Specification:Repair and replacement of terra-cotta anchoring systems

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=GENERAL=

DESCRIPTION
 This specification has been developed for use on historic properties (defined as any district, site, building, structure, or object that is listed in or eligible for listing in the National Register of Historic Places) and provides an overview of accepted practices. Site-specific specifications, when appropriate will be provided by the Architect. All work described herein and related work must conform to the Secretary of the Interior’s Standards for the Treatment of Historic Properties. The Contractor shall provide all labor, materials, equipment, and operations required to complete the rehabilitation work indicated herein. All work described herein and related work must have the approval of a Cultural Resources Manager, Conservator, Historic Architect, or other professional who meets the standards outlined in the Secretary of the Interior’s Standards – Professional Qualifications Standards pursuant to 36 CFR 61. Such person is referred to in this document as the Architect. 

SECTION INCLUDES
 Assessment of terra-cotta interior armature and anchoring system Repair and/or replacement of anchoring system 

RELATED SECTIONS
<ol type="A"> Section 04100 – Historic Mortar</li> Section 04214.01 – Historic Terra-Cotta and Ceramic Properties and In-Kind Replacement</li> Section 04214.02 – Terra-Cotta Patching and Glaze Repair</li> Section 04510.01 – Cleaning and Testing of Atmospheric Soiling, Graffiti, Stains, and Bio- Growth</li> </ol>

SUBMITTALS
<ol type="A"> The Contractor shall submit a detailed schedule to Architect for approval of the work to be conducted, including an assessment of the problem areas and detailed procedure for terra- cotta replacement and repair.</li> Product Literature: The Contractor shall:  Submit manufacturer’s product literature to the Architect for adhesives and anchoring materials specified. Product literature shall indicate conformance to referenced standards and shall also include specification data, Material Safety Data Sheets, and instructions for storage, handling and use.</li> Submit product information on mortars and other products to be used for reassembly of terra-cotta masonry. See Sections 04214.01 and 04214.02.</li> </ol> </li> Shop Drawings: Where new metal fabrications are required for repair or replacement of terra-cotta anchorage system, provide shop drawings of all such pieces. At a minimum, drawings shall indicate dimensions, materials, connection details, piece numbers, and quantities.</li> Material Samples: The Contractor shall submit two samples of each type of dowel, anchor, bolt, and fastener to be used in the work under this section. Samples will be approved by the Architect.</li> </ol>

QUALITY ASSURANCE
<ol type="A"> Work Experience. The Contractor to perform the work in this section shall have a minimum of ten (10) years of recent experience in terra-cotta restoration and installation including at least three (3) projects of comparable scope and scale completed within the previous five years.  The qualifying firm must designate a given individual with commensurate experience to act as the “Terra-Cotta Foreman” for purposes of this contract. Said Terra-Cotta Foreman designation must be approved by the Architect. He/she shall demonstrate a working knowledge of the Secretary of the Interior’s Standards for Guidelines for Treatment of Historic Properties with Guidelines for Preserving, Rehabilitating, Restoring, and Reconstructing Historic Buildings. The “Terra-Cotta Foreman” shall be present at the site whenever terra-cotta work is underway and shall remain on the project for the full duration of the terra-cotta repairs.</li> </ol> </li> Warranty: The Contractor shall provide a warranty in writing against defects in material and installation for a period of five (5) years.</li> </ol>

DELIVERY, STORAGE, AND HANDLING
<ol type="A"> Proprietary materials shall be delivered to the site in original packaging, unopened, with manufacturer’s name and product identification thereon. The Contractor shall protect materials from contamination by foreign matter and deterioration by moisture or temperature. Contaminated or deteriorated material shall not be used and products stored longer than six months shall not be used.</li> <li>Cementitious materials shall be stored off the ground in a clean, dry location. The Contractor shall prevent contamination of materials likely to cause staining and other defects, and shall remove materials that are damaged or otherwise unsuitable for use from the job site.</li> <li>Materials shall be stored in such a manner as not to interfere with the operation and daily maintenance of the facility. Proposed storage locations shall be approved by the Owner prior to the delivery of materials.</li> <li>Deliver new metal fabrications to the site in the order required for installation. Materials shall be stored in a dry, secure area off the ground on pallets or dunnage.</li> </ol>

