Atlas recommends a staggered double layer application of ACFoam-II as the first layer and CrossVent or CrossVent RB as the top layer.This application will improve thermal performance and limit moisture and airflow through the roof system.Atlas CrossVent or CrossVent RB should be installed directly over the vapor/air retarder that has been applied over the approved substrate. CrossVent or CrossVent RB should be installed with the 8 ft.dimension parallel to the eave and with the vent spacer strips running up the slope of the roof. CrossVent or CrossVent RB shall be fastened directly through the vent spacer strips in accordance with fastening patterns contained in the Atlas publication, Guide Details (Current Edition) for Nail Base and CrossVent Insulation.

Atlas requires the use of Atlas Nail Base Fasteners. Refer to Atlas Design Guide for Nail Base and CrossVent Insulation for fastening patterns and other application recommendations.

Heavy snow and ice loads, very steep pitches, high interior humidity conditions, or very high wind load areas may necessitate custom fastening patterns and design. For design conditions beyond those contained in the above referenced Design Guide, a professional engineer or architect should be consulted.

Cover CrossVent or CrossVent RB with Atlas No.15 or No.30 roofing felt.Insulation that has become wet must be replaced with dry product prior to applying the roof coverings. Atlas also offers a wide variety of roof shingle products including three-tab and laminated shingles, as well as felts and accessories.

Ridge and soffit vents are necessary to create an effective ventilating roof system, and should be matched in ventilating capability (NFA/LF) to the CrossVent or
CrossVent RB.

Vapor Retarder

Moisture vapor tends to migrate from warmer to cooler areas. In building construction, vapor/air retarders are used to inhibit or block the passage of warm, moisture-laden air into walls or roofing assemblies.To determine whether a vapor/air retarder is necessary, calculations based on interior relative humidity, interior temperature, and the outside design temperature must be performed. Consult the NRCA Roofing and Waterproofing Manual (Fifth Edition) for more information regarding vapor/air retarders and dew point calculations.

The designer must be aware of the actual conditions of the specific installation. The designer has the responsibility to determine whether a vapor/air retarder is required and what type should be used; however, Atlas strongly recommends the use of a vapor/air retarder with a perm rating of 0.5 or less on all projects except those in extreme cooling climates. This recommendation is made to prevent excessive moisture from construction materials or design conditions from migrating through the roof assembly and causing ridging of asphalt shingles. In addition, a properly installed vapor/air retarder helps to reduce thermal loss at insulation joints, thereby helping to reduce snowmelt and potential ice dams. Consult vapor/air retarder manufacturer for recommended applications and details.

Limitation of Liability

Other than the aforementioned representations and descriptions, Atlas Roofing Corporation (hereafter,“Seller”) makes no other representations or warranties as to the insulation sold herein. The Seller disclaims all other warranties, express or implied, including the warranty of merchantability and the warranty of fitness for a particular purpose. Seller does, however, have a limited warranty as to the R-Value of the insulation, the terms of which are available upon request from the Seller.

The Seller shall not be liable for any incidental or consequential damages including the cost of installation, removal, repair or replacement of this product.The Buyer’s remedies shall be limited exclusively to, at Seller’s option, the repayment of the purchase price or resupply of product manufactured by Atlas in a quantity equal to that of the nonconforming product. Atlas distributors, agents, salespersons or other independent representatives have no authority to waive or alter the above limitation of liability and remedies.