Wood-Use Reduction INTENT: Minimize the total quantity of new wood used in wood-framed buildings through wood-efficient design, detailing, specification, construction practices and verification. REQUIREMENT: Design structural framing using as many Optimum Value Engineering (OVE) measures, as identified in the NRDC\'\'s "Efficient Wood Use in Residential Construction", as possible for the specific building, including minimizing the use of non-structural wood used to hang drywall and specifying wood-efficient lumber products wherever practical. Demonstrate at least a 20% savings in the quantity of wood used compared with conventional, non-OVE wood framing measures. SUBMITTALS: Structural framing plans, details and specifications, a letter signed by the structural engineer outlining the wood-efficient framing measures identified in the design approach, photographs of framing measures under construction, bills of sale of wood-framing materials purchased, and calculations demonstrating at least a 20% savings in the quantity of wood used compared with conventional, non-OVE wood framing measures. DESIGN APPROACH: For a complex multi-family building reaching up to 4 stories with multiple unit types, over 20% wood use reduction is achieved through the following combination of wood-efficient framing measures: 1. Floor and roof have been framed at 24" O.C. Also we have avoided the use of two-or three-ply girder trusses. 2. The floor and roof components are open-web wood trusses, which tends to minimize the use of lumber materials as compared to solid wood joist or plywood-web floor trusses 3. Header beams at wall openings, as well as all other wood beams supporting trusses and wall loads, have been designed and sized for actual loading conditions. 4. The ground levels of the buildings are concrete slabs on grade, thus eliminating a wood-framed first floor level (ie-if a crawl-space were to be used). 5. Wood-efficient finger-jointed lumber is used for all vertical stud applications, structural and non-structural. 6. Interior non-load-bearing partitions are framed at 24" O.C., rather than 16" O.C. 7. Drywall clips are used at to support drywall instead of a third non-structural stud at corners where applicable.
The proposed intent and approach have merit, and the proposed benchmark for wood-use reduction, 20 percent, is appropriate for the building type (wood-framed, four-story construction). However, framing crews often follow their own "standard practice", contract documents notwithstanding. In addition, it is important to establish a baseline against which the reduction is measured. Thus the following documentation will need to be submitted: A standard lumber and wood sheathing takeoff for the project, produced using the same method that the applicant would have used had OVE not been implemented on the project, along with a description of how and by whom that takeoff was done; The actual bill of materials purchased; A spreadsheet comparing the wood quantities shown in the standard takeoff with those in the bill of materials (quantites should be expressed in board feet and board feet-equivalent for sheathing and engineered wood products); Framing plans and elevations showing OVE measures; and A letter signed by a responsible party enumerating the OVE measures used and certifying that the project was built in accordance with the enumerated OVE measures. Should this credit be audited, the applicant also should be prepared to provide photographs of the framing in the field. Photos should show readily identifiable landmarks (e.g., adjoining structures or other unique features) or should be accompanied by a statement witnessed by a credible third party (e.g., building inspector) certifying that the photos are of the project in question. Applicable internationally.