Historic Preservation - Technical Procedures
- General Project Guidelines
- Procedure code:
- General Requirements
- Special Project Procedures
- Last Modified:
- General Project Guidelines
- Last Modified:
GENERAL PROJECT GUIDELINES
THIS STANDARD INCLUDES GENERAL PROJECT GUIDELINES PROVIDED TO
SUPPLEMENT SPECIFIC REPAIR AND PREVENTIVE MAINTENANCE PROCEDURES.
NOT ALL OF THESE REQUIREMENTS WILL BE APPLICABLE GIVEN THE LEVEL OF
DIFFICULTY OF THE PROCEDURE. HOWEVER, WHERE APPLICABLE, THESE
GUIDELINES SHOULD BE USED IN ADDITION TO RECOMMENDATIONS PROVIDED
BY THE REGIONAL HISTORIC PRESERVATION OFFICER (RHPO). THE
INFORMATION IS LISTED IN THE ORDER IT MIGHT APPEAR IN THE USUAL CSI
- The supervisor should ensure that all workers wear adequate,
approved protective clothing and are provided with protective
equipment during work operations and as required at other
- Check manufacturer's literature for precautions and effects of
products and procedures on adjacent building materials,
components, and especially vegetation. Take appropriate
- All workers must be protected from the effects of chemicals
during repair or cleaning operations.
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.
NOTE: SOME OF THE SOLVENTS LISTED COULD BE KNOWN
CARCINOGENS AND MAY BE BANNED IN SOME STATES.
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
7. Avoid skin contact and inhalation of any chemical.
Rubber or plastic gloves should be worn when handling
hazardous (flammable or toxic) chemicals.
a. Follow storage and handling procedures printed on
the container labels of the cleaning solutions,
provide good ventilation while working, and
thoroughly wash hands after completion of the work.
b. Provide protective clothing which must be worn and
protective creams for exposed skin areas.
c. Accidental contact with unprotected skin to these
materials must be treated immediately by washing
with soap and water, never with solvents.
d. Exercise care to avoid skin contact to tool
cleaning solvents and to provide adequate
ventilation for clean-up operations.
- When removing bird droppings: Bird droppings may expose
workers to the effects of cryptococcosis and histoplasmosis
which endanger the human respiratory system. Public health
authorities should be consulted for appropriate precautions.
1. All contractor personnel must wear a National Institute
for Occupational Safety and Health (NIOSH) approved full
face respirator with a high efficiency particulate air
(HEPA) filter for screening particles of 0.3 micron size.
Dust and particle masks are not appropriate.
2. Respirators must be used in accordance with OSHA
regulation, 29 CFR 1910.134 and GSA policy, PBS P
5900.2C, Chapter 3, section 8. This includes fit-testing
of respirators, maintenance, training, and storage
3. All contractor personnel must wear protective coveralls,
gloves, boots, and hats.
4. Prior to removal, all excrement must be saturated with
water under low pressure to prevent debris from becoming
5. On historic structures, only non-metallic tools (such as
plastic spatulas and brushes with natural fiber or nylon
bristles, or their equivalent) must be used to remove the
6. Removed excrement must be collected in plastic bags,
sealed, and disposed of by the contractor at a sanitary
7. All work must be performed from the outside of the
building. Building occupants and the general public must
be kept clear of the work site during all operations. It
is the contractor's responsibility to provide all
barricades, signage, etc. necessary for public
- When removing paint:
1. Paint being removed most likely will contain lead. All
workers must wear protective clothing (including hair),
goggles and respirators with proper filters.
2. No food or drink shall be allowed near any work station
so as to prevent contamination from paint, paint chips,
dust or chemical removers which contain lead and other
3. Protective clothing shall be removed at the end of each
day and kept at the site to prevent workers from tracking
dust and paint chips to other parts of the site or to
4. Wash hands and face often, especially before eating and
at the end of the day.
5. All waste material shall be collected at the end of each
work day and disposed of in a manner consistent with
local environmental regulations. It is considered
HISTORIC STRUCTURES PRECAUTIONS
- The principal aim of any work must be to halt the process of
deterioration and stabilize the item's condition. Repair is
a second option which becomes necessary only where
preservation is not sufficient to ensure mid- to long-term
survival. Repair should always be based on the fundamental
principle of 'minimal disturbance'. The following are good
practices which arise from this principle:
1. Retention of as much existing material as possible;
repairing and consolidating rather than renewing.
2. The use of additional material or structure to reinforce,
strengthen, prop, tie, and/or support existing material
3. The use of reversible processes wherever possible.
4. The use of traditional materials and techniques. New
work should be distinguishable to the trained eye, on
close inspection, from the old.
5. The item should be recorded before, during and after the
- No smoking will be allowed by personnel performing work on or
about Historic Structures.
- RHPO's approval is required for any change, addition or
removal of historic structural fabric or historic property.
