True Cost Guide Architects & Engineers Build a Straw Bale or Cob House

How Much Does Building a Cob House Cost in 2024?

Typical Range:

$30,000 - $90,000

Cost data is based on research by HomeAdvisor.

Updated August 24, 2024

Written by HomeAdvisor.

Highlights

Small cob homes start around $30,000, and larger cob homes can reach $90,000 or more.
Cost factors for cob homes include materials, labor, size, consulting, and location.
Materials for small cob homes typically range from $3,000 to $6,000.
Conventional home cost factors also apply, such as finishes, permits, site prep, and home systems.

A compact straw bale or a cob cottage costs as little as $30,000, while a three-bedroom house costs around $60,000. The price can increase to $90,000 for larger homes, high-end finishes, or additional insulation.

Straw bale and cob homes are an alternative to conventional homes. Their increased popularity is driven by the growing interest in sustainable home construction. While natural materials are often cost-effective and eco-friendly, there are still many costs to consider when building a cob home. In most cases, a typical straw bale or cob home costs the same or more than the cost of a comparable conventional house.

Average Cost to Build a Straw Bale or Cob House

Average Cost	High Cost	Low Cost
$60,000	$90,000	$30,000

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Cob House Cost Factors

Many factors affect the final price of the straw bale or the cob house, such as materials, the size of the home, labor, and more.

Materials

Materials for cob houses, which include straw, clay, gravel, and sand for standard builds, cost from $3,000 to $6,000 for a small house. These figures depend on the exact construction method, which varies between each project. Wall, roof, and foundation materials account for 10% to 15% of the total cost, depending on the availability of salvability of materials in your area. Sourcing non-local materials may increase the time and cost of transportation.

Many people are interested in the reduced costs of natural materials over modern conventional options. Some land plots may even have clay, sand, and straw available, but these materials require proper harvesting and processing to ensure their quality as building materials.

Size and Design

Cob houses cost about $150 to $450 per square foot with labor and materials, averaging around $250 per square foot. Simply engineered homes are often on the lower end of the scale, but costs can increase with a customized or complex build. As with conventional homes, multiple levels add complexity and likewise increase costs.

Once you have an idea of what you’d like in your house, work with a general contractor to put together an accurate cost estimate. Here are the cost ranges for total builds:

Square Footage	Low-End Cost	High-End Cost
500	$75,000	$225,000
1,000	$150,000	$450,000
1,500	$225,000	$675,000
2,000	$300,000	$900,000

Consulting

Some contractors provide stock cob home templates ranging from $500 to $5,000, but they often need to be adapted to your specific land plot and other home needs. Many prospective cob homeowners work with a local architect to either customize a stock plan or build one from scratch, which can cost $750 to $20,000. These services are essential, as clearly outlined plans can reduce costly construction time delays and errors.

Labor

Building a straw bale or a cob house is a labor-intensive job. Working with a local contractor will cost 15% to 20% of the total cost of the house, but hiring a professional can save months of intensive work, prevent costly errors, and provide peace of mind.

Location

Location can be a determining factor in other costs, as it can influence material availability, construction labor rates, and transportation costs. The location may also affect the codes, insulation, and roofing of the buildings.

In general, costs tend to correlate with the local cost of living—for example, a straw bale home in rural Iowa could cost $100 per square foot, while a similar build in California might cost $350 per square foot. Consult a local home builder to get a sense of the cost in your area.

Additional Cob House Cost Factors

In addition to costs specific to cob home builds, consider the standard home-building costs that factor into the final project cost.

Permits and Inspections

Cob homes aren’t generally subject to special permits or codes, but they still must comply with local building codes and regulations. In general, construction permit costs range from $150 to $2,000. Some places include inspection fees as part of the permit cost, but inspections otherwise range from $100 to $500. Working with an engineer can help you create a compliant building plan. Some states and municipalities may even require you to hire an engineer.

Demolition

Factor in demolition costs if you need to remove an existing building on your lot to make room for a cob house. Demolition ranges from $4 to $17 per square foot, depending on location, labor, disposal, and other costs.

