Specification:Repair and reattachment of clay tiles

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=GENERAL=

DESCRIPTION
 This specification provides guidance for the repair and reattachment of clay roof tiles. 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. All work described herein and related work must conform to the Secretary of 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. The Architect will provide site-specific specifications, when appropriate . 

SECTION INCLUDES
 Removal and reattachment of loose tiles</li> Replacement of damaged tiles</li> </ol>

RELATED SECTIONS
<ol type="A"> Section 06200.03 – Installation of Fabricated Historic Wood Elements</li> Section 06400.01 – Historic Wood In-Kind Replacement</li> Section 07321.02 – In-Kind Replacement of Clay Tile Roofing</li> Section 07631 – Flashing, Gutters and Drains Properties and In-Kind Replacement</li> </ol>

SUBMITTALS
<ol type="A"> Schedule of Repair: The Contractor shall submit a detailed schedule for repair of clay roof tiles including annotated drawings and/or photographs of areas to be repaired. A complete external and internal inspection is required prior to submittal. The inspection will also aid in determining a future maintenance plan. Prepare a narrative description of procedures to be used for protection of the existing roof, removal of tiles and installation/reinstallation of roof tiles.</li> Product Literature: Submit manufacturer’s product literature to Architect for all proprietary products specified for clay tile roof repairs including replacement tiles, cements, mortars and metal fabrications. Product literature shall include specification data, Material Safety Data Sheets and instructions for storage, handling and use.</li> Samples: The Contractor shall submit samples of the following items to be used in the repair work.  Replacement roof tiles: Submit samples of replacement roof tiles. Samples shall illustrate the full range of color variation to be expected. Salvaged or replacement clay tile that matches existing tiles should be used for replacement. Modern tiles or cement-based tiles are not an appropriate substitute for historic clay tile.</li> Fasteners: Submit samples of nails, bibs, clips and other metal fasteners to be used in the attachment of the new roof tiles.</li> </ol> </li> </ol>

QUALITY ASSURANCE
<ol type="A"> The building and/or site addressed in this project is an historic property. The property is either listed or eligible for the National Register of Historic Places. These plans and specifications intend to comply with the Secretary of the Interior’s Standards and Guidelines. In recognition of the historic value of these properties, a high standard of care shall be taken during all phases of work, including demolition, repair, renovation and new construction activities. The Contractor shall demonstrate a working knowledge of the Secretary of the Interior’s Standards and Guidelines for Historic Preservation.</li> Work Experience: The Contractor engaged in the completion of the roof tile repairs shall have a minimum of seven years experience in the repair and installation of historic clay tile roofing and shall have completed at least three projects of similar scale and scope within the previous five years. The Contractor shall submit samples of and references for work completed on previous projects.</li> Warranty: The Contractor shall provide a written warranty for the clay tile roof repairs against failures in materials and workmanship for a period of five years after the date of Substantial Completion.</li> </ol>

MOCK-UPS
<ol type="A"> In the presence of the Architect, all personnel to be assigned to the project shall demonstrate their ability to complete the required work in an acceptable manner. Each mechanic shall remove and replace one clay roof tile at locations designated by the Architect. Personnel not completing the sample work in an acceptable manner shall not be permitted to work on the roofing repairs.</li> </ol>

DELIVERY, STORAGE AND HANDLING
<ol type="A"> Deliver clay roof tiles and accessory materials to the site in manufacturer’s original unopened packaging with identification information visible thereon. <ol> <li>Store field tiles on pallets away from general construction operations until ready to begin installation. Special shapes must be stored in manufacturer’s original packaging. Store roof tiles in such a manner as to avoid unnecessary handling.</li> <li>Store accessory materials such as mastic, adhesives, membranes, etc., off the ground in a dry, secure location where ambient temperatures are within the manufacturer’s recommended range.</li> </ol> </li> <li>Provide power equipment as required to safely move tiles to the roof in preparation for installation.</li> <li>The Contractor shall dispose of all packaging, waste materials and construction debris in accordance with local, state and federal environmental regulations. All wood scrap shall be kept separate for recycling. No burning of debris, waste material or trash will be allowed on site.</li> <li>Where possible, clay tiles removed from the roof shall be salvaged for reinstallation. Stockpile salvaged tiles in a location designated by the Owner’s representative. Store salvaged tiles on pallets, off the ground. Do not stack pallets.</li> </ol>