- RHPO should be notified of any visible change in the integrity
of the material or component whether environmental, such as
biological attack, ultraviolet degradation, freeze, thaw,
etc., or structural defects, such as cracks, movement, or
- Architectural features will be repaired rather than replaced
wherever possible. Repair or replacement of missing features
will be based on accurate duplications rather than on
- Work which requires existing features to be removed, cleaned
and reused shall be accomplished without damage to the
material itself, to adjacent materials, or the substrate.
- Existing features removed from the building which are to be
reinstalled shall be carefully labeled and stored within the
building in a place where they will not be damaged or obstruct
- New or replacement materials/features will be permanently
marked in an unobtrusive manner to distinguish them from
original fabric. The manner of identification and location of
these marks shall be recorded in permanent building records.
- Identify the historic importance of the material or feature.
The item's merit, in terms of age, uniqueness of design,
materials, size, technological development, association with
persons or events, exceptional workmanship or design
qualities, must be understood before decisions regarding
repair, maintenance and preservation can be made.
- Statement of Non-Compliance: Wherever it is necessary to
proceed with the use of products, under conditions which do
not comply with the requirements (because of time schedule
difficulties or other reasons which the supervisor determines
that are crucial to the project), prepare a written statement
for the RHPO's Record indicating the nature of the non-compliance, the reasons for
proceeding, the extra or precautionary measures taken to ensure the best possible work,
and the names of the individuals concurring with the decisions
to proceed with the work.
- When cleaning, avoid overcleaning. Aim for achieving 85%
clean. Most damage occurs when attempting to clean the last
1. Do not use acids or flame tools to strip paint from
stone, as it will damage the surface.
2. Do not use steel or metal spatulas or tools to scrape
stone because of the likelihood of scratching, chipping,
gouging, or otherwise marring the surface.
- Product Data (when applicable):
1. Submit to RHPO manufacturer's technical data for each
product indicated including chemical analysis,
recommendations for their application and use, and any
other available technical data. Include test reports and
certifications substantiating that products comply with
2. MANUFACTURERS OFFERING OTHER THAN BRAND NAME ITEMS
IDENTIFIED IN THE PROCEDURE SHOULD FURNISH ADEQUATE
INFORMATION TO ENSURE THAT A DETERMINATION CAN BE MADE AS
TO EQUALITY OF THE PRODUCT(S) OFFERED (SEE THE CLAUSE
ENTITLED BRAND NAME OR EQUAL SET FORTH IN SECTION
552.210-74 OF THE GSA ACQUISITION REGULATION).
1. Clearly labelled samples of all materials to be used on
the job should be submitted to the RHPO for approval
before work starts.
2. The approved samples will become the standard materials
used on the job. Substitutions will not be permitted
without written approval from the RHPO.
- Quality Control Submittals:
1. Submit written program for each phase of process
including protection of surrounding materials during
operations. Describe in detail materials, methods and
equipment to be used for each phase of work.
2. If alternative methods and materials to those indicated
are proposed for any phase of work, provide written
description to RHPO, including evidence of successful use
on other, comparable projects, and program of testing to
demonstrate effectiveness for use on this project.
3. The contractor should supply proof of work on this type
of project by submitting a list of pertinent projects the
subcontractor has worked on which includes the scope of
work, the budget for the scope of work, and a way to
contact the owner and architect of each project.
- Design Data/Test Reports/Certificates:
1. Routine testing of proposed materials, and of final work
for compliance with the procedure will be carried out by
the RHPO or his\her appointed representative.
a. Cleaning methods should be tested prior to
selecting the one for use. The simplest and least
aggressive method(s) should be selected.
b. The level of cleanliness desired also should be
determined. A like-new appearance is both
inappropriate and requires an overly harsh cleaning
2. If test results show that performance criteria are not
met, removal and repair of rejected work should be
1. Restoration Specialist: Work must be performed by a firm
having not less than five years successful experience in
comparable projects and employing personnel skilled in
the processes and operations indicated. Project
supervisor must have five years experience in work
similar to this procedure. Additional personnel must
also have experience.
2. A supervisory craftsperson will be present when a
craftsperson begins to perform the work in order to
explain any procedures. Any modification of the written
procedures will be made at that time.
3. The supervisory craftsperson shall also be present during
the work to instruct personnel as required.
- Source of Materials: Obtain materials from a single source
for each type material required.
- Regulatory Requirements:
1. Engage an approved independent testing laboratory to
examine materials prior to use and continuously inspect
the work for compliance with this procedure and any
2. The required research report and manufacturer's data
shall be at the site and used for reference.
3. Conform with all applicable safety guidelines.
4. For Cleaning: Comply with municipal and Federal
regulations governing cleaning, chemical waste disposal,
scaffolding and protection of adjacent surfaces.
- Mock-ups: After acceptance of the list of materials and
proposed method of cleaning, repair or refinishing, a
representative sample area shall be cleaned, repaired or
refinished as specified.
1. Employ the method proposed and accepted for use. Obtain
acceptance of the sample area from the RHPO before
proceeding with remainder of the procedure.
