile or wood floors.  Do not get the dust mop wet; if the floor is wet, be sure to dry it before dust mopping.

           Purchase a good-quality machine-washable mop and keep it clean. Wash it in cold water with laundry detergent and machine-dry.

 WELCOME MATS, RUGS, AND WALK-OFF MATS

          Another important tool necessary for keeping dirt and debris off your slate floors is some type of mat, rug or what is commonly called a walk-off mat.  A good-quality mat will capture dirt before someone walks on the floor.  If it is placed outside your door, it is only human nature and common courtesy for people to wipe their feet before entering the house.  Studies have shown that it takes approximately seven steps to remove most loose dirt from one’s shoes.  For this reason, I would recommend placing mats both inside and outside.

 

 MAT AND RUG TYPES

           There are hundreds of mats and rugs on the market today.  Be sure to purchase one of good quality. Be careful about using rubber- or jute-backed mats or rugs on slate flooring; either kind of backing can bleed into the slate, causing a stain that may be difficult or impossible to remove.  A mat should be at least as wide as the doorway it serves.

           Clean your mats often, daily if possible. Take them up and clean under them when you dust mop.  Be sure the floor is dry before returning them to the floor. Never place a mat down on a wet surface or put a wet mat on any surface.

 DAMP OR WET MOPPING 

           All slate flooring needs to be cleaned. How often you will need to damp or wet mop will depend on  the amount of traffic and the finish (honed, coated, textured).  The following frequencies are recommended:

 

Residential: Once a week

Light commercial: Twice a week

Heavy commercial: Daily

 

 

          These are only recommendations; you will need to adjust the frequencies to suit your own conditions.  For example, during a heavy rainstorm, dirt is tracked onto the floor and should be mopped up as quickly as possible.

  

REMOVING OLD WAX FROM SLATE FLOORING

           Suppose your slate floor  has been covered with a wax or some other type of coating. How do you remove this coating, and what chemicals should be used?  The procedure used to strip a slate floor is relatively simple, and is outlined below. But before you run out and buy a chemical floor stripper, it is important, as always, to  find out what is on the floor.

  WHAT'S ON MY FLOOR?

           Today’s technology has delivered  hundreds of different types of floor coatings—natural and synthetic waxes, acrylics, thermoplastics, polyurethane’s, epoxies, etc.  To choose the proper chemical for removing them, we must know what type of coating we are dealing with. I suggest the following procedure:

           1.  If you already know what coating is on the floor, contact the product’s manufacturer for removal instructions.

           2.  If you have no idea what is on the floor, perform the following test. Mix one cup of household ammonia in one gallon of warm water; pour a small amount of this mixture on the floor and agitate with a soft scrub brush. Pick up the solution with a wet vacuum or a dry rag.  Examine the area; if you have removed the coating, you will need to use a commercial wax stripper to remove the remaining wax. These coatings are water based and are easily removed with commercial strippers.  Visit your local janitorial supply house and ask for an alkaline acrylic finish stripper.  If the coating has not been removed with the ammonia, there is a good possibility that the finish is urethane- or epoxy-based.   What this means is that some very strong solvents will be needed to remove the finish. At this point, it might be wise to call in a professional.  If you wish to attempt stripping these urethane-based coatings yourself refer to the stripping procedure in this book.  It is common to find urethane-based coating on slate flooring. They can be very, very difficult to remove. The removal process may be so aggressive that the surface  may become damaged. Always test a small area first to make sure you get the desired results.

  STRIPPING PROCEDURE(Acrylics)

 

          To strip a slate floor with commercial alkaline strippers, use the following procedure. A janitorial floor-buffing machine and a wet vacuum are highly recommended. Before setting up to strip the slate be sure to remove all furniture and protect painted surfaces such as baseboards with plastic drape.

