930:
withstand the pressure and moisture of the surrounding ground. For instance, concrete and reinforced masonry, wood, and steel are all viable materials. Concrete is the most common choice for constructing earth-sheltered buildings due to its strength, durability, and fire resistance. Cast-in-place concrete is employed for non-critical structural elements such as concrete foundations, floor slabs, and exterior walls with less than 6 feet (1.8 meters) of earth cover, while precast reinforced concrete can be used for floors, walls, and roofs. Concrete masonry units should be 8 inches (200 millimeters) or greater, with the use of “A” or “H” facilitating unit placement around vertical reinforcing bars, depending on the required structural integrity. It is typically advised to use Type S mortar, grout with a minimum strength of 2,000 psi (14 MPa), and a concrete slab with a minimum strength of 2,500 psi (17 MPa) and 4 inches (100 mm) thickness. Brick or stone masonry reinforced with steel bars can be utilized for walls that will be subjected to lateral or vertical pressure from earth cover. Masonry generally costs less than cast-in-place concrete. Wood can be widely employed in earth-sheltered buildings for structural and internal work, including floors, roofs, and exterior walls. However, wooden frame walls, which must endure lateral pressure, are limited to a burial depth of one story when used as a structural material. Beyond this depth, the cost will rapidly increase while using wood as a structural material. Although wood can be less expensive than other materials, it lacks steel's strength, therefore it might not be the ideal option for structural material in some earth-sheltered dwellings, especially in moist soil type. Steel is used for beams, columns, bar joists, and masonry reinforcement. The advantage is that steel has high tensional and compressional strength, while the disadvantage is that it must be protected from corrosion if it is exposed to air, water, or other chemicals. It must be used effectively because it is also expensive.
921:
may need additional care in maintenance and construction due to condensation problems in regard to the high humidity. The ground temperature of the region may be too high to permit earth cooling if temperatures fluctuate only slightly from day to night. Preferably, there should be adequate winter solar radiation and sufficient means for natural ventilation. Wind is a critical aspect to evaluate during site planning, for reasons regarding wind chill and heat loss, as well as ventilation of the shelter. In the
Northern Hemisphere, south facing slopes tend to avoid cold winter winds typically blown in from the north. Fully recessed shelters also offer adequate protection against these harsh winds. However, atria within the structure have the ability to cause minor turbulence depending on the size. In the summer, it is helpful to take advantage of the prevailing winds. Because of the limited window arrangement in most earth shelters, and the resistance to air infiltration, the air within a structure can become stagnant if proper ventilation is not provided. By making use of the wind, natural ventilation can occur without the use of fans or other active systems. Knowing the direction, and intensity, of seasonal winds, is vital in promoting cross ventilation. Vents are commonly placed in the roof of bermed or fully recessed shelters to achieve this effect.
442:
other forms of heating. This method was first described by inventor and physicist John Hait in his 1983 book. The main component of it is an insulated and waterproof "umbrella" which extends out from the earth shelter for several meters in all directions. Hence the term "umbrella house". The earth under this umbrella is kept warm and dry relative to surrounding earth, which is subject to constant daily and seasonal temperature changes. This creates a large heat storage area of earth, effectively a huge thermal mass. Heat is gained via passive solar in the earth shelter and transferred to the surrounding earth by conduction. Thus, when the temperature in the earth shelter dips below the temperature in the surrounding earth, heat will return to the earth shelter. After a time, a stable temperature is reached which is an average of annual heat changes in the external environment. Some criticize the technique (along with the earth sheltering technique as a whole), stating concerns including difficulty and expense of construction, moisture and lack of evidence.
146:
837:
depending on latitude). This provides maximum solar radiation to bedrooms, living rooms, and kitchen spaces. Rooms that do not require natural daylight and extensive heating such as the bathroom, storage, and utility room are typically located on the opposite (or in-hill) side of the shelter. This type of layout can also be transposed to a double level house design with both levels completely underground. This plan has the highest energy efficiency of earth sheltered homes because of the compact configuration as well as the structure being submerged deeper in the earth. This provides it with a greater ratio of earth cover to an exposed wall than a one-story shelter would.