2. Maintain the sample area in its accepted condition until
final acceptance of the completed work. Manufacturer's
Representative should be present during mock-up and its
inspection for approval. Sample work should be preformed
in an area approved by the RHPO.
3. A SMALLER TEST FOR EACH PRODUCT SHOULD BE DONE ON EACH
MATERIAL IN AN INCONSPICUOUS AREA TO CHECK FOR ADVERSE
EFFECTS AND DAMAGE TO THE MATERIAL.
- For Cleaning:
1. Before cleaning, all drains to be used should be tested
to ensure they are functioning properly. Any clogged
drains should be reported immediately.
2. During cleaning, prevent cleaning residue from entering
the drains or drain lines. Drains or drain lines that
become blocked with cleaner residue must be cleaned out
DELIVERY, STORAGE AND HANDLING
- Packing and Shipping: Deliver materials to site in
manufacturer's original and unopened containers and packaging,
bearing labels as to type and names of products and
- Acceptance at Site: Handle materials in accordance with
project safety guidelines and manufacturer's recommendations.
- Storage and Protection:
1. Every effort must be made to use and reuse materials that
are original to the structure. When removed from their
rightful place, these materials must be stored under
cover inside the building where they cannot be damaged.
2. When pieces are to be removed, mark pieces
inconspicuously in a consistent manner as to their
original location. Document original position and label
3. If salvage material is to be used, treat it as new or
original material with regard to its storage.
4. Protect all materials during storage and construction
from wetting by rain, snow or ground water, and from
intermixture with earth or other types of materials.
5. Protect materials from deterioration by moisture and
a. Store cementitious materials off ground, under
cover and in a dry location. Protect liquid
components from freezing.
b. Comply with manufacturer's recommendations for
minimum and maximum temperature requirements for
c. Store all chemicals in metal cabinets. No cans
shall be left open or out of the cabinet overnight.
- Environmental Requirements:
1. Proceed with the work only when forecasted weather
conditions are favorable.
2. Wet weather: Do not attempt repairing of feature in
raining or foggy weather. Do not apply primer, paint,
putty, or epoxy when the relative humidity is above 80%.
Do not remove exterior elements of structures when rain
is in the forecast or in progress.
3. Work in the shade when the temperature is above 75 degrees F.
Work around the structure in the shade away from the sun.
4. Do not perform exterior wet work when the air temperature
is below 40 degrees F.
5. NEVER begin cleaning, patching, etc. when there is any
likelihood of frost or freezing.
6. If cleaning is done in very hot, sunny weather, the
feature/area should be shielded from excessive heat by
hanging protective netting or tarpaulins around it.
7. No cleaning shall be executed when either the air or the
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.
8. Perform cleaning and rinsing of the exterior masonry only
during daylight hours.
9. Hot weather maximum application temperatures:
a. paint - 85 degrees F
b. putty - 80 degrees F
c. epoxy - 80 degrees F
10. Cold weather minimum application temperatures:
a. paint - 50 degrees F
b. putty - 50 degrees F
c. epoxy - 55 degrees F
- Existing Conditions: Check manufacturer's literature for
precautions and effects of products and procedures on adjacent
building materials, components, and especially vegetation.
SEQUENCING AND SCHEDULING
- Preventive Maintenance and Repair activities should be
scheduled during appropriate environmental conditions to avoid
weather related failures.
- Submit a work schedule indicating the proposed timing and
extent of the work.
- Co-ordinate the work schedule with that of other trades on
- When cyclical maintenance work requires the use of high
ladders and other access equipment, perform as many work items
- Do not change sources or brands of materials during the course
of the work.
- All necessary precautions shall be taken to protect all parts
of the building not being cleaned or repaired from effects of
the work, including excessive amounts of water that should not
be allowed to pond in any area. Also provide protection as
required to prevent damage to adjacent property.
- Provide protection against the spread of dust, debris and
water at or beyond the work area by suitable enclosures of
sheeting and tarpaulins.
- Provide masking or covering on adjacent surfaces and permanent
equipment. Secure coverings without the use of adhesive type
tape or nails. Impervious sheeting which produces
condensation should not be used.
- Prevent the entry of dust, debris and water into the building
by sealing all openings.
- Provide protection from water damage to building, structure,
or building contents as required.
- Protect all landscape work adjacent to or within maintenance
1. Provide plank barriers to protect tree trunks. Bind
2. Covering should allow plants to breathe and should be
removed at the end of each work day. Do not cover plant
material with a waterproof membrane for more than 8 hours
at one time.
3. Set scaffolding and ladder legs away from plants.
Pruning requests should be directed to the RHPO.
- 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 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 designated representative. Do not begin work of this
Section until the drains are in working order.
- 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 any other solids
because of work performed under this Contract.
- Scaffolding, ladders and working platforms, required for the
execution of this work should be provided. These items should
not be attached to the building.
END OF SECTION