Historic Preservation - Technical Procedures
Removing Bird Repellent Gels From Masonry
The Preservation Notebook Series - Gsa/Pbs
Removing Bird Repellent Gels From Masonry
REMOVING BIRD REPELLENT GELS FROM MASONRY
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 THE POROUS MASONRY. USE THE PRODUCTS AND TECHNIQUES
DESCRIBED HERE ONLY FOR THE COMBINATIONS OF DIRT/STAIN AND MASONRY
A. This procedure includes guidance on removing bird
repellent gels from masonry and removing any residual
stains left behind.
B. One method of bird control involves the use of a toxic
irritant gel, applied like caulk to horizontal surfaces
where birds roost. One result is the presence of a
gummy, oily residue which can attract dirt, stain masonry
and soil occupants who come in contact with it.
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
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. Protection Program: Prior to the execution of
cleaning samples, submit to the RHPO a written
description of the methods and materials for
protection of all surrounding materials not to be
2. Waste Water Collection and Removal: Prior to
execution of cleaning samples, submit to the RHPO a
written description of methods of waste water and
chemical collection and removal.
3. Submit to the RHPO in triplicate a written
description of the methods, materials, and
equipment proposed for use in cleaning each type of
masonry specified. Submit actual samples of each
cleaning product to be used, along with
manufacturer certifications that chemical
ingredients conform to those specified for each
1. Clean a representative sample of approximately 10
square feet of stone surface at locations selected
by the RHPO, for each type of stone to be cleaned
and each different procedure to be performed,
including scraping to remove gel bulk. The samples
accepted by the RHPO will be marked and left
undisturbed to serve as standards for the entire
2. Sample cleaning procedures must be executed in the
presence of the RHPO and must demonstrate the
Contractor's ability to perform each specified
cleaning procedure without harming masonry. Damage
to masonry as a result of cleaning operations may
result in the technician's dismissal from the
3. Adjust cleaning materials and methodologies during
test panel cleaning as directed by the RHPO.
4. Allow a minimum of seven calendar days after
completing cleaning samples to permit the RHPO to
study the sample panels for negative reactions.
5. Do not proceed with cleaning until cleaning samples
have been approved in writing by the RHPO.
6. Approved samples shall be marked and left unaltered
for the duration of the project. Approved samples
shall be used as the standard for similar work
throughout the project.
C. Quality Control Submittals:
1. Submit written program for each phase of
restoration process including protection of
surrounding materials on building during
operations. Describe in detail materials, methods
and equipment to be used for each phase of
2. If alternative methods and materials to those
indicated are proposed for any phase of restoration
work, provide written description, including
evidence of successful use on other, comparable
projects, and program of testing to demonstrate
effectiveness for use on this project.
1.03 QUALITY ASSURANCE
1. General Objective: The objectives of stone
cleaning are to remove bird repellent gel without
damaging underlying material and to give the stone
a clean uniform appearance. Protection of the
stone from damage is the highest priority. Overly
aggressive cleaning that damages or discolors the
surface of the stone will not be accepted.
2. Contractor Qualifications: This work must be done
by a firm specializing in the cleaning of historic
masonry. Refer to the Competency of Bidder Clause,
Sections 00120 and 00900 for submission
3. In the event that the Contractor wishes to modify
any cleaning method specified, he must submit his
proposal in writing to the RHPO for consideration.
The RHPO may ask for test samples before approval.
Approval or rejection of the Contractor's request
will be at the RHPO's discretion. Any such changes
shall be at no additional cost to the Government.
B. Regulatory Requirements: Comply with municipal and
Federal regulations governing cleaning, chemical waste
disposal and scaffolding.
