21 cleaning and maintenance 7.2

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2011 Marble Institute of America Cleaning and Maintenance Page 21-1

CLEANING AND

MAINTENANCE

1.0 INTRODUCTION

1.1 ASTM C1515 Standard Guide forCleaning of Exterior Dimension Stone,Vertical and Horizontal Surfaces, New orExisting

1.2 Definition of Terms

1.2.1 Maintenance: Scheduled cleaning,specific procedures, and inspectionsperformed on a daily, weekly, or otherregular basis to keep the stone in propercondition.

1.2.2 Refinishing:Repolishing or honing ofdull, once-polished marble, limestone, orgranite floors and walls. Refinishing of trafficpatterns, for example.

1.2.3 Renovation:Cleaning and repolishingof neglected dimension stone surfaces.

1.2.4 Restoration: Large-scale remedialactions taken to restore a structure or area toits original or acceptable near originalcondition. Generally applies to historicstructures.

2.0 SLIP RESISTANCE OFSTONE FLOOR SURFACES

2.1 The Americans With DisabilitiesAct (ADA) recommends that walkingsurfaces provide an adequate static coefficientof friction so as to provide a safe walking

surface. Local building codes do takeprecedence. The MIA has had extensiveASTM C1028 Coefficient of Friction testsperformed on a number of varieties ofdimension stone. The results of those testsconfirm that dimension stone used for pavingprovides an adequate walking surface whenproperly maintained. Proper maintenanceincludes prompt cleanup of spills and

correcting other conditions that can cause asudden reduction in the static coefficient offriction of the floor.

3.0 BAD WEATHER SAFETYRECOMMENDATIONS

3.1 Wet Flooring Surfaces.All flooringsurfaces can become slippery when wet. It iscommon courtesy as well as prudentmanagement to reduce the hazards caused bywet flooring surfaces.

3.2 Spread carpeted runnersfrom eachoutside door into lobbies and corridors to helpdry shoe soles. Change or clean runners asnecessary.

3.3 Pylons.Place bright-coloredslipperywhen wet pylons on walking surfaces in

conspicuous places.

3.4 Mop or shovel walking surfacesasoften as necessary to remove standing water,ice, or snow. A wet vacuum will also removewater, light snow, and slush efficiently fromthese surfaces.

3.5 Maintenance Instructions. Issue

standard instructions to building maintenancepersonnel and prominently post at alljanitorial workstations.

3.6 Local Codes. Follow local buildingand safety codes.

4.0 MOISTURE DAMAGE

4.1 Efflorescence. Water penetratingexterior wall cavities through defective

flashing or unsealed joints can causeefflorescence, a mineral salt residue left on thesurface of masonry when water evaporates. Inaddition, condensation in wall cavitiesprevented from reaching the exterior surface

because of blocked weep holes can dislodgemasonry in a freeze-thaw climate.


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Page 21-2 Cleaning and Maintenance 2011 Marble Institute of America

4.2 Moisture coming up through afloor slabseeks the easiest possible pathwayto evaporate into the atmosphere. Often, theveining or microcracks in the structures ofsome stones provide that path. The moisturedissolves all the salts from the ground, thesubstrate, and the stone, carries them to the

surface, and deposits them as the moistureevaporates, giving the appearance of a faultystone. Steps to eliminate this moisture can beimplemented during the installation process(refer to chapters on Installation and WetAreas.)

5.0 TOPICAL SEALERS ANDIMPREGNATORS

5.1 Topical sealersare coatings designed

to protect the surface of stone against water,oil, and other contaminants. They areformulated from natural wax, acrylic, andother plastic compounds.

5.2 Impregnators (Penetrating Seal-ers). Impregnators penetrate below thesurface and become repellents. They aregenerally hydrophobic (water-repelling), butare also oliophobic (oil-repelling).Impregnators keep contaminants out, but do

not stop the interior moisture from escaping.These sealers are considered breathable,meaning they have vapor transpiration.

5.3 Treatment Type. The type oftreatment (i.e., impregnator or topical sealer)that is applied to the stone must bedetermined by the type of stone and theenvironment of the application. Alltreatments must be applied in accordancewith the Manufacturers specifications.

