Cordwood House Foundation

All you need to consider before choosing a foundation for your cordwood house

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Since more and more people start getting green these days, choosing eco-friendly products and other stuff for their daily use, even the building and construction sphere has been affected by this trend. Nowadays, thanks to so-called green building, many Americans are turning to more sustainable and more cost-effective ways to build a home. 

And cordwood houses fit that purpose perfectly well! However, even though this method of home building may seem to be quite simple, it still requires a deep understanding of the subject. In particular, one of the most common questions that people ask is about the cordwood house foundation type.

In this article, we did our best to provide you with all the necessary material on this topic. You will find out what a cordwood house is and what you should consider before you start building a foundation for it. Also, we will provide you with a brief instruction on how to build a cordwood house. Finally, we will share a few most common issues that one may face when building thyis type of a house.

Fabulous house made of cordwood on a stone foundation
itishouse.com

What Type Of Foundation Is Best For Cordwood Houses

No matter what type of construction you choose to build your house, the type of foundation it will have is always a crucial point of the building process. Since the foundation serves as a carrier for the walls and all the rest of the building, it must be strong, durable, and stable.

Continuing with the process of building a cordwood house, we delve further into understanding the "cordwood house foundation." Speaking of cordwood type of construction, there is one type of foundation that is considered the optimal. We mean the Frank Lloyd Wright rubble trench foundation. 

Gravel for trench foundation
By vista.com

This method uses a gravel trench which prevents water from accumulating and settling under the foundation of your home. Like this, such a foundation will protect your building against frost heaving. It will also save on construction costs and provide a type of foundation that suits a wide range of soil types, as well as different climates.

Of course, this is just a general description of the process, and below, we are going to provide you with a more detailed one. It will become handy for those of you who are planning on building a cordwood house on their own.

This type of foundation is so great because it will distribute the structural load of the entire building evenly across the surface area of the rubble trench. In addition, this construction technique unites two essential requirements of a building foundation in one system: it combines water drainage and structural bearing. 

And since proper drainage is especially crucial for any type of foundation because both frozen and liquid water may cause serious damage to the structure and even lead to the foundation failure!

The rubble trench foundation, an ancient construction approach popularized by architect Frank Lloyd Wright, is a type of foundation that uses loose stone or rubble to minimize the use of concrete and improve drainage. It is considered more environmentally friendly than other types of foundation because cement manufacturing requires the use of enormous amounts of energy. 

https://en.wikipedia.org/wiki/Rubble_trench_foundation

What Is Cordwood Construction?

Thick Corwood Column
By vista.com

In order to choose the most suitable type of foundation for your home, you need to know more about its method of constructing. So what is cordwood construction,you may wonder?

Cordwood is an ancient method of construction that dates back to more than one thousand years ago! The earliest mentions of it can be traced back to Greece and some parts of Europe. However, in the 1800s, this building technique became popular again.

cordwood house material
By vista.com

What makes it different? Simply saying, cordwood construction is where logs of the same length are laid in a bed of mortar and insulation so that they create a wall. Unlike the traditional log masonry, where the grain of the wood runs along the length of the wall, the wood grain in cordwood masonry faces out instead.

Why would cordwood masonry become so wildly popular these days, you may be wondering? Well, this type of construction has several undoubted benefits:

  1. It is very cost-effective
  2. It is easy to build
  3. It has great insulation characteristics
  4. It has structural excellence

This is why cordwood homes have become the top choice of almost all the DIY builders, and not only is the United States. However, if you want to successfully build a cordwood home that will stand for decades, you should be aware of certain nuances that this method of construction has. This is what we are going to discuss below. 

How to Build a Frank Lloyd Wright Rubble Trench Foundation

As we have promised, here is the detailed guide on how to build this type of foundation. We recommend you opt for this variant since it has shown itself as a trustworthy and reliable building method that has been tested by many homeowners and builders. Besides, this type of a house foundation is considered the best for a cordwood home.

