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Diamond-Furr Lath Attachment System

Diamond-Furr lath attachment is a system of preformed steel brackets that allow metal lath for three-coat stucco finishes to be attached to an exterior wall with reduced need for individual fasteners… Read more
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  • Using materials recovered from the waste stream typically results in less waste, pollution, and energy use than using virgin materials. From an environmental standpoint, post-consumer is typically considered preferable to pre-consumer recycled content because post-consumer recycled materials are more likely to have been diverted from landfills.

    In some cases, we consider products with recycled content green but with some caveats regarding where they should be used. For example, rubber flooring made from recycled automobile tires should not be used in most fully enclosed indoor spaces due to the likelihood of VOC emissions.

    Recycling can have downsides. For example, some studies show that curbside collection programs and some recycling processes use more energy than they save. Closed-loop recycling is generally preferable to “down-cycling,” in which a lower-grade material is produced—but due to contamination of waste streams and the difficulty of extracting high-value ingredients, down-cycling may be as good as it gets. At times recycling can re-introduce hazardous components. Some products, like copper and aluminum, include a high level of recycled content as a matter of course—which we applaud, but don’t consider justification for listing in GreenSpec. As more complete life-cycle information on recycled materials and processes becomes available, we use that to increase our scrutiny of recycled products.

  • Moisture brings durability and air quality problems with it, and myriad green products are designed to manage it and keep it out. Given the variety of products available, we look for those that meet key performance standards and that make sense in a whole building assembly—such as vapor-permeable weather-resistive barriers that not only prevent moisture from entering the building envelope but also allow drying when the envelope gets wet.

Brent Ehrlich
Products Editor

Diamond-Furr lath attachment is a system of preformed steel brackets that allow metal lath for three-coat stucco finishes to be attached to an exterior wall with reduced need for individual fasteners. According to the manufacturer, Brand X Metals, the system reduces fastener penetrations by over 60%, thus reducing holes in the underlying building paper or weather-resistive barrier that could allow water infiltration and compromise the air barrier system. The system includes a weep screed and sheet metal flashing at key termination points at the top, bottom, and corners of walls, as well as around windows and doors. The steel includes 30% recycled content.

In addition to metal and wood lath for interior and exterior plasters and stuccos, GreenSpec lists special forming and trim accessories. Foam and plastic trim substrates—water-blown or extruded—should have high recycled content or be made from polymers with low environmental impacts.

GreenSpec lists products with high recycled content, minimal materials use, or that have other compelling environmental attributes.

Weather barriers are materials intended to resist air and moisture that has penetrated
the cladding system. Standards and building codes refer to materials that resist liquid water as either water- or weather-resistive barriers (WRB). When combined with flashings, WRBs are part of a system of bulk water resistance often called the concealed drainage plane.

Any rigid sheathing, sheathing membrane, or flexible sheet good that resists bulk water can be combined with flashings to create the concealed drainage plane, or weather WRB). WRBs are typically flexible sheet goods (often house wraps and building paper that come in wide rolls) whose sole or primary purpose is resisting bulk water. WRBs can also be fluid-applied designed for roller or spray gun application.

WRBs may also perform as a primary component of air barrier systems. The vapor permeability of WRBs varies considerably; many are formulated with relatively high vapor permeability to promote evaporative or diffusive drying to the exterior of the building assembly.

Flexible sheet products qualifying for GreenSpec comply with ASTM E2556-10, “Standard Specification for Vapor Permeable Flexible Sheet Water-Resistive Barriers Intended for Mechanical Attachment” Type II Minimum Performance Requirements and are neither gross cross woven nor perforated. Liquid applied products comply with AC 212, "Acceptance Criteria for Water-Resistive Coatings used as Water-Resistive Barriers over Exterior Sheathing."

Weather barrier products listed here contribute to durability and/or reduce the potential for indoor air quality problems associated with moisture and mold.

Note that the vapor permeability of materials designated as the weather barrier can vary widely and the desirability of low or high or no vapor permeability is always in the context of the primary direction of wetting, the primary direction of drying, and the vapor permeability of all the other components in the assembly.

Also note that terminology for materials meant to manage moisture in exterior building enclosures varies widely, even among specifiers and code officials. Master Format language is unclear for this section, using terms such as vapor, air infiltration, and thermal variation in language that can only be described as cryptic. GreenSpec uses the term weather barrier to mean the system of materials achieving a continuous manage of liquid moisture, the dedicated drainage plane interior to the building cladding, often referred to as the WRB.

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