Installation Instructions
GlassMaster General Instructions - Ardmore, OK & Hampton, GA
Atlas Roofing
Atlas will not be responsible for damage to shingles as a result of inadequate ventilation.
Ventilation provisions must meet or exceed current FHA Minimum Property Standards and conform
to all building codes and regulations. To best ensure adequate ventilation and circulation of air, a
combination of vents at ridge and eaves should be used. All roof structures, especially mansard and
cathedral type ceilings, must have complete through ventilation from the eaves area to the ridge
area. FHA Minimum Property Standards require one sq. ft. of net free ventilation area for each 150
sq. ft. of attic floor space to be vented; or one sq. ft. per 300 sq. ft., if vapor barrier is installed on
the warm side of ceiling, or if at least one half the ventilation area is provided near the ridge.
3. ROOF DECK
These instructions are for the application of Atlas asphalt shingles to nominal 7/16” thick American
Plywood Association (APA/TECO) rated, code approved plywood, OSB decks or minimum 3 /4”
actual thickness wood decks. The plywood or non-veneer (OSB) decks must comply with the roof
deck specifications of APA/TECO. Solid wood decking must be well seasoned, not over 6” (nominal)
width, and fastened securely to each rafter. The deck surface must be clean, bare, gap free and
flat. GlassMaster® 30 shingles must not be applied to any surface other than roof deck types
described here. Atlas also honors its Shingle Limited Warranty when Atlas shingles are installed on
the Atlas CrossVent® Nailable Insulation panels. Atlas will not be responsible for the performance
of its shingles if applied directly to non-vented, insulated decks composed of perlite board, plastic
foam, fiberboard, gypsum plank, lightweight concrete, cementitious wood fiber, or similar materials
or to any decks with insulation installed directly to the underside of the decking, with the exception
of CrossVent® Nailable Insulation. Spray foam insulation applied directly to the bottom of the
decking will void the warranty. Atlas shingles may be installed over a roof system containing a
radiant barrier material if: 1. the required full, flow through ventilation is maintained directly under
the decking material in all cases, 2. the radiant barrier material is highly vapor permeable ( > 2
perms), and, 3. the radiant barrier is installed on the underside of or below the decking – not used
as an underlayment above the decking. Spray-on types of below deck vapor permeable radiant
barriers will be considered only on a job by job basis, and only if tests confirm > 2 perms or greater
vapor permeability.
4. UNDERLAYMENT
Atlas highly recommends the use of high performance, ASTM 6757 compliant - Gorilla Guard® or
Summit® proprietary underlayment products for long term roof system performance and
WeatherMaster® Granular, self-adhering, waterproofing underlayment for critical areas, such as
valleys and eaves. Atlas does not approve the use of any self-described, metalized or metal
containing category of “Radiant Barrier”, as an asphalt shingle underlayment installed above the
deck. Use of these types of radiant barrier would void the shingle warranty. Underlayment must be
applied flat and unwrinkled. Building codes vary with geographic areas, and the installation must
comply with local building codes or shingle manufacturer’s requirements, whichever is stricter.
Shingles should be applied as soon as possible after the application of organic underlayment felt,
which is not intended for prolonged exposure. Atlas recommends that the shingles be applied the
same day as the felt underlayment application to avoid wetting and wrinkling. If an underlayment is
used for prolonged dry-in, Atlas recommends Summit® Synthetic Underlayment as the dry-in
underlayment, for up to 6 months exposure.
Standard Slope Application: Proper application requires that a single layer of approved
underlayment be applied to decks with slopes of 4” per ft. or greater and consistent with all
applicable building codes. This approved underlayment is a required roof assembly component to
maintain a Class A fire rating of the deck assembly. Install underlayment over the entire deck,
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