 

          1.  Mix the stripper solution in a separate bucket, following  the instructions on the label.

 

          2.  Apply the mixed solution with a string mop to one small section at a time.  Do not apply more than can be scrubbed effectively.  Let the stripper sit for several minutes; this will allow the chemicals to break up the coating.  If the stripper begins to dry, add more of the solution to keep it wet.

 

          3.  Scrub the floor using a 175-rpm standard buffing machine equipped with a black stripping pad or stripping brush (pads and brushes are available at most janitorial and rental supply houses). Continue scrubbing until the coating breaks up.  Some slate may be scratched by stripping pads and brushes; always test a small area first before proceeding with the entire project.  If the pad scratches, your janitorial supply house can  recommend a softer pad or brush.

 

          4.  Pick up the solution with a wet vacuum and rinse immediately.  Use a separate string mop, bucket and wringer for your rinse water. 

          5.  Examine the area thoroughly. If any of  the coating is still present, re-strip.

 

          When you’re through, be sure to rinse the floor thoroughly; most alkaline strippers have a tendency to leave a film. Adding several ounces of a good neutral cleaner or stone soap to the rinse water will help neutralize the stripping solution.

If a coating is to be applied, re-apply according to manufacturers instructions. If a penetrating sealer is to be used, make sure the floor is thoroughly dry.  Allow at least 24 hours before sealer application.

 

 STRIPPING PROCEDURE(Urethanes)

 

          To strip a slate floor that has a urethane coating, use the following procedure.  Before setting up to strip the floor be sure to remove all furniture and protect painted surfaces such as baseboards with plastic drape.

 

Caution: Some of the strippers for removing urethane contains solvents such as methylene chloride that is extremely dangerous to work with.  Make sure to wear protective clothing and goggles and to ventilate the room to avoid being over come with fumes. Many of these strippers also require you to wear a respirator.  These strippers will damage all surfaces so make sure everything is protected. If you do not feel comfortable with these procedure, I recommend you contact a professional.

There are also what are known as “safe strippers” available that do not pose as much as a danger but they take a very long time to react. Some of these strippers require as much as a 24-hour dwell time to remove urethane effectively.

 

          1.  Apply the stripper with a paintbrush or roller. Apply liberally and try not to reapply once you have place the stripper down.  Most of these strippers are in a form of a thick paste..

 

          2. .  Let the stripper sit for several minutes to several hours; this will allow the chemicals to break up the coating. Do not scrub the floor with brushes or a floor machine.  These strippers are flammable and machinery should not be used.  You can tell when the stripper is working by a bubbling or softening of the coating. Take a metal putty knife and try scraping the coating. If it is soft and easily comes off, then it is ready to be removed.

           3. Scrape the coating with a putty knife and place the soften coating into a metal bucket. These materials will need to be disposed of in an approved hazardous waste container and will need to be picked up by a hazardous waste company.  Refer to your yellow pages under hazardous waste. Some counties and cities also will take these containers. Call you’re your local county government and ask how to dispose of these materials.

           4. Once all the coating has been removed restrip the slate as outlined above using a commercial floor stripper for acrylics . 

           5.  Examine the area thoroughly. If any of  the coating is still present, re-strip.

           When you’re through, be sure to rinse the floor thoroughly; most alkaline strippers have a tendency to leave a film. Adding several ounces of a good neutral cleaner or stone soap to the rinse water will help neutralize the striping solution.

If a coating is to be applied, re-apply according to manufacturers instructions. If a penetrating sealer is to be used, make sure the floor is thoroughly dry.  Allow at least 24 hours before sealer application.

  

Important- it is very important that the slate is thoroughly dry before applying any finish. Placing a coating on wet slate will cause the coating to turn a milky white color.

         

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.

  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.

  www.stoneforensics.com

Graffiti Removal

Graffiti Removal Procedure for Stone, Masonry, and Tile Surfaces

By Frederick M. Hueston, www.stoneforensics.com

 

If your beautiful building, wall, or other surface has just become the unintended canvas for graffiti, your first reaction might be to call your maintenance staff to pressure wash the spray paint away. Unfortunately, pressure washing can leave stains behind or shadowing caused by the high-pressured water. If you are dealing with paint, markers, or other water-soluble types of graffiti, as well as post-cleanup stains or shadowing on stone, tile, brick, or masonry, this article offers some guidance on what to do next. 