PROJECT / SITE CONDITIONS
<ol type="A"> <li>The normal temperature range for the work of this Section shall be when the air and surface temperatures are 40 degrees F and rising or less than 90 degrees F and falling. When temperatures are expected to fall outside this range, the Contractor shall employ hot and cold weather procedures as published by the Masonry Institute of America.</li> <li>The Contractor is responsible for protecting existing adjacent materials and surfaces during the execution of the work and shall provide all necessary protection and follow all necessary work procedures to avoid damage to existing material assemblies not a part of the work in this Section. The Contractor shall: <ol> <li>Prevent damage to adjacent masonry or other surfaces to be left exposed. Immediately remove all debris, cavity fill and waste material to be discarded. Protect sills, ledges, and projections from falling material, scaffold, and mortar droppings.</li> <li>Minimize levels of dust during mortar removal and masonry disassembly operations.</li> <li>Protect open copings, reglets, and other vulnerable areas from water penetration to prevent leakage during the course of the work. Open areas shall not be left exposed overnight or when inclement weather is predicted.</li> <li>Temporarily remove and store metal downspouts and downspout boot covers to remain during terra-cotta / cast stonework. Install temporary drainage leaders if required. Reinstall immediately upon completion of work in the immediate area.</li> <li>Protect existing scuppers and downspout outlets from damage and accumulation of mortar debris during restoration of terra-cotta/cast-stone parapets.</li> <li>Where existing masonry components are to be removed, protect adjacent masonry units and surfaces from chipping and cracking during the removal process. Where components are to be reinstalled, the Contractor shall store salvaged components in a safe location in such a manner as to facilitate reinstallation and will protect them from theft and damage until reassembly.</li> </ol> </li> <li>The Contractor shall provide visible barriers and / or warning tape around the perimeter of the work area for visitor protection. Nearby vehicles and adjacent structures shall be protected from damage during the course of the work.</li> <li>The Contractor shall cover partially completed work when work is not in progress.</li> <li>The Contractor shall coordinate masonry repairs and repointing with the other trades involved in exterior and interior restoration work, including but not limited to roofing, masonry cleaning, sealing, and painting.</li> <li>Where welding or burning is required to install or remove building components, the Contractor shall coordinate with the Owner’s representative to obtain the appropriate permits (if required). The Contractor shall ensure that all DOD safety requirements for welding/burning are in place prior to beginning work.</li> </ol> =PRODUCTS=

ADHESIVE MATERIALS
<ol type="A"> <li>Epoxy adhesive for embedding anchors and pins shall be a high modulus epoxy resin conforming to ASTM C-881, Type I, II, IV and V, Grade 3 epoxy resin adhesives.</li> <li>Resin Manufacturers: Products shall be obtained from an industry recognized manufacturer. The Contractor shall submit manufacturer information to the Architect for approval.</li> </ol>

METAL REINFORCEMENT FOR REPLACEMENT ARMATURES
<ol type="A"> <li>New Armature Members: ASTM A36, hot-dipped galvanized in accordance with ASTM A123. Dimensions to match existing members and approved shop drawings.</li> <li>Stainless-steel wire armature, or threaded rods and bolts. All materials are to be reviewed by the Architect. <ol> <li>Wire shall be 12 gauge or heavier.</li> <li>Threaded rods shall be sized according to the need and loading requirements.</li> <li>Stainless steel shall be AISI Type 316.</li> </ol> </li> </ol>

SUPPLEMENTAL ANCHORS
<ol type="A"> <li>Prefabricated anchor systems combine stainless-steel anchors with cementitious grout to tie together masonry units without extensive disassembly. The Contractor shall provide a list of manufacturers that provide supplemental anchorage systems for veneer masonry for approval by the Architect.</li> </ol>

ACCESSORIES
<ol type="A"> <li>Anchors, Flanges, and Inserts: The Contractor shall provide anchoring devices as required for the installation of ornamental metal items, and shall provide toothed steel or lead shield expansion bolt devices for drilled in place anchors.</li> <li>Bituminous Paint: SSPC-Paint 12 (cold-applied asphalt mastic)</li> <li>Non-shrink Nonmetallic Grout: Premixed, factory-packaged, nonstaining, noncorrosive, nongaseous grout. The Contractor shall provide grout specifically recommended by manufacturer for interior and exterior applications of type specified in this procedure or an Architect approved equivalent.</li> <li>Galvanizing Repair Paint: High-zinc-dust-content paint for regalvanizing welds in galvanized steel, with dry film containing not less than 94% zinc dust by weight, and complying with SSPC-Paint-20.</li> </ol> =EXECUTION=

