Skip to main content

Historic Preservation - Technical Procedures

Spectitle:

Treating Bleached Areas On Marble

Procedure code:

0445524R

Source:

Stain Removal Guide For Stone - F. M. Hueston

Division:

Masonry

Section:

Marble

Last Modified:

07/30/2013

Details:

Treating Bleached Areas On Marble



TREATING BLEACHED AREAS ON 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 treating marble which
         has been lightened or etched as a result of improper
         exposure to bleaching agents.  Household bleach contains
         the acid Sodium Hypochlorite.  All acids can be harmful
         to marble materials if they are not sufficiently diluted,
         and cleaners containing acids can be harmful to marble by
         etching or discoloring the surface.

    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).

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


PART 2---PRODUCTS

2.01 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.   Oxalic Acid (COOH)2 or (H2C2O4):

         1.   A poisonous strong acid that occurs in various
              plants as oxalates and is used especially as a
              bleaching or cleaning agent and in making dyes.

         2.   Other chemical or common names include Dibasic
              acid; Ethanedioic acid; Acid of sugar*.

         3.   Potential Hazards:  TOXIC; CORROSIVE TO CONCRETE,
              STEEL, WOOD OR GLASS.

         4.   Available from chemical supply house, dry cleaning
              supply distributor, drugstore or pharmaceutical
              supply distributor, hardware store, or photographic
              supply distributor (not camera shop).  (Often sold
              under a manufacturer's brand name; the chemical
              name may appear on the label.)

    B.   Linseed Oil:  Available from hardware or paint store.

    C.   Clean, soft, white cloths

2.02 EQUIPMENT

    A.   Stiff fiber bristle brush


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 ERECTION, INSTALLATION, APPLICATION

    A.   Thoroughly rinse the area with clean, clear water to
         remove any bleach remaining on the surface.

    B.   If the marble surface is etched, repolish the area with
         a polishing powder such as aluminum oxide or oxalic acid.
         For guidance, see 04455-15-R "Removing Etch Marks in
         Marble" followed by 04455-02-P "Repolishing Marble".

    C.   If the area is lightened, try applying a thin application
         of linseed oil to the affected area.  This might darken
         the stained area so that it is not as noticeable.  NOTE:
         ALWAYS TEST A SMALL AREA FIRST, AND OBTAIN APPROVAL FROM
         RHPO BEFORE PROCEEDING WITH THE TREATMENT OF LARGER
         AREAS.

                         END OF SECTION
 


bleach etching of marble, treating bleach stains on marble, treating bleach lightening on marble, sodium hypochloride stains on marble