General Cleaning Of Exterior Brick Masonry

Procedure code:
National Capitol Region Specifications
Brick Unit Masonry
Last Modified:



1.01     SUMMARY

        A.   This procedure includes guidance on cleaning exterior
             brick masonry.
        B.   Safety Precautions:  
             A   The work specified herein requires knowledge of
                  older materials and methods and a high degree of
                  skill to execute properly.  This work should be
                  performed only by an experienced, pre-qualified
                  contractor.  It is not recommended that building
                  maintenance personnel perform this work.
             B   This outline specification contains recommended
                  materials which may be toxic.  The manufacturer s
                  literature on application techniques, appropriate
                  protection for workers and disposal procedures for
                  materials should be complied with in conjunction
                  with all regulatory requirements referenced in this
        C.   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).  


        A.   Product Data:  
             1.   Submit manufacturer's product literature
                  instructions for use, and Material Safety Data
                  Sheets(MSDS) to the Contracting Officer or the
                  designated representative for all cleaning
             2.   Prior to commencing the cleaning operations, the
                  Contractor shall submit to the Contracting Officer
                  or the designated representative a written
                  description of the entire methods and procedures
                  proposed for cleaning the masonry including, but
                  not limited to:  Method of application, dilution of
                  application, temperature of application, length of
                  time of surface contact, method of rinsing surface
                  (temperature, pressure, and duration), repetition
                  of procedures, etc.
             3.   Prior to commencing the cleaning operations, the
                  Contractor shall submit to the Contracting Officer
                  or the designated representative for approval, a
                  written description of proposed materials and
                  methods of protection for preventing damage to
                  adjacent materials, vehicular and pedestrian
                  traffic, and the building interior during the
                  cleaning of masonry.
        B.   Samples:
             1.   The Contractor shall clean a sample panel(s),
                  approximately 3' x 3' in area, on each type of
                  masonry included in the work of this section for
                  approval by the Contracting Officer.  Locations of
                  sample panels to be selected by the Contracting
                  Officer or the designated representative.
             2.   Adjust the chemical concentrations, working
                  pressures and methodologies during test panel
                  cleaning, as directed by the Contracting Officer or
                  the designated representative.
             3.   Sample panels shall be cleaned by the Contractor
                  using methods, materials, and working pressures
                  previously submitted and approved.  Sample panel
                  cleaning shall be performed in the presence of the
                  Contracting Officer or the designated
                  representative.  The working pressures during
                  sample panel cleaning shall be varied up to the
                  previously submitted and approved capacities to
                  determine the best working pressure.
             4.   Where chemical cleaners and poultices are tested,
                  the manufacturer's representative shall be present
                  during testing.
             5.   The Contractor shall obtain written approval from
                  the Contracting Officer or the designated
                  representative of cleaning methods, working
                  pressures, materials, equipment used and sample
                  panels before proceeding with building cleaning
                  operations.  For this written approval purpose, the
                  Contractor shall allow a minimum of seven calendar
                  days after completion of sample cleaning to permit
                  the Contracting Officer of the designated
                  representative to study the sample panels for
                  negative reaction.  Retain approved panels in
                  unaltered condition, suitably designated during
                  construction as a standard for judging completed


        A.   Qualifications:

             1.   Comply with municipal and federal regulations
                  governing all work included in this section and
                  including, but not limited to waste disposal.
             2.   General Objective: The objectives of masonry
                  cleaning are to remove dirt, grime and coatings
                  from masonry without damaging underlying material
                  and to give all masonry a clean, uniform appearance
                  without blotches, streaks, runs, or any other kind
                  of spotty appearance.  Too aggressive cleaning
                  shall not be acceptable.
             3.   Cleaning Standard:  Prepare sample panels for
                  approval which shall establish a standard for
                  general brick and stone cleaning.  General cleaning
                  shall not commence until written approval is
                  obtained from the Contracting Officer or the
                  designated representative.
             4.   Contractor:  The work of this section shall be
                  performed by a specialist possessing a minimum of
                  five (5) years of specialized experience in the
                  cleaning of historic architectural masonry similar
                  to that which is required by this project.
                  Contractors shall submit to the Contracting Officer
                  or the designated representative references of
                  previous work justifying their experience.  The
                  Contracting Officer or the designated
                  representative reserves the right to approve or
                  disapprove the use of Contractors contingent upon
                  their experience.
             5.   In the event that the Contractor wishes to modify
                  any cleaning method specified, he shall submit his
                  proposal in writing for consideration and review.
                  The Contracting Officer of the designated
                  representative will have the right to ask for test
                  samples before final approval.  Any such
                  modifications or changes shall be at no additional
                  cost to the Government.

        B.   Regulatory Requirements: Comply with municipal and
             Federal regulations governing the cleaning, chemical
             waste disposal, product safety, scaffolding and
             protection to workers and adjacent properties.


