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X-LAM Cross-Laminated Timber

X-Lam cross-laminated timber (CLT) structural panels are made by gluing layers of black spruce one on top of the next at right angles to each other… Read more
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  • Third-party forest certification based on standards developed by the Forest Stewardship Council (FSC) is the best way to ensure that wood products come from well-managed forests. Wood products must go through a chain-of-custody certification process to carry an FSC stamp.

    Manufactured wood products can meet the FSC certification requirements with less than 100% certified wood content through percentage-based claims (30% certified content is required if only virgin wood fiber is used; certified-wood content as low as 17.5% is allowable if the rest of the fiber content is from recycled sources).

    With a few special-case exceptions, FSC-based certification is a requirement for GreenSpec inclusion of any nonsalvaged solid-wood product and most other wood products. A few manufactured wood products, including engineered lumber and particleboard/MDF, can be included if they have other environmental advantages--such as absence of formaldehyde binders. Engineered wood products in GreenSpec do not qualify by virtue of their resource efficiency benefits alone (for more on this, see EBN, Vol. 8, No. 11).

  • Just how low the VOC level needs to be for a given product to qualify for inclusion in GreenSpec depends on the product category. For most products, we require certification to California’s health-based emissions standard, CDPH Std Method v1.1 standard (also referred to as California Section 01350), which tests a product’s resultant VOC concentrations in the space after a given period of time. For wet-applied products like paints, caulks, and adhesives, we still also look for VOC content instead of, or in addition to, verified low emissions; this is because emissions testing doesn’t adequately test initial offgassing, and VOC content is currently the only widely available proxy.

Brent Ehrlich
Products Editor

X-Lam cross-laminated timber (CLT) structural panels are made by gluing layers of black spruce one on top of the next at right angles to each other. The resulting panels are light and dimensionally stable in all directions and can be used for floors, walls, and roofing in commercial and residential construction. These panels use fast-growing, FSC-certified black spruce, with no-added-formaldehyde adhesive. X-Lam panels are available in lengths up to 64 feet long, 8 feet wide, and 15 inches thick.

Engineered timber products can provide a significant environmental advantage over solid wood and other building materials: they efficiently utilize fast-growing, small-diameter trees; in responsibly managed forests they sequester carbon that would otherwise enter the atmosphere; they provide a connection to nature when left exposed on building interiors; and they can even provide a viable replacement for energy-intensive steel and concrete in some structural applications.

For decades, engineered timber has been made with exterior-grade, no-added-urea-formaldehyde (NAUF) resins, including phenol formaldehyde, melamine formaldehyde, resourcinol formaldehyde, or phenol-resourcinol formaldehyde. Similar to exterior sheathing, which also uses phenol formaldehyde, engineered timber is exempt from CARB emissions testing because of low emissions, but engineered lumber products are now available with formaldehyde-free polyurethane resins.

Products listed in GreenSpec contain no-added formaldehyde resins, are available with FSC-certified content, or offer other environmental benefits.

LEED Credits

EQc4.3: Low-Emitting Materials—Carpet Systems

IEQc4.3: Low-Emitting Materials—Flooring Systems

IEQc4.5: Low-Emitting Materials—Systems Furniture and Seating

IEQc4.5: Low-Emitting Materials—Furniture and Furnishings

MRc6: Certified Wood

MRc7: Certified Wood

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