Green from the Ground Up Best Practices
- Use less lumber to perform the same function by adopting Advanced Framing Techniques (OVA)
- Use engineered lumber in place of large-dimension sawn lumber
- Demand FSC-certified lumber from your supplier
- Use reclaimed lumber if it is available
- Give serious consideration to building with SIPs or AAC
- Frame for the highest practical levels of insulation: the house should exceed energy standards by 50%
- Avoid light-gauge stell framing on exterior walls unless steps are taken to prevent thermal bridging. Avoid stell framing on exterior walls completely in areas of severe cold.
Green Framing Resource
Framing is the skeleton of a home. Wood is one of the best suited and most renewable materials used in construction. With new advances in framing, projects can now use less wood, resources and save money at the same time.
Advanced Framing Reduces Waste
During the 1970's energy crisis, the National Association of Home Builder's Research Foundcation conducted studies to identify what structural configuration was necessary to maintain superior strength and allow the maximum insulation in wall cavities to improve energy efficiency. The result was called "Optimal Value Engineering" (OVE).
The basics of OVE:
- Walls are framed with 2x6s on 24-in centers rather than 2x4s on 16-in. center
- Corners are made from two studs rather than four
- Headers are sized according to the load they actually carry.
- Roofs are built with trusses rather than framed conventionally
- Floors are framed with I-joists rather than sawn lumber
- Insulating sheathing replaces conventional plywood or oriented strand board
New Framing Materials
There's a tremendous diversity in the materials, techniques and traditions that go into the building the frame of a house. These new materials all have their advocates and they all have something to offer sustainable building. A few of these new materials are identified and defined below.
Autoclaved Aerated Concrete (AAC) - takes the place of a number of components used in standard stick-frame—wood, insulation, house wrap, and drywall—all in a single product.
Certified Wood - certification bodies like the Forest Steward Council (FSC) and the American Forest and Paper Association's Sustainable Forest Initiative (SFI) can ensure the wood you are using to frame a home is harvested sustainably.
Engineered Lumber - use wood fiber more efficiently than solid sawn lumber, and they can be made from wood species that regenerate themselves.
Steel studes with Recycle Content - made with recycled materials and are also dead straight, so walls and ceilings are true.
Structural Insulated Panels (SIPs) - combine insulation and structure in a single product. They are a sandwich of insulating foam and oriented strand board that can be used for floors, walls, and roofs. In the book, read how one of the authors used structural insulated panels (SIPs) to build his office in January before the snow fell.
A Green Framers' Transition Guide
Frame new walls with advanced framing techniques
- Reduces lumber by placing truss and exterior wall framing at 24” O.C.
- Consult with the structural engineer for applicability in your jurisdiction. Typically advanced framing includes:
- 2x6 on 24” centers
- 2-stud corners
- Ladder blocking for partition walls
- Stacked loads from trusses down to foundation
- Always use double top plates
- Uses up to 20% less material while still maintaining structural integrity.
No headers in non structural walls
Reduced labor and lumber waste
Header dispersers load to prevent strain on a window or door. If there is no load, there is no need for a header.
Use flat-framed 2x headers similar to interior non-load bearing framing
Built wall corners using two studs
A two stud corner leaves more room for insulation and helps reduce thermal bridging. It also uses less lumber.
Drywall can be attached using drywall clips
Three studs may be necessary for some siding applications
Use FSC and finger-jointed lumber when available
FSC wood comes from sustainably managed forests that replant trees that are cut down. Finger-jointed studs utilize shorter lengths of wood that are joined together
Finger-jointed studs are straighter, and easier to work with
Contact your local lumberyard and ask for FSC lumber or Finger-jointed studs.
Use microlams, gluelams, LVLs and other engineered lumber
There are fewer old-growth forests to supply large dimensional lumber. These engineered products are more environmentally friendly, stronger and straighter
Engineered lumber is installed in the same way as conventional lumber.
These materials are readily available and are similar in price to dimensional lumber.
Solid-sawn lumber greater than 2x8 is typically milled from old-growth trees.
Consider using steel studs for interior walls
Steel studs are perfectly straight and easy to install
Nailed in place similar to wood studs or screwed into steel C channel. Not to be used in exterior walls due to thermal bridging.
Readily available and are similar in price to dimensional lumber.
Recycle wood, cardboard and metal on site
Recycling is cheaper or free in some areas than paying dump fees. Keeping these materials out of landfills is very important. Recycling will set you apart from your competitors as a green builder.
Have three labeled recycling bins set up beside your trash dumpster.
Your city may have a recycling program already in place. If not purchase your own bins for this purpose.
Green Building Training & Certification
Find out when the next Green Building Training is and learn more about Green Building Practices.