This page is the open source and free-shared Cob Village (Pod 3) construction materials costs page. It will constantly update with increasingly more accurate information as we open source project-launch blueprint the complete One Community Cob Village. The goal of this page is to provide precise materials needs and costs for every component of the Cob Village.
We discuss this with the following sections:
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Construction with cob can be significantly more affordable than traditional construction. As part of our global transformation approach to Highest Good housing, this page shares our cost analysis for using this building method to construct a commercial-sized Cob Village capable of housing up to 75 people and hosting 100s more. As we go through the process of constructing this village, we will also be adding here complete details for where and how to buy materials, what to buy, what to look for, what to look out for, and more.
One Community’s goal is using open source construction to demonstrate sustainable building for personal and commercial use as easy, affordable, and beautiful. We are first refining and demonstrating the open source strategy and detail of our open source approach with the 3-dome cluster crowdfunding campaign, we’ll then expand this process as we open source the complete Earthbag Village (Pod 1) and Duplicable City Center®, and then we’ll do the same for this village and the other 5 villages.
Open sourcing the cost analysis for this village and all others is purposed to help people better understand the cost savings that are possible through sustainable building and creation of collaborative and open source teacher/demonstration hubs. In so doing, we hope to make cob construction easier to understand and implement, more affordable, and more mainstream-popular.
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Jagannathan Shankar Mahadevan: Mechanical Engineer
Accurately creating the cost analysis for the Cob Village was a process of applying traditional cost analysis protocols and then researching the areas where these approaches needed to be adjusted to account for the differences when building with cob. We discuss here the complete Cob Village cost analysis process and conclusions with the following sections:
As per commercial standards (PDF), a rough estimate for the entire project is predicted in the primary cost analysis. An overview of the Cob Village plan (see Plans Page) aids in segregating the 40,000 ft2 total area into 4 different areas based on the area’s purpose and location inside the village. The 4 segregated areas are listed below and clicking each link will lead to the spreadsheet tab for cost analysis for each area.
It is also noteworthy to observe that the Cob Village includes approximately 31,000 ft2 (in addition to the structural area of 40,000 ft2) of landscaped area in between the 4 wings and in front of the village. This amounts to approximately 44% of the total footprint.
Here is the summary of these costs by area:
For convenience in computations and for more accurate calculations, the following 6 independent units are assumed to have significant contribution to each of the 5 areas’ costs:
Each of these unit costs have been predicted across all the 5 areas using the following approaches:
The electrical unit consists of elements responsible for powering an area. A general summary on how a residential electrical system is constructed is described here. The electrical footage cost (base cost) inclusive of wiring, labor, and overhead (a variable cost based on locality) can be obtained from here. For the current locality, the base cost is found to be an approximate $8.67/ft2. The cost for various power consuming equipment (useful devices like fans, ceiling lights, etc) are not included in the base cost and are accounted for independently.
The plumbing unit is generally responsible for an area’s water supply and sewer management system (here’s a resource about this). Area-specific labor and overhead can be inputted in this web program to get an estimate of the plumbing footage. An approximate $11.42/ft2 base cost which includes the cost for piping, location-specific labor and overhead is used for the Cob Village model. Additional plumbing equipment such as water sinks, bathtubs, toilets, etc., have significant impact on the total plumbing cost and have been accounted for separately.
The HVAC unit primarily maintains the temperature and humidity of an enclosed area to provide a comfortable living environment. Unlike the electrical and plumbing units, we were unable to obtain commercial and standard base-cost data for the HVAC unit. Consequently, we have used the approximate sq. ft cost of $12.51 as derived in the Straw Bale HVAC Cost Analysis section.
The cost of building a structure primarily depends on setting the frames for support. This resource article (link) presents all significant parameters to consider while approximating an estimate for building a structure. With reference to this literature (link), a base cost of $40/ft2 (inclusive of materials and labor) over a useful area of 44,000 ft2 (useful area is the actual build area for the village model excluding outdoor areas) results in $1.6M for building materials for the structure as per commercial practices.
This unit includes area-specific furniture and electronics cost, a part of which can be customized per occupant’s preference.
These costs generally include the costs for design and construction of hardscapes, preparing soil as per locality, and planning and developing a good irrigation system. Commercially (resource link), it is a good practice to allocate 15% of total project cost for landscaping. An alternate approach is to use the cost per sq. foot analysis. For this village, we used the latter approach and assumed the base cost for landscaping as $11/ft2 based on this article for accuracy. With a desire for a conservative cost analysis, we used the latter approach and got $341,000 to landscape a 31,000 ft2 area
The Highest Good Energy plan for power generation and transmission uses grid-tied and open source Wind and Solar to create a net-zero 100% sustainable energy plan. These costs continue to evolve on the Highest Good Energy hub and related open source pages. These costs are not included in the total village cost because:
To create the final Commercial Cost Analysis for this structure, all of the details above plus 15% was added. The additional 15% of the total cost was further considered to account for any and all approximations in determining the estimate for this project. With all this accounted for, the total project as per commercial standard approximates upwards to $4.5M as shown below.
