Free Trial Subscription To MeansCostWorks.com
Now access RSMeans cost data online!

Click here to receive a free 7-day trial to the new MeansCostWorks.com online construction cost estimator or to view our demo.

Manage customized estimates for commerical, residential & heavy construction projects with the entire RSMeans database of unit, facility & assembly costs — all online.

A must-have resource for contractors with costs from the benchmark RSMeans cost data and contractor pricing guide titles, delivered in a secure online environment 24/7.

Green Products: “Alternative” Materials

Several natural, low-tech building techniques – including straw bale, adobe, rammed earth, and cob – have a long history of use around the world, but are just beginning to regain popularity in the U.S. Although these building techniques are labor-intensive and may be unfamiliar to the conventional contractor, they provide many environmental and health advantages. Typically they are associated with very low-embodied energy, no harmful off-gassing of pollutants, locally sourced materials, and good energy performance in appropriate climatic regions.

Straw Bale
Straw is a very low-embodied-energy by-product of the farming industry. While it would be a bad idea to remove all the straw from the field, as some of it needs to be tilled into the soil to provide aeration and organic matter, current agricultural practices produce excess straw, much of which is typically burned as “waste,” creating air pollution.

Use of straw bale construction not only makes use of this “waste” product, it also provides good insulation, fire-resistance (because the tight packing in bale walls eliminates the necessary oxygen for burning), and even protection from most termites. (Only one species will eat straw.) The primary concern with straw bale construction is protection from moisture, but this has been successfully addressed with big overhangs, high foundations with a capillary break next to the straw, and proper interior and exterior plaster detailing, including flashing around openings.

Adobe
Earthen, sun-cured brick is another relatively labor-intensive, but low-embodied-energy materials with a long history of use in hot, dry climates. Adobe lacks the insulating properties of straw, but provides instead a large thermal heat sink that soaks up excess heat during the hot day and re-releases it during the cool night, thereby moderating the building’s internal temperature.

Other Earthen Materials

Rammed earth (earth formed into thick, durable monolithic walls) and cob (earth and straw molded by hand into sculptural walls) are two building methods that work in hot, dry climates along the same principles as adobe. Any of these materials can be (and are) used in other climates, but require supplemental insulation or additional heating or cooling.

Alternative Factory-Made Materials

Excerpted with permission from Green Building: Project Planning & Estimating, 2nd Edition, published by RSMeans.