I’m probably not the only one for whom one of the main draws of small-scale natural building — besides low environmental impact, aesthetic value, and non-toxic building materials — is that such a house can cost considerably less than a conventionally built house. That one could build a home practically debt-free. But it’s hard to find actual estimates for how much a cob house, for example, might end up costing. I want to share here my research-in-progress in case it may be useful for some of you. (I focus on cob building; the situation may be very different in case of straw bale houses, log cabins, earthships etc.)
First, a sobering note I’ve heard from the lips of many experienced builders: a natural building can cost as much as a conventional custom-built home if you have someone else do all the work of designing and building it. More often than not, natural building is very labor-intensive, so if you pay someone else for that labor, it’ll be a pretty penny before your house is done.
But here’s the good news: that is not the only way. For people who are willing and able to do much of the building and design work themselves, and/or have a community of people willing to help out, and/or can find other creative ways to recruit help and keep costs down, cob can in fact be a remarkably affordable way of building a beautiful, unique home.
Here are a few notes on costs. The basic building materials — clay, sand, and straw — are inexpensive, and may even be found on the site itself. The tools needed are also mostly quite basic and inexpensive. What ends up costing the most are things like roofing, doors, windows, finishes, etc. But, in thinking about the total cost, factor in the so-called secondary cost savings: because passive solar design is literally built into cob home design, and because the earthen walls provide thermal mass, you spend less money on heating and cooling. Because the building materials are entirely non-toxic, you’re less likely to spend money on doctor’s bills. And because cob is such an organic, malleable material, it allows for more creative (and therefore inexpensive) solutions than conventional building.
Ways to keep costs down? The Number One answer is: become an owner-builder. Cob building doesn’t require advanced skills, so most people are able to learn what it takes. Secondly, use free or trade labor: workshops, work parties, etc. (Hopefully, your friends will still be your friends when the project is done.). Thirdly, build small. The smaller the structure, the lesser the cost. Fourth: develop creative problem solving. Fifth: use as many salvaged materials as possible. Borrow, trade, buy used. As the Cob Cottage folks say,
With inventiveness and forethought, the costs of other components (doors, windows, roof, floors, etc.) can be extensively reduced. The Cob Cottage Company works primarily with recycled materials and handwork lumber. Using local materials such as poles, bamboo, stone, and cedar shakes, our second cottage was completed for $500.
So cob cottages start at $500. Let’s look at some other examples of size and cost:
Pat’s First Cob is a small, 240 sq. ft. cottage that cost about CAD 1,000 to build.
This house, the first fully permitted cob house in Canada, has 600 sq.ft. on two floors and is fully plumbed and wired. Most of the building was done during a 3-week workshop. The total construction costs were approximately CAD 56,000.
Kate’s Cob, at 1200 sq. ft., is the largest and most expensive of all the examples here. It was also built during a couple of different workshops, and the final construction costs came to just over CAD 100,000.
I first saw this cute house on the cover of Yes! Magazine a couple of years ago. Ziggy built his 200 sq. ft. cottage at The Dancing Rabbit Ecovillage in Iowa in about 9 months, working on it mostly himself. He spent $ 3,000 on building materials and another 1,000 on labor; find the cost breakdown in this article.
A couple in Iowa built this 400 sq. ft house for $ 7,000. Read the article here.
Linda Evans’ house at the Cob Cottage Company was specifically designed to demonstrate the feasibility of a mortgage-free starter cob home. “A couple without construction experience could build it for under $10,000 in a year,” Linda estimates (Tiny Homes: Simple Shelter). Although I would like to add that the particular couple who built this — Linda herself and her husband Ianto — are themselves master builders, which is why the end result is so stunning.
These examples hopefully give a somewhat more concrete idea of what a cob house might cost. The range is huge, from $500 to $100,000, even when the owner-builders are themselves intensely involved in the process. It really depends on where you build, and how, and with whom, and how big. But even if you end up building a house that costs half of what the most expensive one of these houses costs — $ 50,000 — you’re still well below the average American home prices. And there’s a lot of room for creativity and savvy — and fun.