REV.2 081320 WHIS-073130 Wood Shingle Roofing_0004.pdf

WHISKEYTOWN NATIONAL RECREATION AREA PMIS #: 239262/254757

ROOF REPLACEMENT AT FOUR BUILDINGS

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SECTION 07 31 30 - WOOD SHINGLE ROOFING

This specification section was amended on August 13, 2020. Revisions are shown in red.

PART 1 - GENERAL

1.1 CONTENTS

A. This section sets forth the requirements for providing fire-resistant, weather-tight wood shingle roofing systems at two (2) historic buildings in the Tower House Historic District. PART 1 includes the following:

1.1 Contents

1.2 Summary of Work and Estimated Quantities

1.3 Reference Standards

1.4 Submittal Requirements

1.5 Quality Assurance

1.6. Project Site Conditions

1.7 Delivery, Storage and Handling

1.8 Warranty / Guarantee

B. See GENERAL REQUIREMENTS PART 1 of this SOW for additional general requirements.

1.2 SUMMARY OF WORK AND ESTIMATED QUANTITIES

A. The work of this section includes the removal and replacement of existing wood shingle roofing with new, fire-resistant, weather-tight wood shingle roofing systems at five) historic buildings in the Tower House Historic District.

1. Work of PMIS 239262:

a. Camden House – Approximately 17 squares (approximately 1,610 square feet);

b. Tenant House – Approximately 29 squares (approximately 2,860 square feet);

2. Work of PMIS 254757:

a. Guest Quarters - Approximately 4 squares (approximately 380 square feet);

b. Servant Quarters - Approximately 4 squares (approximately 380 square feet);

c. Woodshed - Approximately 4 squares (approximately 390 square feet)

B. Contractor shall provide all materials, labor, equipment and supervision required to perform the Work as specified herein, as indicated on the figures/drawings herein and as required by codes and regulations and by existing field conditions.

C. The following brief description of the Work of this section is provided for the Contractor’s convenience. The contractor is responsible for the completion of all Work required by the Contract, whether listed below or not. Work includes, but may not be limited to, the following:

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1. Removing existing wood shingle roofing to existing sheathing (sheathing varies by building);

2. Repairing existing roof sheathing as required to match and align with existing;

3. Providing new, fire resistant, wood shingle roof system including underlayment;

4. Integrating new flashing with new roofing;

5. Integrating new chimney flashing with new roofing at Camden House;

6. Repairing existing deteriorated fasciae and trim impacted by roofing and flashing;

7. Cement Parging repairs in conjunction with new roof flashing;

D. Special Considerations:

1. Weather Protection: Throughout the duration of the Work the Contractor shall be fully responsible for maintaining the weather-tightness of all portions of the roof of each building.

a. Contractor or his authorized representative shall be available on four (4) hours’ notice, twenty-four hours a day for the duration of this contract, to repair and prevent any and all leaks related to his work.

i. Contractor shall furnish the Government with the name (s) and personal telephone number(s) of person(s) that will respond in the event of an emergency.

b. Damage by water intrusion to any interior features and/or contents of the building(s) shall be restored/replaced as approved by the Government, at no additional cost to the Government.

2. Fire Protection: These are important historic building on a historic site, and shall be protected against fire throughout the performance of the Work. In addition, the Park has recently suffered significant damage due to fire and is extremely sensitive in regards to fire protection.

a. See PART 1 article in this section regarding “Hot Work”;

b. Provide a fire extinguishers, of appropriate type, at each building:

i. Provide a minimum of three (3) fire extinguishers at the Camden and Tenant Houses;

ii. Provide a minimum two (2) fire extinguishers at the Guest and Servant Quarters;

iii. Provide a minimum one (1) fire extinguishers at the Woodshed.

E. Design Criteria:

1. Fire Rating: The entire roof assembly shall be installed to meet the requirements for a Class B fire-rated roofing assembly;

2. Wind Loads: The entire roof assembly shall meet the currently adopted

International Building Code requirement for a Class II Building in this wind zone;

3. Live Load Criteria:

a. Contractor shall assume the existing roofs at the Camden House and the Tenant House, which are sheathed with OSB, are designed for a live load of 15 pounds per square foot (psf);

b. Contractor shall assume the existing roofs at the Servant and Guest Quarters and the Woodshed, which are sheathed with spaced board sheathing, are designed for a live load of 10 psf.

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F. Estimated Quantities: Pursuant to the GENERAL REQUIREMENTS section of this SOW, Estimated Quantities for the Work of this section are as follows:

1. Roof Sheathing (OSB): 50 square feet;

2. Roof Sheathing (Board): 100 square feet;

3. Molded Trim Consolidant Repair: 20 linear feet;

4. Molded Trim Dutchman Repair: 10 linear feet;

5. Cement Parging Repair (beyond that required to install new chimney flashing): 10 square feet.

1.3 REFERENCE STANDARDS:

A. Contractor shall incorporate applicable standards into the Work of this contract as if they are spelled out in their entirety within this SOW.

B. The latest currently adopted publications listed below form a part of this SOW as applicable.

1. International Building Code (IBC), all applicable sections;

2. Occupational Safety and Health Administration (OSHA) standards all applicable sections;

3. American Society for Testing and Materials (ASTM) Standards, latest approved standards, as applicable.

4. Underwriters Laboratory (UL), latest approved edition for fire rating;

5. Cedar Shake and Shingle Bureau (CSSB) Roof Manual, latest edition; and shingle manufacturer’s printed installation instructions.