162:
787:
more when the earth/soil is layered on top of them. If the vents or ducts are held rigidly in place during this deflection, the result is usually the failure of the waterproofing layer. To avoid this difficulty, vents can be placed on other sides of the building (besides the roof), or separate segments of pipes can be installed. A narrower pipe in the roof that fits snugly into a larger segment of the building can also be used. The threat of water seepage, condensation, and poor indoor air quality can all be overcome with proper waterproofing and ventilation.
1348:
514:
1332:
1360:
868:. Clay soils, while least susceptible to erosion, often do not allow for proper drainage, and have a higher potential for frost heaves. Clay soils are more susceptible to thermal shrinking and expanding. Being aware of the moisture content of the soil and the fluctuation of that content throughout the year will help prevent potential heating problems. Frost heaves can also be problematic in some soil. Fine grain soils retain moisture the best and are most susceptible to heaving. A few ways to protect against
1313:
1379:
752:). Terms carbon zero and negative carbon buildings refer to the net greenhouse gas emissions over these four phases. Questions therefore arise as to whether certain structures are truly environmentally friendly. For example, raw materials must be extracted from the earth, transported and then manufactured into building materials and transported again to be sold and finally transported to the build site. A lot of fossil fuels may be used during each of these stages.
525:-axis represents time. Blue line: external temperature fluctuations between day maximum and night minimum (could also represent Summer maximum and Winter minimum temperature fluctuation on a longer timescale). Red line: Internal temperature. 1: Phase shifting (delay between maximum/minimum external temperature and internal temperature). 2: Amplitude dampening (the reduction in maximum or minimum internal temperature relative to that of the external temperature).
1102:
One reason for this is that it provides protection for the waterproof membrane against freeze damage, another is that the earth shelter is able to better retain its desired temperature. There are two types of insulation used in earth shelter construction. The first is close-celled extruded polystyrene sheets. Two to three inches glued to the outside of the waterproofing is generally sufficient. The second type of insulation is a spray on foam (e.g.
1054:
sure that all of the seams are carefully sealed. It is very difficult to locate and repair leaks in the waterproofing system after the building is completed. Several layers are used for waterproofing in earth shelter construction. The first layer is meant to seal any cracks or pores in the structural materials, also working as an adhesive for the waterproof membrane. The membrane layer is often a thick flexible polyethylene sheeting called
1013:
138:
38:
991:
construction. It is strong and readily available. Steel can be used but needs to be encased by concrete to keep it from direct contact with the soil which corrodes the metal. Bricks and concrete masonry units are also possible options in earth shelter construction but must be reinforced to keep them from shifting under vertical pressure unless the building is constructed with arches and vaults.
1111:
insulation designs relies on using the thermal mass of the earth to store heat, rather than relying on a heavy masonry or cement inner structures that exist in a typical passive solar house. This is the exception to the rule and cold temperatures may extend down into the earth above the frost line making insulation necessary for higher efficiencies.
1029:
well. One method uses finely meshed metal bent into the intended shape and welded to the supporting armature. Onto this mesh concrete is sprayed forming a roof. Terra-Dome (USA) is a company specializing in construction of earth-sheltered houses and sells a modular system of concrete domes intended to be covered by earth. Others advise the use of
917:
ventilating during the summer, and avoiding winter winds and cold pockets. For hot, arid climates objectives include maximizing humidity, providing summer shade, maximizing summer air movement, and retaining winter heat. For hot, humid climates objectives include avoiding summer humidity, providing summer ventilation, and retaining winter heat.
948:
repeated for the roof structure. If the walls, floor, and roof are all to be poured in place, it is possible to make them with a single pour. This can reduce the likelihood of there being cracks or leaks at the joints where the concrete has cured at different times. The foundation of the buildings designed by Vetsch are built conventionally.
1058:. EPDM is the material usually used in a water garden, pond and swimming pool construction. This material also prevents roots from burrowing through the waterproofing. EPDM is very heavy to work with and can be chewed through by some common insects like fire ants. It is also made from petrochemicals, making it environmentally unsustainable.
570:
other measures of heating and cooling, saving energy. A potential disadvantage of a thermally massive building in cooler climates is that after a prolonged period of cold, when the external temperature increases again, the structures internal temperature tends to lag behind and take longer to warm up (assuming no other form of heating).