5.4 When to Use. A treatment may beused when a defined benefit can bedetermined. Situations in which a benefit may

be derived from the use of surface treatmentsinclude:

5.4.1 Where the risk of staining is present.

5.4.2 As an aid in daily maintenanceprocedures.

5.4.3 Where a coating may help to preservethe stone finish in excessively high wearconditions.

5.4.4 Where weathering has or may affectthe integrity of the surface of the stone.

5.4.5 To prolong the aesthetic beauty of theoriginal installation.

5.4.6 Where the risk of graffiti or othervandalism is high.

6.0 MAINTENANCE OFINTERIOR STONE

6.1 Polished-finish stone has a glossysurface that reflects light and emphasizes thecolor and marking of the material. It is used ininteriors as wall veneer, furniture and desktops, counter and lavatory tops, tables, andtiles for commercial and residentialinstallations.

6.2 Honed-finish stone has a satin-smooth surface with relatively little light

reflection. It is generally preferred for floors,treads, thresholds, and other pedestrian trafficlocations where heavy traffic would wear off apolished finish.

6.3 Normal Maintenance. All stoneflooring should be dust mopped as necessaryto remove debris and dirt. A dry, untreateddust mop should be used. Normalmaintenance involves periodic washing withclean, potable water and neutral (pH 7)

cleaners. Soapless cleaners are preferredbecause they minimize streaks and film. Mild,phosphate-free, biodegradable liquiddishwashing soaps or powders or stone soapsare acceptable if rinsing is thorough.

6.3.1 Wet the stone surfaces with cleanwater. Using the cleaner solution (followingManufacturers directions), wash in small,


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overlapping sweeps. Work from the bottomup if it is a vertical surface. Rinse thoroughlywith clean, potable water to remove all tracesof soap or cleaner solution. Change the waterin the rinse pail frequently. Dry with softcloth and allow to thoroughly air dry.Alternatively, employ the use of a wet

vacuum to extract contaminants. Incommercial applications with high trafficlevels, the use of an automatic scrubber fittedwith a disc-type brush system and continuousextraction is generally the most effectivemethod.

6.4 Safety Precautions. Any flooringsurface, regardless of how it is finished, can beslippery when wet. Promptly remove liquidsor foreign materials that might result in safetyhazards before permitting pedestrian traffic.

6.5 For honed finishes, a neutral (pH7), mildly abrasive cleaner may be used. Useonly according to Manufacturers directions.

6.6 For counter or table tops, usecoasters under all glasses, particularly thosecontaining alcohol or citrus juices. Manycommon foods, drinks, and cosmetics containacids that will etch or dull the surface of manystones. Use trivets or mats under hot dishesand place mats under china, ceramics, silver,or other objects that can scratch the surface.Blot spills with a paper towel or cloth as theyoccur or as soon a possible thereafter. Cleanregularly with a neutral cleaner that does notcontain solvents.

6.7 In food preparation areas, thestone may need to have an impregnator ortopical sealer applied. If an impregnator ortopical sealer is applied, it must be nontoxic

and safe for use on food preparation surfaces.

6.8 Never use any acidic cleaner orchemicalon marble or limestone surfaces. Itis best to use a cleaner specifically formulatedfor stone cleaning.

New equipment is continually beingdeveloped (e.g. integral pressurized waterwithin vacuum systems) to clean stoneflooring surfaces. Contact your MIA membercompany for advice on the best practices tomaintain your stone.

7.0 EXTERIOR STONE

7.1 Exterior stone is a general termdenoting stone installed in a place wheretemperature, moisture, and airbornecontaminants are caused primarily or solely bythe forces of nature. It can be used in ahoned, textured, or polished finish in anymode in an exterior environment. Usesinclude building cladding, walkways, steps orstairs, retaining walls, paving, fountains,

benches, planters, and decorative items suchas sculptures.

7.2 Normal Maintenance. In accessibleareas, routinely follow maintenanceprocedures as specified in Section 6.0 of thischapter, as applicable.

7.2.1 The large expanses of stone generallyfound on exterior applications may make itimpractical to perform normal maintenanceon a frequent basis. Large installations,however, should be given periodic overallcleaning as necessary to remove accumulatedpollutants. Easily accessible stone surfacessuch as steps, walkways, fountains, etc.,should be kept free of debris and soiling byperiodically sweeping and washing withwater.