Graffiti Types

 

There are many kinds of paints, markers, or other mediums that are used for graffiti. The most common types are aerosol paints and felt tip markers because they are easy to acquire and relatively inexpensive. Other graffiti mediums include chalk, charcoal, foods such as ketchup and mustard, red clay, and more. Any graffiti created with water-soluble material will be easy to remove with a mild washing.

Scribing is a type of graffiti that often causes permanent damage since a knife, screwdriver, rock, or other sharp object is used to scrape away the surface.

 

Graffiti Removal Rules

 

When it comes to graffiti removal, here are some very important considerations.

Time
The longer graffiti remains on a surface, the more likely it is to soak into the surface. The deeper it penetrates into the surface, the more difficult it will be to remove. For this reason, you will want to attempt removal as soon as possible.

Temperature
During summer months and in areas with warm climates, graffiti will dry faster and will have a tendency to penetrate deeper than in colder climates.

Abrasives
High pressure washing, and abrasive brushes should be avoided, especially on soft stone, brick, and masonry surfaces. These methods may remove the graffiti but could leave a deep mark or what is called shadowing which is nearly impossible to correct.

Cleaners
Be careful choosing the proper cleaners or stain removers. Certain chemicals will emulsify the paint and drive it deeper into the surface making removal even more difficult.

Removing Graffiti

 

Step 1 
Attempt to identify the graffiti type. Identification is key, since it will help you chose the proper chemical. Paint or marker are water-based or solvent-based mediums. Water-based paints can generally be removed with mild detergents, whereas solvent-based paints will require mineral spirits, paint stripper, or other solvent-based cleaning agents.  The best way to find out what type of medium you are dealing with is to test a small area as follows. Once you know the medium, proceed to Step 2.

CAUTION: Make sure to do the water-based test first, since water-based paints can give false-positive test results with the solvent-based test.

Water-Based Test
Mix some mild detergent, such as a pH-neutral cleaner or dish soap and water in a spray bottle. Saturate a small area and allow it to sit for a few minutes. Wipe it off with a soft, white cloth. You may also agitate the area with a soft nylon bristle brush. If the graffiti comes off easily, then you are dealing with a water-based paint.

Solvent-Based Test
Moisten a clean, white rag with a small amount of mineral spirits. Gently blot the graffiti. If the graffiti is easily removed, then you are dealing with a solvent-based paint. 

Step 2

1. Prepare a solution, per the manufacturer's dilution instructions, of a pH-neutral cleaner or dish soap and water in a bucket or sprayer.
2. Rinse the surface with plain, clean water. This step is important, because it removes any potentially abrasive material such as dust, dirt, or grit from the surface.
3. Apply the cleaning solution with a soft nylon scrub brush. Work from the bottom of the wall to the top. Do not let the solution dry. If necessary, work in small sections. Lightly scrub the surface with the nylon brush and rinse with clean water.
4. If the above technique does not remove the graffiti, proceed to Step 3.

Step 3

1. Make sure the surface is dry before proceeding further.
2. Put some paint stripper, such as mineral spirits, in a chemical-resistant spray bottle.
3. Apply a mist to the graffiti and scrub with a dry nylon brush. 
4. Rinse the area with paint stripper.
5. Repeat this process, working in small areas at a time, from the bottom of the wall up. Be sure to rinse any streaks as you work.
6. If the graffiti is not totally removed, this means it is a stain. To remove a stain, proceed to Step 4.

Step 4
To remove a stain, apply a poultice, that is, a paste made of an absorbent powder mixed with a chemical. As the poultice dries, it wicks or lifts the stain out of the pores in the surface. First, select the appropriate ingredients.

