Historic Preservation - Technical Procedures
- Supplemental Guidelines For Specifying Repairs To Ornamental Copper Metal Work
- Procedure code:
- Us Ct Of Appeals/New Orleans, La - Fromherz Engineers, Inc.
- Ornamental Copper
- Last Modified:
- Supplemental Guidelines For Specifying Repairs To Ornamental Copper Metal Work
- Last Modified:
SUPPLEMENTAL GUIDELINES FOR SP= ECIFYING REPAIRS TO ORNAMENTAL
Margot Gayle, David W. Look, John Waite. Metals in America's Historic Buildings. Washington, DC: National Park Service, 1992.
L. William Zahner. Architectural Metals. New York: John Wiley & Sons, Inc., 1995.
A. This procedure provides supplemental guidelines to be
used when specifying any type of repairs to copper metal
work. Guidelines for shop drawings, qualifications for
subcontractors, materials and finishes, shop assembly,
and general guidelines for installation are included.
B. These guidelines may be used in conjunction with the
1. 07602-01-R "Repairing Pinch Cracks in Long Copper
2. 07610-02-R "Installing a Transverse Expansion Joint
in a Standing Seam Copper Sheetmetal Roof".
3. 07610-03-R "Repairing a Bowing Sheetmetal Roof".
4. 07610-04-R "Repairing a Wind-damaged Copper
Sheetmetal Roof Ridge and Installing a New Ridge
5. 07610-05-R "Repairing Holes in a Sheetmetal Roof".
6. 07610-06-R "Repairing Corroded Copper Sheetmetal
7. 07610-12-R "Repair of Star Cracks in Copper Roofs".
C. Procedures for the repair of copper metalwork shall
include all work, materials and equipment required to:
1. Remove required ornamental metalwork and securely
re-install ornamental metalwork to its original
place and position.
2. Repair ornamental metalwork with RHPO approval.
3. Provide for historical photos of work done.
D. 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
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: Submit product data for each product used
in ornamental metalwork, including finishing materials
and methods to RHPO for prior approval.
B. Shop Drawings: Submit to RHPO three copies of shop
drawings showing fabrication and installation of
ornamental metalwork including plans, elevations and
details of components and attachments to other units of
work. Indicate materials, profiles of each ornamental
metalwork member and fitting, joinery, finishes,
fasteners, anchorages and accessory items.
1. Include setting drawings, templates, and directions
for installation of anchor bolts and other
anchorages to be installed as unit of work of other
2. Where installed products are indicated to comply
with certain design loadings, include structural
computations, material properties, and other
information needed for structural analysis which
has been prepared by, or under the supervision of,
a qualified professional engineer.
C. Samples: Submit to RHPO samples for initial selection
purposes in form of conservator's color samples of patina
consisting of actual units or sections of units showing
full range of patina colors and other finish
characteristics for each item indicated below.
D. Submit to RHPO samples for verification purposes of each
type of metal finish required, prepared on metal of same
thickness and alloy indicated for final unit of work.
Where finishes involve normal color and texture
variations, include sample sets composed of two or more
units showing full range of variations expected.
E. Submit to RHPO conservator/installer certificates signed
by Contractor certifying that conservator/installers
comply with requirements specified under "Quality
F. Submit to RHPO qualification data for firms and persons
specified in "Quality Assurance" article to demonstrate
their capabilities and experience; Include list of
completed projects with project name, addresses, names of
architects and owners, plus other information specified.
1. Contractor shall ensure that the conservator takes
one 8" x 10" black and white photo "before" shot of
each metalwork assembly as required. "After"
photos in the same format shall be taken from the
same locations and of the same items after all
items are re-installed and conservation is
complete. Submit two copies and the negatives of
each shot. All copies shall be archivally sound.
2. Submit one set of color slides showing de-
installation, progress of repair and restoration,
and re-installation, to RHPO at close of contract.
Views shall be chosen by conservator. The slides
shall present a picture story of the entire
3. Label all photos and slides in such a manner that
photo location and process shown corresponds to
1.03 QUALITY ASSURANCE
1. Conservator/Fabricator Qualifications: Firm
experienced in successfully producing ornamental
repousse metalwork similar to that indicated for
this project, with sufficient production capacity
to produce required units without causing delay in
2. Conservator Qualifications: Contractor shall
provide a professional conservator who must be
approved by RHPO and GSA Contracting Officer prior
to award of contract. The conservator shall have
the following qualifications:
a. Experience of at least five years in providing
services of the kind indicated which has
resulted in the successful installation of
assemblies similar in material, design, and
extent to that indicated for this project.
b. Extensive repousse metalwork experience is an
absolute requirement for this project. Common
sheet metal work does not qualify as
experience in this instance.
c. The same conservator used for the repair of
metalwork should be used to remove and re-install the metalwork.
d. For conservation referral services, write or
call the following:
American Institute for Conservation of
Historic and Artistic Works
This agency is listed for Contractor
convenience ONLY. Any conservator chosen by
the contractor must submit their
qualifications for government approval.
