RFI Roof Insulation Revision.pdf

The following revisions are meant to clarify a previous response given to a verbal question as to whether or not the attic space should remain ventilated due to the increased thermal heating and cooling loads emanating from the attic to the 3rd floor conditioned areas. The previous answer was that the design was to remain intact as the 3rd floor FCU’s were up-sized to account for the additional loads. However, the previous answer was incorrect. Instead, delete the requirement for rigid insulation on the new sloping metal trusses and metal decking and relocate the building thermal envelope ‘cap’ to the existing metal decking that is designed to remain per the current contract documents. More specifically, abide by the following:

1) Drawing Sheet A-501: Delete Detail B1 and replace with new Detail B1, attached. New detail B1 shall apply to Roof Section D4, except that no insulation shall be included on the breezeway ceiling and no roof overhangs will exist.

2) Drawing Sheet AC-130: Detail D1; New R-38 rigid insulation and 5/8” recovery board will appear around the attic hatches per new Detail B1 on Sheet A-501.

3) Drawing Sheet A-310: New detail B1 shall apply to Wall Section D1, and shall be similar to Wall Section D2, except that no insulation shall be included on the elevator tower roof or as a ceiling.

4) Drawing Sheet A-311: New detail B1 shall apply to Wall Section D1.

5) Specifications Section 07 22 00, Roof and Deck Insulation:

Part 1.1, References: Delete Reference to FM 4450, (1989) Approval Standard for Class 1 Insulated Steel Deck Roofs.

Part 1.7, FM Approval Requirements: Delete this part in its’ entirety.

Part 1.8.1, Insulation in Roof Systems: Replace the first word of the 2nd sentence, ‘Roof’ with the word ‘Attic’. Revise flame spread rating of 75 or less to “25 or less”.

Part 2.1.1, Insulation Types, Subpart (a.): Replace the required minimum compressive strength of 20 pounds per square inch (psi) with ‘25’ psi.

Part 2.2, Fasteners: Delete the last sentence in its’ entirety.

Insert Part 2.4, Sheathing: Include the wording “Foam plastic insulation and the underside of the standing seam metal roofing system shall be separated from metal decking by a layer of fiberglass mat-faced, gypsum core sheathing of the specified thickness meeting requirements of ASTM E136. Certified by UL for use as a fire barrier over combustible and noncombustible decks in accordance with the ANSI/UL 790 and ULC S114 test standard.”

Insert Part 2.5, HT Underlayment: Include the wording “Roofing Underlayment shall be a High Temperature (HT), self-adhering, waterproofing underlayment composed of a non-slip, cross-laminated polymer film, laminated to a high temperature, aggressive rubberized asphalt adhesive over top surface of sheathing. It shall be adhered to the gypsum core sheathing before application of any metal roofing panels.”

Part 3.2, Insulation Installation: Delete the 2nd sentence in its’ entirety and replace with “Lay insulation so that continuous longitudinal joints are perpendicular to direction of existing metal deck flutes, and end joints of each course are staggered with those of adjoining courses.”

Part 3.2.1: Rename this part ‘Installation Using Mechanical Fasteners and Adhesive.’

Also, delete the wording of this part in its’ entirety and replace with “Secure bottom layer of insulation with penetrating type fasteners at a rate of 6 fasteners per sheet of four feet by eight feet insulation. Fully adhere top layer of insulation to bottom layer using adhesive approved by the insulation manufacturer. Tape and seal all joints in top layer.”

Part 3.2.2, Special Precautions for Installation of Foam Insulation: Delete this Part in its’ entirety.

Part 3.3.1, Protection of Applied Insulation: Delete the first sentence and replace with “Completely cover each day’s installation of insulation with a temporary waterproof membrane on same day.”

6) Specifications Section 07 61 14.00, Steel Standing Seam Roofing:

Part 1.4 Submittals, SD-03 Product Data: After Insulation, insert ‘Roof Sheathing; G, AE.’

Part 2.1.1 Material: After the first sentence, insert the sentence “Tension level coil stock must be used if panel texture is smooth without intermediate striations.”

Part 2.2, Attachment Clips: In the last sentence, replace the word ‘insulation’ with the word “sheathing”.

Part 2.4: Delete ‘Thermal Insulation and its’ reference and instead insert “SHEATHING Fiberglass mat-faced, non-combustible (as described & tested in accordance with ASTM E136) nonstructural, gypsum core panels.”