PROJECT / SITE CONDITIONS
<ol type="A"> <li>The Contractor is responsible for protecting existing adjacent materials during the execution of the work. Provide all necessary protection and work procedures to avoid damage to existing material assemblies not a part of the work of this Section. At a minimum, the Contractor shall: <ol> <li>Provide sturdy, weather-proof protection at all areas exposed during clay tile roof repairs and installation. Do not leave interior spaces exposed to the elements overnight. The Contractor shall maintain adequate supplies of protective materials on site at all times in the event of sudden weather changes.</li> <li>Protect roof framing during clay tile installation by distributing materials in such manner as to avoid overloading.</li> <li>Protect new and existing clay tile roofing by limiting foot traffic over installed tile and ensuring the use of proper soft-soled footwear by all roofing personnel. Use sand bags, planks, suspended ladders and/or platforms where possible to avoid damage to roof surfaces.</li> <li>Protect roofing and gutters from damage by ladders or work platforms. Keep gutters clear of debris from clay tile repair work.</li> </ol> </li> <li>Provide sturdy barriers around the work area to protect other trades and passers-by. At least one entrance must remain accessible during the course of the work.</li> <li>The Contractor shall coordinate roofing work with the work of other trades to minimize delays in the construction process. Coordinate roofing with other work including, but not limited to, structural framing, exterior finish carpentry, flashing and gutter work and chimney restoration. Schedule roof work to avoid traffic by other trades over newly installed areas.</li> </ol> =PRODUCTS=

MANUFACTURERS:
<ol type="A"> <li>The tile product and manufacturer must be pre-approved by the Architect.</li> <li>For repair projects, the Contractor shall have the option of providing salvaged roof tile, subject to approval of submitted samples, if this provides a better match to the existing roof materials.</li> <li>Where necessary, tiles may be removed from inconspicuous areas of roof and relocated to patch more visible areas to ensure the best match.</li> </ol>

GENERAL
<ol type="A"> <li>Characteristics: Incombustible, vitrified tile manufactured from shale and fire clays, having less than two percent moisture absorption when tested in accordance with ASTM C 67, and meeting Grade 1 freeze/thaw resistance requirements when tested in accordance with ASTM C 1167. No substitute materials such as pigmented concrete, metal, or plastic shall be accepted.</li> <li>Special Shapes and Fittings: Supply special shapes and fittings of same material and finish as adjacent field tile, factory-formed before firing, as indicated on drawings or specified in manufacturer's instructions for project conditions including, but not limited to, the following: <ol> <li>Hip caps</li> <li>Ridge caps</li> <li>Rake edges</li> <li>Detached gable rake edges</li> <li>Eave edges</li> <li>Valley edges</li> <li>Termination caps</li> <li>Half tile</li> <li>End bands</li> </ol> </li> <li>Historic tile roofs often incorporated variations in tile exposure and size to compensate for the effects of perspective when viewed from the ground. When attempting to match existing tiles, the Contractor shall note variations in size and exposure in the historic tile and procure replacements to fit accordingly.</li> </ol>

TYPES OF ROOFING TILES
<ol type="A"> <li>Pan Tiles <ol> <li>Spanish (also called S shaped) Tiles: One-piece interlocking tiles with both a convex and a flat (or almost flat) surface for nailing. A raised lip on the edge of the flat section interlocks with the convex portion of the adjacent tile. These tiles are laid directly on the roof deck on top of the underlayment and held in place with nails and/or mortar.</li> <li>Barrel (also called Mission) Tiles: Half-cylinder tiles, either straight or tapered laid with alternating convex and concave vertical rows. Concave tiles are laid first in vertical rows and nailed directly to the roof sheathing. The convex tiles are laid to overlap the vertical spaces and nailed to vertical battens fastened to the roof deck.</li> <li>Roman Tiles: Two-part system consisting of flat shingle-like tiles laid in vertical rows and convex barrel tiles to cover the vertical spaces between rows. The flat tiles are nailed directly to the roof deck and/or cemented in place while the barrel tiles are nailed to vertical battens fastened to the roof deck. Both tiles often have molded nibs to interlock with succeeding rows. A variation of the Roman tile is the Greek tile which employs a gable-shaped piece in lieu of the convex barrel.</li> </ol> </li> <li>Flat Tiles <ol> <li>English Shingle: Either plain or corrugated flat tiles with molded projections that interlock between adjacent tiles and course to course. Shingle tiles are nailed in place.</li> <li>English Flat: Plain or corrugated flat tiles laid in overlapping courses shingle fashion and nailed in place.</li> <li>French: Slab-like tiles with two deep vertical grooves and a projecting lug that interlocks with succeeding tiles laid above. French tiles are nailed in place, often with cement added for additional security.</li> </ol> </li> </ol>