6. Sheet Metal and Air Conditioning Contractors National Association (SMACNA)

Manual, current edition, for flashing;

7. Stucco Manufacturers Association Technical Bulletins, latest editions, as applicable.

1.4 SUBMITTALS

A. Provide all required submittals pursuant to the requirements PARTS 2 and 3 of the GENERAL REQUIREMENTS section of this Scope of Work (SOW).

B. Preconstruction Submittals:

1. Qualifications Documentation pursuant to PART 1 Article “Quality Assurance” of this section. Submit list of a minimum of three (3) projects of similar size and scope as the Work of this contract. As least one projects shall have involved a historic building.

a. Definition: Historic Building is a structure listed on or eligible for listing on the National Register of Historic Places;

b. Include project location (physical street address), completion date and contact information for owner and/or designer.

C. Action Submittals: See “Product Submittal Requirements” in the GENERAL REQUIREMENTS section of this SOW for further requirements.

1. Manufacturer’s product literature for all products proposed for use;

2. Required Samples:

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a. Two (2) shingles of the grade, type and size specified;

b. Two (2) 6-inch square samples of each underlayment material specified;

c. Two (2) of each type of nail and fastener specified;

d. Two (2) 6-inch square samples of sheet metal flashing.

3. Mock-up:

a. Parging Repairs: Provide mock-up of parging repairs to match existing color and texture for Government review and approval before proceeding with the work.

i. Provide three (3) 18-inch square mock-ups of three-part stucco to match existing in color and texture on plywood substrate.

ii. If mock-up is not approved by the Government, contractor shall redo mock-up until it is acceptable to the Government.

iii. Retain approved mock-up(s) for comparison of the work.

b. Nail Gun Use: If Contractor proposes to substitute a nail gun for the hand nailing specified, Contractor shall provide a mock-up illustrating the contractor’s use of a nail gun in a manner that will not damage shingles or existing wood sheathing.

i. Provide a 6-foot square mock-up on a portion of one of the buildings that has historic plank sheathing to demonstrate use of nail gun in manner that does not compress the surface of the shingles and does not crack the existing wood sheathing.

ii. Locate mock-up as approved by the Government.

iii. If mock-up is not approved by the Government, contractor shall redo mock-up until it is acceptable to the Government.

D. Required Closeout Submittals: Pursuant to PART 3 of the GENERAL REQUIREMENTS section of this SOW.

1. Extra Materials:

a. Provide a minimum of one (1) square (100 square feet) of roofing material for each building (Camden House and Tenant House).

b. Deliver required extra materials in unopened cartons or bundles to location designated by the Government;

2. Manufacturers’ maintenance recommendation for all applicable products;

3. Record Documents.

1.5 QUALITY ASSURANCE

A. Due to the historic nature of this site and these buildings, the Contractor shall be familiar with and incorporate the applicable recommendations of the following documents into the Work of this contract:

1. Secretary of the Interiors Standards for the Treatment of Historic Properties;

2. National Park Service Preservation Brief No. 19 – The Repair and Replacement of

Historic Wooden Shingle Roofs.

B. The Company performing the Work shall be a contractor that has been installing wood shingle roofing on a regular basis for a minimum of five (5) years. A list of installations

December 2019 WOOD SHINGLE ROOFING 07 31 30 - Page 5 of 22 of similar size and complexity shall be provided as proof of experience. See PART 1 Article “Submittals” of this Section for submittal requirements.

1. The Contractor shall provide qualified workers, trained and experienced in installing roofing systems of similar configuration(s).

C. The Contractor shall be familiar with, and shall perform work, in accordance with the referenced standards.

D. Work Plan: After a thorough, close-up examination of the existing roofs, submit a written, project specific Work Plan. At a minimum the Work Plan shall include:

1. Description of the sequence, means, materials, and methods of Work for each phase of the reroofing of each building;

2. Description of any sheathing replacement required and how this will be accomplished;

3. Description of all flashing types and placement;

4. Description of stucco repairs;

5. Description of how the surrounding materials within the Project Site and adjacent areas not scheduled for Work under this contract will be protected;

6. Description of how the building will be protected in the event of inclement weather when the roofing is not watertight;

7. Provide written verification of concurrence with Estimated Quantities cited in

PART 1 Article “Summary of Work and Estimated Quantities” of this section.

1.6 JOB CONDITIONS

A. The Contractor shall carry out all work in compliance with the applicable OSHA standards.

1. Provide safe, OSHA compliant, access to work area for Contractor’s personnel and

Government representatives.

B. Protection of Historic Materials: Ensure that all existing and historical materials not scheduled for work under this contract are not adversely impacted by the Work.

C. Fire Prevention: See PART 1 article “Summary of Work and Estimated Quantities” of this section for requirements.

D. Weather Constraints: Roofing work shall proceed only when existing and forecast weather conditions allow work to be performed in accordance with manufacturer's recommendations and warranty requirements.

1. Follow all manufacturer’s recommendations regarding temperature and moisture constraints.

2. Units of work, including removal of existing materials, preparation of existing surfaces, application of underlayment and nailers, and related temporary and/or permanent flashing shall be sequenced so that it can be completed prior to the end of each working day.

3. Should inclement weather occur when roofs are not watertight, install temporary roofing as required to protect buildings and their contents.

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a. Materials shall be provided and maintained on the site at all times to provide temporary roofing, flashing, and other protection when delays and/or changed weather conditions do not permit completion of each unit of work prior to the end of each working day.

b. Materials used for temporary roofing, flashing and other protection shall not be used in the permanent construction, are the property of the Contractor and shall be removed from the site.

