The Anatomy of Earth Sheltered Homes
There are many ways to build homes beyond the typical four walls and a roof we see along most suburban streets. Earth sheltered homes are built with soil or vegetation surrounding the walls or buried completely underground.
Earth sheltered homes are ideal for homeowners who are looking for sustainable living quarters that withstand weather conditions better than typical homes. Before you start building one, it’s important to understand what the different types of homes are and how the environment is less impacted from them. You can start learning about the different types of homes below, or jump straight to our infographic.
Types of Earth Sheltered Homes
There are many types of earth sheltered homes. These types differ based on how they are integrated with or into the earth. The degree of covering affects the indoor temperature, environmental impact and overall design. Many refer to “bermed” and “underground” as the main types, but we’re highlighting a couple more.
Earth Covered Homes
Building features of an earth covered home:
- Walls are not covered by earth
- Living roofs found are commonly found in urban settings
Earth covered homes only cover the roof with earth. These roofs are typically called “living roofs,” “green roofs” or “earth roofs.” Living roofs can be as simple as dirt or soil while more intricate roofs feature lush foliage and vegetation. Most other types of earth sheltered homes also feature a living roof.
Building features of an in-hill earth sheltered home:
- Up to three walls covered
- One wall is exposed to allow for a door and windows
- Built above ground
In-hill homes are built into slopes or hills with one wall facing out while the earth covers the other walls and the roof. These homes are typically built above ground. The exposed wall features windows to absorb passive heat from the sun. To effectively accomplish this, most in-hill homes are located in areas where the exposed wall can face south to absorb as much sunlight as possible.
Rooms that need natural sunlight like bedrooms, kitchens and living rooms are constructed closer to the exposed wall. Rooms that do not need daylight like storage rooms and bathrooms are commonly constructed farther away from the exposed wall.
Features of a bermed earth sheltered home:
- Can be built above ground or partially below ground
- Earth covers walls and sometimes the roof
Bermed homes typically have earth pushed up against the exterior walls and may have earth covering the roof. The earth surrounding the home helps insulate the interior temperature by absorbing and storing heat. The soil also helps manage storm drainage since the earth against the walls slopes away from the home. If additional drainage is needed, residents can add pipes and drains.
Similar to in-hill homes, bermed houses are normally built where the exposed walls can face south to absorb the most heat. Skylights are sometimes used to increase ventilation and sunlight in northern parts of the home. Bermed homes have less issues with moisture in comparison to underground homes since they are built either above or only partially below ground.
Features of an underground earth sheltered home:
- Can be built right below surface level or deeper underground
- Typically built on a flat site
- Have a central courtyard or atrium
Underground earth sheltered homes are built below ground level and typically feature a central, open atrium or courtyard to allow residents access to light and air. These homes have rooms that need heat like bedrooms and living rooms close to the center to get the most heat. This central opening also gives residents a private outdoor space and protection from strong winds. Since underground homes are secluded, they’re also best suited for people who want to get away from noisy areas or want more privacy in a densely populated location.
These homes are normally more spread out than other types of earth sheltered homes, so they’re not as great at capturing heat. If poorly constructed, the lack of heat may lead to issues with humidity, condensation or mold. Most underground homes are constructed in warmer climates to combat these issues.
Underground homes without a courtyard or atrium instead use skylights and other means of ventilation to make the house livable. Geothermal tubes are also used to mitigate issues with heating. Underground homes are sometimes referred to as “subterranean” or “chambered.”
Benefits of Earth Sheltered Homes
Homes made with the earth naturally come with many environmental benefits. In addition, earth sheltered homes are great for conserving energy and saving money over time. Below, we’ve listed many of the benefits of residing in an earth sheltered home.
Earth sheltered homes have a lower environmental impact because they are created in natural surroundings. This helps the natural ecosystem thrive since it’s not interrupted by the presence and construction of a traditional building. Take a look below to see just how the environment benefits from a sheltered home.
- Biodiversity: A study from Eastern Meditterranean University explains that a couple advantages to earth sheltered homes include a small environmental footprint and preservation of the natural landscape. These homes coexist with the surrounding natural habitat better than traditionally built homes since the earth is incorporated in its construction. The natural incorporation helps sustain existing flora and fauna in the area.
- Drainage: The National Park Service (NPS) explains that green roofs in particular absorb and filter rainwater and return it to the atmosphere via evaporation. This absorption helps slow the flow of rainwater to sewer systems and prevents flooding. Green roofs captured up to 80 percent of rainfall compared to 24 percent captured by typical roofs.
Earth homes are great at protecting the home structures and can withstand extreme weather conditions better than normal homes. Certain styles of homes also offer more seclusion.
- Durability: The vegetation and soil on living roofs can withstand the elements much better than normal roofs. It protects things like the waterproofing membrane that keeps outside forces from penetrating the home.Having a living roof that can better withstand UV rays and temperature fluctuations can double or triple a roof’s lifespan according to the British Columbia Institute of Technology. This level of protection also applies to the earth surrounding the rest of the home.
- Privacy: Depending on the style of home, earth sheltered houses can offer more privacy compared to traditional homes. Underground homes offer the most privacy since it’s difficult for passersby to peer inside.
Initial construction expenses for an earth sheltered home can be costly, sometimes costing about 20 percent more than the cost of building a traditional house. However, living in an earth sheltered home can save money over time. Take a look at the different ways earth home dwellers save money over time.
- Insulation: The earth surrounding these homes absorbs and slowly releases heat instead of attracting and trapping heat like a typical roof. Additionally, the earth reduces outside air infiltration and results in a more maintained indoor climate. Stable indoor temperatures reduce the need to use central heating or cooling, therefore reducing overall energy usage and costs over time.
- A case study from Energy Sage found that energy savings were significantly higher compared to conventional homes. The home featured in the case study cited warmed floors from sunlight in the winter, less exposure to heat because of the home’s overhang and a constant low of 70 degrees farenheit in the home.
- Low maintenance: After construction is complete, earth sheltered homes are relatively low maintenance and don’t require much upkeep if correctly constructed.
- Noise control: Earth homes provide natural soundproofing. This saves on the cost of soundproofing rooms and is especially helpful for homes built near noisy areas.
- Cheaper Insurance: Many insurance companies offer incentives and discounts for having “green” features in your home. Insurance may also cost less since these types of homes can better withstand the elements compared to traditional homes. Your exact cost savings depends on the state the home is located, building codes in your area and the insurance policy.
Earth sheltered homes can result in many environmental, safety and financial benefits when correctly built. Taking on a project like this is no easy task and requires proper investment in the right equipment, contractors and more to create a safe home. Take a look at our selection of earth moving equipment to see what your options are for your earth sheltered home and other construction projects.