BUILDING WRAP PRODUCT DATA FOR SPEC.docx

18-121 / 636A821700 - IOWA CITY EHRM INFRASTRUCTURE UPGRADES

Data for Specification Section TBD

BUILDING WRAP PRODUCT DATA

See also attached NFPA Compliant Data Air Barrier Association, Walpole, MA

Woven polymeric wraps are made of crisscrossing plastic tapes coated with a waterproof film and may be micro-perforated to allow vapor to pass; the film can also include UV inhibitors if prolonged exposure, up to about four months, is expected.

Nonwoven polymeric is made of spun-bonded polymer resins; the fibers are melted and flattened to form a fabric-like material.

Application Wraps are either mechanically attached, self-adhered, liquid- or fluid-applied, or pre-attached to a composite wall product. Always refer to the applicable building code for fastening requirements for wraps intended for mechanical attachment. An example fastening pattern could be 1-inch plastic caps, or 1-inch crowned staples, at 24 inches on center maximum.

Self-adhesive wraps can be impermeable or permeable, the latter of which may be appropriate for wood-based construction projects. Less than ideal weather conditions—wind and water—during installation can affect the seal.

Liquid-applied wraps can also be permeable or impermeable. They are the most expensive type of wraps, Compatibility Comparison A building wrap must also work in concert with compatible materials, such as sheathing tape, flashing, and sealants. Sheathing tape aims to prevent water intrusion at seams and reduce wind damage to the wrap. Flashing is necessary at penetrations through the building wrap and to manage transitions between different materials. Primer can help when other chemicals are present, such as at joint and window materials. For example, Dunlap says, “If you put in a window and want to use a sealant joint, you have verify the compatibility of the wrap with the sealant joint.” To be certain of compatibility, “you have to ask the manufacturers and get a letter in writing,”

ASTM E96, Standard Test Methods for Water Vapor Transmission of Materials and ASTM D779, Standard Test Method for Determining the Water Vapor Resistance of Sheet Materials in Contact with Liquid Water by the Dry Indicator Method.