Best House Framing Systems for Building a Home

Green building expert Chris Magwood compares wood framing systems to cob walls, compressed earth blocks, and straw bale walls in pursuit of a sustainable home building practice.


| February/March 2016



Wood Framing

Wood framing can produce buildings with curved- or straight-wall designs.


Photo by David Elfstrom

In the sustainable home building industry, many prospective homeowners want to make environmentally friendly choices, but struggle to make sense of a building industry that labels every house framing option as “green.” For environmentally conscious builders, like me, sustainable construction encompasses many factors, including ecosystem impacts, carbon footprint, material waste, energy efficiency, cost, durability and indoor air quality. Ultimately, those sustainability considerations must mesh with practical concerns, such as labor, building compliance, and material sourcing and availability. One measurement that helps builders and future homeowners compare various materials’ environmental impact, embodied energy (EE), totals the amount of energy invested in a product during sourcing, shipping and installation. Further, when sustainable home builders include the energy associated with a material’s use and disposal, or that product’s “downstream,” they have completed a life cycle impact assessment. Now, no house framing system — neither cob, compressed earth blocks, straw bale, nor wood frame — scores top marks in all criteria, and embodied energy and life cycle analyses differ based on site-specific circumstances, so homebuilders must determine their priorities and make choices that best reflect those goals. One size never fits all in green building.

House framing systems are often the first thing an owner-builder wants to discuss. And no wonder: Walls support the windows and doors that physically define a space, play a crucial role in a home’s energy efficiency, and dominate a building’s aesthetic.

To help homeowners refine their ideas into buildable homes, I created these charts: Wall-Framing Systems and Conventional vs. Improved Wood Framing. The charts compare five house framing systems systems according to 11 criteria, and show how each system rates relative to the others. Many people assume that alternative wall systems (such as straw bale, cob and compressed earth block) are more sustainable choices, but if you study this chart, you’ll see that wood-framed walls perform well when paired with improved materials.

Straw Bale Building

In the 20 years since the resurgence of interest in straw bale building, the number of houses raised using this type of so-called alternative construction has grown quickly. Straw bale building is one of the few alternatives with comprehensive code language, and the International Residential Code incorporated straw bale walls in 2015 — a fast ascent from fringe following to mainstream acceptance.

In straw bale building, workers stack  bound, rectangular bales of leftover stalks from grain crops (such as wheat, rice, oats, barley and even hemp) to form walls (see photo). The exposed surfaces require a coating of clay, lime or cement-lime plaster to provide external structure, seal and finish. Straw bale walls easily adapt to many aesthetic possibilities — the material is equally at home in straight, square buildings as it is in round or curvy structures.

Accurately rating straw bale walls can be difficult because numerous building systems incorporate straw bales, but differ greatly in process and materials. For example, simple, load-bearing straw bale wall systems score well when builders choose minimal window and door framing, a simple wooden top plate, and site-made earthen plaster (see Wall-Framing Systems chart). However, when straw bale builders use complex framing systems with plaster mesh and cement-based plasters, they significantly raise environmental impacts, along with financial and labor input.





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