Flashing Standards Get Code Expansion
Two standards addressing flashing systems, both self-adhered and liquid applied, are now integral to the commercially oriented International Building Code.
According to the American Architectural Manufacturers Association, appropriate material specifications for flashing play a key role in a building’s ability to minimize the potential for water penetration and air leakage at windows and door openings.
Correctly flashed windows and doors integrate flashing materials with the drainage plane to provide an effective weather-resistive system, AAMA said.
The association reported that its flashing standards had been adopted in the IBC on Dec. 1. The standards were previously adopted by the International Residential Code.
The standards are AAMA 711 and AAMA 714. Below are descriptions provided by AAMA.
Self-Adhering Flashing Guidance
AAMA 711-13, Voluntary Specification for Self-Adhering Flashing Used for Installation of Exterior Wall Fenestration Products, describes tests used to simulate real-world conditions. It specifies minimum performance requirements to ensure that the flashing does not detach from the sheathing, according to the AAMA.
Some products (Type B) can require the use of a primer in certain field applications, while others (Type A) do not, AAMA said. Each of these types are further categorized by exposure level: Level 1 is for exposures up to 122°F (50°C); Level 2 for exposures up to 149°F (65°C); and Level 3 is for exposures up to 176°F (80° C), the organization explains.
The standard outlines methods for testing water penetration resistance around nails and evaluates how well a self-adhering flashing tape remains bonded to the substrate under conditions of constant stress after thermal cycling and water immersion. Other tests address pliability at cold temperatures (0°F) and tensile strength.
The guideline also discusses the compatibility of adhesives used in self-adhering flashing with other building materials.
Liquid Applied Flashing Spec
The second standard recently included in the code is AAMA 714-15, Voluntary Specification for Liquid Applied Flashing Used to Create a Water-Resistive Seal around Exterior Wall Openings in Buildings, which provides performance criteria for flashing that is fluid at the time of application.
|Photo courtesy of W. R. Meadows|
The flashing standards cover both self-adhered and liquid applied systems.
Installation is by spray, trowel, brush or similar means and must be durable enough when cured or dried to provide a water-resistive seal through the exposure life of the installation, according to the AAMA.
“Of the several performance tests recommended by this specification, heat exposure is perhaps the most meaningful,” the association said.
“This is because the surface temperature of the exterior sheathing surface and/or behind the wall cavity behind the face will often greatly exceed ambient temperature due to direct sunlight exposure, conductive heat through the façade surface, radiant heat buildup and exposure to reflective surfaces near the building.”
Three levels of heat exposure qualification are the same as those described above.
Additionally, there are tests for adhesive strength to a variety of substrates, including concrete block, stucco and plywood; water penetration around nails or fasteners; accelerated UV exposure and water immersion.
Founded in 1936, the AAMA is the leading trade association representing window, door, skylight, curtain wall and storefront manufacturers and their suppliers.