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Historic Preservation - Technical Procedures

Spectitle:

Removing Wood Stains From Concrete

Procedure code:

0371042R

Source:

Hstrc Concrete: Investigation & Rpr/Pre-Conf Training - 1989

Division:

Concrete

Section:

Concrete Cleaning

Last Modified:

02/24/2012

Details:

Removing Wood Stains From Concrete



REMOVING WOOD STAINS FROM CONCRETE


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


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on removing wood stains
         from concrete using a hypochlorite solution.

    B.   Wood stains on concrete may appear as yellow or brown in
         color.  Stains from rotten wood may appear as chocolate
         brown in color.

    C.   Safety Precautions:

         1.   DO NOT save unused portions of stain-removal
              materials.

         2.   DO NOT store any chemicals in unmarked containers.

         3.   EXCELLENT VENTILATION MUST BE PROVIDED WHEREVER ANY
              SOLVENT IS USED.  USE RESPIRATORS WITH SOLVENT
              FILTERS.

         4.   No use of organic solvents indoors should be
              allowed without substantial air movement.  Use only
              spark-proof fans near operations involving
              flammable liquids.

         5.   Provide adequate clothing and protective gear where
              the chemicals are indicated to be dangerous.

         6.   Have available antidote and accident treatment
              chemicals where noted.

    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).


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.   Glycerol (C3H8O3):

         1.   A sweet syrupy hygroscopic trihydroxy alcohol
              usually obtained by the saponification of fats and
              used especially as a solvent and plasticizer.

         2.   Other chemical or common names include Glycerine;
              Glyceryl hydroxide; Glycyl alcohol; 1,2,3-propanetriol; Propenyl alcohol.

         3.   Potential Hazards:  FLAMMABLE.

         4.   Available from chemical supply house, drug store or
              hardware store.

    B.   Sodium Hypochlorite (NaOCl):

         1.   An unstable salt produced usually in aqueous
              solution and used as a bleaching and disinfecting
              agent.

         2.   Other chemical or common names include Bleaching
              solution*; Household bleach*; Laundry bleach*;
              Solution of chlorinated soda*.

         3.   Potential Hazards:  CORROSIVE TO FLESH.

         4.   Available from chemical supply house, grocery store
              or supermarket, hardware store or janitorial supply
              distributor.

         -OR-

         Job-prepared Hypochlorite:  Made by user, see 03710-01-S
         for guidance on preparation.

         1.   Calcium Hypochlorite (CaCl2O2):

              a.   A white powder used especially as a bleaching
                   agent and disinfectant.

              b.   Other chemical or common names include
                   Chlorinated calcium oxide; Bleaching powder*;
                   Calcium oxymuriate*; Chloride of lime*;
                   Chlorinated lime*; Hypochlorite of lime*;
                   Oxymuriate of lime*.

              c.   Potential Hazards:  CORROSIVE TO FLESH;
                   FLAMMABLE (WHEN IN CONTACT WITH ORGANIC
                   SOLVENTS).

              d.   Available from chemical supply house, dry
                   cleaning supply distributor, drugstore or
                   pharmaceutical supply distributor, janitorial
                   supply distributor, swimming pool supply
                   distributor, or water and sanitation supply
                   distributor.

         2.   Sodium Orthophosphate:

              a.   Other chemical or common names include
                   Tribasic sodium phosphate; Trisodium
                   orthophosphate; Trisodium phosphate; TSP*;
                   Phosphate of soda*.

              b.   Potential Hazards:  CORROSIVE TO FLESH.

              c.   Available from chemical supply house, grocery
                   store or supermarket or hardware store.

    C.   Clean, potable water

    D.   Accessible source of water, soap and towels for washing
         and rinsing in case of emergencies associated with the
         use of chemicals

2.02 EQUIPMENT

    A.   Stiff, natural bristle brushes

    B.   Clean, dry cloths


PART 3---EXECUTION

3.01 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 concrete even though the stain is gone.

3.02 ERECTION, INSTALLATION, APPLICATION

    NOTE:  DO NOT TRY MORE THAN ONE TREATMENT ON A GIVEN AREA
    UNLESS THE CHEMICALS USED FROM PRIOR TREATMENT HAVE BEEN
    WASHED AWAY.

    A.   First, scrub the surface thoroughly with a solution of 1
         part glycerol in 4 parts water.

    B.   Next, scrub the stained area with a hypochlorite
         solution.  Use job-prepared hypochlorite (see 03710-01-S
         for guidance on preparation), or dilute 1 part household
         bleach (5% sodium hypochlorite) with 4 to 6 parts water.

    C.   Rinse thoroughly with clean, clear water and allow to
         dry.

    D.   Repeat the process as required to achieve the desired
         level of cleanliness.

                         END OF SECTION