The rubble trench foundation - diagram
itishouse.com
  1. Dig a trench that is 4 inches (10.16 cm) deeper than the frost depth in your area
  2. Keep the slope of the trench a minimum of ⅛ inch per linear ft. The width can be 16 inches, but you can adjust it to fit the load and the bearing capacity of your home
  3. Line the trench with a filter fabric to prevent fine silt from filling the gaps between the gravel that will fill the trench
  4. Fill the trench with up to four inches of gravel and tamp it down. Make sure that the surface of the grave is either at or below the frost depth. Also, it should conform to the drainage slope
  5. Run a perforated pipe (at least 4 inches in diameter) on top of the sloped gravel hill
  6. Fill the rest of the space left in the trench flush to or just below grade
  7. Use 1-5 inches gravel and tamp it down after each vertical foot of gravel fill
  8. Add a layer of biodegradable oil over the formwork (you can opt for any vegetable oil)
  9. Set the formwork for the concrete grade beam
  10. Pour in your concrete grade beam

This is it, now you have your trench foundation finishes. Of course, if you are not sure that you will manage to pour concrete properly, you should consider hiring professionals to do this for you. But in general, the procedure is quite easy and quick to complete.

And since you are now aware of what type of a home foundation is best for a cordwood home, let’s learn more about cordwood construction as it is.

Cordwood House Foundation Considerations

Like with any building project, there are always nuances that one should take into consideration before proceeding. Such nuances are especially important when it comes to a house foundation building. This is why below you can familiarize yourself with a couple of essential factors that should always be considered before starting your cordwood home’s foundation construction.

Supporting The Walls

Whatever foundation you choose, you should make sure it can support the immense weight of your wall. A 16-inch thick cordwood wall at 8-feet high weighs roughly 500 pounds per lineal foot. That means an 8-foot section of wall weighs 4000 pounds.

By this math, the cordwood sections of our home weigh roughly 56,000 pounds or 28 TONS, minus whatever weight is negated by the windows.

Not only should your foundation be able to support the weight, it needs to be able to support its width. Standard stud framed walls are only 6 inches deep, not counting the sheathing and siding or veneer. Most cordwood walls are somewhere between 12-24 inches thick (ours are 16″) so make sure your foundation will accommodate the extra thickness of the walls.

Meeting Code Requirements

Whether you have to deal with code officials in your area or not, you should make sure that your foundation type is code approved for your area. This is actually part of the reason we chose the foundation we did, even though we could have saved TONS of money doing it another way.

Make sure you double check your building plans with any relevant code officials in your area. If there aren’t any, make sure you run your plans by an experienced builder to make sure you won’t be wasting thousands of dollars on a failed system.

With this information in mind, you will feel much more confident and you will be able to start your home construction project without being afraid that something might go wrong suddenly.

Problems And Advantages Of a Cordwood House You Should Be Aware Of

When you are going to start building a house for yourself and for your family, you definitely want to know what type of the house would be the most comfortable for you to live in. There are many different materials out there now that can be used for construction, which often makes people feel slightly puzzled. Shall I use brick? Is it going to be clay? Maybe a wooden house will be the optimal choice?

And since cordwood is a very popular material these days, many people choose it for building their home. If you have chosen to have a cordwood house, you should be aware of some pros and cons this material has. It will be useful to know for those of you who are still hesitating, by the way!

Benefits Of Cordwood Homes

If we try to list the most prominent pros of cordwood construction, we will have to mention the following things:

  1. It’s cost-effective
  2. It is environmentally-friendly
  3. Building it doesn’t require any special skills
  4. Cordwood is energy-efficient
  5. It has a unique appearance

Now let’s take a closer look at each of these benefits so that you have a better and clearer understanding of them in general.

Anyone Can Build It

Well, almost anyone. For sure, this type of masonry is more time consuming and labor intensive in comparison to some other popular alternatives. However, almost anyone could build such walls and moreover, you do not need to be a talented architect or exceptionally skilled builder to manage such a project!

It Will Save Your Money

First of all, the biggest advantage of stackwall homes is that they are economical and have a lower cost than other types of houses. The price for construction will depend on the availability of suitable wood material in proximity to the construction site. 

