Skip to main content

Historic Preservation - Technical Procedures

Spectitle:

General Cleaning Of Granite

Procedure code:

0446506R

Source:

Hsr - Interior Building, Washington, Dc, 1988

Division:

Masonry

Section:

Granite

Last Modified:

01/07/2014

Details:

General Cleaning Of Granite



GENERAL CLEANING OF GRANITE


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on the removal of
         surface dirt and environmental pollution from exterior
         granite.

    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 precautions relating to pressure washing, see 04510-04-S.



PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.   Diedrich Technologies, Inc.
          www.diedrichtechnologies.com        
         

    B.   ProSoCo, Inc.
          www.prosoco.com       
        
         

2.02 MATERIALS

    A.   Commercial masonry cleaner with a maximum 4% acid
         concentration, surfactants and wetting agents such as
         "Sure Klean Restoration Cleaner" - undiluted (ProSoCo,
         Inc.), or "Diedrich 101G Granite, Terracotta and Brick
         Cleaner" - diluted 1:4 to achieve a maximum 4% acid
         concentration (Diedrich Technologies, Inc.), or approved
         equal.

    B.   Clean, potable water

2.03 EQUIPMENT

    A.   Pressure water rinsing equipment (measuring between 100
         and 400 psi for low-pressure; between 400 and 800 psi for
         medium pressure).

    B.   Fan-type spray tips (15 degree fan spray)

    C.   Stiff bristle brushes (non-metallic)

    D.   Plastic spatula


PART 3---EXECUTION

3.01 ERECTION, INSTALLATION, APPLICATION

    NOTE:  WHEN CLEANING, AVOID OVERCLEANING.  AIM FOR ACHIEVING
    85% CLEAN.  MOST DAMAGE OCCURS WHEN ATTEMPTING TO CLEAN THE
    LAST 15%.

    NOTE:  TEST CLEAN A SMALL AREA BEFORE ATTEMPTING TO CLEAN
    LARGE AREAS.

    NOTE:  DO NOT TREAT THE SURFACE WITH ACID CLEANER MORE THAN
    ONCE.

    A.   Saturate the granite with clean, warm water sprayed at a
         low pressure (between 100 and 400 psi).  Remove bird
         excrement and debris from granite prior to the
         application of acidic granite cleaner (see 04510-02-R for
         guidance).

    B.   Spray-apply cleaner evenly to the stained surface at 125
         psi. or as recommended by manufacturer, or brush-apply
         cleaner using a soft fiber bristled brush.

    C.   Allow cleaner to stand on the surface for 3-5 minutes or
         as recommended by manufacturer.

    D.   Thoroughly rinse the surface with clean, clear water at
         medium pressure (between 400 and 800 psi).  Nozzle should
         be held between 18 and 30 inches from the surface.  Stone
         should be left clean without streaking or staining.

                         END OF SECTION
 


surface dirt, environmental pollution, granite, cleaning granite