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Historic Preservation - Technical Procedures

Spectitle:
Removal Of Copper-Based Stains From Brick, Concrete & Limestone

Procedure code:
0420007R

Source:
National Capitol Region Specifications - Cohen Building

Division:
Masonry

Section:
Unit Masonry

Last Modified:
02/24/2012

Details:
Removal Of Copper-Based Stains From Brick, Concrete & Limestone



REMOVAL OF COPPER-BASED STAINS FROM BRICK, CONCRETE AND LIMESTONE


PART 1--- GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on removing coppe= r
         staining on exterior brick, concrete and limestone.

         1.   Remove soiling, stains and crusts from the
              limestone and granite without damaging underlying
              material and to give all stone a clean, uniform
              appearance without blotch= es, streaks or other
              irregularities. Use the gentlest means to meet the
              cleaning objective.

         2.   If the exterior masonry has been previously
              subjected to inappropriat= ely harsh and uneven
              cleaning, it is expected that the cleaning will
              reveal the original colors and textures of the
              brick, but that it will not completely correct the
              differential effects of the previous cleaning.
              Clean brick to remove soiling, stains and crusts to
              the extent feasible witho= ut further damaging the
              brick.

    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).  


PART 2---PRODUCTS

    A.   Diedrich Chemicals Restoration Technologies, Inc.<= br>          300A East Oak Street
         Oak Creek, WI  53154
         414/764-0058 or 800/323-3565

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

2.01 MATERIALS

    A.   Copper-Based Stain Remover: Commercially available, two
         part poultice cleaning system specifical= ly designed to
         remove green copper stains from masonry surfaces, such as
         "Sure Klean T-515 Copper Stain Remover"(ProSoCo, Inc.),
         or approved equal.

    B.   Liquid Strippable Masking Agent: Manufacturer's standard
         liquid, film forming, strippable masking material for
         protecting glass, metal and polished stone surfaces from
         damaging effect of acidic and alkaline masonry cleaners,
         such as "Sure Klean Acid Stop" (ProSoCo, Inc.), "Diedrich
         Acid Guard" (Diedrich Chemicals), or approved equal.

    C.   Plastic material for covering poultice

    D.   Water: Potable, non-staining and free of oils, acids,
         alkalis and organic matter.

2.03 EQUIPMENT

    A.   Brushes: Natural fiber bristle only. The use of wire
         brushes or steel wool is not permitted.<= br>
    B.   Stainless steel trowel

    C.   Wood spatula


PART 3---EXECUTION

3.01 PREPARATION

    A.   Protection:  Protect from run-off the surfaces below the
         sections of masonry to be cleaned of copper-based stains
         using liquid strippable masking agent.
    B.   Surface Preparation:

         1.   Filter water with a 5 micron particulate filter
              placed in line with the water supply. Replace the
              filter as needed during the work.

         2.   Commence copper-based stain removal immediately
              after cleaning of masonry (see 03710-15-R, 04211-
              04-R and 04460-03-R for guidance on the general
              cleaning of concrete, brick and limestone
              respectively).

         3.   The work shall proceed from the top of the wall
              downward. Work shall not be considered complete
              until the Contracting Officer of designated
              representative has so notified the Contractor in
              writing.

3.02 ERECTION, INSTALLATION, APPLICATION

    A.   Prepare the copper-based stain remover by mixing the
         liquid additive with the dry poultice (Fuller's earth) to
         a thick cream. Mix thoroughly so that poultice has a
         smooth, even consistency.

    B.   Clean dirt or dust from surface being treated prior to
         application of poultice.

    C.   Prewet masonry and apply a =AC" thick layer of poultice to
         the stained surface using a stainless steel trowel or
         other non-ferrous implement.

    D.   Cover the poultice with a plastic membrane and allow to
         dry for 8 to 24 hours depending on test samples.

    E.   Scrape the poultice from the masonry with a non-me= tallic
         implement and scrub with water and a fiber bristle brush.

    F.   Rinse all traces of chemical residue with pressuri= zed
         cold water. Rinse water pressure shall not exceed 300
         psi, and shall be sprayed through nozzles fitted with 15
         to 20  wide tips. Nozzles shall be held perpendicular to
         the surface at a working distance of 1.5 to 2.5 feet. All
         pressure pumps shall be equipped with working pressure
         gauges.

    G.   Repeat procedure if necessary to remove all traces of
         copper-based staining.

                         END OF SECTION