GENERAL
<ol type="A"> <li>Project-specific specifications are required for all terra-cotta work contained herein. As material and methods of construction vary greatly, each building must be evaluated and work scheduled accordingly. The Contractor shall submit schedules, including methods and materials to be used.</li> <li>Terra-cotta repairs and restoration shall use techniques, methods and materials as similar as possible to those of the original. Work should be sequenced not only to assure the stability of the structure and protection of personnel during the work, but also to address a sensible order of construction to integrate new work with existing work.</li> <li>The Contractor shall complete a survey to determine the extent and severity of the deterioration and whether the deterioration involves visual aspects of the surface terra- cotta, the failure of joints between units, the structural failure of the terra-cotta units, the failure of support systems, or the overall structural stability of the building façade. <ol> <li>Existing general failures that contribute to terra-cotta deterioration shall be noted and should be scheduled for repair prior to completion of the work scheduled or in conjunction with terra-cotta restoration.</li> <li>Complete testing shall be conducted. The extent and type of analysis shall be determined by the Architect. See Sections 04214.01 and 04214.02 for Terra-Cotta Testing, Analysis, Replacement, and Repair.</li> </ol> </li> <li>The Contractor shall protect adjacent materials, installed non-masonry materials, and openings.</li> <li>Manufacturer’s instructions for mixing and installation of materials and equipment use shall be followed.</li> <li>Complete façade cleaning prior to beginning repair or restoration work.</li> <li>The Contractor shall stabilize deteriorated and loose units that are not scheduled to be removed or that cannot be easily removed. Areas where units are missing or have been removed should be protected against moisture penetration until replacement units can be installed.</li> </ol>

TERRA-COTTA ANCHORING AND ARMATURE CONDITION ASSESSMENT
<ol type="A"> <li>Deterioration of anchoring systems can be difficult to assess by visual examination alone. Visible evidence of water penetration may include staining and material spalling.</li> <li>Deterioration and lack of anchoring may result in loosening of the units themselves and be a sign of a serious threat to the structural integrity of the building.</li> <li>Visible shifting and falling terra-cotta units are symptoms of serious degradation of the anchoring system and a major safety issue.</li> <li>Internal damage may be located by striking surface with a wooden mallet. Damaged units produce a flat thud, while undamaged units give off a clear, ringing sound. Check for consistent tonal values to aid in the location of damaged units.</li> <li>Infrared Scanning: Although still considered experimental, the process appears to be effective method to locate deteriorated internal material.</li> <li>Metal Detection: Metal detectors are a noninvasive method for locating the position of metal anchoring. However, this technique can only indicate the location of embedded metal. It does not provide information regarding the size or condition of the members.</li> <li>Archival Materials: Original drawings and records of previous repairs are good source for construction-related information that can greatly aid in the analysis of a building’s condition.</li> <li>Material Removal: Often, the only way to truly document and assess the condition of a terra-cotta anchorage system is to remove a limited amount of material in a representative, and where possible, unobtrusive location. <ol> <li>Removal may be limited to opening observation ports at multiple locations through which a borescope may be inserted to view inside the terra-cotta assembly. This technique is only successful where the terra-cotta units have not been infilled.</li> <li>Where a terra-cotta installation has been grouted or otherwise filled solid, the use of a moisture probe, inserted through bore holes at regular intervals, may help to assess the level of moisture throughout the assembly. High moisture levels may highlight areas of failure in the mortar or flashings and also potential locations for structural deterioration.</li> </ol> </li> <li>Where the nondestructive techniques and the limited material removals described above cannot be used or fail to provide sufficient information, and where safety and structural concerns justify more intrusive investigation, disassembly of a small portion of the terra- cotta system should be pursued.</li> </ol>

