Product Specifications

Fiberglass-Based Asphalt Shingles & Accessories
C. If another installer is responsible for roof deck preparation, notify the architect, designer-of-record on
the project, or building owner of unsatisfactory preparation prior to proceeding with installation.
Commencement of installation constitutes acceptance of conditions.
D. Underlayment and shingles installed directly over roof insulation or similar type decks is not approved.
1. Roof deck must be dry, minimum 3/4 in (19 mm) thick, minimum 6 in (152 mm) wide boards
with maximum 1/4 in (6.4 mm) spaces, or APA rated sheathing (exposure 1): minimum 3/8 in
(9.5 mm) plywood, minimum 7/16 in (11.1 mm) oriented strand board. Consult your
manufacturer for other approved constructions.
2. Ventilation under the roof deck must meet local code requirements.
3.2 PREPARATION
A. Prepare surfaces using the methods recommended by the manufacturer for achieving the best result
for the substrate under the project conditions.
B. Remove all existing roofing down to the roof deck.
C. Verify that the deck is dry, structurally sound, clean and smooth. It shall be free of any depressions,
waves, and projections. Cover ALL holes 1 in (25 mm) or less in diameter, cracks over 1/2 in (13 mm)
in width, loose knots and excessively resinous areas with minimum 28 gauge; 0.0187 in (0.475 mm)
galvanized steel, 0.0156 in (0.396 mm) stainless steel, or 0.0126 in (0.320 mm) aluminum sheet metal.
Decking or deck boards with holes greater than 1 in (25 mm) in diameter shall be replaced.
D. Replace damaged deck with new materials.
E. Verify installed roof deck is acceptable to receive shingles. Acceptable roof decks include the
following:
1. Wood boards: 6 in (152 mm) minimum width, 3/4 in (19 mm) minimum thickness.
2. Plywood sheathing: 3/8 in (9.5 mm) minimum thickness Exposure 1 grade plywood sheathing
as recommended by APA and in compliance with local building code requirements.
3. OSB panels: 7/16 in (11.1 mm) minimum thickness non-veneer structural panels as
recommended by APA and in compliance with local building code requirements.
4. Spacing between boards or panels shall not exceed 1/4 in (6.4 mm) between roof boards or 1/8
in (3.2 mm) between plywood or OSB sheathing panels.
3.3 UNDERLAYMENT INSTALLATION
A. Install Owens Corning™ underlayments using Owens Corning, installation instructions and in
accordance with local building code requirements. When local codes and installation instructions are
in conflict, the local building code requirements shall take precedence.
1. Install self-adhering ice and water barrier from the eaves edge of roof up the slope a full 36 in
(914 mm) but not less than 24 in (610 mm) beyond the interior edge of the exterior wall. Lap
ends 6 in (152 mm) on roof decks sloped 5:12 and greater. On roofs with slopes from 2:12 up to
4:12, see application instructions printed on each package.
B. Drip Edge
1. Drip edge shall be installed on all roof edges.
2. Install drip edge on eaves first with underlayment installed over the drip edge, or install per local
code requirements.
3. Install drip edge on rakes after underlayment is installed, with the drip edge fastened over the
underlayment.