ACCESSORY MATERIALS:
<ol type="A"> <li>New sheet metal for forming clips shall be 26 gauge Type 304 dead soft stainless steel coated with 50 percent zinc and 50 percent tin alloy to a thickness of 20 microns (TCS II).</li> <li>Underlayment: Where sheathing is present, asphalt-saturated organic felt conforming to ASTM D 226, Type II, non-perforated. Nominal weight 30 pounds per 100 square feet (1.5 kg/sq m); two layers required.</li> <li>Wood: <ol> <li>Wood Stringers: S4S, maximum 19 percent moisture content, nominal one inch (25 mm) thick, of height required to support tile.</li> <li>Wood Nailers and Cant Strips: Preservative-treated wood.</li> </ol> </li> <li>Flashing: See Section 07631 – Flashing, Gutters and Drains.</li> <li>Tile Fasteners: Corrosion-resistant; types and sizes specified in manufacturer's instructions for indicated uses and conditions. <ol> <li>Copper Wire: 18 gauge (1.2 mm) minimum.</li> <li>Screws: No. 8 or No. 9 brass or stainless steel, flathead Phillips or square drive, not less than 1-3/4 inches (45 mm) long.</li> <li>Nails for Solid Wood Deck: Corrosion resistant copper, brass, or stainless steel;  minimum 3/8-inch (9.5 mm) head diameter;  shank of minimum 11 gauge (3 mm) diameter and length sufficient to penetrate 3/4 inch (19 mm) into the deck but not through the underside.</li> <li>Nails for Plywood Sheathing: Slater's copper ring shank nail, 11 gauge (3 mm), not less than 1-3/4 inches (45 mm) long with 3/8 inch (9.5 mm) head;  point must penetrate through underside of deck.</li> </ol> </li> <li>Mortar Materials: <ol> <li>Mortar or grout is not a substitute for weatherproof tile repairs. Sometimes a dab of mortar is added for extra stability or to deter wind-blown rain.</li> <li>Mortar for setting tile and grout for finishing rake and eave edges, if used, shall have comparable flexibility and always be lower in strength and peremeability than the tile itself. Mortar mixes must be approved by the Architect.</li> </ol> </li> <li>Sealants and adhesives: Waterproofing compounds are not appropriate for use on clay tile.</li> </ol> =EXECUTION=

GENERAL
<ol type="A"> <li>Examine all framing, sheathing and lath, where applicable, for any conditions that may affect the repair and reinstallation of the clay tile roofing. Notify the Architect if any framing and/or decking is found to be unsuitable for roofing. The absence of sheathing is not necessarily unsuitable. If sheathing was historically absent on the roof, the repairs should be conducted in the same manner.</li> <li>Roofing contractor to coordinate roof repairs with chimney restoration, carpentry, flashing and gutter work if required to ensure that structural repairs are completed and eave configurations and tile projections are suitable to receive new gutter work and that flashings and other items may be installed prior to tile installation.</li> <li>The roofing contractor shall transport and stage tiles in such a way as to avoid overloading the roof framing during installation.</li> <li>Protect roof tiles to remain using sandbags, planks, or padded ladders as required to distribute the weight of personnel required to access the roof. Do not walk over roof tiles unnecessarily.</li> <li>Where roofing to remain is too fragile for foot traffic, remove tiles as required to create a path to the repair area. Salvage all sound tiles for reinstallation.</li> </ol>

REMOVAL OF EXISTING ROOF TILES
<ol type="A"> <li>Remove slipped or mismatched tile(s) using a hacksaw blade or slate ripper to cut the nails or wire ties. Gently remove the tile(s) without damaging the edges of adjacent tiles to remain. Broken tiles may be cracked with a mallet to facilitate removal.</li> <li>Where flashing and/or gutter replacement is required, remove all tiles covering the full extent of the metalwork to be replaced.</li> </ol>

REPLACEMENT TILE INSTALLATION
<ol type="A"> <li>Sound all tiles prior to installation by tapping lightly. All tiles should ring clear. Tiles that rattle or produce a muffled sound when tapped are likely defective and shall not be used.</li> <li>Nails shall not be driven so as to produce strain on tiles. Nails shall be driven so that the head protrudes slightly from the surface of the tile. The tile shall be loose when fully nailed. If this is not executed properly, building movement could crack the tile.</li> <li>Some early tiles utilize only their hook shape to secure themselves to the roof lath or battens. The original installation should be used unless the Architect confirms that the method is causing roof damage. If the Architect deems appropriate, spot replacement of damaged, missing or non-matching tile may be done by one of the following methods: <ol> <li>Clip Method <li>A noncorrosive sheet metal strip is nailed in place underneath the location where the replacement tile will be installed. The strip shall be long enough to protrude several inches below the bottom edge of the replacement tile. Fold the exposed portion of the strip to double thickness.</li> <li>Slide the replacement tile into position. Hold in place by folding the doubled sheet metal strip and crimping tight to the bottom edge of the tile.</li> </ol> </li> <li>Hook Method <li>A pre-formed wire or noncorrosive sheet metal hook is placed over the top edge of the course beneath the tile to be replaced.</li> <li>Slide the new tile into position under the course above, bending the bottom of the sheet metal/wire hook up and over the bottom edge of the tile.</li> </ol> </li> <li>Nail and Tie Method Where multiple tiles are removed, reinstall using nails or wire ties fastened to nails driven directly into the roof deck or battens.</li> </ol> </li> <li>Replacement ridge tiles shall be laid in to match the pattern of the remaining tiles.</li> <li>Entire surfaces of all roofs, except as noted, shall be covered with tile in a proper and weatherproof manner. Upon completion, all tiles must be sound, whole and clean. The roof must be left watertight and neat in every respect, and subject to the Architect's approval.</li> </ol>

FINAL REPORT
<ol type="A"> <li>The Contractor shall submit a final report of the completed repairs including all approved submittals, photographs taken before, during and after construction and written warranty. The Architect shall develop an effective maintenance and repair program for the clay tile roof for future use.</li> </ol>