LUMBER AND ENGINEERED WOOD
This section lays out the environmental considerations for solid and engineered lumber products. Application-specific information is also available: For engineered panels, see guides to Wood Panels, Structural Insulating Panels, and Sheathing. For treated lumber, see Exterior Decks and Fencing.
Considerations:
Design assemblies to match the standard dimensions of the materials to be used, reducing waste and material cost. Measure twice and cut once.
Consider salvaged or reclaimed wood, particularly for non-structural applications such as interior walls, finish carpentry, and wood flooring.
Where salvaged or reclaimed wood is not available or applicable (such as many structural applications), specify “FSC certified” wood.
For framing interior walls, consider steel studs with high-recycled content.
Engineered wood may be used for more efficient framing:
- Engineered joists and rafters for floors and ceilings use less wood than solid lumber, and can offer structural advantages.
- For interior floors, consider steel trusses.
- Choose engineered lumber for structural headers and beams, and for vertical applications. Consider finger-jointed studs.
- For non-load-bearing headers, use doubled smaller dimension lumber when appropriate (i.e. double 2x6 when a solid 4x6 is not structurally necessary.)
Try advanced framing (24" on center with insulated headers)
Order materials that can be delivered pre-cut for rapid, almost waste-free installation, such as panelized wood framing and structural insulated panels.
Consider designing for disassembly, so materials can be readily reused or recycled.
Use clips and stops to replace blocking at top plates, end walls, and corners. Clips can provide the potential for two-stud corners, reducing wood use, easing electrical and plumbing rough-in, and improving thermal performance.
Summary: Impact of Lumber
Wood is a renewable product, and requires less energy than most materials to process into finished products. However, logging, manufacture, transport, and disposal of wood products have substantial environmental impacts. Standard logging practices cause erosion, pollute streams and waterways with sediments, damage sensitive ecosystems, reduce biodiversity, and lead to loss of soil carbon. The key to reducing these impacts is minimization of wood use by substituting preferable materials, reuse of salvaged wood, selection of wood from responsibly managed forests, and designing to control waste and minimize redundant components.
Forest Stewardship Council (FSC) certification is a widely recognized and respected standard for responsible forest management. FSC labeled products are certified as produced from responsibly managed forests, lumber is among the growing range of FSC certified products available in Santa Cruz and Monterey counties. Note the FSC's use of the term, ‘responsibly managed,’ rather than ‘sustainable.’ Sustainable (or even environmentally beneficial) products are the goal, and FSC standards are a well regarded indicator of environmental performance. However, overall sustainability in forestry is a complex, site-specific endeavor that is difficult to define to everyone's satisfaction, let alone to attain.
FSC certification is a desirable feature in a wood product, but minimization of waste and overall wood use is critical to sustainable design. Three ways to reduce wood use are to:
- Substitute other materials (reducing wood use but not necessarily reducing overall energy use or pollution),
- Design for common material dimensions, and order materials accordingly, to minimize on-site cutting, and
- Design for efficient wood use.
Substitute material options can be found throughout this guide, and designing for common dimensions is self-explanatory and can reduce waste, material costs, and labor. Designing for efficient wood use, however, represents a revolution in construction. The diversity, availability, and performance of engineered wood products continues to expand as the availability of mature trees suitable for large-dimension solid lumber declines. Engineered wood, along with braces and fasteners (such as blocking clips) improves the opportunity for designs to gain necessary strength while efficiently using only the necessary amount of wood fiber. Reductions in total wood fiber use (of as much as 40% vs. conventional practice) have been achieved, without structural compromises, because engineered products can be stronger along critical axes than their similar-sized solid counterparts. In fact, such options as structural insulated panels, engineered trusses, and panelized wall systems often offer superior structural performance, with appropriate design and installation.
To Learn More:
Forest Certification Resource Center
Natural Resources Defense Council (1998) “Efficient Wood Use in Residential Construction: A Practical Guide to Saving Wood, Money, and Forests”
California Integrated Waste Management Board
Links to reusable material retailers
CalMAX Materials Exchange
ACWMA Green Building Guidelines (for new construction and remodels)
GreenSpec
A fee-based service searchable by the standard UniFormat. It is probably the most comprehensive single source of green building product information.
Oikos
A free website with information about a wide range of greener construction products
Center for Resourceful Building Technology
A free website with information about a wide range of greener construction products
| Program Contact: Green Building |
Ecology Action
Phone: 831.426.5925
Fax: 831.425.1404
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