So what if someone built their strawbale house for $1,000. I want to know how. Too often we have relied on singled-out houses and general opinions to illustrate the costs of alternative housing. In our society, we cannot afford to ignore questions of cost-effectiveness and efficiency. We are involved in a competitive market where "money is the driver." This essay will focus specifically on the economic side of building.

I spent the last year investigating the economics of strawbale, cob, and cordwood-masonry construction. I documented the costs of 27 alternative residential houses from across the US and overseas. They illustrate general cost trends and average cost figures. Though this information is helpful, it does not show the costs of the wall systems themselves. For this purpose, I compiled two complete material lists for identical strawbale and stud-frame "Twin Houses." The results will help answer the question of "which costs more: strawbale or stud-frame construction?"

The results of this study, The Comparative Cost Analysis Between Building Methods, prove that alternative building is not always but can be cost effective. More specifically, it proves that strawbale construction is not only competitive in price to stud-frame, but can be substantially less. It explores which factors raise, as well as lower, the costs of construction.

Do you ever wonder why it costs one person $10,000 to build their house, while someone else's house cost $100,000? Similarly, cost per square foot figures are not good storytellers either. Without knowing about the building materials, how they were acquired, at what cost, and the amount of labor performed by the owner, the figures remain unhelpful.

All of these aspects were documented for the 27 residential case studies (CS). They exist in 16 US states, one from South Africa, and one from British Columbia. Out of the 27 houses, 14 are strawbale, 9 are cordwood masonry, and 4 are cob houses. (I acquired this cost data through an in-depth questionnaire and follow-up interview involving over 130 people.)

The total house costs range from as low as $500 all the way up to $187,000. The average cost per sf of the 27 CS is $27.50, and 18 out of 27 CS or 67% were built for under $40,000. These are low costs when compared to average stud-frame prices. Standard cost data suggests that a 1000-2000sf stud-frame home would cost an average of $75,000-$120,000 total cost, or $75-$65/sf.

How are these homes so affordable, and what major factors raised as well as lowered the price tag? The cost figures point to four major factors that affected the costs of the 27 CS. They include the amount of owner-labor; amount of "deconsumer" materials; location factors; and the quality of finish materials and amount of custom work.

1. The Amount of Owner Labor. All but one of the 27 owners built at least the walls of their house. The average percentage of owner labor is 75%. In general, since labor costs represent about 50% of a total house cost, owner participation is the best way to reduce building costs.

Strawbale construction is an efficient technique that allows the walls to be built by the owner or a contractor. The technical simplicity and wall-raising workshops make owner-built walls a realistic adventure, even for the formerly unskilled. (I know of no weekend or week-long workshops that teach stud-wall techniques.)

The strawbale CS mostly or entirely built by a contractor are in the high-cost range. In cob and cordwood, the labor intensity of wall construction makes it impractical to hire the labor.

2. The Amount of "Deconsumer" Materials. "Deconsumer" refers to materials that were not bought at retail cost. Instead, they were acquired second-hand, grown or taken from the building site, salvaged from demolition, and/or bought from a farmer. The more a house is built with "deconsumer" materials, the lower the material costs.

Most of the primary materials in each method are of a "deconsumer" nature. In the cob CS, most primary wall materials (clay and sand) were acquired for free during excavation of the site. In the cordwood CS, most owners obtained the wood for free by using trees off their land. A cordwood wall is approximately 60% wood; the other 40% is a mortar mixture (sawdust, sand and Portland Cement) which was purchased at a minimal cost. While most of cob and cordwood's primary materials were free, the primary strawbale materials were purchased. However, the 14 owners bought their bales from a farmer rather than a retail feedstore, which reduced the cost.

3. Location. The other factors that affected the CS costs have to do with location. Building with local materials makes more economical sense than using materials that have to be shipped into a region. Accordingly, the cordwood CS were built in the Northern regions of the US where wood is readily available. The strawbale houses were the most widespread in location, since straw is available wherever grain crops are grown.

Another location issue is permit costs. Depending on your local building department, permit costs can either be free, affordable, or expensive. Surprisingly, seven case houses were not even required to obtain a building permit, and for 11 out of 14 houses the permit costs were under $600. Only one house was built within city limits (Eugene OR) with a higher permit cost of $5,500. In general, the more densely populated the region, the higher the permit costs due to the more careful nature of the building codes in areas of high population.