7.2.2 Normal maintenance should includeperiodic inspection of stone surfaces forstructural defects, movement, deterioration,or staining.

8.0 STAIN REMOVAL

8.1 Surface stains can often be removedby cleaning with an appropriate commercialcleaning product or household chemical.Identifying the type of stain is the key to


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removing it. Look for color, shape, andenvironmental factors that could be causingthe staining.

8.2 Types of Stains And RemovalProcedures

8.2.1 Oil-based stains(grease, tar, cookingoil, cosmetics). An oil-based stain will darkenthe stone and normally must be chemicallydissolved so the source of the stain can beflushed or rinsed away. Remove excessstaining agent by wiping or chipping (if tar)first. Clean gently with a soft liquid cleanser,household detergent, ammonia, mineralspirits, or acetone. Do not pour the cleanerdirectly on the staining agent this can resultin thinning the contaminant and furthering its

spread. Partially saturate a paper or clothtowel with the cleaner and attempt to drawthe stain into the towel. Commerciallyavailable specialty cleaners, such as alkalinedegreasers and/or poultices may also be used.

8.2.3 Organic stains (coffee, tea, fruit,tobacco, paper, food, urine, leaves, bark, birddroppings) may cause a pinkish-brown stainand may disappear after the source of the stainhas been removed. Outdoors, with the

sources removed, normal sun and rain actionwill generally bleach out the stains. Indoors,clean with 12% hydrogen peroxide and a fewdrops of ammonia. Commercially marketedcleaners and poultices are also available.

8.2.4 Inorganic metal stains (iron, rust,copper, bronze). Iron or rust stains areorange to brown in color and leave the shapeof the staining object, such as nails, bolts,screws, cans, flowerpots, or metal furniture.

Copper and bronze stains appear as green ormuddy brown and result from the action ofmoisture on nearby or embedded bronze,copper, or brass items. Metal stains must beremoved with a poultice (see Section 9.0 ofthis chapter on Poultices). Deep-seated, rustystains are extremely difficult to remove, andthe stone may be permanently stained.

8.2.5 Biological stains (algae, mildew,lichens, moss, fungi). Clean with dilute (cup in a gallon of water) ammonia, bleach, orhydrogen peroxide. WARNING: DO NOTMIX BLEACH AND AMMONIA! THISCOMBINATION CREATES A TOXIC GAS!

8.2.6 Ink Stains (magic marker, pen, ink).Clean light-colored stones with bleach orhydrogen peroxide. Use lacquer thinner oracetone for dark-colored stones. Do not pourthe cleaner directly on the staining agent this can result in thinning the contaminant andfurthering its spread. Partially saturate apaper or cloth towel with the cleaner andattempt to draw the stain into the towel.

8.2.7 Paint Stains. Small amounts can beremoved with lacquer thinner or scraped offcarefully with a razor blade. Heavy paintcoverage should be removed with acommercial liquid paint stripper. DO NOTUSE ACIDS OR FLAME TOOLS TO STRIPPAINT FROM STONE.

8.2.8 Water spots and rings (surfaceaccumulation of hard water). Buff with dry0000 steel wool.

8.2.9 Fire and Smoke Damage. Olderstones and smoke- or fire-stained fireplacesmay require a thorough cleaning to restoretheir original appearance. Commerciallyavailable smoke removal products may savetime and effort.

8.2.10 Etch Marks. Caused by acids lefton the surface of the stone, some will etch thefinish but not leave a stain; others will bothetch and stain. Once the stain has beenremoved, wet the surface with clear water

and sprinkle with marble polishing powder.Rub the powder into the stone with a dampcloth or by using a buffing pad with a low-speed power drill or polisher. Continue

buffing until the etch mark disappears and themarble surface shines. Honing may berequired for deep etching. This process may


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require the services of a ProfessionalRefinisher.

8.2.11 Efflorescence. A white powderthat may appear on the surface of the stone, itis caused by water carrying mineral salts from

below the surface of the stone to the surface

and evaporating. When the water evaporates,it leaves the powdery salt residue. If theinstallation is new, dust mop or vacuum thepowder. Repeat as necessary as the stone driesout. Do not use water to remove the powder.If the problem persists, contact theContractor to identify and remove the causeof the moisture.

