Specification:Fasteners for historic exterior wood

__NUMBEREDHEADINGS__ =GENERAL=

DESCRIPTION
 This specification provides guidance for selecting and installing appropriate fasteners for historic exterior wood. 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 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
 Appropriate Fasteners  Identification and Selection of Fasteners</li> Installation of New Fasteners </li> </ol>

RELATED SECTIONS
<ol type="A"> Section 06200.02 – Wood Properties and Appropriate Lumber</li> Section 06200.03 – Installation of Fabricated Historic Wood Elements</li> Section 05010.02, General Cleaning of Metal</li> </ol>

SUBMITTALS
<ol type="A"> Fastener Schedule: Submit a detailed fastener schedule for installation and/or repair of all exterior wood. Schedule should include at minimum the following: type, size, material, finish and application.</li> Product Literature: Submit manufacturer’s product literature to the Architect for all proprietary products specified. Product literature shall include specification data, Material Safety Data Sheets and instructions for storage, handling and use.</li> Samples: Submit to the Architect at least one sample of each type and style of fastener to be used.</li> </ol>

QUALITY ASSURANCE
<ol type="A"> Work Experience: The Contractor shall have a minimum of seven years experience in the repair and restoration of wooden structures and shall also have successfully completed at least three exterior wood restoration projects of similar scope within the previous five years. Other prerequisites include a demonstrated knowledge of fasteners for historic wood and appropriate installation techniques. 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 &amp; Reconstructing Historic Buildings.</li> The Contractor shall provide a ten-year warranty on materials and workmanship for wood and associated fasteners, hardware, etc.</li> </ol>

DELIVERY, STORAGE AND HANDLING
<ol type="A"> Deliver restoration materials and proprietary products to the project site in manufacturer’s or distributor’s packaging, undamaged, complete with instructions as applicable.</li> Store and transport non-corrosion resistant fasteners under dry conditions to protect from damage by weather or humidity.</li> If existing fasteners are removed, a minimum of three samples of each type and style of    fastener shall be labeled and retained as evidence of earlier details of construction. These shall be labeled and submitted to the Architect. Labels should include all of the necessary information to identify their approximate age, use, and location on the structure.</li> </ol>

PROJECT / SITE CONDITIONS
<ol type="A"> 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. </li> The Contractor shall be responsible for disposal of waste material and other debris associated with the work of this Section in accordance with local, state and federal environmental regulations.</li> </ol> =PRODUCTS=

APPROPRIATE FASTENERS
<ol type="A"> General  <li>All fasteners should meet or exceed the ASTM Fastener Standards for their respective applications.</li> <li>Selection of appropriate fasteners will be justified by historical appropriateness, or by        existing fasteners on site. See also criteria for selection in PART 3 – EXECUTION. For repair of existing metal fasteners see Section 05010 – Historic Metals – Metal Materials.</li> <li>Screws: Shall conform to American Society of Mechanical Engineers (ASME) Standard B18.6.1.</li> <li>Bolts, Nuts, Lag Screws, and Studs: Shall conform to ASME B18.52.1, ASME B18.2.2, and ASTM A687.</li> </ol> </li> <li>Fasteners – Historic Compatibility <ol> <li>Fasteners are generally defined as nails, screws, and bolts, while elements such as joist hangers, straps, hinges, post anchors, and truss plates are categorized separately as “connecting hardware.” Where necessary, new fasteners for historic exterior wood applications should match the original corresponding fasteners in design, color, texture, and material. Where it is not possible to match the fasteners, substitute materials may be used at the discretion of the Architect. For example, wire nails are the industry standard today and, unless the fasteners are to be intentionally left exposed near eye level, will be appropriate for the majority of historic exterior wood applications.</li> <li>Replacement of missing features shall be substantiated by documentary and physical evidence. Where original fasteners are missing, physical documentation may be available in the form of “scars” in the existing wood, paint lines, or other remaining fasteners used for similar applications elsewhere on the structure or object. In the absence of evidence to indicate what the original fasteners were, historically appropriate replacement fasteners may be chosen in consultation with the Architect and based on the established period of construction. Nails are the most commonly encountered fastener for historic exterior wood and can be divided into the following basic categories: wrought nails, cut nails, and wire nails. They can be identified according to the following general characteristics: </ol> </li> </ol>