4. Finish Level and Custom Work. The last considerable factor that affected the CS costs was the owner's choice in the quality of materials (level of finish), and the amount of custom work. These affect the cost no matter what the building method is. For example, trim on a house can be an expensive material. A handful of owners in the 27 CS chose to hand-make their trim at a minimal cost. Keeping the design simple can also reduce the cost of labor for "custom" work. However, if all the labor is done by the owner, then a house can have many custom features without extra cost.



The strategies described above not only lead to an affordable home, but there are many benefits that lie beyond a balance sheet. By using owner-labor, "deconsumer" and regional materials for example, we attain "priceless" benefits of sustaining our environment, local community, health, and ourselves. These 27 CS provide existing evidence of people who have made their dreams manifest.

Though the CS are helpful in showing low-cost strategies and general trends, each contain far too many variables to be compared on a house-to-house basis. A way to specifically isolate and compare the cost of wall systems was to create the Twin Houses, which are two identical houses with different wall systems. One is a post-and-beam strawbale, and the other a 2x6 stud-frame. The Twins are hypothetically built for the Pacific Northwest region.

The Twins are identical in every possible way: interior sf, floor plan, foundation, floor and roof. In accordance with the Thurston County Building Department, and the help of local builders and architects (principally Ted Butchart and Brent Tyson), I generated two extremely detailed material lists, quantified and priced using local building store costs.

I chose materials that were most commonly used in the Northwest. This way the estimates represent realistic costs of houses built in this region.

The Twins have poured concrete foundations with rebar, wood-joist floors, and hip roofs with composite shingles. The Stud-Twin uses 2x6 studs spaced 16 inches o.c., R-19 fiberglass insulation, OSB sheathing and lap siding, and a drywall and paint interior. [Note from your friendly Webster, surprised that this wasn't already noted: For this cost comparison to be more truly appropriate, the Stud-Twin would have to have superinsulated walls, which would be some orders of magnitude more expensive than a typical R-19 wall. Otherwise, the comparison is apples and oranges. This comparison also takes only first-cost into consideration, and not lifecycle costs, as pointed out almost in passing below. Thanks for listening.] The Straw-Twin walls are 2-string bales pinned with bamboo stakes every 2 ft. A series of wooden "box columns" provide the structural support. Chicken wire and stucco cover the exterior and interior wall surfaces. The roof plate is a 3-1/2x9-1/2 paralam.

The total material estimate for the Straw-Twin is $33,646 and $33,236 for the Stud-Twin. The Straw-Twin costs $410 dollars more, which considering the total material cost, is insignificant. While the total Straw-Twin walls are 1% less expensive, the foundation is 3% and the roof is 5% more expensive than the Stud-Twin. The increased foundation and roof area for the Straw-Twin is just enough to offset the wall savings. [It should be noted that foundations for strawbale structures do not as a rule have to be any different than foundations for stud-built houses; using bale-wide concrete foundations, particularly in areas of deep frost, is very unusual. However, to maintain an identical interior sf for the "Twin Houses" of this study, increased overall footprint would have been required, resulting in higher costs. See TLS #16 for thirteen uninterrupted pages of foundation options for strawbale.—ed.]

In addition to being competitive in price, strawbale can be substantially less than stud-frame construction if all factors are considered. Any amount of owner-labor results in sizable savings. In addition, the long-term heating and cooling savings of strawbale walls further reduce costs over a lifetime.



In conclusion, strawbale, cob, and cordwood masonry have shown to be cost effective. Unlike conventional construction, alternative methods provide unique opportunities: a chance for the unskilled to build the walls, and the ability to use primary materials that are of a "deconsumer" nature.

Finally, to purely base an evaluation of alternative methods on economics alone would be a narrow perspective. The environmental, health, and community benefits of building alternatively make these building methods far superior to conventional construction. In effect, alternative building merges economical and ecological values; what is environmentally-friendly can also be cost-effective. Usually, these values are perceived as being in conflict with each other.

All building methods serve useful functions in our society. As in nature, diversity benefits any situation whether we are talking about diversity in opinions, sex, race, religion, habitat, building methods and materials. We can all benefit from the diversification of the building field. Using diverse materials can help sustain our natural resources, our bodies and ourselves.