B08_Attach3_-_Specifications_Addendum.pdf
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- Attached to
- YOSE 231409 - Re-Roof the Big Trees Lodge
- Solicitation number
- 140P2022R0132
About this file
This addendum document provides clarification on equivalent materials that may be proposed for a re-roofing project at Yosemite National Park. Specified materials requiring equivalents include metal framing anchors, self-adhering waterproofing and underlayment membranes, fiberglass cap sheet, ventilated underlayment, UV-resistant self-adhering flashing, and fleece-reinforced acrylic waterproofing membrane for Division 06 and 07 work. It also provides requirements for equivalent primer, tape, and low-sheen latex paint products in Division 09. The mechanical catwalk and sight screen in Division 07 has manufacturer requirements that could allow for an equivalent if all criteria are met. The related solicitation is for the re-roofing of the Big Trees Lodge at Yosemite National Park and was amended to include an attendee sign-in sheet from a pre-bid site visit.
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Yosemite National Park
RE-ROOF THE BIG TREES LODGE (WAWONA HOTEL)
MAIN BUILDING
YOSE PMIS NO. 231409
CONSTRUCTION DOCUMENTS SUBMITTAL
SPECIFICATIONS
ADDENDUM 1- EQUIVALENT MATERIALS CLARIFICATION
NATIONAL PARK SERVICE
DENVER SERVICE CENTER
August 8, 2022
OVERVIEW
This addendum serves as a supplemental document to the construction documents submittal specifications document, for YOSE PMIS NO. 231409, dated 1/31/20. The purpose of this addendum is to clarify the salient characteristics of materials that may have an approved equal. Additionally, salient characteristics are provided for materials that are listed as having no known equals, such that an equivalent material could be proposed if found.
EQUIVALENT MATERIALS IN DIVISION 06 10 00 – ROUGH CARPENTRY
• Section 2.4 “Metal Framing Anchors”
A single manufacturer is defined in addition to approved equals. An approved equal must comply with the criterion referenced in section 2.4 B. The criterion is to meet or exceed design load of the basis-of-design product(s). An independent testing agency should perform comprehensive testing to verify empirical data or rational engineering analysis provided by the manufacturer.
EQUIVALENT MATERIALS IN DIVISION 07 31 29– WOOD SHAKE ROOFING
• Section 2.3. A “Self-Adhering Waterproofing Membrane and Self-Adhering Valley Underlayment”
An approved equal must comply with ASTM D 1970. The sheet must be at least 40 mm thick, with Styrene Butadiene Styrene (SBS) modified asphalt. This material should be intended for high temperature, it shall not have mineral-granule surface. It shall come with release backing and applied using cold adhesive.
• Section 2.3 B “Fiberglass Cap Sheet”
An approved equal must comply with ASTM D 3909. The minimum weight of this material must be 76 lb. per 100 sq. feet of roll. The fiberglass cap sheet must be coated with asphalt that is not modified. It shall have a mineral surface and comply with UL 55-A.
• Section 2.3 C “Ventilated Underlayment”
The available manufactured product recommended is Cedar Breather I, by Benjamin Obydke. While there is no known equal, an equivalent manufacturer could be used if it meets the specified requirements. The underlayment must be a compression resisting, three-dimensional, non-woven, entangled filament, nylon mat that is designed to permit the movement of air and gravity drain incidental moisture. The manufacturer of this underlayment material must be able to provide written evidence that it is qualifying as a Class A assembly with the specified cedar shakes/shingles and the fiberglass cap sheet when tested in accordance with ASTM E108.
• Section 2.3 E “UV-Resistant Self Adhering Flashing”
An approved equal must be aluminum-faced flashing, with self-adhesive. It must be intended to be exposed to the environment and withstand temperatures up to 200 degrees Fahrenheit.
• Section 2.3 F “Fleece-Reinforced Acrylic Waterproofing Membrane”
An approved Equal must be able to be installed in the vertical position without losing water seal. It must be of acrylic material with fabric reinforcement.
EQUIVALENT MATERIALS IN DIVISION 07 72 00
• Section 2.2 “MECHANICAL CATWALK WITH SIGHT SCREEN”
Section 2.2.A (1-8) outlines the requirements for a mechanical catwalk and sight screen. A single manufacturer is specified in Section 2.2.A.9 which satisfies these requirements, however an approved equal would be considered if all of the requirements are met.
EQUIVALENT MATERIALS IN DIVISION 09 91 00 – PAINTING
• Section 1.6 E.6.a.2) “Use the following tape for testing: ScotchBlue Painter’s Tape Original Multi- Surface 2090-.75N, 0.75 in. x 60 yd”
An approved equal for this tape should be 0.75” wide. It should have adhesive such that it is suitable for multiple materials such as such as smooth or lightly textured walls, trim, baseboards, tile and glass. It should be able to be adhered on the surface up to 14 days and removed without leaving adhesive behind. It shall be resistant to UV light (undamaged from sunlight)
• Section 3.5 A.1. a. “Prime Coat: Primer, alkyd for exterior wood, MPI#5”
Two manufacturers are specified for this material. An approved Equal in addition to these two manufacturers would be an alkyd/oil-based primer intended for exterior wood siding and trim. This primer must be mildew resistant.
• Section 3.5 A.1 c. “Topcoat: Latex, exterior, low sheen (MPI Gloss Level 3-4), MPI#15”
Two manufacturers are specified for this material. Approved equals would need to be latex based, low sheen with a gloss level 3-4. The approved equal would need to be suitable fort the prime coat specified in Section
3.5 A.1. a. Additionally, the selected paint would need to be used as specified in section 3.5 A.1 b.
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