9.0 POULTICES

9.1 General Application

9.1.1 Definition And Use. Applied tostone to remove stains, a poultice is achemical or mixture of chemicals combinedwith an absorbent material, forming a thickpaste. The poultice is spread over the stainedarea to a thickness of about " to " with awood or plastic spatula or scraper coveredwith plastic, and left to work for 24 to 48hours. The chemical will draw out the stain

into the absorbent material. Poulticeapplications may have to be repeated tothoroughly remove a stain, but some stainsmay never be completely removed.

9.2 Materials

9.2.1 Poultice materials include kaolin,fullers earth, whiting, diatomaceous earth,powdered chalk, white molding plaster, andtalc. Approximately one pound of prepared

poultice material will cover one square foot.Do not use whiting or iron-type clays such asfullers earth with acid chemicals; the reactionwill cancel the effect of the poultice. Apoultice can also be prepared using whitecotton balls, white paper towels, or gauzepads, which may be more effective whenusing highly volatile solvents such as acetoneor mineral spirits.. Premixed poultices that

require adding only water are also availablefrom stone maintenance supply companies.

9.3 Poultice Mixtures ForVarious Stains

9.3.1 Oil-Based Stains. Poultice with

baking soda and water or one of the powderedpoultice materials and mineral spirits or acommercial degreaser.

9.3.2 Organic Stains.Poultice with one ofthe powdered poultice materials and 12%hydrogen peroxide solution, or use acetoneinstead of hydrogen peroxide.

9.3.3 Iron Stains. Poultice withdiatomaceous earth and a commercially

available rust remover. Rust stains areparticularly difficult to remove; professionalassistance may be required. Many rustremovers contain acids that will etch marble,limestone, and certain granites.

9.3.4 Copper Stains. Poultice with one ofthe powdered poultice materials andammonia. These stains are difficult to remove;professional assistance may be required.

9.3.5 Paint Stains (Water-based).Poultice with one of the powdered poulticematerials and a commercial paint remover.

9.3.6 Paint Stains (Oil-based). Poulticewith one of the powdered poultice materialsand mineral spirits. Deep stains may requiremethylene chloride. When using highlyvolatile solvents in poulticing, use a papertowel, pouring the solvent on the paper toweland then placing the towel on the stained area.

9.3.7 Ink Stains. Poultice with one of thepowdered poultice materials and mineralspirits or methylene chloride. When usinghighly volatile solvents in poulticing, use apaper towel, pouring the solvent on the papertowel and then placing the towel on thestained area.


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9.3.8 Biological Stains. Poultice with oneof the poultice materials and dilute ammoniaor bleach or hydrogen peroxide. WARNING:DO NOT MIX AMMONIA AND BLEACH!THIS COMBINATION CREATES A TOXICGAS!

9.3.9 Flammable Materials. The pre-ceding text does not purport to addresspossible safety concerns associated with theuse of flammable solvents. The user isdirected to the manufacturers labeling andMSDS for further direction in the safehandling and use of these products.Commercially available cleaners exist forremedy of many of the common stains. Thesecleaners may have fewer health and safetyconcerns in some cases.

9.4 Applying The Poultice

9.4.1 Prepare The Poultice. If using apowdered poultice material, mix with thecleaning agent or chemical to a paste with athick, creamy consistency. If using paper, soakin the chemical and let drain. Dont let theliquid drip.

9.4.2 Prepare Stain Area. Wet the stainedarea with distilled water.

9.4.3 Apply the poultice to the stainedarea about " to " thick, and extend thepoultice beyond the stained area by about 1".Use a wood or plastic scraper to spread thepoultice evenly.

9.4.4 Cover the poultice with plasticand tape the edges to seal it. Punch severalsmall holes in the plastic to allow vapor toescape.

9.4.5 Allow the poultice to drythoroughly, usually about 24 to 48 hours.The drying process draws the stain out of thestone and into the poultice material. Afterabout 24 hours, remove the plastic and allowthe poultice to dry.

9.4.6 Remove the poultice from thestain. Rinse with distilled water and buff drywith a soft cloth.

9.4.7 Repeat the poultice application ifthe stain is not removed. It may take five ormore applications for difficult stains.

