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Historic Preservation - Technical Procedures

Spectitle:

Stripping And Cleaning Dirty Or Discolored Terrazzo Floors

Procedure code:

0940002R

Source:

J. Weinberger Us Cthouse/San Diego, Ca - Hallenbeck Chamorro

Division:

Finishes

Section:

Terrazzo

Last Modified:

02/24/2012

Details:

Stripping And Cleaning Dirty Or Discolored Terrazzo Floors



STRIPPING AND CLEANING DIRTY OR DISCOLORED TERRAZZO FLOORS


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


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on stripping and
         cleaning existing terrazzo which is dirty, has minor
         damage or has a surface residue from removal of newer
         materials.

    B.   Discoloration of terrazzo may be caused by wax build-up,
         soap scum, overuse of disinfectant, epoxies and coatings
         that have yellowed, or by dirt tracked into an unsealed
         floor.  

    C.   Historic Structures Precautions:  Injurious acids,
         caustic soda or any ingredient independently or in
         combination in any compound fluid or solution which will
         damage the terrazzo shall NOT be used.

    D.   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).

1.02 REFERENCES

    A.   NTMA Standards:  Comply with specified provisions and
         recommendations of National Terrazzo and Mosaic
         Association, Inc. (NTMA), 3166 Des Plaines Avenue, Ste.
         132, Des Plaines, IL  60018, 800/323-9736 or 708/635-
         7744, FAX (708) 635-9127.

1.03 QUALITY ASSURANCE

    A.   Where current codes cannot be complied with, and/or
         construction limitations (including deterioration of
         existing substrate) are such that the intended finish
         cannot be achieved, notify the Regional Historic
         Preservation Officer (RHPO) for clarification and/or
         decision prior to proceeding with the work.  

    B.   Mock-ups:  Strip and clean 20 square feet of each
         terrazzo type for review by RHPO before stripping and
         cleaning all the terrazzo.


PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.   ProSoCo, Inc.
         755 Minnesota Avenue
         P.O. Box 1578
         Kansas City, KS  66117
         800/255-4255 or 913/281-2700

    B.   BASF-Wyandotte Corporation
         Chemical Specialties Division
         1609 Biddle
         Wyandotte, MI  48192
         313/246-6100

2.02 MATERIALS

    A.   Cleaner:  Liquid, neutral chemical cleaner, with Ph
         factor between 7 and 10 of formulation recommended by
         sealer manufacturer for type of terrazzo used, and
         complying with NTMA requirements, such as Sure Klean 859
         (ProSoCo, Inc.), or approved equal.

    B.   Interior Floor Sealer:  Colorless, slip and stain
         resistant penetrating sealer with Ph factor between 7 and
         10, that does not affect color or physical properties of
         terrazzo surface.

    C.   Compound Cleaner:  A mildly abrasive phosphate free
         cleaning compound containing no caustic or harsh fillers,
         manufactured specifically for restorative type cleaning
         of terrazzo surfaces, such as "Wyandotte Detergent"
         (BASF-Wyandotte Corporation) or approved equal.

         -OR-

         Sure Klean Grout and Tile Cleaner (ProSoCo, Inc.), or
         approved equal.

    D.   Clean, potable water

2.03 EQUIPMENT

    A.   Wet vac

    B.   Paint roller

    C.   Low pressure tank sprayer

    D.   Power scrubber with scrub brush attachment

    E.   Stiff bristle brushes (natural or nylon bristle)


PART 3---EXECUTION

3.01 EXAMINATION

    A.   Perform a thorough examination of the existing
         conditions.  Perform any necessary tests on an
         inconspicuous surface to determine the current conditions
         and appropriate steps and materials necessary for
         stripping terrazzo surfaces.

3.02 ERECTION, INSTALLATION AND APPLICATION

    NOTE:  The following procedure calls for stripping the floor
    down to the original surface, cleaning if necessary, and then
    sealing with a long-lasting sealer.

    A.   Strip existing sealers and coatings from floor:

         1.   Apply chemical floor cleaner with paint roller and
              let stand for five to ten minutes.  Work in areas
              no more than four feet wide to insure that the
              applicator is always standing on a dry floor.

         2.   Using a low pressure tank sprayer, apply a mist of
              water over the cleaner already on the floor.  The
              water will emulsify the old sealer and dilute the
              thixotropic cleaner.  

         3.   Pick up all remaining residues with a wet vac.

         4.   Using a power scrubber with a scrub brush
              attachment, scrub the floor until all coating
              material has been removed.  

         5.   Pick up all liquid residues with a wet vac.

         6.   Thoroughly rinse the surface with clean, clear
              water.

         7.   Pick up all remaining liquid residues with a wet
              vac and allow to dry.

         -OR-

         If dirt and scratches have become so severe that normal
         stripping and cleaning no longer restore the floor to its
         original luster, the surface may be stripped using fine
         grit stones and resurfacing screens.

         CAUTION:  THIS METHOD OF REMOVING SEALERS AND COATINGS
         INVOLVES GRINDING OFF A THIN LAYER OF THE TERRAZZO.  IT
         SHOULD ONLY BE USED AS AN EXTREME MEASURE AND A
         SPECIALIST MUST BE CONSULTED.

    B.   If the floor is still dirty, clean using Sure Klean Grout
         and Tile Cleaner (ProSoCo, Inc.), or approved equal.

         1.   Dilute three to four parts water to one part Grout
              and Tile Cleaner.

         2.   Pre-wet area to be cleaned.

         3.   Apply cleaning solution with floor scrub brushes.

         4.   Let stand two to three minutes while lightly
              agitating with a stiff, natural bristle brush,
              broom, or nylon brush.

         5.   Thoroughly rinse the surface with clean, clear
              water.

         6.   Pick up all remaining liquid residues with a wet
              vac and allow to dry.

    C.   Seal the terrazzo surface with high strength sealer
         according to manufacturer's instructions.

                             END OF SECTION