410:', proposed to use a wide and deep cylindrical shaft sunk into the earth, with a domed skylight roof. Artificial caves can be constructed by making a tunnel into the earth. Building greenhouses underground has also been speculated about. Schools, commercial centres, government buildings and other buildings could be built underground.
558:
values include 5–6 m (16–20 ft), 6 m (20 ft), 15 m (49 ft), 4.25 m (13.9 ft) for dry soil, and 6.7 m (22 ft) for wet soil. Below this level the temperature increases on average 2.6 °C (5 °F) every 100 m (330 ft) due to heat rising from the interior of the Earth.
345:(also termed "bunded") type, earth is banked against the exterior walls, sloping down away from the building. The berm can be partial or total. The polar facing wall may be bermed, leaving the equator-facing wall un-bermed (in temperate regions). Usually this type of earth shelter is built on, or only slightly below the original
734:
experience with earth-sheltered construction, potentially compromising the physical construction of even the best designs. The specific architecture of earth houses usually leads to non-righted, round-shaped walls, which can cause problems concerning the interior decoration, especially regarding furniture and large paintings.
349:. Due to the building being above the original ground level, fewer moisture problems are associated with earth berming in comparison to underground/fully-recessed construction, and it costs less to construct. According to one report, earth berming provided 90-95% of the energy advantage as a completely below grade structure.
1025:
structure. Some advise to have just enough thickness of earth on the roof to maintain a green roof (approximately 6 inches / 15 cm), since this means less load on the structure. Increasing the amount of earth on the roof past this gives only modest increases in the benefits while increasing costs significantly.
487:
US at the time, cost less to regulate temperature, was less affected by stormy weather, had pipes which wouldn't freeze where they entered the house, were "ecologically sound", relatively fireproof, soundproof and had an increased garden space as compared to regular house on a similarly sized plot of land.
1101:
One or more layers of insulation board or foam are added on the outside of the waterproofing. If the insulation chosen is porous, a top layer of waterproofing is added. Unlike the conventional building, earth shelters require the insulation on the exterior of the building rather than inside the wall.
1088:
as a 'sealer' and stop the internal vapor pressure of the moist concrete exploding bubbles of vapor up underneath the membrane when exposed to hot sun. The bond strength of epoxy to concrete is stronger than the internal bond strength of concrete so the membranes won't 'blow' off the wall in the sun.
1028:
Despite being underground, drainage of water is still important. Therefore, earth shelters do not tend to have flat roofs. A flat roof is also less resistant to the weight of the earth. It is common for earth shelter designs to have arches and shallow domed roofs since this form resists vertical load
888:
in the middle of the berm is also helpful or the back of the berm can be terraced with retaining walls. On sloping sites, runoff may cause problems. A drainage swale or gully can be built to divert water around the house, or a gravel-filled trench with a drain tile can be installed along with footing
786:
The threat of water seepage occurs around areas where the waterproofing layers have been penetrated. Earth usually settles gradually. Vents and ducts emerging from the roof can cause specific problems due to the possibility of movement. Precast concrete slabs can have a deflection of 1/2 inch or
641:
While residents of earth sheltered homes report noticing more minor earthquakes, the homes are resilient against large earthquakes, as their subterranean nature allows them to move with the earth. Picture a small twig house sitting on top of a tub of dirt: Shake the dirt, and the house will dance and
599:
Compared with the material needs of standard buildings, earth-sheltered homes can greatly reduce the number of natural resources. Traditional wood structure home requires lumber for framing and interior finishes, which is quite a big demand. Soil as the main building material and blending in with the
569:
Partially covering a building with earth adds to the thermal mass of the structure. Combined with insulation, this results in both amplitude dampening and phase shifting. In other terms, earth sheltered structures receive both a degree of cooling in summer and heating in winter. This reduces need for
497:
He claimed his homes could be used as fallout shelters in case of nuclear wars and also claimed that, in the case of complete societal collapse, his design would be more defensible than a regular house in the case of random attacks, as well as being better concealed from potential hostiles (without a
323:
There are an estimated 30-40 million
Chinese living in such earth homes today still, mostly along the Yellow River in Northern China. There are mainly two kinds of earth homes in the area. The first type is pit cave dwellings. Usually, people dig a sunken courtyard, which is a rectangular underground
287:
Since the late 1980s, earth sheltered homes have become increasingly popular. The technique is more common in Russia, China and Japan. It is possible that
Northern China has more earth shelters than any other region. As of 1987, approximately 10 million people live in underground homes in the region.