A. ProSoCo, Inc.
755 Minnesota Avenue
P.O. Box 1578
Kansas City, KS 66117
800/255-4255 or 913/281-2700
A. Cleaning Products:
1. Repellent Gel Remover: Solvent based, methylene
chloride paint stripper formulated for removal of
paint, tar, and adhesives from stone, such as Sure
Klean 509 Paint Stripper (ProSoCo, Inc.), or
2. Oily Stain Remover: Solvent mixture of methylene
chloride, ketone, methyl alcohol, and aromatic
hydrocarbon, formulated for the removal of oily
stains from stone, such as Sure Klean T1012
(ProSoCo, Inc.), or approved equal.
3. Poultice: Blend the following to form a paste:
a. Sure Klean T1012 (ProSoCo, Inc.), or approved
b. Poultice clay containing soda ash (sodium
carbonate), talc (magnesium silicate hydrate),
and fullers earth (magnesium aluminum
silicate) (ProSoCo, Inc.), or approved equal.
B. Clean, potable water
1. Gel Scraper (use for removal of gel residue only):
Sharp steel blade, held at a shallow angle against
surface to avoid damage to stone
2. Poultice Scraper: Non-metallic spatula
3. Brushes: Fiber bristle brushes (non-metallic)
A. Protection: Following approval of proposed protection
scheme as outlined in 1.02, install protection as
1. Take all precautions necessary 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, overspray, or runoff.
2. Use polyethylene film, masking tape, and whatever
means necessary to protect plantings, automobiles,
building occupants, and building surfaces not being
cleaned. Remove such coverings when masonry
cleaning operations have been completed at that
area of the building.
3. Repair or replace with new stock, at no cost to the
Government, to the RHPO's satisfaction, any
materials or plantings damaged by scaffolding,
laborers, cleaning materials, or cleaning
4. Prior to full scale cleaning, perform, in the
presence of the RHPO, a site test of the protective
methods to prove that chemical damage to stone,
glass, interior finishes, and other surfaces not
being cleaned will not occur.
5. Test all drains and other water removal systems to
assure that they are functioning properly prior to
initiating cleaning operations. Notify the RHPO
immediately of all blockages. Repair drains if so
directed by the RHPO. Do not begin cleaning until
drains are in working order.
6. Provide a method to prevent solids such as stone or
mortar residue from entering drains or drain lines.
Clean out drains or drain lines that become blocked
because of work performed under this Contract.
7. Follow manufacturer instructions regarding the safe
storage and use of all products and equipment.
Remove all solvents, soiled rags, applicators, and
other flammable materials daily and dispose off-
site according to Federal and municipal
B. Surface Preparation:
1. Examine masonry to be cleaned prior to installing
protection and executing sample panels. Notify
RHPO immediately of any masonry damage observed.
Use caution in installing protection and
undertaking cleaning in damaged areas. Clean and
rinse by gentlest means possible and follow RHPO's
recommended precautions to avoid further damage to
2. Following approval of submitted materials and
written description of methods as stipulated under
1.02 A, execute sample panels as directed in 1.02
3.02 ERECTION, INSTALLATION, APPLICATION
A. Removal of Bird Repellent Gel:
1. Remove bulk of gel by carefully scraping masonry
surface with a steel blade. Hold blade at a
shallow angle to avoid scratching or abrading stone
surface. Scratching or otherwise damaging masonry
will result in the cleaning technician's dismissal
from the project.
2. Apply and remove solvent paint stripper, as
directed by manufacturer, as many times as
necessary to remove surface coatings remaining
after scraping bulk of repellent gel.
B. Removal of Repellent Gel Stains:
1. Apply Oily Stain Remover to dry stone in areas
where gel stains remain after removal of repellent
2. Trowel apply poultice-solvent mixture immediately
after application of Oily Stain Remover. Apply
poultice to a minimum thickness of 1/4 inch.
3. Cover the poultice with plastic film to keep it
from drying out for a minimum of 24 hours. Press
film to poultice and tape or otherwise seal the
edges to exclude air.
4. Remove plastic cover and allow the poultice to dry
5. Remove poultice by scraping with a nonmetallic
spatula. Wash the surface thoroughly with clean,
6. Repeat steps 1 through 5 as necessary to obtain
results matching approved samples.
END OF SECTION