E. Structural Loading: Do not put excessive loads on existing roof structures.

1. Distribute materials over roof deck to minimize loads;

2. Do not store materials over mid-span of existing roof framing.

1.7 DELIVERY, STORAGE AND HANDLING

A. Materials shall be delivered in manufacturer's unopened bundles and containers with the manufacturer's brand and name marked clearly thereon.

1. Roofing materials shall be stored in accordance with manufacturer's printed instructions;

2. Roll goods shall be stored on end in an upright position.

B. Follow manufacturer’s recommendation regarding allowing materials to acclimate to temperature and humidity at Project Site prior to installation.

1.8 WARRANTY / GUARANTEE

A. The Contractor shall warrant all materials and workmanship against defects to insure a water tight installation for a period of one (1) year from the date of final acceptance of the Work.

B. Provide manufacturer’s standard warranty for all roofing products.

C. Submit in compliance with the requirements of the GENERAL REQUIREMENTS section of this SOW.

PART 2 - PRODUCTS

2.1 CONTENTS

A. PART 2 sets forth material and product requirements. Part 2 includes the following:

2.1 Contents

2.2 General

2.3 Sheathing Materials

2.4 New Wood Shingle Roof System at Solid Substrate

2.5 New Wood Shingle Roof System at Spaced Board Substrate

2.6 Flashing

2.7 Wood Repair Materials

2.8 Stucco Repair Materials

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B. See GENERAL REQUIREMNTS PART 2 of this SOW for general requirements pertaining to Products.

2.2 GENERAL

A. All products shall be new at time or delivery to site and installation, unless otherwise noted.

2.3 SHEATHING (SUBSTRATE)

A. Existing sheathing may vary from building to building, it may be spaced board sheathing and/or plywood and/or oriented strand board (OSB).

1. Repaired sheathing shall match existing and meet the roofing manufacturer’s requirements for sheathing configuration as it impacts roofing warranties.

B. Plywood and/or OSB Sheathing shall comply with the APA grading recommendations and match existing in material, thickness and alignment.

C. Spaced Board Sheathing: If board sheathing repair/replacement is necessary match existing materials in species, size (width, thickness and length) and configuration (tongue and groove, etc. – where applicable).

1. Repaired spaced board sheathing shall provide a firm substrate for the installation of shingles and meet the roofing manufacturer’s requirements for sheathing configuration as it impacts roofing warranties.

D. See PART 1 Article “Summary of Work and Estimated Quantities” for estimated quantities of framing and sheathing repairs.

1. Contractor shall verify concurrence with estimated quantities before proceeding with the work.

2.4 NEW WOOD SHINGLE ROOF SYSTEM AT SOLID SUBSTRATE

A. Underlayment - provide the following:

1. Roofing Felt: 30-pound high grade organic mat with high asphalt saturation, Meeting the requirements of ASTM D-4869 Type II.

B. Nylon Matrix - provide the following:

1. Three-dimensional, nylon, matrix sheet with 96.8% free air space;

2. Basis of Design: The basis of design is the standard of quality and performance established by “Cedar Breather,” as manufactured by Benjamin Obdyke.

a. Other products matching the salient characteristics of the Basis of Design product may be used with Government approval.

C. Roof Shingles: Provide Number One, Blue Label, Red Cedar with sawn faces and uniform butt thickness and taper. Shingles shall be manufacturer by a CSSB certified manufacturer and meet the requirements for CSSB Certi-Guard, for pressure treated fire retardant shingles.

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1. Shingles shall be impregnated and pressure treated with a Class B fire retardant meeting California Fire Code requirements for fire retardant roof systems;

2. Shingles shall be clean, dry and free of mildew, with a moisture content of 12% or less at time of installation.

3. Size:

a. Shingle length, butt thickness and exposure shall match sample of historic shingles to be provided by the Government;

i. Sample shingle appears to be 16-inches long, with a 5-inch exposure;

ii. See Figure 7 of this SOW for photo of sample shingle;

iii. Contractor shall verify actual dimension prior to ordering shingles.

b. Provide random width shingles as required to match existing.

4. Provide special shaped shingles as required to finish ridges and hips.

D. Fasteners: Provide Type 316 stainless steel box nails complying with ASTM F593 F1667, as recommended by manufacturer for use with fire-retardant treated cedar shingles.

1. Use lengths as required to penetrate sheathing ½-inch minimum and as required by the International Building Codes for this zone.

2. Nails for double courses and ridge shingles shall be a minimum of 2 in. long, or as required to penetrate sheathing ½ inch minimum.

2.5 NEW WOOD SHINGLE ROOF SYSTEM AT SPACED BOARD SUBSTRATE

A No underlayment required.

B. Roof Shingles: Provide Number One, Blue Label, Red Cedar with sawn faces and uniform butt thickness and taper. Shingles shall be manufacturer by a CSSB certified manufacturer and meet the requirements for CSSB Certi-Guard, for pressure treated fire retardant shingles.

1. Shingles shall be impregnated and pressure treated with a Class B fire retardant meeting California Fire Code requirements for fire retardant roof systems;

2. Shingles shall be clean, dry and free of mildew, with a moisture content of 12% or less at time of installation.

3. Size:

a. Shingle length, butt thickness and exposure shall match sample of historic shingles to be provided by the Government;

i. Sample shingle appears to be 16-inches long, with a 5-inch exposure;

ii. See Figure 6 of this SOW for photo of sample shingle.

4. Provide special shaped shingles as required to finish ridges and hips.

C. Fasteners: Provide Type 316 stainless steel box nails complying with ASTM F593 F1667, as recommended by manufacturer for use with fire-retardant treated cedar shingles.

1. Use lengths as required to penetrate sheathing ½-inch minimum and as required by the International Building Codes for this zone.