883:
Atrium designs have an increased risk of flooding, so the surrounding land should slope away from the structure on all sides. A drain pipe at the perimeter of the roof edge can help collect and remove additional water. For bermed homes, an interceptor drain at the crest of the berm along the edge of
733:
Overall it is more technically challenging to design an earth shelter compared to a regular home. Because of the unorthodox design and construction of earth-sheltered homes, local building codes and ordinances may need to be researched and/or navigated. Many construction companies have limited or no
713:
of not having time to go to work) and recycled materials, e.g. windows and planks for the wall, is estimated to be 30% cheaper to construct when compared to paying a contractor to build a regular house using new construction materials at standard prices, although Oehler's design will quickly rot and
632:
Compared to other building materials, such as wood, earth houses feature efficient fire protection owing both to the use of concrete and the insulation provided by the roof. Taking the example of
Earthships, there is a reported case where the structure survived fire better compared to other types of
590:
The unique architecture of earth houses protects them against severe windstorms. They cannot be torn away or tipped over by strong winds. Structural engineering and, above all, the lack of corners and exposed parts (roof), eliminate vulnerable surfaces which would otherwise suffer from storm damage.
573:
The reduction of air infiltration within an earth shelter can be advantageous. Because three walls of the structure are mainly surrounded by earth, very little surface area is exposed to the outside air. This alleviates the problem of warm air escaping the house through gaps around windows and door.
561:
Diurnal temperature changes between maximum and minimum temperatures can be modelled as a wave, as can seasonal temperature changes (see diagram). In architecture, the relationship between the maximum fluctuations of external temperature compared to internal temperature is termed amplitude dampening
486:
In 1981, Oehler promoted his low-budget building design (a simple hole in the ground with walls of wooden planks backed by plastic sheeting) by claiming it needed no foundation, used less building material and labour, had less maintenance, was aesthetically pleasing, had a lower taxation rate in the
396:
With an atrium earth shelter, the living spaces tend to be located around the atrium. The atrium arrangement provides a much less compact plan than that of the one or two-story bermed/in hill design; therefore it is commonly less energy efficient, in terms of heating needs. Therefore, atrium designs
1061:
There are various cement-like coatings that can be used as waterproofing. The product is sprayed directly onto the unprotected surface. It dries and acts like a huge ceramic layer between the wall and earth. The problem with this method is, if the wall or foundation shifts in any way, it cracks and
1053:
On the outside of the concrete, a waterproofing system is applied. The most frequently used waterproofing system includes a layer of liquid asphalt onto which a heavy grade waterproof membrane is affixed, followed by a final liquid water sealant which may be sprayed on. It is very important to make
920:
Regions with extreme daily and seasonal temperatures emphasize the value of earth as a thermal mass. In this way, earth sheltering is most effective in regions with high cooling and heating needs and high-temperature differentials. In regions such as the southeastern United States, earth sheltering
892:
Soil stability should also be considered, especially when evaluating a sloping site. These slopes may be inherently stable when left alone, but cutting into them can greatly compromise their structural stability. Retaining walls and backfills may have to be constructed to hold up the slope prior to
872:
responsible for frost heaves are placing foundations below the freezing zone or insulating ground surface around shallow footings, replacement of frost-sensitive soils with granular material, and interrupting capillary draw of moisture by putting a drainage layer of coarser material in the existing
675:
Earth sheltered dwelling express itself with the color harmony of soil and earth. Meanwhile, the material properties of soil and earth give earth homes the simplicity of geomatic masses. Also, earth homes blend in perfectly with the landscape and highlight the beauty of the surroundings, which is a
557:
Indeed, at a deep enough point underground, the temperature remains constant year round, and this temperature is approximately the mean of summer and winter temperatures. Sources vary in their stated values for this deep earth constant temperature (also termed amplitude correction factor). Reported
428:
systems. A large double glazed window, triple glazed, spanning most of the length of the south wall is critical for solar heat gain. It is helpful to accompany the window with insulated drapes to protect against heat loss at night. Also, during the summer months, providing an overhang, or some sort
324:
pit about 10 meters deep, then arrange rooms dug off the main courtyard. The second type is dwelling space carved out of earth cliffs which are often south-facing, and the facades are sometimes faced with bricks or stone. They usually come with larger courtyards since it doesn't bother to excavate.