It is best if you choose local types of wood and consult with professionals or people who have already had experience with cordwood building. See, this method of building can be very resource efficient as it may use wood that might not have much other value!

It’s Environmentally-Friendly

A cordwood house is environmentally friendly and energy efficient in addition. Since it is built with natural materials and due to the particular construction, the temperature inside the home remains at a relatively constant level. It will be cool in summer and warm in winter due to the insulating properties of wood.

It Looks Unusual!

In terms of aesthetic appearance, cordwood homes have a unique appearance. With such a house, your property will definitely be a noticeable spot in your neighborhood! The particular construction of this house, as well as the natural look, gives it a beautiful rustic vibe that is reminiscent of a mountain huts. You can also add a decorative element to the walls by using colorful glass bottles mortared into the wall. Like this, you will decorate your house and help it bring natural light in. 

Disadvantages Of Cordwood Houses

If only we could say that these houses have no drawbacks! However, if we did that, we would tell you lies. Cordwood homes do have certain cons and you should know about them in advance.

They Require a Lot Of Labor

Even though this house can’t be considered extremely hard to build, the main drawback is that building such a house will require a lot of time and labor, especially if you are planning a DIY project. 

The time needed will depend on how much time you can spare for the project and you have to compare money saving against the time spent. 

It Might Be Difficult to Sell It

For some reason, cordwood homes are often hard to sell! Perhaps, this happens because the potential buyers are not familiar with this type of construction and its specifics, which is why they choose to search for something more familiar.

Anyway, now that you know more about some pros and cons of this type of home construction and building technique, it will be easier for you to decide whether or not you should opt for it.

Links on this topic to authoritative sources:
  1. Cordwood construction : https://en.wikipedia.org/wiki/Cordwood_construction
  2. Using Cordwood – 1 Building Technique but with Many Names : https://theownerbuildernetwork.co/house-hunting/sustainable-and-green-homes/cordwood/

Facts

  1. Sustainable Material: Cordwood, also known as stackwall or log-end, is an eco-friendly building material. It uses short, debarked logs - often sourced from sustainable forests or fallen trees - making it an excellent choice for those conscious about their environmental footprint.
  2. Thermal Efficiency: Thanks to the superior insulating properties of wood, cordwood houses have excellent thermal efficiency. This means they can retain heat during winters and stay cool in summers, potentially saving on energy costs.
  3. Affordability: Building with cordwood is relatively inexpensive. Because you can use locally sourced wood, it often costs less than traditional building materials. Plus, with some instruction, you can do a lot of the work yourself, further reducing costs.
  4. Unique Aesthetic: Cordwood homes are instantly recognizable due to their unique aesthetic. The end-grain of the logs is exposed, creating a beautiful, rustic pattern that many homeowners find appealing.
  5. Strong and Durable: When constructed properly, cordwood foundations are incredibly strong. The combination of cordwood and mortar creates a foundation that can stand up to the pressures of holding up a house for generations.
  6. Thick Walls: Cordwood walls tend to be thick, which can be an advantage in terms of insulation and soundproofing. However, this does mean that cordwood homes typically have a larger footprint than those made from other materials.
  7. Slow Construction: One potential downside to cordwood construction is that it can be slow. The mortar between the logs needs to cure before more weight is added, so building a cordwood house can take quite some time.
  8. Mortar Matters: Choosing the right mortar mix is crucial in cordwood construction. The wrong mix can lead to instability, while the right mix helps the wood and mortar bond together to create a strong, durable structure.

 

The cordwood house foundation presents a beautiful blend of resilience, aesthetics, and sustainability. It is truly a testament to human ingenuity and the infinite potential of natural resources. With these facts in mind, it's easy to appreciate the unique charm and practical benefits of cordwood construction.

History

Our story begins in the ancient forests of North America, where the Native American tribes first recognized the potential of abundant, fallen logs. They noticed the insulating properties of these logs during harsh winters and scorching summers. This observation ignited the spark of cordwood construction. As time progressed, the practice spread across the continent, eventually reaching the early European settlers in the 19th century.

