Earth-sheltered homes are the correct choice if you want a home with energy-efficient features and a comfortable, tranquil environment.
Underground and bermed earth-sheltered homes designs are the two most common forms.
Earth-Sheltered Homes in the Subterranean World
A subterranean structure is when an entire earth-sheltered dwelling is below grade or underground. You can accommodate an underground house in an atrium or courtyard design while maintaining an open sense. The principal living rooms are around a central outdoor courtyard, which we build fully below ground on a level site. The atrium’s uncovered walls have windows and glass doors that allow light, solar heat, outdoor views, and access via a stairway from the ground level.
Moreover, the atrium design is barely visible from ground level, creating a secluded outdoor space that is well protected from winter winds. This design is suitable for construction sites with no picturesque views from the outside, in dense developments, and noisy places. Because of the location of the home’s windows, passive solar gain (heat gained through windows) is likely to be limited, and courtyard drainage and snow removal should be carefully considered during design.
Earth-Sheltered Bermed Homes
The dirt may cover one or more walls of a bermed house, which we can build above or partially below grade. To protect and insulate the building, an “elevational” bermed design exposes one elevation or face while covering the other sides—and sometimes the roof—with soil.
The sun can light and heat the interior thanks to the house’s exposed front, which is usually facing south. The floor design ensures that communal areas and bedrooms benefit from the southern exposure’s light and warmth. This is the cheapest and most straightforward approach to constructing an earth-sheltered structure. In the northern parts of the home, strategically positioned skylights can provide ample ventilation and daylight.
Except where there are windows and doors, earth covers the entire house in a penetration bermed style. We usually build the home at ground level, with soil raised around and on top of it (or bermed). This layout allows for cross-ventilation and access to natural light from multiple directions.
Advantages and Disadvantages
Earth-sheltered dwellings, like any other housing design, have benefits and drawbacks.
On the plus side, unlike a conventional house, an earth-sheltered home is less susceptible to the effects of severe external air temperatures. Earth-sheltered houses also require less exterior care and provide soundproofing due to the earth surrounding them. Furthermore, most earth-sheltered house ideas “blend” the structure into the landscape more gracefully than a traditional dwelling. Finally, earth-sheltered homes may be less expensive to insure since they provide more protection from high winds, hailstorms, and natural disasters like tornadoes and hurricanes.
The initial cost of construction, which can be up to 20% higher than a conventional house, and the additional level of care required to minimize moisture problems, both during construction and over the life of the house, are the main disadvantages of earth-sheltered dwellings. Reselling an earth-sheltered home can also be more difficult, and buyers may face greater challenges in the mortgage application process.
Site-Specific Factors in the Design of Earth-Sheltered Homes
You must examine the climate, terrain, soil, and groundwater level of your building site before opting to design and build an earth-sheltered house.
In areas with substantial temperature swings and low humidity, such as the Rocky Mountains and northern Great Plains, studies demonstrate that earth-sheltered dwellings are more cost-effective. In some places, earth temperatures change significantly less than air temperatures, allowing the earth to absorb extra heat from the home in hot weather or insulate the house in the cold season.
Microclimate and Topography
The geography and environment of the site dictate how easily the structure can be encased with the earth. A gentle slope necessitates more excavation than a steep one, and a flat location necessitates substantial excavation. An earth-sheltered building is best on a south-facing slope in a climate with moderate to long winters. While the rest of the home is nestled back into the hill, south-facing windows can let in the sunshine for direct heating. A north-facing slope may be beneficial in areas with mild winters and scorching summers. A designer that is aware of earth sheltering may plan carefully to take maximum advantage of the characteristics of your specific site.
Another important factor to consider is the type of soil on your property. The greatest soils for earth sheltering are granular soils like sand and gravel. These soils compress well and are porous, allowing water to drain fast. The most impoverished soils are cohesive, such as clay, which expands when wet and has low permeability.
Professional soil testing can establish the load-bearing capacity of the soils on your property. Another thing to examine is the amount of radon in the soil, as excessive amounts of radon can be dangerous. However, there are ways to reduce radon levels in both conventional and earth-sheltered homes.
The level of groundwater at your construction site is also crucial. Natural drainage away from the building is the greatest technique to reduce water pressure against subsurface walls. But we can draw water away from the structure using engineered drainage systems.
Earth-Sheltered Home Construction Materials and Considerations
The materials used to build each earth-sheltered structure will differ depending on the site’s conditions and the type of design. To endure the pressure and wetness of the surrounding ground, materials must provide a good surface for waterproofing and insulation.
Because it is strong, durable, and fire-resistant, concrete is the most frequent material to construct earth-sheltered structures. Concrete masonry units (also known as concrete blocks) that are reinforced with steel bars put in the masonry’s core can also be utilized, and they are often less expensive than cast-in-place concrete.
We can use wood for both interior and light structural work in earth-sheltered construction. We can use steel for beams, bar joists, columns, and concrete reinforcement; however, it must be sheltered from the environment or groundwater to avoid corrosion. It’s also pricey, therefore we must use it wisely to be cost-effective as a structural material.
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