Designing a Sustainable(Green) Stone Floor Maintenance Program

Designing a Sustainable (Green) Stone Floor Maintenance Program
By Frederick M. Hueston PhD



Walk into any stone, terrazzo or janitorial chemical supplier and you will find an endless selection of cleaners, sealers, restorers, etc to keep you terrazzo and stone floors looking new. The problem is many of these chemicals can be harmful to the user, occupants and the environment. How does one design a program that is not only sustainable and safe but to also keep your terrazzo and stone flooring in like new condition?

Fortunately there is an effective way to not only maintain these surfaces but also to keep them looking new. The following guideline will show you how to develop a sustainable maintenance program. This is especially important for schools, hospitals and other buildings were children and people sensitive to these harmful chemicals are present everyday.

The dangers of floor strippers, finishes etc have been studied by many organizations including universities, etc. Here is a partial list of those studies

- Green Seal Report
Floor Care Products: Finishes and Strippers
www.greenseal.org/resources/reports/CGR_floorcare.pdf

-Safe and Effective Use of Floor Finish Strippers
Janitorial Products. Pollution Prevention Project
Sponsored by US EPA
www.wrppn.org/janitorial/factsheet/floor.htm

-Health Hazard Evaluation Report 95-0313-2589, University of Michigan Hospitals, Ann Arbor, Michigan

-NIOSH [1990]. NIOSH criteria for a
recommended standard: occupational exposure to
ethylene glycol monobutyl ether and ethylene
glycol monobutyl ether acetate. Cincinnati, OH:
U.S. Department of Health and Human Services,
Public Health Service, Centers for Disease
Control, National Institute for Occupational
Safety and Health, DHHS (NIOSH) Publication
No. 90–118.

-Ruth JH [1986]. Odor thresholds and irritation
levels of several chemical substances: a review.
Am Ind Hyg Assoc J 47:A142–A151.
WHO [1983]. Indoor air pollutants: exposure
and health effects. World Health Organization
Regional Office for Europe. WHO–EURO report
and studies no. 78, Copenhagen, Denmark.



Program Guidelines

Step 1. A good sustainable maintenance program starts with proper identification of the stone. Is it granite, marble, terrazzo or limestone? If it’s marble is it soft or hard? What type of finish does it have? Polished, honed, flamed, etc.? Is the type of stone the proper material for the traffic it is to receive? If not maintenance costs will be higher. If the answer to these questions are unknown, I suggest you contact a reputable stone supplier or restoration company to find out. A complete understanding of your particular stones characteristics is an absolute must for designing a sustainable maintenance program.

Step 2. Once the stone’s characteristics are identified determine the quality of the installation. Are the tiles flat and even? Do they contain lippage (uneven tiles). If so, proper maintenance may prove difficult. The floor should be ground flat, honed and polished using sustainable restoration procedures that utilize non-chemical methods. Are there any cracked tiles? Dirt will have a tendency to accumulate in these cracks. These tiles should be replaced or if replacements are not available at least repaired.

Step 3. What is the present condition of the stone? Has it been coated with waxes, acrylics, urethane or other coatings? If so these coatings need to be ground off to determine the condition of the stone as well as eliminate any toxic and unsafe properties. I have seen stone floors that appear to be in great shape until the coatings are removed to unveil a pitted, scratched mess. If a poor condition is found, complete restoration is necessary before a successful sustainable maintenance program can begin.

Step 4. Once the stone is restored to like new condition, then and only then will a sustainable maintenance program provide good results. This applies not only to the following program but any program. If the stone will be exposed to water, coffee, spills etc, an application of a an approved Green impregnator is recommended. These impregnators are designed to penetrate into the stone, without leaving coatings on the surface and still allowing the stone to transpire(breathe). They contain no harmful vapors or off gases when cured.


Step 5. Daily Maintenance

The three most important tasks that can be done on a daily basis to keep the stone looking new and extending the time before restoration is required are: Dust Mop, Dust Mop and Dust Mop. The most destructive material to most stone is sand, dirt and miscellaneous grit. If these substances could be eliminated, maintenance of the stone would be almost non-existent. A stone floor can never be dust mopped too often. Use a clean, non-treated, dry dust mop at least two to three times a day in high traffic areas and less often in low traffic areas. Walk off mats placed outside and inside an entrance will also eliminate a good portion of sand, dirt and grit. It takes approximately seven steps to remove all loose dirt from the bottom of ones shoes. Walk off mats also need to be removed and cleaned daily. Keep this in mind when purchasing walk off mats. Remember if sand, dirt and grit are eliminated there will be nothing left behind to scratch and dull the stone.