2. Nails for double courses and ridge shingles shall be a minimum of 2 in. long, or as required to penetrate sheathing ½ inch minimum.

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2.6 FLASHING

A. Galvanized Sheet Metal: Hot dipped zinc-coated, commercial quality steel sheet conforming to ASTM A123.

1. Provide all flashing required for a weather-tight installation as recommended by

SMACNA including, but not limited to, the following:

a. Sidewall flashing;

b. Drip edge flashing;

c. Ridge flashing;

d. Cricket flashing;

e. Chimney flashing.

2. Gage: 22 gage.

B. Fabrication:

1. Fabricate sheet metal flashing and trim that fit substrates and result in waterproof and weather resistant performance once installed;

2. Fabricate sheet metal flashing and trim to comply with applicable recommendation of SMACNA’s “Architectural Sheet Metal Manual”;

3. Verify shapes and dimensions of surfaces to be covered before fabricating sheet metal;

4. Form exposed sheet metal work that is without excessive oil canning, buckling, and tool marks and that is true to line and levels indicated, with exposed edges folded back to form hems;

a. Form a 1/2 inch hem on underside of all exposed edges.

5. Expansion Provisions: Provide for thermal expansion of metals per SMACNA recommendations;

6. Sealed Joints: Form non-expansion, but movable joints in metal, to accommodate elastomeric sealant to comply with SMACNA standards;

7. Conceal fasteners and expansion provisions where possible. Exposed fasteners are not allowed on faces of sheet metal exposed to public view.

C. Fasteners: 316 stainless steel size and spacing as recommended by SMACNA and sheet metal fabricator.

2.7 WOOD REPAIR MATERIALS

A. Single Source: To ensure best performance provide patching products of a single manufacturer.

B. Wood Consolidant - provide the following:

1. Salient Characteristics: Two-part, deep penetrating, epoxy wood consolidant designed for hardening and sealing soft fibers of wood materials that have deteriorated due to weathering and exposure and designed specifically to enhance the bond of wood patching compound to existing wood.

2. Technical Characteristics:

a. Tensile Strength: 1460psi;

b. Compressive Strength: 5200 psi;

c. Flexural Strength: 900 psi;

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d. Hardness Shore D: 42;

e. elongation: 84%.

3. Subject to meeting the salient characteristics specified and with Government approval, the following products are acceptable:

a. Abatron, Inc.; Liquidwood;

b. Advanced Repair Technology; Primatrate;

c. Gougeon Brothers, Inc.; West System;

d. Other products meeting the specified salient characteristics and as approved by the Government.

C. Epoxy for Wood Repair - provide the following:

1. Salient Characteristics: Paintable, light-weight, shrink-free, two-part epoxy adhesive putty system as recommended by manufacturer for type of wood repair indicated.

a. Material designed for filling wood materials that have deteriorated due to weathering and exposure;

b. Material shall be capable of filling deep holes and capable of spreading to feather-edge;

c. Material shall expand and contract at roughly the same rate as surround materials;

2. Technical Characteristics:

a. Tensile Strength: 2500psi;

b. Compressive Strength: 2300-2800 psi;

d. Hardness Shore D: 53-55;

e. elongation: 4%.

3. Subject to meeting the salient characteristics specified and with Government approval, the following products are acceptable:

a. Abatron, Inc.; Liquidwood with WoodEpox;

b. Advanced Repair Technology; Primatrate with Flex-Tec HV;

c. Gougeon Brothers, Inc.; West System;

d. Other products meeting the specified salient characteristics and as approved by the Government.

D. Rafter Repair Materials: Where required provide new material to match existing rafters in materials, species, size and configuration.

E. See PART 1 Article “Summary of Work and Estimated Quantities” for estimated quantities of wood trim repairs.

1. Contractor shall verify concurrence with estimated quantities before proceeding with the work.

2.8 PORTLAND CEMENT PARGING REPAIR MATERIALS

A. Provide cement plaster (stucco) for repair of existing chimney stucco to match existing can comply with the following:

1. Type I Portland Cement:

a. ASTM C 150, Type I;

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b. Lime: ASTM C 206, Type S: ASTM C 207 Type S;

c. Sand Aggregate: ASTM C 897;

d. Color / Texture: As required to match and blend in with existing.

B. See PART 1 Article “Summary of Work and Estimated Quantities” for estimated quantities of parging repairs.

1. Contractor shall verify concurrence with estimated quantities before proceeding with the work.

2.9 MISCELLANEOUS MATERIALS

A. Prefabricated Penetration Assemblies: Provide hot dipped galvanized assemblies to seal roof penetrations such as vents, pipes and the like.

B. Sealants: Provide sealants as recommended by the roofing manufacturer and sheet meal fabricator.

C. Cricket Underlayment:

1. Plywood and associated wood framing as sizes required to provide a firm substrate for cricket(s) flashing to shed water and match existing.

D. Cant Strips: Tapered Edge Strips, and Flashing Accessories:

1. Types and sizes as recommended by roofing and sheet metal fabricator.

PART 3 EXECUTION

3.1 CONTENTS

A. PART 3 sets forth the execution requirements for the replacement of existing w roofs with new roof systems to match existing. PART 3 includes the following:

3.1 Contents

3.2 General

3.3 Examination

3.4 Protection

3.5 Existing Shingle Removal

3.6 Framing and Sheathing Repair

3.7 Wood Trim Repairs

3.8 Shingle Installation at Solid Sheathing

3.9 Shingle Installation at Spaced Sheathing

3.10 Roof Flashing

3.11 Chimney Flashing

3.12 Chimney Paging Survey and Repairs

3.13 Roof Accessories

3.14 Completion

3.15 Clean-up

B. See GENERAL REQUIREMNTS PART 3 of this SOW for general requirements pertaining to Execution.

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3.2 GENERAL

A. The Contractor shall supply all labor, materials, tools, equipment and services necessary to execute the Work as required by the Contract. Work shall be completed in the highest quality, workmanlike manner as indicated on the Drawings, as specified herein, and as required by job conditions and all applicable codes and regulations.