306:
Overall earth shelter construction is often viewed by architects, engineers, and the public as an unconventional method of building. Techniques of earth sheltering have not become common knowledge, and much of society is unaware of this type of building construction. Generally speaking, the cost of
173:
Earth sheltered is one of the oldest forms of building. It is thought that from about 15,000 BC migratory hunters in Europe were using turf and earth to insulate simple round huts that were also sunk into the ground. The use of some form of earth sheltered construction is found across many cultures
1119:
After previous construction stages are complete, the earth is backfilled against the external walls to create the berm. Depending on the drainage characteristics of the earth may not be suitable to place in direct contact with the external wall. Some advise that topsoil and turf (sod) be put aside
1110:
In some low budget earth shelters, insulation may not be applied to the walls. These methods rely on the U factor or thermal heat storage capacity of the earth itself below the frost layer. These designs are the exception however and risk frost heave damage in colder climates. The theory behind no
916:
Depending on the region and site selected for earth-sheltered construction, the benefits and objectives of the earth shelter construction vary. For cool and temperate climates, objectives consist of retaining winter heat, avoiding infiltration, receiving winter sun, using thermal mass, shading and
836:
Earth sheltered homes are often constructed with energy conservation and savings in mind. Specific designs of earth shelters allow for maximum savings. For bermed or in-hill construction, a common plan is to place all the living spaces on the side of the house facing the equator (or north or east,
541:
of about 0.65-R per centimeter (0.08-R per 1 inch), or 0.25-R per 1 inch. Variations in R-value of soil may be attributed to different soil moisture levels, with lower R values as moisture level increases. The most superficial layer of earth typically is less dense and contains the root systems of
319:
has had much wider uptake in modern times. Over 20,000 buildings certified to PassivHaus standards have been constructed across
Northern Europe. Some postulate that over time the reducing availability of building space, and the increasing need and interest for environmentally friendly housing will
247:
As early as the 1960s in the US, some innovators were designing contemporary earth shelters. After the oil crisis and until the early 1980s there was a new resurgence in interest earth shelter/underground home construction, which has been termed the first wave of earth covered dwellings. Architect
947:
Once the site is prepared and the utility lines installed, a foundation of reinforced concrete is poured. The walls are then installed. Usually, they are either poured in place or formed either on or off-site and then moved into place. Reinforced concrete is the most common choice. The process is
929:
The selection of construction materials should consider the type of structure, characteristics of the site, climate, soil type, and design. Stronger, longer-lasting building materials are required for structures that are buried deeply. Waterproof and insulated materials should also be utilized to
701:
Three main factors influence overall cost of home construction, namely, design complexity, materials used, and whether the owner(s) carries out some or all of the construction or pays others to do it. Custom houses with complex designs tend to be more expensive and take longer to build than stock
332:
Three main types of earth shelter are described. There is also great variation in the approach to earth sheltering in terms of materials used and expenditure. The "low tech" approach might involve natural building techniques, wooden posts and shed style roofs, recycling of materials, owner labor,
608:
Earth homes organically embrace animals and poultry as well as water, soil, and plants. Arcology studies the relationship between animals and plants and man-made buildings during ecological development. For example, raising poultry and domesticated animals is an important part of the traditional
549:
Approximately 50% of the heat from the Sun is absorbed at the surface. Consequently, the temperature at the surface may vary considerably according to the day / night cycle, according to weather and particularly according to season. Underground, these temperature changes are blunted and delayed,
441:
in an earth shelter by means of direct gain passive solar heating and a thermal battery effect lasting several months. It is claimed that an earth shelter designed according to these principles would store the sun's heat in the summer and release it slowly over the winter months without need for
1065:
Bituthene (registered name) is very similar to the three coat layering process only in one step. It comes already layered in sheets and has a self-adhesive backing. Applying it manually is the same as with the layering method, in addition, it is sun sensitive and must be covered very soon after
227:
In China, man-made cave dwellings have been used as a shelter since 2,000 BC. In certain areas of northern China, like the provinces of
Shaanxi and Shanxi, since the loess earth is structurally uniform and compacted, providing easy access to good quality building material with stable structure,
1024:
