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Before you build or add an addition to your home, size up your structural options. Each has ecological and economic pros and cons.
While wood framing is the most common and familiar type of home structure, you have other options, including insulating concrete forms (ICFs), structural insulated panels (SIPs), and lightweight concrete blocks. Of course, if you’re adventurous, many other systems have been around for decades, including log homes, straw bale, adobe, and others. Not every method of construction may be right for your geography, but most technologies can be modified to accommodate your taste and your region. For the purposes of this primer, however, let’s stick to the structural systems your builder is most likely to know and understand.


WOOD FRAMING


VIRTUES
> Renewable (if forest is well managed)
> Familiar to contractors
> Excellent durability


CAVEATS
> May create unwanted thermal bridging
> Requires skilled labor


WOOD FRAMING OLD AND NEW
Wood, by its very nature, is a green product. If forests are managed properly, trees grow back. How do you know if forests are being treated with respect? Look for lumber that is certified by the The Forest Stewardship Council www.fsc.org or the Sustainable Forestry Initiative www.sfi program.org. Typically, energy-efficient builders prefer 2x6 lumber for studs in wall cavities and cathedral ceilings because the wider space allows for more insulation.


Another more recent wood framing technology is called engineered wood products (EWP). Products such as studs and joists are created in a factory with special water-resistant glues and fibers from leftover mill lumber or fast-growing tree species. They are pressed and glued into lightweight floor joists, rafters, or other structural pieces. The green advantages? First, engineered products use more of the tree—there’s virtually no waste. Second, they tend to be more stable and straight than dimensional lumber. The downside? Certain products need to be stored carefully and installed exactly as intended, or they can lose their structural integrity.


 


ARXX ICFS
With an effective insulating value of up to R-50 (depending on insulation thickness,) ARXX insulating concrete forms can withstand 200 mph winds and have a 2- to 5-hour fire rating. The forms are made with no ozone- depleting agents. and sheathing or drywall can be attached directly to the vertical plastic sections of the forms. www.arxx.net


ILEVEL TIMBERSTRAND LSL WALL FRAMING
This framing system grew out of demand for long, straight floors and walls in modern homes. The collection includes engineered headers, sill plates, beams, and other components—all made in the factory with precision engineering and little waste wood generated. www.ilevel.com

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