Poultice Ingredients
Following are some types of poultice powders to mix with your cleaning agent:

• Clays (Attapulgite, Kaolin, Fullers earth) WARNING: DO NOT USE ON RUST STAINS
•  Talc
•  Chalk (whiting) 
•  Sepiolite (hydrous magnesium silicate) 
•  Diatomaceous Earth
•  Methyl Cellulose

Clays and diatomaceous earth are usually the best. Do not use whiting or iron-type clays, such as Fullers Earth, with acidic chemicals. They will react with the material, canceling the effect of the poultice.

Many stains are so deeply imbedded that the poultice alone will not be completely effective. Some type of chemical solution will need to be added to the poultice. When the poultice and chemical are applied, the chemical is absorbed into the stone or masonry. The chemical reacts with the stain and is re-absorbed into the powder/material. 

Following are suggested poultice ingredients. Please use extra caution when handling the chemicals listed below. Thoroughly read the Safety Data Sheets for each chemical before use.

• Iron (rust) - Poultice with Iron Out + powder + water. Iron Out is available at hardware stores. This may etch polished marble. If so, re-polishing will be necessary.
•  Ink - Poultice with mineral spirits or methylene chloride + powder.
•  Oil - Poultice with ammonia + powder. Methylene chloride can also be used on tough oil stains.
•  Coffee, Tea & Food - Poultice with 20 percent hydrogen peroxide + powder.
•  Copper - Poultice with ammonium chloride + powder.
•  Water-Based Paint - Poultice with a commercial paint remover + powder.
•  Oil-Based Paint - Poultice with mineral spirits + powder. Deep stains may require methylene chloride.

 

Applying the Poultice

1. Wet the stained area with distilled water. Pre-wetting fills the pores of the stone with water, which will help isolate the stain and accelerate the removal by the chemical.
2. Prepare the poultice. Mix the powder and the chemical of choice into a thick paste, about the consistency of peanut butter or thick enough that it will not run. 
3. Apply the poultice to the stain. Apply the paste approximately 1/4-inch thick, extending beyond the stained area by about one inch. Be careful not to spill any on the surrounding area.
4. Cover the poultice with plastic (food wrap works great). Tape the plastic down to seal the edges. It also helps to poke several small holes in the plastic, so that the powder will dry out. Failure to do this may result in the poultice staying wet. The idea is to allow the moisture to slowly evaporate from the poultice.
5. Allow the poultice to dry thoroughly. This is a very important step. The drying of the poultice is what pulls the stain from the stone into the poultice material. If the poultice is not allowed to dry, the stain may not be removed. Drying usually takes from 24 to 48 hours.
6. Use a flat, plastic scraper to carefully remove the poultice from the stain. Rinse with distilled water and buff dry with a soft cloth. If the stain is not removed, reapply the poultice. It may take up to five poultice applications to remove very difficult stains.
   
   

Some chemicals may leave etch damage on honed or polished marble and limestone surfaces. If etching occurs on a polished surface, apply polishing powder and buff with a piece of burlap to restore the shine. If etching occurs on a honed surface, do not use polishing powder, because this will leave a polished area that does not match with the surrounding finish. Contact a professional stone restoration contractor to remove the etch and restore your honed finish.

Why is my Grout Turning Yellow

Why is My Client’s Grout Turning Yellow?

By Frederick M. Hueston, Stone Forensics

Over the years I have received many calls from stone and tile restoration professionals asking how to identify the cause of grout yellowing and resolve grout yellowing problems. The reasons for this discoloration are many. Testing can help determine what is causing the problem. Solutions vary, depending on the cause. Here are the details.

Top Ten Reasons for Grout Yellowing

1.      Shampoos, soaps, etc. – Many of the personal items your clients use contain chemicals that can cause discoloration, and hence yellowing of grout. This is especially true of hair dyes and shampoos that contain coloring agents.