with only a minimal thickness of earth. Alternatively a larger mass of earth might cover the roof. Such roofs must deal with significantly greater dead load and live load (e.g. increased weight of water in the earth after rain, or snow). This requires stronger and more substantial roof support
423:
Earth sheltering is often combined with solar heating systems. Most commonly, the utilization of passive solar design techniques is used in earth shelters. In most of the
Northern Hemisphere, a south-facing structure with the north, east, and west sides covered with earth is the most effective
259:
The majority of publications about earth sheltering date to this period, with dozens of books dedicated to the topic being published in the years leading up to 1983. The first
International Conference on Earth-Sheltered Buildings was hosted in Sydney, Australia in 1983. A second conference was
1069:
Eco-Flex is an environmentally friendly waterproofing membrane that seems to work very well on foundations, but not much is known about its effectiveness in earth sheltering. It is among a group of liquid paint-on waterproofing products. The main challenge with these products are they must be
762:
The materials involved tend to be non-biodegradable substances. Because the materials must keep water out, they are often made of plastics. The excavation of a site is also drastically time- and labor-consuming. Overall, the construction is comparable to conventional construction, because the
990:
Untreated wood in direct contact with earth rots within five years of use in earth shelter construction, but can be used for structural support construction in a well-insulated and water/moisture-proofed home. Reinforced concrete is the most commonly used structural material in earth shelter
174:
in history, distributed widely across the world. Normally these examples of cultures using earth sheltered buildings occur without any knowledge of the construction method elsewhere. These structures have many different forms and are referred to by many different names. General terms include
405:
Depending on what definition of earth sheltering is used, other types are sometimes included. In culvert homes ("Cut and Cover"), precast concrete containers and large diameter pipes are arranged into a connecting design to form a living space and then backfilled with earth. An experimental
896:
On land that is relatively flat, a fully recessed house with an open courtyard is the most appropriate design. On a sloping site, the house is set right into the hill. The slope will determine the location of the window wall; the most practical orientation in moderate to cold climates is a
581:
of the earth, the protection against unwanted air infiltration and the combined use of passive solar techniques, the need for extra heating and cooling is minimal. Therefore, there is a drastic reduction in energy consumption required for the home compared to homes of typical construction.
722:). Another important cost factor that tends to be unique to earth shelters is site excavation and backfilling. The amount of waterproofing is also more costly. On the other hand, earth shelters should have lower maintenance costs since they are mostly covered with little exposed exterior.
374:, or east just outside the Tropics. There is only one exposed wall in this type of earth sheltering, the wall facing out of the hill, all other walls are embedded within the earth/hill. This is the most popular and energy efficient form of earth shelter in cold and temperate climates.
620:
Some claim that the construction method is advantageous to the nitrogen-fixation of the soil on the roof, because it would otherwise be covered by the foundation of a traditional house. Contrary to conventional roofs, earth-house roofs allow plants to grow semi-naturally on them.
705:
Both earth sheltered projects and construction of regular houses have significant variability in the design, materials and labor involved. As such it is difficult to make a precise comparison of cost between the two, however in general an earth shelter is much more expensive.
111:"A building can be described as earth-sheltered when it has a thermally significant amount of soil or substrate in contact with its external envelope, where “thermally significant” means making a functional contribution to the thermal effectiveness of the building in question.
357:
The in-hill (also termed "earth covered", or "elevational") construction is where the earth shelter is set into a slope or hillside, and earth covers the roof in addition to the walls. The most practical application is using a hill facing towards the equator (south in the
1106:
solid foam insulation). This works very well where the shape of the structure is unconventional, rounded or difficult to get to. Foam insulation requires an additional protective top coat such as foil or fleece filter to help it resist water penetration.
938:
In earth-sheltered construction, there is often extensive excavation done on the building site. An excavation several feet larger than the walls' planned perimeter is made to allow for access to the outside of the wall for waterproofing and insulation.
717:
A particular factor that strongly influences the cost of an earth shelter is the amount of earth that covers it. The more earth covering the structure, the greater the expense is needed in having a structure capable of withstanding the load (see also:
554:. The thermal properties of earth therefore mean that in winter the temperature below the surface will be higher than the surface air temperature, and conversely in summer the earth temperature will be lower than the surface air temperature.