Site Prep

Ranging from $2,000 to $500,000 or more, land prep and excavation are typically necessary before starting the actual building. This expense may account for:

Excavation
Soil grading
Impact fees
Finish work
Permits
Inspection
Survey

Home Systems

Like a conventional home, straw bale and cob homes need plumbing, HVAC, and electrical systems, which cost between $30,000 and $75,000. With long-term cost, sustainability, and self-sufficiency in mind, many cob homeowners opt for off-grid electrical options such as solar power and wind energy, as well as self-sufficient plumbing installations like wells, composting toilets, and septic tanks. Integrating these customized options into your build may increase the total costs.

In non-customized designs, rough-in plumbing, electrical, and HVAC systems fall within these cost ranges.

System	Low-End Cost	High-End Cost
Electrical	$2,000	$13,500
Plumbing	$12,000	$20,000
HVAC	$5,000	$15,000

Exterior and Interior Finishes

Walls are only part of the work that goes into a house. Interior and exterior finishing elements, such as cabinetry, plaster, paint, windows, and doors, add to the overall price. On average, exterior and interior finishes account for about 35% of a new home’s overall cost.

Finishing costs to consider include:

Finish	Cost Range
Paint	$2–$6 per sq. ft.
Trim	$2–$3 per sq. ft.
Interior doors	$30–$2,500 each
Flooring	$3–$22 per sq. ft.
Lighting fixtures	$90–$2,000 each
Countertops	$8–$120 per sq. ft.
Cabinetry	$100–$1,200 per sq. ft.
Windows	$180–$410 each

Budgeting for Building a Cob House

Cob homes offer some cost perks. For example, a properly built straw bale home can offer enhanced insulation and energy savings over conventional home builds. Keep your cob house project costs low with these budgeting tips:

Design: Where possible, opt for a simple and compact design. Design multifunction areas, such as combined kitchen and dining, to reduce overall square footage and wall needs.
Energy efficiency: To maximize your home's overall efficiency, ensure proper insulation and incorporate energy-efficient systems, such as solar cells.
Material sourcing: When available, use locally sourced clay, sand, and straw. Look for reclaimed or recycled windows, doors, and other building materials.
Budget management: Create a detailed budget to define your spending limits. Include upper-limit budget padding so you’re prepared for extra costs.
Quotes: Get quotes from multiple contractors to ensure you’re getting the best value from your investment.

How HomeAdvisor Gets Its Cost Data

No place is more important than your home, which is why HomeAdvisor connects homeowners with local pros to transform their houses into homes they love. To help homeowners prepare for their next project, HomeAdvisor provides readers with accurate cost data and follows strict editorial guidelines. After a project is complete, we survey real customers about the costs to develop the pricing data you see, so you can make the best decisions for you and your home. We pair this data with research from reputable sources, including the U.S. Bureau of Labor Statistics, academic journals, market studies, and interviews with industry experts—all to ensure our prices reflect real-world projects.

Still Have Questions About Cob Homes?

FAQs

What is the difference between a straw bale and cob construction?

Both cob and straw bale construction use straw as a primary material. Straw bale construction uses straw as an insulating, structural, or combination building material. This method usually involves stacking bales like bricks to form walls and covering them with a plaster or stucco finish. Cob construction uses clay, sand, straw, and other materials to build thick and solid walls in layers.

How are straw bale and cob homes different from conventional homes?

The main differences between straw bale and cob homes and conventional homes are the structural components, such as the walls, roof, and foundation. Conventional homes use wood, concrete, steel, and brick and generally follow standardized methods and procedures. The use of local clay and sand makes cob and straw bale homes less environmentally impactful than conventional builds.

How long do straw bale homes last?

Cob and straw bale homes can last 100 years or more if built and maintained correctly. Modern cob homes derive methods from ancient versions, many of which still stand. Regular inspections and maintenance, quality of materials, expert workmanship, and other factors influence overall durability.

What are the pros and cons of cob houses?

Cob houses offer advantages such as environmental sustainability through the use of natural and local materials. They’re long-lasting, pest-resistant, highly insulated, and visually unique. However, the building methods and materials may require intensive labor, expert building skills, and careful maintenance. Some cob home projects may face challenges with building codes and permits.