B. All new roofing and flashing shall replicate the appearance and details of the existing roofing and flashing, unless otherwise noted.

3.3 EXAMINATION

A. Before removing existing roofing, inspect existing roof rafters to ensure existing framing is sound and will support the Work.

B. Following removal of the existing roofing inspect the areas and conditions where new roofing is to be installed and correct any conditions detrimental to the proper and timely completion of the work.

1. Do not proceed with the work until unsatisfactory conditions are corrected to permit proper installation of the Work.

2. Proceeding with the Work will signify Contractor’s acceptance of the substrate and ability to warrant the Work.

C. Following removal of roofing, Contractor shall make a detailed examination of each roof to determine condition of existing substrate to determine work necessary to prepare sheathing for installation of new roofing.

1. Substrate shall be even, smooth, sound, thoroughly clean and dry, and free from defects that might affect proper installation. Correct deterioration as required by this SOW.

2. The Contractor shall promptly notify the Government of defective substrates and correct all defects before commencing with the Work of this section.

3. If deterioration beyond that covered by this SOW is encountered, report all defectives to the Government for resolution prior to starting the Work.

D. Contractor shall inspect the stucco clad chimney at the Camden House for damage/deterioration to the stucco.

1. If additional repair work is necessary include methods and materials in Work Plan.

E. Work Plan: Following the examination, Contractor shall prepare Work Plan as required by PART 1 Article “Quality Assurance” of this section.

3.4 PROTECTION

A. Weather Protection: Contractor shall ensure that buildings are protected from damage due to water intrusion at all times throughout the course of the Work.

1. See PART 1 Article “Job Conditions” for weather protection requirements.

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B. Fire Protection: Contractor shall ensure that buildings are protected from damage due to fire at all times throughout the course of the Work.

1. See PART 1 Article “Job Conditions” for fire protection requirements.

C. The Contractor shall protect existing and historic materials not scheduled for work under this contract at all times throughout the course of the Work.

D Protect persons, motor vehicles, surrounding surfaces of building, building site, plants, and surrounding buildings from harm resulting from the Work.

E. The Contractor shall protect finished materials from damage:

1. Contractor shall be responsible for controlling damage to new roofing and shall promptly replace any and all roofing damaged in the course of the Work.

a. Use equipment (such as padded ridge ladders) and techniques that prevent damage to roof as a result of foot or material traffic.

b. Personnel who are working on the roof shall have proper foot ware that will not damage roofing and aid in preventing falls.

3.5 EXISTING ROOFING REMOVAL

A. Full Roof Tear-Off: Remove all existing roofing, all other roofing components and existing flashing down to the existing wood sheathing.

1. Remove existing fasteners from sheathing surface.

B. Salvage existing roof accessories for reinstallation.

1. Take care not to damage mechanical unit and ducting when removing from the

Tenant House roof;

2. Removed roof accessories shall be safely stored throughout reroofing and reinstalled in appropriate sequence with roofing;

3. If existing accessories cannot be reused, or are damaged during removal, storage or reinstallation, provide new to match existing;

C. Spaced Board Sheathing at Servant and Guest Quarters and Woodshed is historic material.

1. Take care when removing existing roofing and nails not to damage existing board sheathing;

D. Disposal: Promptly dispose of demolished materials outside of park in a legal manner.

1. Do not allow demolished materials to accumulate on-site.

2. Storage or sale of demolished items or materials on-site is not permitted.

3.6 FRAMING AND SHEATHING REPAIRS

A. Roof Framing: Roof framing shall be structurally sound and able to support the weight of the new roofing. If, during examination and/or after removal of deteriorated sheathing, deteriorated roof framings is found it shall be repaired by “sistering” new framing members to the existing framing, unless otherwise noted.

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1. Existing framing is historic. Do not replace remove/replace existing framing without approval of the Government.

2. New framing members shall match the existing in material, species, size and configuration;

3. New framing members shall extend a minimum of three (3) times the length of the deterioration onto sound wood, e.g. if 12-inches at the end of a rafter is deteriorated, new framing shall extend 36-inches up the rafter.

a. Attach new framing with stainless steel screws at 6-inches on center staggered at 1-1/2-inch away from each edge of the rafter.

B. Sheathing: Sheathing shall be smooth, clean, firm, dry, and free from rot, loose boards, large cracks, checks and projections that might damage the roofing.

1. Solid Sheathing at Camden and Tenant Houses: Deteriorated sheathing that has reached the end of its useful life shall be replaced as specified.

2. Spaced Board Sheathing at Servant and Guest Quarters and Woodshed:

a. The board sheathing is historic material, replace only those pieces that can no longer contribute to support roof loads and/or hold roofing nails.

b. Boards with loss of more than 25% of the surface area, deeply checked and/or cracked boards and/or boards that are no longer able to hold nails for shingle installation shall be replaced with new material to match existing as specified;

c. Maintain original spacing and align with new sheathing with remaining sheathing;

d. Attach new boards to framing with a minimum of two (2) stainless steel nails set a minimum of 1-1/2-inches into framing.

3. Replace missing, damaged and/or deteriorated sheathing fasteners with new stainless steel fasteners set a minimum of 1-1/2-inches into existing framing.