3. Use Only experienced riggers with at least three
years successful experience to move all pieces from
their existing positions to the truck, to the
studio, and back again.
B. Pre-Installation Conference: Conduct conference at
project site to review scope of project and ensure the
understanding of the Scope of Work by all parties.
Attendees shall include the RHPO, GSA Contracting
Officer, contractor and conservator. The installer and
fabricator may be in attendance as necessary.
1.04 DELIVERY, STORAGE, AND HANDLING
A. Packing and Shipping: Perform conservation work in such
a manner that the safety of all ornamental metal
components is assured during all loading and unloading
operations, removal from existing locations,
transportation to place of repair, repair itself,
transportation back to building, reinstallation, and
B. Storage and Protection:
1. All conservation work on removed ornamental metal
shall be performed in the conservator's studio.
The studio shall comply with OSHA regulations
regarding environmental precautions for the work
necessary to repair and refurbish required pieces.
2. Store all materials in clean, dry location, away
from uncured concrete and masonry. Cover with
waterproof paper, tarpaulin or polyethylene
sheeting in a manner that permits air circulation
3. Handle ornamental metalwork on site to a minimum.
Exercise care to avoid damaging metal finishes.
1.05 PROJECT/SITE CONDITIONS
A. Field Measurements: Take field measurements prior to
preparation of shop drawings and fabrication, where
possible, to ensure proper fitting of ornamental
metalwork. Do not delay job progress. Allow for
adjustments and fitting where taking of field
measurements before fabrication might delay Work.
1. General: Provide ornamental copper metalwork
composed of the forms and types which comply with
project requirements and match as closely as
possible existing copper metalwork.
2. New and repaired work is to be free from surface
blemishes where exposed to view in the finished
unit. Exposed-to-view surfaces exhibiting pitting,
seam marks, roller marks, "oil canning," stains,
discolorations or other imperfections on finished
units are not acceptable.
B. Miscellaneous Materials:
1. Welding Electrodes and Filler Metal: Type and
alloy of filler metal and electrodes as recommended
by producer of metal to be welded, complying with
applicable the American Welder's Society (AWS)
specifications, and as required for color match,
strength and compatibility in the fabricated items.
Conservator shall supply the Government with
manufacturer's certification that material
recommended is compatible with metal on which use
2. Fasteners: Of same basic metal and alloy as
fastened metal, unless otherwise indicated. Do not
use metals which are corrosive or incompatible with
a. Provide concealed fasteners similar to
existing fasteners for interconnection of
ornamental metalwork components and for their
attachment to other work, except where
b. Provide exposed fasteners for interconnection
of ornamental metalwork components and for
their attachment to other work only where
exposed fasteners are unavoidable.
3. Anchors and Inserts: Provide anchors of type, size
and material required for type of loading and
installation condition shown, as recommended by
manufacturer, unless otherwise indicated. Use
nonferrous metal or hot-dipped galvanized anchors
and inserts for exterior locations and elsewhere as
required for corrosion resistance. Use toothed
steel or expansion bolt devices for
1. General: Prepare, pretreat, and apply patina and
protective acrylic lacquer and/or wax coating to
all raw copper that results from repair of
metalwork copper. The patination color shall match
existing as closely as possible. Patina color
shall be as approved by RHPO. Comply with patina
and coating manufacturer's instructions.
2. Copper: Finishes shall conform with the system
established by the Copper Development Association
for designating copper alloy finish systems.
Protective finishes shall be as directed by project
A. Shop Assembly:
1. Form ornamental copper metalwork to required shapes
and sizes, with true curves, lines and angles using
repousse technique similar to original repousse
technique. Provide components in sizes and
profiles indicated, but not less than required to
comply with requirements indicated by Secretary of
the Interior's "Standards for Rehabilitation and
Guidelines for Rehabilitating Historic Buildings."
