Specification:Stone masonry repair by mechanical pinning or structural reinforcement

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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
 Stone masonry repair through pinning Stone masonry repair through disassembly and rebuilding 

RELATED SECTIONS
<ol type="A"> Section 04100 – Historic Mortar</li> Section 04400 – Stone</li> Section 04500 – Masonry Restoration</li> Section 04510 – Masonry Cleaning</li> Section 07631 – Gutters, Drains, and Flashing</li> Section 07900 – Joint Sealers</li> </ol>

SUBMITTALS
The Contractor shall submit to the Architect: <ol type="A"> A detailed schedule of the areas for repair, including an assessment of the problem areas, historic mortar analysis, and detailed procedure for masonry repair for approval.</li> Product data for all manufactured masonry repair materials. Manufacturer’s product data shall include technical data, certification of compliance with referenced standards, and instructions for handling, storage, and installation of the material. Also submit Material Safety Data Sheets for each material.</li> Samples of the following masonry repair and replacement materials for approval of color and texture match. No masonry restoration work shall proceed until all samples are approved. Once a matching mortar color is achieved, placement of on-site mock-ups may begin. Cured pointing mortar for stone masonry. See Section 04100 – Historic Mortar.</li> </ol>

QUALITY ASSURANCE
<ol type="A"> Work Experience: The Contractor performing the work in this section shall have a minimum of ten (10) years experience in historic masonry restoration and shall have successfully completed at least three projects of similar scope within the previous five years. He/she shall demonstrate a working knowledge of The Secretary of the Interior’s Standards for the Treatment of Historic Properties with Guidelines for Preserving, Rehabilitating, Restoring & Reconstructing Historic Buildings.</li> The Contractor shall not change sources or manufacturers of mortar or stone materials during the course of the work unless approved by the Architect.</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>

MOCK-UPS
<ol type="A"> After completion of the masonry cleaning mock-ups specified in Section-04510, the Contractor, at locations designated by the Architect, shall prepare test panels of the following work:  Stone Masonry Restoration: All personnel proposed for work on the project shall prepare 3x3-foot samples demonstrating stone restoration techniques, including mortar removal, repointing, and stone replacement.</li> <li>Mock-ups will be reviewed by the Architect after the mortar removal and again after completion of repointing.</li> <li>Mock-ups shall display the full range of materials and workmanship required for completion of the project for approval by the Architect.</li> <li>Color matching: Contractor shall match existing mortar color(s). The Contractor shall place the initial sample panel using the mix from the approved sample. The sample panel must be cured in the same manner as is expected for the work based on anticipated temperatures.</li> <li>The Contractor shall prepare up to three additional mock-ups of each mortar, joint type, and mortar color with no further compensation if required to achieve approval. Approved test panel(s) shall become part of the work and shall serve as the quality standard for all subsequent work.</li> </ol> </li> <li>Stone Pinning: <li>The Contract shall prepare one mock-up for pinning of broken masonry units. Unit to be repaired shall be designated by the Architect.</li> <li>The Contractor shall prepare up to three additional mock-ups of stone pinning repair with no further compensation if required to achieve approval. Approved mock-up shall become part of the work and shall serve as the quality standard for all subsequent work.</li> </ol> </li> </ol> </li> </ol>

DELIVERY, STORAGE, AND HANDLING
<ol type="A"> <li>Materials shall be delivered to the site in original packaging, unopened, with manufacturer’s name and product identification thereon. Cementitious materials shall be protected from contamination by foreign matter and deterioration by moisture or temperature. Contaminated or deteriorated material shall not be used. Products stored longer than six months shall not be used.</li> <li>Masonry 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 Architect.</li> <li>Liquids shall be stored at temperatures between 40 and 85 degrees. Liquids shall not be allowed to freeze.</li> <li>Masonry Units will be protected from the ground and weather, and kept free from exposure to contaminants such as mud, dust, or materials that could cause staining.</li>

PROJECT / SITE CONDITIONS
<li>Normal conditions for the work of this Section shall be defined as when the air and surface temperatures are 40 degrees F and rising or less than 90 degrees F and falling. When temperatures are predicted to rise above or fall below this temperature range, the Contractor may proceed using approved hot and cold weather procedures as defined by the Masonry Institute of America. Work shall not commence when rain, snow, or below-freezing temperatures are expected within the next 24 hours. All surfaces shall be free of standing water, frost, and ice.</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 the Section. The Contractor shall: <ol> <li>Minimize levels of dust during mortar removal and masonry repointing 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 during masonry restoration work. Install temporary drainage leaders if required. Reinstall immediately upon completion of work in the immediate area. Protect open boots at grade from accumulation of masonry debris.</li> <li>Protect existing gutters and gutter outlets from damage and accumulation of mortar debris during restoration of roof elements.</li> <li>Protect window sashes and frames with plywood or other sturdy barrier during repointing and repair of masonry around window openings.</li> <li>Protect the existing roof surfaces from damage during the course of the masonry restoration work. Repair all damage to wood and metal roofing, gutters, flashing, etc., to the satisfaction of, and at no additional cost to, the Owner.</li> <li>Remove and store light fixtures, signage, security devices and miscellaneous appurtenances from masonry surfaces to be repointed. Provide temporary protection for exposed fixture boxes.</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>Stone, brick, mortar, waste material, packaging and other debris associated with the masonry work shall be disposed of in accordance with local, state, and federal environmental regulations. Remove debris from masonry restoration work from the site on a daily basis and at the completion of the work.</li> <li>The Contractor shall coordinate masonry repairs with the other trades involved in exterior and interior restoration work, including but not limited to masonry cleaning, sealing, and painting.</li> </ol> =PRODUCTS=