4. Reset all remaining nails to align with top of sheathing;

5. Remove all nails, wood chips and other deleterious materials from areas to receive new roofing;

6. Verify deck surfaces are dry and free of ridges, warps, or voids.

C. See PART 1 Article “Summary of Work and Estimated Quantities” for estimated quantities of framing and sheathing repairs.

1. Contractor shall verify concurrence with estimated quantities before proceeding with the work.

3.7 WOOD TRIM REPAIRS

A. Existing wood trim adjacent to and to be covered by new roofing and flashing shall be repaired to match existing and as described below.

B. Class I Maintenance Treatment – Paint Preparation: Components exhibiting sound or better condition of wood and paint. If deterioration is less than 1/8 inch deep, no repair is necessary.

1. Scope of Work:

a. Remove loose paint and coating from wood surfaces to sound substrate;

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b. Lightly sand, clean, prepare and prime surface of components;

c. Paint the exterior surfaces of all components to match existing with one (1) -coat high quality exterior latex primer and two (2) - coats high quality exterior latex paint.

C. Class II Maintenance Treatment - Wood Epoxy Consolidant and Filler: Wood components exhibiting isolated pockets of decayed wood shall be repaired with consolidant and epoxy filler. If deterioration is deeper than 1/8-inch, but less than half the depth of the member and/or less than 33-percent of the existing member is compromised/deteriorated make epoxy repairs as recommended by epoxy manufacturer and as follows:

1. Scope of Work:

a. Remove loose paint and coating from wood surfaces to sound substrate;

b. Remove decayed material until sound material is reached. Clean out all loose material and prime void with wood consolidant following manufacturer’s recommendations.

c. Fill void(s) with two-part epoxy filler, following manufacturer’s recommendations, when cured sand flush with the surrounding surfaces;

d. Lightly sand, clean, prepare and prime surface of components;

e. Paint the exterior surfaces of all components to match existing with one (1) -coat high quality exterior latex primer and two (2) - coats high quality exterior latex paint.

D. Class III Maintenance Treatment - Dutchman Repairs: Components exhibiting voids or pockets of decay deemed too large for filler shall be repaired using Dutchman.

1. Scope of Work:

a. Remove loose paint and coating from wood surfaces to sound substrate;

b. Cut out deteriorated wood in the member until sound wood is reached;

c. A wood infill piece (Dutchman) shall be fabricated to fill the void. The

Dutchman shall match the host material in species, grain orientation, size and profile.

i. Attach Dutchmen using exterior grade waterproof wood glue.

d. Sand Dutchmen flush with the surrounding surface;

e. Lightly sand, clean, prepare and prime surface of components;

f. Paint the exterior surfaces of all components to match existing with one (1) -coat high quality exterior latex primer and two (2) - coats high quality exterior latex paint.

E. See PART 1 Article “Summary of Work and Estimated Quantities” for estimated quantities of wood trim repairs.

1. Contractor shall verify concurrence with estimated quantities before proceeding with the work.

3.8 SHINGLE INSTALLATION AT SOLID SUBSTRATE

A. Verify that flashing and roof penetrations are in place and flashed to deck surface, where applicable.

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B. Underlayment:

1. Felt: Lay uniformly over entire roof service as follows:

a. Fasten felt as recommended by felt and shingle manufacturers with non-corrosive nails or staples to prevent wind uplift during installation.

b. Lay felt parallel to eaves with 6 inch horizontal laps to allow for free drainage. Vertical laps shall be 4 inches and securely fastened.

c. At roof penetrations, cut membrane neatly and accurately and turn flanges up to give a tight, water-shedding fit. Install a second membrane sheet on the up-slope side to shed water to either side of the penetration.

2. Nylon Matrix Underlayment: Lay uniformly over felt over entire roof surface.

a. Follow manufacturer’s installation guidelines;

b. Lay nylon matrix while installing shingles and avoid walking directly on the matrix.

C. Shingles shall be installed as recommended by the CSSB and shingle manufacturer; and as required to match the original construction and for a weather-tight installation without hip shingles:

1. Weather Exposure: Shingles shall be installed with the same exposure as historic shingles, based on sample provided by the Government. Exposure appears to be 5-inches on sample historic shingle.

a. See Figure 6 of this SOW for photo of sample shingle.

2. Keyways: Spaces (joints) between adjacent shingles shall be a minimum of 1/4-inch and a maximum of 3/8 inch.

a. Joints in any one course shall be offset and separated not less than 1½ inch from the joints in adjacent courses.

b. In any three courses, no two joints should be aligned.

3. Shingle Widths: Match existing roofing in mix of different shingle widths.

D. Triple shingle starter courses at the eaves of upper roof and cupola roof, projecting a minimum of 1-1/2-inches beyond the fascia;

E. Extend shingles a minimum of 3/4-inches beyond eave and rake edges and shed roof ridge.

F. Nailing: Each roof shingle shall be rigidly secured in place with not more than two nails.

1. Fasteners shall be installed to securely attach shingles to the substrate and be flush with the surface of the shingle;

a. Do not over drive nails such that the head crushes the surface of the wood;

b. The preferred installation method is hand nailing.

c. At Contractor’s option a nail gun may be used, however mock-ups are required to ensure contractor can attach the shingles without damage to the surface of the shingle or the existing sheathing below. See PART 1 “SUBMITTALS” of this specification section for mock-up requirements.

i. Surface damage to shingles or damage to sheathing is grounds for rejection.

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2. Nails shall be placed not more than 3/4-inch from side edges of shingles and concealed approximately 1 inch above the butt line of the shingle in the following course.