Note: Coatings in addition to potentially being hazardous contribute to accelerate wearing of the stone or terrazzo surface by acting as a magnet for dirt and debri. It has been shown in studies that a stone or terrazzo floor without any coating will be easier to maintain as well as more cost effective.


Step 6. Cleaning

All natural stone, both polished and unpolished should be cleaned daily in high traffic areas and less often in lower traffic areas. A clean rayon or cotton string mop should be used with cold to warm water with the addition of a quality Green Approved neutral cleaner or stone soap. Approved Green Neutral cleaners are defined as surfactant type detergents that have a Ph of 7. Acidic and alkaline cleaners should not be used. Be sure to follow the directions very carefully.






Why Does Stone Shine?

All stone is taken from the earth in a raw block form. This block is cut into slices that we call slabs. The slabs are then cut further to a smaller size such as a tile or countertop. It is then polished using a series of abrasive materials. The mechanics are relatively simple. A piece of stone is rubbed with a series of abrasives starting with a course grit size followed by
Finer and finer grit sizes. The scratch pattern left behind from one grit is removed by the next grit creating finer and finer scratches. This process is continued until the scratch pattern becomes microscopic. The process is similar to refinishing a piece of wood, starting with a course sandpaper and ending with a fine sandpaper. The shine is placed on the stone by continuing this abrading process using very fine powders. With sustainable(Green) restoration methods no chemicals are used.



Restoration

Periodically the stone will need to be restored. Perhaps you have not followed a proper maintenance program or the type of stone you have is not suited to the conditions it receives or for what ever other reason it is not responding to maintenance, then restoration is required. How often this will need to be done is difficult to determine. Generally if all the precautions above are followed, restoration may only be needed as often as once per year or as little as once every five years or so. The restoration process re-hones the stone to remove deep scratches and is then re-polished. Do not attempt the re-honing process yourself, this requires a great degree of skill and experience, please call a reputable restoration company who specializes in sustainable methods for this task.

Natural stone was the first building material used by man. Its care and maintenance is one of the oldest tasks performed by our ancestors and was maintained without any of today’s modern chemical products. The above guidelines were developed by our years of experience with this beautiful material and with the addition of sustainable practices will provide many years of beauty.


Written by

Frederick M. Hueston, PhD
Stone University
E-Mail: Fhueston@aol.com
Web Site: www.stoneuniversity.org

Comparison of Two Maintenance Systems for stone

Purpose of Study: To compare and evaluate the advantages,disadvantages,required labor of two popular stone maintenance programs.

Introduction: The maintenance of stone flooring in the United States today is a million dollar a year business and continues to grow. This increased growth results from the desire to maintain a highly polished mirror finish. As of this date there are basically two methods to keep stone in this condition. One method is to place some type of a coating on the surface of the stone. These coatings can be natural or synthetic waxes, acrylics, urethanes and epoxies. The majority used today on marble are composed of acrylics. The second method used to maintain stone is to polish the stone with the use of abrasive diamonds and polishing powders. This method uses no coatings. It simply smooths the stone to produce a high shine. The purpose of this study is to compare the advantages and disadvantages of these two methods as well as their labor and material requirements. A third method becoming popular is the use of flurosilicate compounds applied to the stone. This method is commonly called Recrystallazation or Vitrification and is applied as a final finish in place of powder polishing or it is applied on top of the polished finish for added shine. This study will not address this process.

Maintenance of coatings:

Once a stone floor is coated the following is the standard procedure for maintenance:

1. The entire floor is dust mopped(daily) .

2. The floor is then damp mopped or machine scrubbed with a neutral cleaner(daily).

3. Worn areas are spray buffed using a standard floor machine and a red pad. If a high speed finish is used the floor is burnished using a high speed buffer(daily).

4. Areas that do not shine after buffing or spray buffing are re-coated(daily as needed).

5. Periodically the floor is stripped and re-coated(every six
months or more often).




Maintenance using honing and polishing.

Once the stone floor is honed and polished the following is the standard procedure for maintenance:

1. The entire floor is dust mopped(daily).

2. The floor is damp mopped or machine scrubbed with a neutral cleaner or stone soap(two-three times per week).

3. Traffic areas are polished with polishing powder(once per week in high traffic, less often in lower traffic).

4. Severely worn areas are lightly honed and re-polished(once every six months)



Both maintenance procedures described above are typical. Frequencies will vary depending on traffic, type of stone and desired finish. Both procedures assume that floor is in maintainable condition at start of maintenance program.