        A.   Environmental Requirements:
             1.   No cleaning shall be executed when air or masonry
                  surface temperature is below 45 degrees (F.), unless adequate,
                  approved means are provided for maintaining a 45 degrees (F.),
                  temperature of the air and materials during, and
                  for 48 hours subsequent to, cleaning.
             2.   Perform cleaning and washing of the exterior
                  masonry only during hours of natural daylight



        A.   ProSoCo, Inc.

        B.   Diedrich Technologies, Inc.

2.02     MATERIALS

        A.   Masonry Cleaner:  Commercially available very mild blend
             of inhibited acidic ingredients and wetting agents
             specifically formulated for restorative cleaning of brick
             and natural stone surfaces such as "Sure Klean
             Restoration Cleaner" (ProSoCo, Inc.), "101 G Granite,
             Terra Cotta and Brick Resoration Cleaner" (Diedrich Technologies),
             or approved equal.

             Masonry cleaner should have the following physical
             Form:     Clear liquid
             pH:  1.2
             Specific Gravity (Typical): 1.05

        B.   Water: Potable, non-staining and free of oils, acids,
             alkalis and organic matter.
        C.   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 Strippable Masking" (ProSoCo, Inc.), or approved

2.03     EQUIPMENT

        A.   Brushes:  Natural fiber bristle only. The use of wire
             brushes or steel wool is not permitted.

        B.   Garden hose with fan tip nozzles


        A.   Protection:

             1.   Take all necessary precautions and measures to
                  protect surrounding materials on the site, surfaces
                  of the building not being cleaned, adjacent
                  buildings, pedestrians and vehicles from coming in
                  contact with cleaning chemicals, over spray, or
                  runoff.  Products used for masonry cleaning may be
                  harmful to painted, polished, glazed, or metallic
                  surfaces.  Any damage to materials caused by the
                  cleaning operations is unacceptable and shall be
                  repaired or replaced by the Contractor to the
                  satisfaction of the Contracting Officer or the
                  designated representative at no cost to the
             2.   Provide protection from water damage to building,
                  structure, or building contents as required.
             3.   Protect trees and plants around the building from
                  contamination or damage as directed by the
                  Contracting Officer or the designated
                  representative.  The Contractor shall be
                  responsible for replacing with new stock, any
                  trees, shrubbery or grass damaged by the cleaning
             4.   Test all drains and other water removal systems to
                  assure that drains and systems are functioning
                  properly prior to performing any cleaning
                  operations.  Notify Contracting Officer or the
                  designated representative immediately of any and
                  all drains or systems that are found to be stopped
                  or blocked.  Contractor shall repair drains if so
                  directed by the Contracting Officer or the
                  designated representative.  Do not begin work of
                  this Section until the drains are in working order.
             5.   Provide a method to prevent solids such as stone or
                  mortar residue from entering the drains or drain
                  lines.  Contractor shall be responsible for
                  cleaning out drains and drain lines that become
                  blocked or filled by sand or other solids because
                  of work performed under this Contract.


        A.   Dilute masonry cleaner with 16 parts water to 1 part
             concentrate, or use appropriate dilution based on sample
             panel cleaning. When diluting, always pour water into
             empty bucket first, then carefully add concentrate.
             Handle in rubber or polyethylene buckets only.  Acidic
             liquids and fumes will attack metal.
        B.   After protecting all non-masonry surfaces, thoroughly wet
             the area to be cleaned.
        C.   Apply the cleaning solution liberally using low pressure
             spray (50 psi), roller or densely filled (tampico)
             masonry washing brush.  Do not apply restoration cleaner
             with high pressure spray.  Such application will drive
             the chemicals deep into the surface, making it difficult
             to rinse completely. Discoloration to the surface may
        D.   Allow the cleaning solution to remain on the surface for
             three to five minutes in accordance with approved test
             procedures.  Light scrubbing of the surface will improve
             cleaning results.  Caution: Do not allow cleaning
             solution to "dry in" to the masonry - bleaching may
             1.   Begin rinsing with low pressure flood rinse to
                  remove initial acidic residue with minimum risk of
                  wind drift.

             2.   Then rinse the treated area thoroughly using
                  pressurized 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 1.4 to 2.0 feet.  All pressure
                  pumps shall be equipped with working pressure
             3.   Rinse from the bottom of the treated area to the
                  top flushing each section of the surface with a
                  concentrated stream of water.  To avoid streaking
                  on vertical walls, take care to keep the wall below
                  wet and rinsed free of cleaner and residues.
             4.   Application of rinse water is extremely important
                  to assure that all surface staining matters and
                  cleaning residues are thoroughly flushed from the
                  treated surface.
        E.   Surrounding stone surfaces below the section of brick to
             be cleaned shall be pre-wetted and rinsed periodically
             during cleaning operations to prevent etching of stone.
        F.   The surfaces below the sections of brick to be cleaned
             shall be protected from run-off.
        G.   Repeat procedures if necessary to remove heavier build-up
             of soiling.

                         END OF SECTION

Last Reviewed 2015-11-17