333:
hand excavation, etc. The relatively more high tech approach would be larger, using concrete and steel. While typically more energy efficient post construction, the high tech approach has higher embodied energy and significantly more costs.
303:, the brand of passive solar earth shelters sold by Earthship Biotecture. Earthships are concentrated in New Mexico, USA, but are found less commonly throughout the world. In other areas such as the UK earth sheltering is more uncommon.
490:
He also claimed the view from a window below the ground was better than that from other windows, and that the flooring he used in his an underground home (plastic sheeting over bare dirt) was "superior" to what is elsewhere available.
1003:
are becoming more readily available. They claim to be environmentally friendly and either reduce or eliminate the need for additional waterproofing. However, these have not been extensively used in earth shelter construction yet.
994:
Unfortunately, reinforced concrete is not the most environmentally sustainable material. The concrete industry is working to develop products that are more environmentally friendly in response to consumer demands. Products like
1076:
clay is an alternative that the most environmentally friendly. It is naturally occurring and self-healing. The drawback to this material is that it is very heavy, difficult for the owner/builder to install, and subject to
1611:
392:
or courtyard constructed in the middle of the shelter to provide adequate light and ventilation. The atrium is not always fully enclosed by raised ground, sometimes a U-shaped atrium is used, which is open on one side.
397:
are found mainly in warmer climates. However, the atrium does tend to trap air within it which is then heated by the sun and helps reduce heat loss. Atrium designs are well suited to flat sites, and are fairly common.
307:
excavation, increased need for damp-proofing and the requirement for the structure to withstand greater weight relative to above grade houses means that earth sheltering remains relatively rare. In this respect, the
1089:
Epoxies are very brittle so they are paired up with an overcoat of a high-build flexible water-based acrylic membrane in multiple coats of different colors to ensure film coverage—this is reinforced with non-woven
574:
Furthermore, the earth walls protect against cold winter winds which might otherwise penetrate these gaps. However, this can also become a potential indoor air quality problem. Healthy air circulation is key.
658:
Due to the mass of the earth between the living area of an earth house and the surface grade, an earth home offers significant protection from impact/blast damage, or fallout associated with a nuclear bomb.
1128:
In the earth houses designed by Vetsch, interior walls are furnished using loam rendering which provides superior humidity compensation. The loam rendering is finally coated with lime-white cement paint.
667:
Earth shelters may provide privacy from neighbors, as well as soundproofing. The ground provides acoustic protection against outside noise. This can be a major benefit in urban areas or near highways.
709:
A small "underground home" built in the style of Oehler, as only a simple, non-waterproofed hole in ground with simple planks and a plastic sheet to a wall, despite using free labour (ignoring the
205:, in southwest USA. These building are constructed directly onto the ledges and caves on the face of the cliffs. The front wall is built up with local stone and earth to enclose the structure.
114:"Structures built with the use of earth mass against building walls as external thermal mass, which reduces heat loss and maintains a steady indoor air temperature throughout the seasons."
2373:
388:
The true underground (also termed "chambered" or "subterranean") earth shelter describes a house where the ground is excavated, and the house is set in below grade. They can feature an
240:
saw the price of oil dramatically increase, which influenced vast social, economic and political changes worldwide. Combined with growing interest in alternative lifestyles and the
1608:
909:
the
Tropics, the most practical way to avoid afternoon heat excess may be an east-facing house or, if near a west coast, exposure of the east end and the west end, with the two
2684:
983:
Oehler prescribed a very low budget method he termed "post, shoring and polyethylene". This involves buried wooden posts to act as a frame, shored up with planks, and with a
779:
or mildew growth, associated with a musty smell and potentially with health problems. The below-ground orientation of many earth-sheltered homes can allow accumulation of
799:), many earth-sheltered homes have dark areas in the areas opposite the windows. All natural light coming from one side of the home can give a "tunnel or cave effect".
96:"Earth-sheltering is a generic term with the general meaning: building design in which soil plays an integral part." This definition is problematic however, since
702:
houses. Houses which use expensive materials will be more expensive than houses which use low cost materials. Owner labor can dramatically cut construction costs.