Here is a graphic showing what percentage each area contributes to the total cost:
After calculating the costs for the complete Cob Village as described above and with standard commercial materials and practices, we then calculated our actual costs by incorporating sustainable practices and materials. This led to the revised costs that incorporated and included consideration of the following factors:
According to the National Association of Home Builders (Link), it is seen that the cost for initial survey, foundation and framing (which accounts for 35.2% of total cost – approximately $32/sq. ft) almost remains the same irrespective of the build material used.
To adjust this for sustainably building this village with cob, we initially calculated the wall area for the entire structure. The central dining/kitchen area has a section height of around 30’ whereas the other 4 wings in the village (and the corresponding maker spaces) are approximated to have an average section height of 17’. The section heights for the North wings are much lower than 17’ as they do not have the 2nd-level rooms that the South wings have. However, for ease in calculations and to derive a conservative estimate, we have considered the average section height as 17’ across all 4 wings. This allowed us to calculate the total wall volume.
The next step was to consider the ingredients that go into the cob mixture. This resource (link) suggests that the cob mix mainly consists of sand, clay, and straw of varying amounts depending on the material properties. For our calculations we assumed that the cob mixture consists of 20% straw, 40% clay, and 40% sand. Then we calculated the amount of clay and straw that we need to purchase to produce enough cob to build this structure by assuming 100% of the needed sand and 50% of the needed clay to be available on site and 50% of straw to be recycled from the Straw Bale Village that will be built before this village. Integrating all of this, the materials’ cost with cob is $1.13/ft2 versus $8/ft2 commercial materials’ cost.
As per commercial practice, the base cost for electrical, plumbing and building is inclusive of labor. One Community’s open source project launch-blueprinting model for showcasing sustainability in action includes open source and DIY approaches and tutorials that will cover these areas and more. This labor and these tutorials will be created by our all-volunteer team of qualified professionals. To account for this, we’ve approximated the variable labor costs we’ll save (depending on location) to 20% of the total cost of the project.
Because of the size and scope of the One Community project and our extensive construction plans for the first 5 years, it makes sense to own (vs. rent) our earth moving and landscaping machines. Although the principal cost incurred for this equipment is fairly high, it can be seen as working to our advantage as this equipment would ultimately be retained, resulting in significant cost savings in total landscaping and construction for successive villages.
For the Cob Village, we estimate the sustainable landscaping cost to be just 30% of the commercial landscaping due to retainable machinery and the extensive use of recycled materials. Therefore, the total sustainable landscaping cost for 31,000 ft2 area sums up to $102,300 – a net reduction of 70%.
For large-scale constructions, the majority of the products that are designed and manufactured by suppliers are commonly marketed and sold through a retailer. It is often easy to under appreciate the intangible costs processed in the supplier-retailer relationship. As part of our strategy to make sustainability easier, more affordable, and more attractive, we will be developing purchasing relationships directly with suppliers that we expect to increase their profit margins while reducing consumer costs when building teacher/demonstration communities, villages, and hubs using our plans. This will also reduce our total project cost while further increasing business for the recommended supplier.
We will add here the resources and contacts for all direct purchasing options as these options are identified, used by us, and proven reliable.
The following adjusted cost analysis incorporates the building materials savings and volunteer labor savings discussed above to produce a total project estimated cost of $3.1M. This cost is further expected to reduce once the savings resulting from direct-supplier purchasing can be accounted for.
Here is a chart showing the difference in cost between the conventional and sustainable models:
Overall, it is seen that the cost of sustainable construction is significantly less than commercial construction – about $1.4M less. We can also observe a small fraction of the commercial costs for labor when applying our open source sustainability model. This is due to the use of volunteer labor. The labor cost for the commercial estimate is 20% of the total project cost. Also, the materials and landscaping cost for open source sustainability is assumed to be approximately 30% of the commercial costs. An additional 15% is added to the final total to adjust for details we may have missed.
Summing up, the sustainable Cob Village model results in 32% savings (4.5M vs 3.1M) for the overall construction over commercial estimates. Here is a graphic showing the adjusted contribution of each area to the total cost:
Construction with cob can be significantly more affordable than traditional construction. As part of our global transformation approach to Highest Good housing, we are open source sharing our cost analysis for using this building method to construct a commercial-sized Cob Village capable of housing up to 60 artisans and hosting 100s more. By open sourcing the cost analysis for this village and all others, we desire to help people better understand the cost savings that are possible through sustainable building and creation of collaborative and open source teacher/demonstration hubs. These savings, when calculated for this structure as compared to the same structure built with conventional means, are estimated to reduce the cost by about 32%.
Q: Where can I get more information about the Cob Village, benefits and challenges of building with cob, etc.?
Please visit the Cob Village open source hub.
Q: When do you anticipate starting construction on the Cob Village?
We are first refining and demonstrating the open source strategy and detail of our open source approach with the 3-dome cluster crowdfunding campaign, we’ll then expand this process as we open source the complete Earthbag Village (Pod 1) and Duplicable City Center®, and then we’ll do the same for this village and the other 5 villages.
Q: Where can I get more information about your philosophies for world change?
Please take a look at each of these additional pages: (click icons)
Q: How do you intend to pay for construction of the Cob Village?
One Community is projected to easily generate sufficient revenue to construct this village and the other 5 villages once the Earthbag Village (Pod 1) and Duplicable City Center® are operational. Visit the One Community Highest Good Economics page for details on our revenue streams, rental revenue projections, and other open source revenue-generation details related to this and all other aspects of One Community.
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