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Historic Preservation - Technical Procedures

Spectitle:

Removing Smoke Stains From Brick Masonry

Procedure code:

0421107R

Source:

Tech Notes On Brick Construction - 20

Division:

Masonry

Section:

Brick Unit Masonry

Last Modified:

02/24/2012

Details:

Removing Smoke Stains From Brick Masonry



REMOVING SMOKE STAINS FROM BRICK MAS= ONRY


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 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 removing smoke stains
         from brick masonry.

    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 Precaution= s

         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).=0CPART 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 adequa= te
    for stain removal work, and these products should be purchas= ed
    when available, as they tend to be less expensive.  Com= mon
    names are indicated below by an asterisk (*).

    A.   Scouring powder containing bleach

         -OR-

         Alkali detergent or commercial emulsifyi= ng agent.

    B.   Trichloroethylene (highly refined solvent):

         CAUTION:  TRICHLOROETHYLENE IS HIGHLY TOXIC AND MAY REACT
         WITH STRONG ALKALIS SUCH AS FRESH CONCRE= TE TO FORM
         DANGEROUS GASES.

         1.   Other chemical or common names include Ethinyl
              trichloride.

         2.   Potential Hazards:  TOXIC= .

         3.   Available from automotive supply distributor,
              chemical supply house (both commercial and
              scientific), dry cleaning supply distributor, paint
              store, photographic supply distributor (not camera
              shop), or printer's supply distributor.

    C.   Filler material such as diatomaceous earth or powdered
         talc

    D.   Clean, potable water

2.02 EQUIPMENT

    A.   Glass or ceramic container for mixing the solution=

    B.   Wooden utensil for stirring the ingredients

    C.   Wood or plastic spatula

    D.   Stiff bristle brush

    E.   Masking tape


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.

    A.   Scrub the affected area with a stiff bristle brush and
         scouring powder containing bleach.

         -OR-

         Brush or spray apply an alkali detergent or commercial
         emulsifying agent.

    B.   For small stubborn stains, apply a poultice of
         trichloroethylene and inert filler mater= ial.

         1.   Thoroughly rinse the area to be treated with
              mineral water.

         2.   Mix the liquid solution to be used in a glass or
              ceramic bowl.

         3.   Thoroughly moisten the stained surface with this
              liquid.  Be sure to dampen well beyond the stain.

         4.   Mix the remaining liquid with the white absorbent
              material to form a paste the consistency of oatmeal
              or cake icing.  (App= roximately one pound of paste
              is needed for every square foot of surface area to
              be treated).

         5.   Using a wooden or plastic spatula, apply the paste
              to the stained surface in layers no more than 1/4
              inch thick.  The poultice should extend well beyond
              the stain to prevent forcing the stain into
              previously clean masonry.=

         6.   Check the coating for air pockets or voids.

         7.   Cover the poultice with plastic sheeting and seal
              with masking tape.

         8.   Let set for 48 hours (unless otherwise specified).

         9.   After set period, dampen the poultice with mineral
              water.

         10.  Remove the poultice with a wooden or plastic
              spatula to avoid scratchi= ng the surface.

         11.  Thoroughly rinse the cleaned area with mineral
              water, blot with clean towels and allow the surface
              to dry.

         12.  Repeat the process as necessary to remove any
              remaining residue until a desired level of
              cleanliness is achieved.<= br>
                         END OF SECTION