3. In nailing double and triple coursing, the nails shall be concealed from 2 to 3-inches above the butt line of the shingle in the following course.

G. Rejects: Shingles wider than eight inches shall be sawn and not split. All split shingles shall be promptly removed and replaced.

H. Hips and Ridges: All hip and ridge shingles shall be laid in the modified “Boston” method, with concealed nails and weather exposure to match existing hip and ridge shingles.

1. Lay hip and ridge shingles in two parallel rows that overlap at the hip; with alternate courses overlapping in opposite directions, to provide a weatherproof joint.

2. The first hip shingle shall be sawed across the butt on a line parallel with the eave and secured in place with the nails penetrating at least ½ inch into the sheathing and concealed by the following hip shingle. The edge of the first shingle shall be sawn flush with the face of the opposite hip shingle.

3. The second and following hip shingles shall be laid in similar fashion, but in reverse order, so that the final trimmed-off edges alternate on opposite roof planes.

3.9 SHINGLE INSTALLATION AT SPACED SHEATHING

A. Verify that flashing and roof penetrations are in place and flashed to deck surface, where applicable.

B. Shingles shall be installed as recommended by the CSSB and shingle manufacturer; and as required to match the original construction and for a weather-tight installation without hip shingles:

1. Weather Exposure: Shingles shall be installed with the same exposure as historic shingles, based on sample provided by the Government. Exposure appears to be 5-inches on sample historic shingle.

a. See Figure 6 of this SOW for photo of sample shingle.

2. Keyways: Spaces (joints) between adjacent shingles shall be a minimum of ¼ inch and a maximum of 3/8 inch. Joints in any one course shall be offset and separated not less than 1½ inch from the joints in adjacent courses. In any three courses, no two joints should be aligned.

3. Shingle Widths: Match existing roofing in mix of different shingle widths.

C. Triple shingle starter courses at the eaves of upper roof and cupola roof, projecting a minimum of 1-1/2-inches beyond the fascia;

D. Extend shingles a minimum of 3/4-inches beyond eave and rake edges.

E. Nailing: Each roof shingle shall be rigidly secured in place with not more than two nails.

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1. Fasteners shall be installed to securely attach shingles to the substrate and be flush with the surface of the shingle;

a. Do not over drive nails such that the head crushes the surface of the wood;

b. Do not split existing plank sheathing;

c. The preferred installation method is hand nailing.

d. At Contractor’s option a nail gun may be used, however mock-ups are required to ensure contractor can attach the shingles without damage to the surface of the shingle or the existing sheathing below. See PART 1 “SUBMITTALS” of this specification section for mock-up requirements

i. Surface damage to shingles or damage to sheathing is grounds for rejection.

2. Nails shall be placed not more than 3/4-inch from side edges of shingles and concealed approximately 1 inch above the butt line of the shingle in the following course.

3. In nailing double and triple coursing, the nails shall be concealed from 2 to 3-inches above the butt line of the shingle in the following course.

F. Rejects: Shingles wider than eight inches shall be sawn and not split. All split shingles shall be promptly removed and replaced.

G. Hips and Ridges: All hip and ridge shingles shall be laid in the modified “Boston” method, with concealed nails and weather exposure to match existing hip and ridge shingles.

1. Lay hip and ridge shingles in two parallel rows that overlap at the hip; with alternate courses overlapping in opposite directions, to provide a weatherproof joint.

2. The first hip shingle shall be sawed across the butt on a line parallel with the eave and secured in place with the nails penetrating at least ½ inch into the sheathing and concealed by the following hip shingle. The edge of the first shingle shall be sawn flush with the face of the opposite hip shingle.

3. The second and following hip shingles shall be laid in similar fashion, but in reverse order, so that the final trimmed-off edges alternate on opposite roof planes.

3.10 ROOF FLASHING

A. General: Provide appropriate flashing where new roofing abuts existing construction for a weather tight installation, as recommended by SMACNA and as required to match existing.

1. Securely and properly support, attached and install flashing in with all lines and corners true, level, plumb and in accurate alignment in the manner recommended by the referenced standards;

2. All new work shall match existing details in kind, unless specified otherwise, or determined by the Government to be of a design detrimental to the integrity of the installation.

3. Install work watertight, without waves, warps, buckles, fastening stresses, or distortion;

4. Allow for expansion and contraction;

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5. Angle bottom edges of exposed vertical surfaces to form drips;

6. Seams: Provide seams as recommended by SMACNA and as required to match existing and to provide a weather tight installation.

7. Soldering: All soldering shall be done slowly with well heated coppers to heat sheet thoroughly and to sweat all solder completely through full width of seam.

a. Clean and flux metals before soldering.

b. Ample solder shall be used and seams shall show at least one full inch of evenly flowed solder.

c. Whenever possible, all soldering shall be done in flat position.

i. Seams on slopes steeper than 45 degrees shall be soldered a second time. Remove excess solder and flux from joints.

d. Open flames shall not be permitted on-site without a prior issues Hot Work Permit for each occurrence.

8. Cleats: Space 2 feet on center maximum. Secure to substrate with fasteners and cover heads with cleat tabs. For continuous cleats, secure to substrate with fasteners spaced 1 foot on center.;

9. Reglets: Where applicable, install in accurate locations, straight, in-line, and with leak-proof joints.

10. Sealant Installation: Where applicable and as recommended by referenced standards apply sealant.

B. Typical Flashing Types: Typical flashings shall be fabricated and installed as recommended by SMACNA for a weather tight installation and to match existing, unless otherwise noted. Flashing shall meet the following special conditions:

1. Eave Flashing at all eaves:

a. Extend 4-inches on to roof over ice and water barrier and under breathable membrane;

b. Extend vertical leg of flashing only to bottom of top vertical edge of molded trim at eaves, provide drip edge and attach with concealed fasteners.

