How Much Does It Cost to Build a Cob House in 2023?

You’ve probably heard the tales of adventurous homesteaders and crafty DIY enthusiasts discussing the cost of building a cob house.

Unfortunately, these stories can sometimes seem unrelatable, with the protagonists possessing superhuman determination and endurance. So, assuming a normal work rate and time investment on your part, how much does it cost to build a cob house in 2023?

Building a cob house in 2023 costs between $150 and $450 per square foot, depending on size, climatic conditions, labor, and location. This amount translates to anything between $4,000 and $10,000 or $2,000 and $5,000 on average.

In the rest of this article, I’ll give a breakdown of the cost of building a cob house and the factors that affect the cost. I’ll also discuss how to lower the cost of building a cob house.

Let’s get right into it!

A Breakdown of the Cost of Building a Cob House

Like any other sustainable construction, labor and materials mainly affect the cost of building a cob house.

While materials account for 70 percent and labor 30 percent of the total construction cost in conventional building, the opposite is true for cob house construction.

Since clay, sand, gravel, and silt – the basic ingredients for cob – are freely available, the cost of cob house materials is quite low. The main cost of building a cob house is labor.

So, is cob building cheaper?

Although cob building is cheaper than conventional building, the cost is significantly impacted by your labor source and type. As with any construction, skilled labor is costly but worth it in terms of quality.

However, if you’re willing to do some of the work, like mixing cob and laying the walls, you can save thousands of dollars.

That said, the table below breaks down the typical costs of building a cob house:

Feature	Cost in USD
Sand (30 tons)	507
Gravel (13 tons)	177
Straw (16 bales)	36
Timber	120
Windows	220
Electrical	28
Galvanized wire	30
Nails	100
Raw linseed oil	72
EPDM pond liner	622
Polycarbonate for skylight	400
Firebricks (for a rocket stove)	72
Flue pipe	228

Table 1: Breakdown of the cost of building a cob house. Source: The Year of Mud

Factors That Affect the Cost of Building a Cob House

When looking at the construction cost of any project, you ideally want a fixed figure to work with. However, the cost of building a cob house depends on several factors that can change the final figure.

Here are the primary factors that affect the cost of building a cob house:

Size

As mentioned, building cob houses costs between $150 and $450 per square foot.

With that in mind, the bigger the cob house, the more it will cost.

To put that into perspective, let’s assume you’re building a 200-square-foot cob house while maintaining very high quality standards. In this case, you can expect to spend between $30,000 and $90,000 on the construction project.

On the other hand, if you build a 300-square-foot cob house, the cost shoots to between $45,000 and $135,000.

But how big can a cob house be?

Theoretically, a cob house can be as big as you want; but practically, they don’t go up to three stories.

Location

The construction cost of a cob house is also affected by its location.

Cob houses are cheaper to build in rural areas where materials and labor costs are relatively low.

Besides the unavailability of materials, urban areas have strict building codes that increase the cost of construction.

Moreover, labor costs are higher in urban areas than rural areas due to the high demand for construction workers.

For instance, while building a cob house in Oregon may cost you $200 per square foot on average, the same may cost you $150 per square foot in rural Iowa. The same house in California will cost you upwards of $350 per square foot.

Labor

For most cob house builders, labor accounts for the highest percentage of construction costs.

Labor costs depend on the type and qualifications of the workers, availability, and location.

Hiring skilled labor will cost more than unskilled labor. But you get what you pay for–skilled cob house builders are experienced and deliver quality results in a shorter time frame.

Materials

Materials for building cob walls account for between 10 and 15 percent of the total construction cost. However, you can expect the cost to be higher if the site doesn’t have the right composition of clay, sand, straw, and gravel. In this case, you’ll have to import the building materials.

Climatic Conditions

The climate in which you plan to construct your cob house matters since it affects some of the materials and labor costs.

For example, if you’re building a cob house in an area with extreme weather conditions like cold or hot climates, you’ll need additional insulation with specific building codes.

Moreover, since cob takes longer to dry, building in a humid climate will slow the process, increasing labor costs.

Can You Get a Mortgage on a Cob House?

Although you can get a mortgage on a cob house, it may be difficult to find a lender who will finance the construction of one. This is because cob houses are rare and lack mainstream recognition in most states.

Moreover, some mortgage companies consider cob house building an alternative building method. Therefore, you must prove that the structure meets safety standards to qualify for a loan.

That said, you can increase your chances of getting a mortgage on a cob house by working with an experienced lender or asking around in your local community. You’ll likely find a lender willing to offer you a loan.

If all else fails, consider alternative financing options like:

• Government grants
• Crowdfunding campaigns
• Personal savings

How to Lower Cob House Building Costs

The high cost doesn’t mean you can’t build a cob house on a tight budget. Here are the ways to lower the cost of building one.

• Use salvaged materials like windows and doors to lower your material costs.
• Employ a do-it-yourself approach where some members of your family or friends assist with the construction process to cut labor costs.
• Consider building in a rural setting to take advantage of the lower materials and labor costs.
• Finally, look for government grants and crowdfunding campaigns to help finance your cob house.

What Is the Longevity of Cob Houses?

With proper care and maintenance, cob houses can last a lifetime. Some cob houses have existed for more than 10,000 years, demonstrating the high durability of cob.

The key to a long-lasting cob house is protecting its walls from moisture by applying a breathable moisture barrier like lime plaster and ensuring the roof overhangs the walls appropriately, two to three feet is good.

Final Thoughts On The Cost to Build a Cob House

The cost of building a cob house largely depends on size, location, labor, and materials.

Fortunately, getting a mortgage on a cob house is possible if you find the right lender. Alternatively, you can take advantage of alternative financing options like grants.

Now that you know how much it costs to build a cob house, check out these top four companies to source your straw bale house plans to compare this with other sustainable building materials.