MATERIALS
<ol type="A"> <li>Mortar Materials <ol> <li>Lime: ASTM C-207, Type S</li> <li>Portland Cement: ASTM C-150, Type I, non-staining and without air entrainment. Gray and white portland cement may be combined as required to match existing mortar.</li> <li>Sand: ASTM-C-144, free of clay, silt, soluble salts, and organic matter, and shall match the color and texture of the original mortar sand.</li> <li>Water: Potable and free of deleterious amounts of oil, soluble salts, alkali, acids, organic impurities, or other substances that may impair the strength or bond of the finished mortar.</li> <li>Mortar colorant, if required to match the color of the existing mortar, shall be a standard, alkali-resistant, non-fading product manufactured by an approved manufacturer. Submit product and manufacturer information to the Architect for approval.</li> </ol> </li> </ol>

MIXES
<ol type="A"> <li>Mortar mixes shall be the appropriate the strength and hardness for the masonry units and existing mortar. The mix shall match the composition, color, and texture existing mortars. Refer to Section 04100 – Historic Mortar.</li> </ol>

ACCESSORY MATERIALS
<ol type="A"> <li>Stainless-steel pins for stone repair shall be Type 316 stainless-steel all-thread rods, ¼ inch diameter. Length shall be as required by the size of the stone to be repaired.</li> <li>Epoxy adhesive for embedding 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>Replacement cramps and other embedments shall be Type 316 stainless steel.</li> <li>Joint reinforcement for rebuilding masonry shall be Type 316 stainless-steel all-thread rods, ¼ inch diameter. Verify number and spacing of rods with the Architect.</li> </ol> =EXECUTION=

GENERAL
<ol type="A"> <li>Masonry cleaning shall be completed prior to beginning masonry restoration or repointing.</li> </ol>

PINNED REPAIRS FOR BROKEN STONES
<ol type="A"> <li>Remove loose flakes of stone, dirt, and debris from both the fragments to be reattached. Dry fit to verify placement, using register marks to align and mask edges to protect surface from excess adhesive.</li> <li>Drill holes for new stainless steel rods parallel to the long dimension of the stone and centered in the thickness of the stone. Use register marks to ensure that holes in mating surfaces align perfectly and shall remove debris and dust after drilling with pressurized water or air (40 to 60 psi).</li> <li>Mix adhesive according to manufacturer’s instructions. Fill anchor holes for reinforcing rods full with epoxy to ensure full adhesion and apply epoxy adhesive to both mating surfaces in a uniform layer, working product well into surface.</li> <li>Install rods and work stone fragment back into place, ensuring full contact with the adhesive. Immediately remove any excess adhesive from joint edges. Immobilize fragment until epoxy adhesive has cured.</li> </ol>

RE-ANCHORING INDIVIDUAL BUILDING STONES
<ol type="A"> <li>The Contractor shall complete any required pinning, patching or other repair to individual stones prior to reinstallation.</li> <li>Remove damaged material from the area to be repaired and clean masonry backup and adjoining stones of mortar. Vacuum or rinse area free of dust and loose debris.</li> <li>Install stainless steel pins as required to secure the unit to the existing substrate. Allow for 1 pin per 20 square inches of surface area to be patched. Pins shall penetrate a minimum of one third the thickness of the stone to be installed but under no circumstance be allowed to penetrate beyond half the depth of the stone.</li> <li>The diameter of the holes for stainless steel anchor pins shall be drilled ? inch greater than the diameter of the pins. The Contractor shall anchor pins in specified setting adhesive. The use of hammer drills is NOT permitted.</li> <li>Use lead, slate, or plastic shims of the thickness required to maintain the required joint width. The use of wood shims is NOT permitted. Where the repair extends to the edge of the masonry unit, maintain the existing joint thickness. Joints occurring in the field of the masonry unit shall be hairline joints and shall not be pointed out. The Contractor shall dry fit the stone to assess the snugness of the fit and adjust as required.</li> <li>Set stone straight, plumb, and true to line and level in full mortar bed. Ensure head joint and vertical joints, if required, are packed full with mortar. Tool joints flush to existing stone surface profile.</li> </ol>

MASONRY DISASSEMBLY AND RECONSTRUCITON
<ol type="A"> <li>The Contractor shall carefully dismantle selected areas of masonry. 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 attempted removal of the stones. Avoid excessive prying against the arrises of the selected masonry units to avoid spalling and chipping. Label each unit on a concealed side with non-removable marking. Numbers shall be keyed to a drawing to ensure reinstallation in the original location.</li> <li>Clean old mortar and sealants from masonry units to be reassembled.</li> <li>Reset masonry units to proper position, straight, plumb, and true to line and level, with full mortar bed. The Contractor shall embed reinforcing rods in mortar bed, ensuring full coverage, and ensure that vertical head joints are completely filled with mortar. Rake and point as described above except at coping head joints, which shall be pointed with flexible sealant.</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>Revisit the site with the Architect and compare the finish and color of the repair to determine if the desired affect has been achieved after the stone masonry repairs have been executed and new mortar has cured at least 30 days.</li> <li>Document the work and finished product with photographs.</li> <li>Provide a written summary of the project and results upon final inspection and approval. The summary shall outline steps taken or new findings not addressed in the initial documentation.</li> </ol>