Method of study
In order to evaluate both of the above methods three commercial lobby floors were studied. All three floors have used both methods for a period of one year or more. Maintenance personnel and executive housekeepers were interviewed to obtain costs, advantages and disadvantages of both methods. Since hourly labor rates vary from state to state, this study will provide labor hours only.


Case Study #1

Property

Busy Hotel lobby located near a major theme park.

Floor Description

12,000 square feet of rosa perlino marble in a palandiana terrazzo pattern.

Very busy lobby. Traffic areas include large reception check in and four elevator banks. Floor is adjacent to a swimming pool area.


Maintenance procedure(coating) from date of installation to 1992.

When floor was complete several coats of a carnauba based sealer was applied.

1. Floor was dust mopped daily in the evenings during third shift.

2. Floor was wet mopped daily using a commercial, neutral floor cleaner.

3. Floor was spray buffed every night to remove scuffing, black heel marks and wear.

4. Floor was recoated daily in heavy traffic areas with a light coat of the carnauba based sealer.

Total daily man hours required 16 hours

Comments on maintenance program(coating) from staff and executive housekeeper:

Floor very difficult to maintain. It appears to mar, scuff very easily.
Once floor is spray buffed it looks great but once traffic starts the finish rapidly deteriorates.
The finish on the floor is turning yellow and becoming very dark and dirty looking.
The wax is accumulating in holes in the marble and turning black.


Maintenance procedure(polishing)from 1992 to present.

In 1992 the entire floor was stripped, the holes filled and then honed and polished using standard marble polishing powders.

1. Floor is dust mopped every evening.

2. Floor is damp mopped three times per week using a stone soap.

3. Traffic areas are re-polished once every two weeks using standard marble polishing powders.

4. As of this date no re-honing has been performed. Inspection of the floor and wearability indicates that honing of traffic areas will need to be about once per year.

Total daily man hours required 6 hours


Comments on maintenance program(polishing) from staff and executive housekeeper.


Our labor costs have been cut dramatically and the floor looks and stays clean longer.

Dirt doesn't seem to stick to the floor like it did before.

Case Study #2

Property

Busy hotel lobby, located next to major interstate exchange.

Floor description

3500 Square feet of rosa alicante marble, 12x12 inch tiles.

Busy hotel lobby floor. Constant traffic due to adjacent meeting rooms.



Maintenance procedure(coating) prior to 1992

Floor was initially stripped and several coats of an acrylic floor finish were applied.

1. Floor was dust mopped daily.

2. Floor was wet mopped daily with a neutral cleaner.

3. Once per month the entire floor was re-coated with acrylic floor finish. No spray buffing was performed between re-coatings.

4. Once every three months the entire floor was stripped and re-coated.

Total daily hours required- 4 hours

Comments on maintenance program(coating)from staff and executive housekeeper.

Floor looks great for one day a month, immediately after it is re-waxed. During the remaining time it looks just terrible.

Floor has a real plastic look, it doesn't even look like marble anymore.

The bellman carts are leaving marks on the floor all over and the area in front of the reception desk is very dull.


Maintenance procedure(polishing)from 1992 to present.

The entire floor was stripped to remove all the old wax, re-honed and then powder polished using standard marble polishing powders.

1. Floor is dust mopped daily.

2. Floor is wet mopped daily.

3. Traffic areas are re-polished once per week using polishing powder.

4. As of this date re-honing is required about once per year of approx. 800 square feet.

Total daily man hours required 1 3/4 hours.


Comments on maintenance program(polishing)from staff and executive housekeeper.

Our floor looks like marble again and the carts are no longer marking the floor.

Dust mopping and wet mopping are now a snap. The mop seems to glide very easily over the floor and we are not picking up as much dirt as before.

Case Study #3

Property

High rise apartment building lobby located in Canada


Floor description

1000 square feet of a negro marquina and white carrara in a checker board pattern.

Very busy residential condo with approx 80 condo units.


Maintenance procedure(coating)from date of installation to 1992.

This floor has been waxed for the past several years with the following maintenance program.

1. Floor was dust mopped several times per week.

2. Floor was damp mopped several times per week, daily during the winter months.

3. Floor was spray buffed once per week.

4. Floor was stripped and re-coated with an acrylic floor finish once every three months.

Total daily man hours required 1 hour


Comments on maintenance program(coating)from staff and property manager.


Floor always looks dull and scratched.

I can never seem to keep up with the floor, it is always scuffing (Janitor)


Maintenance procedure(polishing)from 1992 to present.