These settlers were quick to adapt cordwood construction, partly out of necessity and partly out of an appreciation for its advantages. They had an abundance of felled timber, often left over from clearing land for farming, and cordwood presented an economical way to make use of these resources. It was during this period that the cordwood technique developed significantly, evolving from rudimentary structures to more sophisticated homes.

In the late 1800s, cordwood construction crossed the Atlantic to Europe. It found particular popularity in France, where it was known as "bois cordé". The French developed their own techniques, including the use of lime-based mortars, which proved to be more resilient and weather-resistant.

However, as industrialization took hold in the 20th century, cordwood construction fell out of favor. New, mass-produced materials such as concrete and steel became prevalent. Yet, despite this, cordwood construction never completely disappeared.

A resurgence of interest in cordwood construction emerged in the 1970s during the back-to-land movement. People were drawn to its environmental sustainability, affordability, and unique aesthetic. Notable proponents like Rob Roy and Jack Henstridge played significant roles in refining and teaching the cordwood masonry techniques we know today.

Presently, cordwood construction continues to enchant homeowners around the world. The story of cordwood house foundations remains one of enduring ingenuity, a testament to the possibilities presented by nature, and the human capacity to make the most of what's readily available.

Expert Advice

  1. Choosing the Right Wood: Not all wood species are suitable for cordwood construction. Use softwoods like cedar, pine, and spruce, which are naturally rot-resistant. Also, make sure the logs are properly dried before using them to prevent future shrinkage.
  2. Wood Length Matters: The length of your cordwood logs will determine the thickness of your walls. Generally, the length of logs should be 12-24 inches. Keep in mind that thicker walls offer better insulation.
  3. Seal the Deal: To protect your cordwood house foundation from moisture and potential insect infestation, apply a high-quality sealer to the logs. This should be reapplied every few years for long-lasting protection.
  4. Proper Insulation: Ensure good insulation by filling the spaces between the logs with a mixture of lime and sand. This not only provides excellent insulation but also helps in preserving the wood.
  5. Structural Integrity: While cordwood is sturdy, remember to include additional structural support like posts and beams, especially for multi-story structures.
  6. Sustainability: If possible, source your wood locally to reduce environmental impact and to ensure the wood is suitable for your local climate.
  7. Professional Guidance: Building a cordwood house foundation can be a rewarding DIY project, but for first-timers, it's wise to seek professional guidance or attend a cordwood masonry workshop to avoid common pitfalls.
  8. Building Regulations: Check with your local building department. Not all areas have building codes that allow for cordwood construction, and you may need to apply for specific permits.

Frequently Asked Questions

Is It Possible To Build A Cordwood House Yourself?

Basically yes, but it will take you quite a lot of time, especially if you will be doing everything alone.

What’s The Price For A Cordwood House To Build?

The average price may vary anywhere between $90.000 and $115.000. It depends on the size of the house and how complicated the construction is.

Are Cordwood Homes Good For Rainy Climates?

This type of home does very well in rainy and humid climates.
Is Alaska An Okay Place To Build A Cordwood House?
Alaska is a great place to build a cordwood house and lots of people have already done so.
How Deep Should A Cordwood House Foundation Be?

The foundation depth depends on factors like soil type, frost line, and local building codes, but it typically ranges from 18 to 48 inches below ground level.

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Comments

Koby Baumbach:
Hi! I'm from Canada and I really want to build my green home. But it’s kinda hard to choose good material. Where I'm from, it gets really hot during the summer and freezing-cold during the winter. On my land, there is only forest and one little river beside… Anyway, if you have an idea of what I could use for material, that would be appreciated !
Mack Brown:
Hi! From your description, I might suggest that you investigate using the cordwood technique for your walls, since you have forests that could provide the pieces of wood. Cordwood is naturally quite insulating against the cold and the heat, does not require maintenance over time, is pretty to look at, easy to construct, and can be done to satisfy most building codes. So I guess you should consider this option!
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