2. Allow for thermal movement resulting from the
following maximum change (range) in ambient
temperature, in the design, fabrication, and
installation of installed metal assemblies to
prevent buckling, opening up of joints and
overstressing of welds and fasteners. Base design
calculations on actual surface temperatures of
metals due to both solar heat gain and night time
sky heat loss. Range of temperature change shall
be from 10 degrees F to 180 degrees F.
3. Provide necessary lugs and brackets for assembly of
units. Use concealed fasteners wherever possible.
4. Comply with AWS for recommended practices in shop
welding. Provide welds, if needed, behind finished
surfaces without distortion or discoloration of
exposed side. Clean exposed welded joints of all
welding flux, and dress on all exposed and contact
5. Mill joints to a tight, hairline fit. Cope or
miter corner joints. Form joints exposed to
weather to exclude water penetration.
6. Provide bronze bracket castings that are sound and
free of warp or defects which would impair strength
7. Finish exposed surfaces to smooth, sharp,
well-defined lines and arises.
8. Pre-assemble items in shop to greatest extent
possible to minimize splicing and assembly.
Disassemble units only as necessary for shipping
and handling limitations. Clearly mark units for
re-assembly and coordinated installation.
B. Performance Requirements: Structural Performance of
Repaired Statuary Assemblies: Design, engineer, remove,
fabricate, repair and install ornamental metalwork to
comply with requirements of this specification for
A. Surface Preparation:
1. Coordinate and furnish anchorages and setting
drawings, diagrams, templates, instructions and
directions for installation of items having
integral anchors which are to be embedded in
concrete or masonry construction. Coordinate
delivery of such items to the project site.
2. Preparation for Patina: Clean metal surfaces of
dirt, grease, black atmospheric pollution, and
corrosion products, including any material that
would prohibit adherence of patina.
3.02 ERECTION, INSTALLATION, APPLICATION
A. De-Installation: De-installation of all ornamental
metalwork is the responsibility of the conservator and
shall be performed according to the conservator's
instructions and under the conservator's supervision.
B. Repair and Restoration:
1. All repair and restoration work of this contract
shall be performed in accordance with the Secretary
of the Interior's "Standards for Rehabilitation and
Guidelines for Rehabilitating Historic Buildings"
(see 01091-04-S through 01091-19-S for guidance).
2. Repair to sound condition all ornamental metalwork
and seams using RHPO approved fabrication and
C. Installation, General:
1. Provide anchorage devices and fasteners where
necessary for securing ornamental metalwork and
other items to in-place construction including,
threaded fasteners for concrete and masonry
inserts, toggle bolts, through-bolts, lag bolts,
wood screws and other connectors as required.
2. Contractor shall provide for conservator to perform
cutting, drilling and fitting required for
installation of ornamental metalwork, and to
reinstall items accurately in same location and
position, alignment and elevation, from which
removed. These items shall be plumb, level and
true, measured from established lines and levels.
Provide temporary bracing or anchors for items
which are to be built into concrete, masonry or
3. Fit exposed connections accurately together to form
tight, hairline joints or, where indicated, with
uniform reveals and spaces for sealants and joint
fillers. Where cutting, welding and grinding are
required for proper shop fitting and jointing of
ornamental metal items, restore finishes to
eliminate any evidence of such corrective work.
4. Do not cut or abrade finishes which cannot be
completely restored in the field. Return items
with such finishes to the shop for required
alterations, followed by complete refinishing or
provide new units as required.
5. Install concealed gaskets, joint fillers, and
flashings as the work progresses, so as to make
6. Restore protective coverings which have been
damaged during shipment or installation of the
work. Remove protective coverings only when there
is no possibility of damage from other work yet to
be performed at the same location.
7. Retain protective coverings intact and remove
simultaneously from similarly finished items to
preclude nonuniform oxidation and discoloration.
8. Field Welding: Comply with applicable AWS
specification for procedures of manual shielded
metal-arc welding, for appearance and quality of
welds made, and for methods used in correcting
9. Perform all other functions required to effect
complete conservation and repair of all ornamental
A. Touch-Up Patination: Conservator shall perform touch-up
patination and coating with acrylic sealer and/or wax at
all areas of ornamental metalwork that are not patinated
to the satisfaction of the RHPO.
A. Protect finishes of ornamental metalwork from damage
during construction period by use of temporary protective
coverings approved by ornamental metalwork conservator.
Remove protective covering at time of Substantial
B. Restore finishes damaged during installation and construction period so that no evidence remains of
correction work. Return items which cannot be refinished
in the field to the shop. Make required alterations and
refinish entire unit, or provide new units as required.
END OF SECTION