9.4.8 If the surface is etched by thechemical, apply polishing powder and buffwith a polishing pad recommended by thePolishing Powder Manufacturer.

10.0 EXTERIOR BUILDINGCLEANING

10.1 General.The purpose of this section isto give the Specifying Authority the basic

information to prepare a specification for thecleaning of exterior building stone.

10.2 Exterior building stone isconsidered in this section to be all stone usedon the exterior of a structure, either as astructural component or as a facing material,with the exception of polished, finishedmarble. Even though polished marble is notrecommended for exterior use, it isoccasionally used on storefronts, column

facings, and similar treatments.

10.3 Regular Cleaning. The ideal inmaintaining exterior building stone is to cleanit at periodic intervals (at least annually,depending on atmospheric conditions) bysimply hosing down with clean water. Thiswill prevent accumulation of dirt andimpurities.

10.4 Sporadic Cleaning. If cleaning the

stone is not done regularly, one of the watersystems (hydraulic, hydro-air, plain water)will be the most effective method at thelowest cost.

10.5 Dirt on Older Buildings. Wheredirt has accumulated on older structures overa long period of time, a combination ofmethods may have to be employed to


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properly clean the stone. Plain waterjet issatisfactory for removing most accumulation.No chemicals should be used which would beinjurious to the stone.

10.6 Brushes may be necessary for theremoval of certain surface impurities. Soft-

fiber brushes are recommended.

10.7 Test Panels. By cleaning andinspecting test panels, the SpecifyingAuthority can determine if the method issatisfactory. This procedure eliminates thepossibility of improper cleaning, since theOwner and Specifying Authority can see whatresults will be obtained prior tocommencement of the total contract. It alsogives the Cleaning Contractor a standard towork toward, making definition of thecleaning more specific for all partiesconcerned.

10.8 Further ReadingSuggestions:

10.8.1 Cleaning Masonry Review of theLiterature

by Grimm, Clayford T., P.E.Construction Research Center,

University of Texas at Arlington, 1988.

10.8.2 Cleaning Stone and MasonryClifton, James R. , Editor.ASTM Special Technical Publication 935,American Society for Testing and Materials,1983.

10.8.3 Keeping It Cleanby Grimmer, Anne E.U.S. Department of the Interior,

National Park Service, Washington, DC: U.S.Government Printing Office, 1988.

10.8.4 Cleaning of Masonry Interiors ofPublic Buildings, Cleaning Stone andMasonry by Roth, J.W., ASTM STP 935,1986.

10.8.5 Chemical Cleaning of HistoricalStructures A Practical Approach,CleaningStone And Masonry by Rudder, T.H., ASTMSTP 935, 1986.

10.8.6 A Case Study of the Cleaning ofMarble at the Schenectady, New York, City

Hall,

Cleaning Stone and Masonry, by Waite,J.C. and R.J. Chen, ASTM STP 935, 1986.

10.8.7 A Macrosteriogrammetric Tech-nique for Measuring Surface Erosion Losses onStone, Cleaning Stone and Masonry byWinkler, E.M., ASTM STP 935, 1986.

11.0 SPECIFICATIONSBUILDING CLEANING

11.1 General. Information to be shownon drawings:

11.1.1 Location, size, or area and items tobe cleaned.

11.1.2 Location, size, and number of testpanels.

11.1.3 Areas not included in cleaningcontract.

11.1.4 Location, size, and description ofmaterials requiring protection.

11.1.5 Building and property boundaries.

11.2 Description

11.2.1 General. This section pertains tothe furnishing of all labor, materials,equipment, and services necessary for the

complete cleaning of exterior building stoneas indicated on the plans and described in thespecifications.

11.2.2 Repointing, Sealing, andReplacement. Repointing or sealing of

joints and replacement of stone are notincluded in the cleaning contract.


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11.2.3 Related Sections. To bedetermined by design requirements.

11.3 Requirements

11.3.1 General. The Plans, GeneralConditions, Supplementary General

Conditions, and Executed Agreement are all apart of this section as if written out in full.

11.3.2 Certification. Furnish certifiedstatements, as required, attesting that allmaterials to be used meet the requirementsspecified and approved.

