2022 Library Roofing Project
Community College of Allegheny County Pittsburgh, Pennsylvania
4.
Prepare the roof substrate prior to installing the new roof system. a. Install pressure treated wood blocking as required to match new insulation heights at wall junctions, roof edges, and penetrations and as indicated on detail drawings. b. Where needed, install pressure treated wood blocking to top-side of parapet wall to accommodate the attachment of a new metal coping. Attach wood blocking to wall using appropriate fasteners. c. Raise existing roof curbs and plumbing vent stacks to a minimum of 8 inches above the new roof surface. d. Clean roof deck and wall surfaces of dust, debris, and other substances
detrimental to roofing installation according to roofing system manufacturer’s written instructions. Remove sharp projections.
5.
Install tapered roof insulation system. a. General: (1)
Sweep roof deck clean prior to roof insulation application. Install tapered insulation plan as specified for insulation,saddle, and cricket requirements. Install tapered edge up against ½” isocyanurate cricket dimension. Install one or more layers of roof insulation to achieve the specified R-Value or thickness. (a) Individual insulation board thickness shall be 1.5 inches minimum thickness and 3.5 inches maximum thickness. Install insulation boards in two (2) or more layers when required board thickness exceeds 3.5 inches. Install insulation with long joints of insulation in a continuous straight line with end joints staggered between rows, abutting edges and ends between boards. Stagger insulation board joints a minimum of 12 inches in both directions from joints of the previous insulation layer. Adhere insulation, saddles, crickets, and tapered edge strips using Tremco Low Rise Foam Insulation Adhesive as specified below.
(2)
(3)
(4)
(5)
(6)
c.
Install tapered insulation system. (1)
Install minimum 5.2-inch thick, tapered polyisocyanurate insulationsystem with specified slope.
(2)
Adhere insulation layer(s) as specified below.
d.
Install tapered insulation saddles or crickets to promote positive drainage along valley lines between roof drains and scuppers, along walls, at high side of roof curbs and as instructed at Pre-Job Walk. (1) Tapered insulation saddle and cricket slope shall equal a minimum of twice the roof slope. (2) Saddle widest width shall equal or exceed 1/3 of the distance between the roof drains or scuppers. (3) Subcontractor is responsible for the elimination of ponding water along valley lines.
e.
Install tapered edge strips. (1)
Install and adhere tapered edge strips where blocking height exceeds insulation height.
01010-4 SUMMARY OF WORK
February 2022
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