INSTALLATION OF SUPPLEMENTAL ANCHORS
<ol type="A"> <li>Installation requirements will vary widely with the type of anchor selected and the configuration of the terra-cotta assembly. The Contractor shall provide project-specific specifications for anchor installation where required, follow anchor manufacturer’s recommended installation procedures, and install all work in accordance with approved shop drawings.</li> <li>Any structural repairs to the terra-cotta masonry anchorage system require some level of disassembly of the masonry to access the affected anchors. Disassembly may range from creating small openings in the back-up masonry for reinforcement of selected anchors to complete disassembly, salvage, and reconstruction with new anchors.</li> <li>Holes: <ol> <li>Drill holes shall be sized according to the wire or rod used. The hole shall be no greater in diameter than ½ to ¼ inch larger than the pin to be embedded, and 10 to 15 bar diameters deep.</li> <li>Drill shall be non-impact type rotary drill with a masonry bit.</li> <li>Depth of hole shall be sufficient to reach sound backing material.</li> <li>Space wire armature reinforcing as indicated on the approved submittals, arranged in a grid or mesh where applicable, or as recommended by the Architect.</li> <li>Clean holes with high-pressure air (not to exceed 1,200 psi).</li> </ol> </li> <li>Protect surfaces around holes from contact with adhesives. Use petroleum jelly, modeling clay, or polyethylene sheets as required.</li> <li>Installation: <ol> <li>Verify rod length is appropriate for the depth.</li> <li>Prepare epoxy resin for setting anchors. <li>Automatic Pressure-Injection Equipment: Resin shall be automatically measured and mixed in the mixing nozzle. Equipment should be in accordance with manufacturer’s recommendations.</li> <li>For Hand Mixing: Mix each component by volume as directed by the manufacturer in a clean pail. Do not use additives. Mix thoroughly for time specified by manufacturer with low-speed drill fitted with appropriate paddle. Blend until uniform in color.</li> </ol> </li> <li>Pack resin into holes.</li> <li>Slowly insert the wire armature or threaded rod into the resin to the full depth of the hole. Countersink head of rods.</li> <li>Do not disturb anchor until the adhesive has cured; follow manufacturer’s instructions.</li> <li>No gaps shall be visible between the rod and the masonry.</li> </ol> </li> <li>Plug counter-sunk holes and build out face of damaged patches flush with surrounding surfaces using patching mortar. See Section 0214.02, Part 3.04, Repair Patching.</li> <li>Immediately remove spills and excess adhesive with absorbent material and flush with water. Uncured material can be removed with solvent as recommended by the manufacturer. Do NOT allow excess material to cure as cured adhesive can only be removed mechanically.</li> <li>Apply one coat of glaze-repair finish to protect the patched or damaged areas. See Section 04214.02.</li> </ol>

TERRA-COTTA REMOVALS: GENERAL PROCEDURE
<ol type="A"> <li>For terra-cotta unit replacement, see Section 04214.01.</li> <li>Carefully dismantle selected areas of masonry where designated on the Drawings. Dismantle adjacent assemblies as required for access to the designated masonry, salvaging components for reuse to the greatest extent possible.</li> <li>Rake or grind mortar from joints to the greatest extent possible before attempting removal of the terra-cotta units. Avoid excessive prying against the arrises of the masonry units to avoid spalling and chipping.</li> <li>Carefully cut existing metal anchors and armature to release terra-cotta units. Provide padded shoring as required to hold assembly in place once anchors are removed. Remove embedded metal parts down to the terra-cotta surface by drilling or grinding. Do not burn metal next to terra-cotta surfaces.</li> <li>Label each unit on the concealed side with non-removable marking keyed to the Drawings to ensure reinstallation of each unit in its original location.</li> <li>Clean old mortar and sealants from terra-cotta units to be reassembled. Stockpile salvaged masonry units in a secure location, away from general construction operations. Store units on pallets or in sturdy crates as required for protection. Stockpile in order of reinstallation to minimize unnecessary handling.</li> </ol>

REINSTALLATION OF TERRA-COTTA – GENERAL PROCEDURE
<ol type="A"> <li>Install new terra-cotta armature in accordance with the approved Shop Drawings and product manufacturer’s recommendations, providing secure support to the finished assembly. Install salvaged terra-cotta masonry units in their original locations in accordance with the annotated drawings prepared during disassembly.</li> <li>Ensure each terra-cotta unit is firmly fastened to the armature with new ties and/or anchors. No original anchor materials are to remain in place.</li> <li>Reset masonry units to proper position, straight and plumb, and true to line and level, with full mortar bed. Ensure that vertical head joints are completely filled with mortar. Rake and point as described in Section 04100.01 Removal of Mortar Joints and Repointing except at coping head joints, which shall be pointed with flexible sealant.</li> <li>Complete additional surface patching and glaze repair only after all structural work has been completed.</li> <li>Reinstall adjacent materials or patch in kind as required to complete the installation.</li> </ol>

FINAL REPORT
The Contractor shall: <ol type="A"> <li>Document the work and finished product with photographs taken before, during, and after completion of the work. Document original anchors and/or armature system prior to removal.</li> <li>Provide a written summary of the project and results upon final inspection and approval. The summary shall include a discussion of steps taken or new findings not specified in the initial documentation.</li> </ol>