=EXECUTION=

IDENTIFICATION AND SELECTION OF FASTENERS
<ol type="A"> <li>Determine the types and sizes of any existing fasteners that are to be replaced.</li> <li>Select material, type, size and finish of fasteners required by each substrate for both historic compatibility (see 2.01, PRODUCTS – APPROPRIATE FASTENERS, above) and secure anchorage. If through-wood metal-to-metal connections are involved, ensure that compatible metal types are used.</li> <li>Nails: Nails shall be the size and type best suited for the purpose and shall conform to ASTM F547 (2001), Nails for Use with Wood and Wood-Base Materials. Nails shall be hot-dip galvanized, aluminum or stainless steel when used on exterior work. Screws for use where nailing is impractical shall be sized as best suited for purpose.</li> <li>Anchors: Select material, type, size and finish required by each substrate for secure anchorage. Provide nonferrous metal or hot-dip galvanized anchors and inserts on inside face of exterior walls and elsewhere as required for corrosion resistance. Provide toothed steel or lead expansion bolt devices for drilled-in-place anchors. Furnish inserts and anchors, as required to be set into concrete or masonry work for subsequent woodwork anchorage.</li> </ol>

INSTALLATION OF NEW FASTENERS
<ol type="A"> <li>Finish Work – General <ol> <li>Finish Nails: Fasten finish work with finish nails. Nails should be countersunk and the depression filled with wood filler applied over the nail heads. Wood filler should be paint grade if appropriate or a color matched filler if applying to stained wood. </li> <li>Provide blind nailing where practicable. Set face nails for putty stopping. In addition to nailing, glue joints of built-up items with waterproof glue as necessary for weather-resistant construction. Stagger end joints in built-up members.</li> </ol> </li> <li>Flat Surface Work <ol> <li>Soffits: Wood panels shall be applied with edges at joints spaced in accordance with manufacturer's instructions and with all edges backed with framing members. Panels shall be nailed 3/8 inch from edges at 6 inches on center and at intermediate supports at 12 inches on center. </li> <li>Fascias and Exterior Trim: Joints of built-up items, in addition to nailing, shall be glued as necessary for weather-resistant construction. </li> </ol> </li> <li>Siding – General <ol> <li>For siding, length of nails shall be sufficient to extend 1-1/2 inches into supports, including wood sheathing over framing.</li> <li>For siding to have a stain finish, set nails and stop with stainable putty to match finished siding. For siding to have a paint finish, drive nails flush.</li> </ol> </li> <li>Horizontal Board Siding <ol> <li>Pre-drill ends of siding if necessary to prevent splitting when nailed. Only one nail at each vertical support is required to attach six inches or less wide siding (unless horizontal drop siding – see 3 below).</li> <li>For horizontal bevel or plain lap siding, overlap and nail into each support in accordance with recommendations of siding manufacturer.</li> <li>For horizontal drop siding, work each course into top edge of previous course. Nail two nails into each support: one near the lower edge to clear top of previous course, and one just above mid-height of course. </li> </ol> </li> <li>Vertical Board Siding <ol> <li>Work each board into edge of previous course. Nail into supports at 24 inches on center with two nails: one blind, if possible, at or near joint with previous board; and one just outside board center line.</li> <li> Vertical Board and Batten Siding: Apply with horizontal joints only at locations indicated in plans. Install each board with 1/2-inch space between it and previous board. Nail at center of board and into supports at 24 inches on center. Center battens over space between boards and nail down center at 16 inches on center.</li> </ol> </li> <li>Panel Siding <ol> <li>Apply panels with edges at joints spaced in accordance with manufacturer's recommendations. Nail panels at edges six inches on center and at intermediate supports 12 inch on center. Nails should be applied 3/8-inch from edge of panel.</li> <li>For shiplap joints, nail 3/8 inch from visible joint and at a location to penetrate lap with previous panel. When panel siding is part of an engineered shear wall or used as wall-bracing, nail shiplap joints to supports with double rows of nails. Space battens at 12-16 inches on center and nail down center at 24 inches on center.</li> </ol> </li> <li>Wood Wall Shingles <ol> <li>Weather exposure should be 7-1/2 inches for 16 inch shingles, 8-1/2 inches for 18 inch shingles, and 11-1/2 inches for 24 inch shingles. </li> <li>Wood shingles shall be applied by single-coursing method and with the appropriate weather specified above. Nail each shingle with two nails one inch above butt line of the next course, except shingles more than eight inches in width that shall be nailed with three nails.</li> </ol> </li> </ol>

FINAL REPORT
<ol type="A"> <li>After completion of the installation work, the Contractor shall submit a final report including copies of approved submittals, photographs of the fasteners and installation work before, during and after construction. </li> </ol>