11.3.3 Scheduling. Furnish SpecifyingAuthority with schedule of cleaningoperations indicating time of day work will be

performed. The

wet method

of cleaningshall not be performed when temperaturesreach 35F or lower.

11.3.4 Test Area(s). Clean for approvalby Specifying Authority at least a 4' x 4' testarea for each type of soiling, stone variety,and finish required to be cleaned. Test panelsshall be so located to include intersection ofhorizontal and vertical joints. The approvedpanel(s) shall be the standard for cleaningmethods and finish of all areas to be cleaned.

11.3.5 Protection. Furnish for approvalby Specifying Authority types of materials andmethods to be used in the protection ofadjacent materials and surfaces from damage,moisture, and staining. If other refurbishingoperations are being conducted, protectcleaned stone areas with an approvednonstaining covering.

11.3.6 Cleaning. After the surface hasbeen cleaned, it shall be rinsed with potablewater applied at the temperature and pressureof the municipal water supply.

11.4 Materials

11.4.1 Water shall be potable,nonstaining, and free of materials detrimentalto the surface being cleaned.

11.5 Methods

To be determined by approved test area(s).

11.5.1 Hydraulic. Water at varyingpressures between 300 and 600 psi and atmunicipal supply temperatures shall be jettedagainst the surface to be cleaned. Care must

be exercised in selecting nozzle tip degree; 0(zero) nozzle tips are never to be used.

11.5.2 Water Misting. Cleaning thesurface with water. Misting heads are set up

on scaffolding and water is misted onto thesurface of the building. The misting heads maybe set on a timer so that they go on and offintermittently. The intermittent cycle allowsthe building to dry and prevents over-saturation of the stone. This method is thesafest for cleaning and is widely used onhistorical buildings.

11.5.3 Pressure washing employs theuse of high-pressure waterjets of up to 2,500

psi or more. Pressure washing works byblasting the dirt off the surface of the stone,and can cause irreversible damage to the stonesurface. Pressure washing can be an effectiveand efficient means of removing dirt and othercontaminants. Modern pressure washers canproduce pressure in excess of 2,500 lbs/in,which is capable of permanent damage tomany stone types. Maximum allowablepressure should be determined by slowlyincreasing pressure while testing in an

inconspicuous area. In no case is pressure inexcess of 1,000 lbs/in recommended, andusually much less pressure is appropriate.Always use a fan-tip spray nozzle. Thismethod should be employed only by highlytrained technicians.

11.5.4 Chemical cleaning is used incombination with one or several of the water


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washing methods to dislodge soiled particles.Chemicals can be dangerous to the stone, theOperator, and the surrounding landscape;therefore, all chemicals used must be testedand monitored.

11.5.5 Acids. Chemicals with a pH less

than 7 should not be used on calcareous ordolomitic stones.

11.5.6 Alkalis. Chemicals with a pHgreater than 7 are safe for use on most stones.These are usually followed with a mild acidwash to neutralize the alkaline salts.

11.5.7 Neutral Cleaners. Chemicalscontaining surfactants with a pH equal to 7 aresafe for most stones.

11.5.8 Solvents.Waterless chemicals suchas mineral spirits and acetone. Rarely used for

building cleaning due to their highflammability.

11.5.9 Bacteria. Application of specialbacteria to eatdirt and salts.

11.5.10 J.O.S. System for removal of dirtand graffiti. Uses low-pressure washer andmilled glass or dolomite powder. Prerinserequired.

11.5.11 Dry Cleaning. Uses organicpowder or mineral powder (aluminumsilicate) crystals sized between 10 and 90microns.

11.5.12 Sandblasting should never beused to clean stone surfaces. Soda blasting(using baking soda in lieu of sand) is generallynot as distructive and has some limited usage

in the cleaning of natural stones.

11.5.13 Safety Requirements. All ofthese methods require specialized equipment.Adherence to OSHA safety requirements byhighly skilled technicians is mandatory.

11.5.14 Testing. All methods must betested for potential damage to the stone.

MIA Bookstore Resources:A consumer brochure, Care & Cleaning ofNatural Stone Surfaces, can be purchasedseparately from the MIA Bookstore.


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Notes:

21 cleaning and maintenance 7.2

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