Skip to main content

Historic Preservation - Technical Procedures

Spectitle:

Removing Mortar Deposits And Stains From Marble

Procedure code:

0445527R

Source:

Stain Removal Guide For Stone - F. M. Hueston

Division:

Masonry

Section:

Marble

Last Modified:

08/13/2013

Details:

Removing Mortar Deposits And Stains From Marble



REMOVING MORTAR DEPOSITS AND STAINS FROM MARBLE


THE CLEANING OR REMOVAL OF STAINS FROM STONE MAY INVOLVE THE USE OF
LIQUIDS, DETERGENTS OR SOLVENTS WHICH MAY RUN OFF ON ADJACENT
MATERIAL, DISCOLOR THE STONE OR DRIVE THE STAINS DEEPER INTO POROUS
STONES.  USE THE PRODUCTS AND TECHNIQUES DESCRIBED HERE ONLY FOR
THE COMBINATIONS OF DIRT/STAIN AND STONE SPECIFIED.


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on removing mortar
         deposits or other concrete-based residues from marble.
         Mortar deposits may be spattered onto adjacent surfaces
         during repointing or other repair work.  If left on the
         surface, these deposits and residual film can be
         difficult to remove.

    B.   See 01100-07-S for general project guidelines to be
         reviewed along with this procedure.  These guidelines
         cover the following sections:

         1.   Safety Precautions

         2.   Historic Structures Precautions

         3.   Submittals

         4.   Quality Assurance

         5.   Delivery, Storage and Handling

         6.   Project/Site Conditions

         7.   Sequencing and Scheduling

         8.   General Protection (Surface and Surrounding)

         These guidelines should be reviewed prior to performing
         this procedure and should be followed, when applicable,
         along with recommendations from the Regional Historic
         Preservation Officer (RHPO).

    C.   For guidance on the general cleaning of marble, see
         04455-06-R.

    D.   For general information on the characteristics, uses and
         problems associated with marble, see 04455-01-S.


PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.   ProSoCo, Inc.
         www.prosoco.com 


2.02 MATERIALS

    NOTE:  Chemical products are sometimes sold under a common
    name.  This usually means that the substance is not as pure as
    the same chemical sold under its chemical name.  The grade of
    purity of common name substances, however, is usually adequate
    for stain removal work, and these products should be purchased
    when available, as they tend to be less expensive.  Common
    names are indicated below by an asterisk (*).

    A.   Hydrochloric Acid (30-35%):

         1.   A strong corrosive irritating acid.

         2.   Other chemical or common names include Chlorhydric
              acid; Hydrogen chloride; Muriatic acid* (generally
              available in 18 degree and 20 degree Baume
              solutions); Marine acid*; Spirit of salt*; Spirit of
              sea salt*.

         3.   Potential Hazards:  TOXIC, CORROSIVE TO FLESH;
              CORROSIVE TO CONCRETE, STEEL, WOOD OR GLASS,
              FLAMMABLE. CAN CAUSE ETCHING OF POLISHED MARBLE.

         4.   Available from chemical supply house, drugstore or
              pharmaceutical supply distributor, or hardware
              store.

    B.   Clean, potable water

    C.   Liquid Marble Cleaner:  A water-soluble non-acidic
         chemical cleaner manufactured specifically for
         restorative type cleaning of polished and honed marble
         surfaces.  Cleaner shall contain no abrasives, grease,
         lye, or other caustic or corrosive ingredients, such as
         "Sure Klean 942 Limestone and Marble Cleaner" (ProSoCo, Inc.) or
         approved equal.  May damage highly polished surfaces, do test sample area.

    D.   Drying Materials:  Clean natural fiber rags

2.03 EQUIPMENT

    A.   Garden hose and nozzle

    B.   Stiff bristle brushes (non-metallic)

    C.   Wood or plastic scraper


PART 3---EXECUTION

3.01 EXAMINATION

    A.   Examine the marble surface CAREFULLY to determine the
         cause of staining before proceeding with any cleaning
         operation.

3.02 PREPARATION

    A.   Protection:

         1.   Provide adequate wash solutions (i.e. water, soap
              and towels) before starting the job.

         2.   Whenever acid is used, the surface should be
              thoroughly rinsed with water as soon as its action
              has been adequate.  Otherwise it will continue
              etching the masonry even though the stain is gone.

3.03 ERECTION, INSTALLATION, APPLICATION

    NOTE:  TEST CLEAN A SMALL AREA BEFORE ATTEMPTING TO CLEAN
    LARGE AREAS.  LET TEST AREA REST FOR SEVERAL WEEKS AND EXAMINE TO DETERMINE IF ANY ADVERSE IMPACTS.  SEEK          ADVICE FROM THE RHPO.

    A.   If possible, remove large pieces of mortar deposits using
         a wood or plastic scraper.

    B.   For light staining: Clean the surface with a commercial
         stone cleaner and water.  Follow manufacturer's
         instructions.

    C.   For more difficult staining:

         1.   Wash down the affected area with a diluted solution
              of hydrochloric acid.  CAUTION: HYDROCHLORIC ACID
              CAN SEVERELY ETCH POLISHED MARBLE SURFACES.  USE
              EXTREME CAUTION AND FOLLOW MIXING INSTRUCTIONS
              CAREFULLY.

              a.   For textured stone, mix 1 part hydrochloric
                   acid with 20 parts water.

              b.   For polished stone, mix 1 part hydrochloric
                   acid with 40 parts water.

         2.   Agitate the treated surface with a stiff fiber
              bristle brush.

         3.   Thoroughly rinse the surface with clean, clear
              water and allow to dry.

         4.   If necessary, re-hone or re-polish the surface.
              See 04455-02-P for guidance on re-polishing.

                         END OF SECTION
 


removing mortar deposits from marble, removing stains from marble, marble