Man With Arms Outstretched Outside of Cob House

With the shift toward natural solutions to modern problems, many people are considering alternative housing options to reduce their carbon footprints or be energy efficient. This shift in thinking has pioneered the tiny house movement, but it’s also brought an ancient building material back into focus: cob. Also called unburned clay masonry, adobe and puddled clay rich soil in the structural context, cob has been used as building materials since prehistoric times and offers a sustainable way to create enduring structures.

Affordable and good for the environment, cob houses offer an abundance of advantages when you’re looking to create a sustainable space for you and your family.

Cob: The All-Natural Building Material

So just what is cob anyway, and why a cob house? Made from subsoil, fibrous organic materials like straw, water and sometimes lime, eco-friendly cob is an all-natural building material that utilizes low-cost components. Cob mixtures vary from area to area due to the subsoil contents, most natural builders also mix cob with sand or clay to create the right consistency for shaping bricks or smoothing out domes. Keep in mind that your cob house needs a good roof and factor that into your cob building plans.

Benefits of Building Homes with Cob

Though building a cob house is rather labor intensive, your own cob house confers numerous advantages, including an energy-efficient design that’s termite-proof. Resistance to fire and seismic activity provides added confidence in the safety of your space, while the material itself has a very low cost for economical building as it comes from natural resources. Additionally, since you shape cob materials yourself, you have opportunities to put personal touches on every aspect of your cob house building process by adding sculpted fixtures and detailing.

In terms of living inside an eco-friendly cob home, thermal regulation is one of the biggest benefits. The thickly packed materials in cob houses keep spaces cool in the summer and warm in the winter for comfortable year-round living. Likewise, after drying out completely and curing, cob homes boast excellent air quality, and cob walls offer superior sound insulation so you don’t hear as much outside noise or bother your neighbors when you crank up your favorite tunes. Durability also makes cob one of the most advantageous building materials in the market, with many old cob buildings lasting for centuries.

How to Build Houses with Cob

Piqturesque cob house

The first step to building cob houses is fashioning a foundation for your cob house using a simple building technique. Since cob walls are thick, these mud houses must support lots of weight, so you need a solid foundation in your building site that starts below the frost line. First, clear off all the topsoil from your cob building site, then start digging out the sides and tamping down the base, adding French drains or swales where necessary to keep water outside your cob home. Make sure you are following all the building codes in your area while building cob houses.

The next step is creating a cob mix and building the first cob wall, shaping the natural materials as you go in two- to three-foot intervals and leaving holes at the top for the next layer.

Typically cob houses have thick walls at the base and thinner near the top, and you need to let your cob construction dry a bit after building vertically so it doesn’t slump as you go. You can also add windows and doors as you build a cob house so long as you support these structures with timber by adding headers and footers as natural rebar to absorb the extra weight.

After you finish with the cob structure itself, you can build features into the interior with the earthen mixture, including counters, shelves, stairs and fireplaces. This step is also where you can shape the natural materials into artistic elements and add detailing to cob walls. After you finish with your cob house construction, then it’s time to add color to your home and seal it inside and out to keep out moisture.

Finishing Cob Houses with Real Milk Paint Products

The Real Milk Paint Co. makes high-quality products ideal for finishing your cob home to perfection. All-natural formulations designed for eco-friendly use make our paints, oils and solvents a great choice for those who want sustainable options for decorating and enhancing their living spaces. Best of all, many of our products work especially well on cob structures, beautifying your cob construction inside and out while minimizing moisture and ensuring long-term durability.

Adding Color with Real Milk Paint

Our nontoxic milk paint colors offer a handy way to dress up beautiful cob homes. Made with no volatile organic compounds (VOCs), our milk paint arrives in powdered form so you can mix up as much or as little as you need for covering cob walls and coating interior design elements. Mixed paint lasts for up to two weeks in an airtight container, and mixing it with our Outdoor Additive lets you use our high-quality formulation to paint the exteriors of cob homes.

Waterproofing Exterior Walls with Outdoor Defense Oil

Use outdoor defencse oil in building cob houses

If you don’t want to paint the exterior when building a cob house, consider waterproofing the exterior with Outdoor Defense Oil from the Real Milk Paint Co. Made with tung oil, pine oil and zinc, this formulation works alone or over Real Milk Paint to protect your cob building from the elements. Designed to absorb deeply, Outdoor Defense Oil requires no mixing with solvent before use and provides cob homes with an attractive matte finish.

Sealing Interior Walls with Pure Tung Oil

build a cob house with pure tung oil as protection

Made from China wood oil, our Pure Tung Oil resists marring and penetrates deeply, making it the perfect choice for use on walls made from earthen materials. This medium cures into a hardened surface to boost structural integrity, and it imbues resistance to water to better protect your cob house from humidity. You can use Pure Tung Oil straight, but mixing it with our Citrus Solvent or Odorless Mineral Spirits may aid absorption and help speed up the coverage process.

Finishing Earthen Flooring with Half and Half

half and half maintains durability of cob house built

Since earthen floors must endure lots of wear and tear, finishing them with our Half and Half formulation helps them maintain their durability over time. This product combines Pure Tung Oil with Citrus Solvent for easy absorption and convenient use, making it simple to add multiple coats to the floor of your cob home without much effort. If you wish to paint your cob floor with Real Milk Paint before sealing and waterproofing it, Half and Half works well over the medium.

Sustainable living is the wave of the future, making housing solutions like tiny houses and cob homes something to consider going forward. To enhance the eco-friendliness of the structures you create, the Real Milk Paint Co. offers high-quality finishing options to help transform small cob houses into a customized home.