2.      Body oils – Skin and hair oils contain many contaminants that can cause discoloration of not only grout but also tile. These body oils are what cause the familiar yellow stain, ring-around-the-collar.

3.      Sealers and waxes – Sealers and various waxes can contain polymers that can discolor over time and cause yellowing.

4.      Grout types – There are numerous grout types that are prone to yellowing. White epoxy grouts are notorious for turning yellow.

5.      Cleaning products – Certain cleaners, especially those that contain dyes, can cause discoloration of grout. Household bleach commonly discolors grout.

6.      Iron – Certain water supplies contain iron. Water containing iron can deposit minerals on the grout that can oxidize and cause a yellow discoloration. If the water used to mix the grout during installation contained iron this can also cause discoloration. Check your water supply for iron.

7.      Dirty water – Water used to mop floors can rapidly get dirty. The dirt, oils, etc. will settle on the grout lines and cause a yellow cast. Encourage your client, or the cleaning or janitorial services they use, to keep mop heads clean and change mop water often.

8.      Smoke – Cigarette smoke can settle on grout lines, causing the grout to turn yellow.

9.      Aerosol sprays – Sometimes aerosol sprays, such as hair sprays and even air fresheners, cause grout discoloration.

10.   Bleed over – Certain tile types, such as white marble, contain iron. Iron from the tile can bleed into the grout and oxidize, causing the grout to turn yellow.

How to Test for Yellowing

As mentioned above, there are many reasons why grout can turn yellow. Here are some suggestions for inspecting the grout to determine the cause:

1.      Determine what cleaning products and toiletries have been used in the area. Look up the SDS on the product to determine whether products contain dyes, polymers, or other ingredients that may cause grout to turn yellow.

2.      Test the grout lines for iron using a product from Alpha Tools called RSR 2000. Place a small dab on the grout and wait several minutes. If it turns purple, it is positive for iron.

3.      Test the water for iron if iron oxidation is suspected. Test kits can be purchased at most home centers or water supply stores. If iron is present in the water, suggest that your client install a water filtration system.

4.      Try to determine the grout type. Epoxy grout can be problematic.

5.      Take a knife and scrape the grout. Examine the scraped area to see if the discoloration is on the surface or all the way through. Surface discoloration usually indicates chemical discoloration.

Once the cause of grout yellowing is determined, you can attempt to resolve grout yellowing problems. Be sure to instruct your client about using preventative measures such as discontinuing the use of stain-causing products, smoking outside, installing a water filtration system, etc.

How to Clean Yellowed Grout

To clean yellowed grout, you will need sulfamic acid, which can be purchased at most home centers and can also be found at most tile supply companies, and a good floor wax stripper, which can be purchased at most janitorial supply houses. Ask for an alkaline-based floor wax stripper. Caution: Sulfamic acid will damage marble surfaces.

Here are cleaning instructions:

1. Sweep the floor thoroughly, removing any loose dirt, dust, etc. For showers and walls, wipe with a dry rag.

2. In a cleaning pail, mix warm water and a good floor cleaner or ammonia. For showers and walls, use a clean rag and for floors, use a clean mop to clean the grout. Empty the pail.

3. Next, mix alkaline stripper with warm water, being sure to follow the directions on the bottle.

4. Apply a small amount of this solution to the grout. Allow it to stand for several minutes. Agitate the solution with a scrub brush, toothbrush, or similar type brush. Apply additional solution if the grout begins to dry.

5. Pick up any excess solution with a mop or a wet vacuum.

6. Rinse the grout with plain, warm water. Empty the pail.

7. Mix sulfamic acid with warm water, per the directions on the label.

8. Apply the acid solution to the grout and agitate.

9. Rinse the grout several times with clean water and allow to dry overnight.

10. Once dry, seal the grout with a good penetrating sealer.

If the above technique does not work and the grout is in good condition and not falling apart, then apply a high-quality grout color sealer. As a last resort, remove and replace the grout.