2. Rake Edge Flashing at all gable and shed end:

a. Extend 4-inches on to roof over ice and water barrier and breathable membrane;

b. Extend vertical leg of flashing only to bottom of top vertical edge of molded trim at eaves, provide drip edge and attach with concealed fasteners.

3. Headwall/Apron Flashing where roof runs parallel to wall:

a. Run vertical leg of flashing a minimum of 4-inches up wall and/or to first joint in existing siding. Run flashing under joint and secure with concealed fasteners;

b. Extend lower leg of flashing 4-inches minimum onto roof surface and run exposed on roofing. The zinc in the galvanized flashing will help control biological growth on roofing.

4. Stepped Sidewall Flashing where roof runs perpendicular to wall:

a. Install stepped flashing pieces interwoven with roof shingles;

b. Cut top edge of vertical leg of flashing to follow roof slope and run a minimum of 4-inches up wall plane;

c. Secure top edge of flashing to existing wood siding with termination bar and seal top edge of termination bar;

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d. Cover termination bar and flashing with wood trim. Notch wood trim as required to accommodate termination bar. Hold wood trim a minimum of 1-inch above roofing.

5. Open Valley Flashing: Maintain existing open valley dimensions and appearance.

a. Run metal flashing full length of open valleys.

b. Install after all underlayment is in place.

c. Dimensions:

i. Minimum metal valley width, 18 inches;

ii. Minimum metal valley lengths, 8’-0”.

d. Fabricate with edges folded back 1/2 inch and with 1-inch-high deflector at valley center;

e. Overlap joints 8 inches minimum in direction of water flow, bedded in sealant;

f. Attachment:

i. Cleat folded edges to substrate on 2-foot centers.

ii. Fasten top of each section to deck with nail compatible with the flashing material.

g. Breathable underlayment shall lap over side edges of flashing 6-inches minimum. 4 inches minimum at top, and 6 inches minimum at bottom;

h. Shingles shall lap valley flashing a minimum of 7” at each side.

6. Ridge Flashing at Shed Roof(s):

a. Extend vertical leg of flashing only to bottom of top vertical edge of molded trim at eave, provide drip edge and attach with concealed fasteners.

b. Extend flashing onto roof a minimum of 6-inches and cover flashing with two layers of shingles.

7. Roof Penetration Flashing: Provide flashings per existing configurations. as recommended by referenced standards.

a. Incorporate flashing into shingling work as it progresses. Install flashing on top of shingles on downhill side of flashings.

3.11 CHIMNEY FLASHING AT CAMDEN HOUSE

A. Provide new chimney flashing at existing stucco covered chimney at Camden House for a weather tight installation as recommended by SMACNA and as required to match existing.

B. Flashing of the chimney will impact a portion of the existing cement parging on the chimney.

1. Following installation of the new flashing, the parging shall be repaired to match existing in materials, texture and appearance;

C. New chimney flashing includes, but may not be limited to the following special conditions:

1. Cricket at uphill side of chimney:

a. Install wood cricket structure sloped to direct water away from chimney.

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b. Install one piece metal cricket flashing over structure. Cricket flashing shall extend under shingles 8-inches minimum. Turn up edge of cricket flashing at chimney wall 2-inches minimum.

c. Install counter flashing over turned up edge of cricket.

i. Extend counter flashing a minimum of 4-inches above high point of cricket and lap turned up edge of cricket flashing by 1-inch minimum.

Due to the narrow aspect of the chimney in this direction, stepped counter flashing may not be necessary;

ii. Set counter flashing a minimum of ¾” into chimney masonry joints, secure with lead wedges and seal joints with sealant;

iii. Extend counter flashing to within 1-inch of top of roof surface.

2. Apron Flashing at downhill side of chimney:

a. Extend apron flashing a minimum of 4-inches above the roof plane;

b. Set counter flashing a minimum of ¾” into chimney masonry joints, secure with lead wedges and seal joints with sealant;

c. Extend apron flashing around corners to lap under step counter flashing 4-inches minimum.

d. Extend apron flashing 4-inches on top of roofing.

3. Stepped Base and Counter Flashing at sides of chimney parallel to roof slope:

a. Base Flashing: Interweave base chimney flashing with roofing as the work progresses.

i. Base flashing shall lap roofing a minimum of 4-inches and turn up chimney wall 4-inches minimum.

ii. The upper edge of each piece of base flashing shall extend 2” above each course of shingles. The lower edge shall be 1/2-inch above the butts of the shingles forming the next course,

iii. Lap corners of base cricket and apron flashing 4 inches minimum;

b. Counter Flashing: The length and width of each piece of counter flashing will vary with the slope of the roof, however no step shall be more than 3 brick courses in height nor be less than wide enough to lap base flashing by 4-inches minimum.

i. Set counter flashing a minimum of ¾” into chimney masonry joints, secure with lead wedges and seal joints with sealant;

ii. Extend counter flashing to within 1-inch of top of roof surface.

3.12 CHIMNEY PARGING SURVEY AND REPAIRS

A. Contractor shall make an up close survey of the condition of the existing chimney at the time of roofing and flashing installation. Any damaged and/or deteriorated parging shall be repaired.

B. See PART 1 Article “Summary of Work and Estimated Quantities” for estimated quantities of parging repairs.

1. Contractor shall verify concurrence with estimated quantities before proceeding with the work.

3.13 ROOF ACCESSORIES

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A. Reinstall salvaged roof…