Floor was stripped, ground flat, rehoned and polished using standard marble polishing powders.

1. Floor is dust mopped daily every morning.

2. Floor is damp mop once per week, daily in winter.

3. Traffic areas are repolished once per month.

Total daily man hours 25 minutes

Comments on maintenance program(polishing)from staff and property manager.

Our floor is shiny again, it looks great.

I can't believe how easy the floor is to maintain, no more stripping and waxing.







Maintenance Methods Summary

Daily labor hours required

Project Strip & Wax Hone & Polish
_________________________________________________________________


Case Study #1 16 hours 6 hours

Case Study #2 4 hours 1 3/4 hours

Case Study #3 1 hour 25 minutes

_________________________________________________________________




Material Costs:

Cost for materials and consumption was difficult to obtain from housekeeping staff. Based on guess estimates, material cost were insignificant compared to labor cost. The costs of polishing powders and diamond abrasive were slightly lower than the use of strippers and coatings.



Conclusions & Discussion

Based on the above case studies it is apparent that the honing and polishing method is more economical than the use of coatings on stone flooring. Labor costs are reduced by one-half or more.
This reduction in labor costs is a significant savings per year.
Case Study #1 is saving 3650 hours per year, at an average labor cost of $12.00 per hour this is a savings of $43,800.00 per year.
Case #2 labor savings is equal to 821 hours per year or $9852.00 per year saved based on average labor cost of $12.00 per hour.
Case #3 saves 212 hours or $2544.00 per year.


Although costs are a major consideration when comparing the above two maintenance programs, it is also apparent that their are distinct advantages to the honing and polishing program as well as some disadvantages to the coating program. Coatings will mar, scuff and wear very easily. It is a well known fact that there are no coatings currently available for stone that are harder than the stone itself. For this reason coatings will scuff and mar much more than the stone itself. It is often argued that these coatings place a sacrificial layer on the stone protecting it from dirt and staining. Although this would make sense the opposite is true. These coatings are soft and will attract dirt faster than a natural polish. This is easy to prove if one takes a section of stone floor and applies a coating and on another section performs a hone and polish. After one or two days it will be discovered that more dust and debris is attracted to the coated surface than the honed and polished surface. It will also be discovered that removing the dust and debris from the coated surface is much more difficult. Coatings also will build on the surface producing a plastic like appearance. Some coatings will also turn dark and yellow rapidity. This is especially true if the stone is exposed to ultraviolet light. The removal of coatings by the use of harsh strippers can also damage the stone. Many strippers contain Sodium Hydroxide , which can form what is known as an alkaline salt. These salts can penetrate into the stone and cause premature spalling. Some coatings may also block the breathing of the stone causing it to suffocate and rot.

How does one protect the stone from staining if coatings are not used? Stone can be protected with products known as penetrating sealers or impregnators. These materials are designed to penetrate below the surface of the stone and keeping water and debris on the surface. Since they are not a coatings they will not require repair. They do not however add gloss to the stone surface.

The following table outlines the advantages and disadvantages of the two maintenance programs studied. Although only three case studies were used, many contractors and maintenance companies were interviewed to obtain these conclusions. Those who use the hone and polishing programs are very pleased and will not return to the old strip and coat method. Those companies interviewed who use the strip and coat method were not aware that another program existed.


Although this study shows that the polishing method is more economical, caution is advised. Each case must be studied carefully. Labor skill, budget requirements and existing condition of the stone must be evaluated before choosing the proper maintenance system. Those using marble polishing powders and diamond abrasives must be trained in there proper application. There are many quality coatings available that may be a good alternative to the above system if these special skills are not available. It is advisable to contact a reputable stone maintenance professional for advise.




Advantages & Disadvantages Summary

Coatings- Advantages

* Can be repaired by buffing

* Easy to apply

* Provides a sacrificial Coating(?)

Coatings- Disadvantages

* Will mar and scuff

* Can Yellow

* Stripping is required

* Can appear plastic-like

* Can block breathing of stone causing spalling

* Will attract dirt like a magnet.

* Labor intensive


Hone and polish-Advantages

* Will not scuff and mar

* Provides a natural shine

* Longer lasting than coatings

* Allows stone to breathe

* Reduced labor costs

Hone and polish- Disadvantages

* Increased skill level- Training required
* Does not provide stain protection

Fred Hueston is the founder of The National Training Center for Stone and Masonry Trades(www.ntc-stone.com) and Stone University(www.Stoneuniversity.org)