897:
south-facing exposed wall in the
Northern hemisphere (and north-facing in the Southern hemisphere) due to solar benefits. The most practical orientation in the
775:, bad acoustics, and poor indoor air quality can occur if an earth shelter has not been properly designed and ventilated. Very high humidity levels can allow
815:
Compared to above ground house, earth-shelters may have limited escape routes in case of emergency, which can fail egress and fenestration building codes.
740:
An earth shelter cannot be enlarged with an extra room - this will require breaking the waterproofing sealant cladding the concrete walls of the building.
502:). Because his design was not waterproofed, one would be "closer to a source of water", and could potentially simply dig a well in the middle of the room.
2677:
1465:
807:
Reports of collapse seem to be rare. In one case, an author and proponent of earth sheltering died when an earth roof he designed collapsed on him.
2282:
617:
Compared to conventional buildings, earth houses can fit into their surroundings. The soil-covered roofs hide the building within the landscape.
291:
Some claim that thousands of people live underground in Europe and America. Notable European examples are the "Earth Houses" of Swiss architect
2384:
2670:
725:
Many financial institutions outright exclude financing on earth-sheltered homes, or require this type of property to be common for the area.
1331:
987:
of polyethylene sheet between the planks and the backfill, but no foundation and nothing on the floor except a plastic sheet and carpeting.
748:
In "green building", four "lifetime" phases of a building are described, namely material sources, construction, in use, and deconstruction (
759:
in particular needs to be used in much larger quantities per building. The manufacture of concrete is a major source of greenhouse gases.
1226:
996:
783:
gas (which is known to increase the risk of lung cancer) or other undesirable materials (e.g. off gassing from construction materials).
208:
In North America, almost every native American group used earth sheltered structures to some extent. These structures have been called '
1000:
498:
map and unfamiliar with the area). He believed that underground, inhabitants would be better protected from "atmospheric radiation" (
1084:
Bi-membranes have been used extensively throughout Australia where 2 membranes are paired together—typically 2 coats of water-based
880:
is crucial. Drainage, both surface, and subsurface must be properly dealt with. Waterproofing applied to the building is essential.
609:
Chinese rural human settlements and these elements create a stable and sustainable ecological cycle that benefits the environment.
1347:
684:
and pit cave dwellings in Northern China hide themselves underground and blend in perfectly within the Loess plateau environment.
1312:
1070:
carefully applied, making sure that every area is covered to the right thickness, and that every crack or gap is tightly sealed.
295:. There are about 50 such earth shelters in Switzerland, including a residential estate of nine earth shelters (Lättenstrasse in
1233:
755:
Earth sheltering often requires heavier construction materials to resist the weight of the earth against the walls and/or roof.
3218:
2333:
2305:
848:, and help to retain heat. With respects to drainage, the most suitable type of soil for earth sheltering is a mixture of
80:, making it easier to maintain a steady indoor air temperature and therefore reduces energy costs for heating or cooling.
737:
Repairs to the walls are very difficult to service; and may require re-evaluating and rebuilding the house from scratch.
3069:
856:. Well graded gravels have a large bearing capacity (about 8,000 pounds per square foot), excellent drainage and a low
2349:
2152:
1229:, Bushey Heath Watford, Hertfordshire, Build 1996 modern earth sheltered building 4 bedroom 170m2 in the UK. see here
2637:
2417:
2258:
2192:
2109:
2052:
1990:
1916:
1881:
1833:
1755:
1689:
1252:, on the shore of Lake Washington (Medina, Washington, USA). This is a well-known example of an earth-sheltered home.
244:, the public of the US and elsewhere were becoming more interested in saving energy and protecting the environment.
145:
1359:
823:
An earth shelter may not be able to be adapted to existing local building codes, and may not legally be lived in.
1950:
469:
and then into the house living space. This also provides fresh air to occupants and the air exchange required by
438:
157:
from the book "Maximilian, Prince of Wied's Travels in the Interior of North America, during the years 1832–1834"
688:
in a halite mountain near the city of Zipaquirá, Colombia hugs the contour and highlights the natural features.
87:. However, the practice has been around for nearly as long as humans have been constructing their own shelters.
3115:
2978:
2973:
2958:
2150:
1807:
1787:
1255:
2525:
876:
Water can cause potential damage to earth shelters if it ponds around the shelter. Avoiding sites with a high
3213:
3198:
1681:
The Complete Guide to Building Affordable Earth-Sheltered Homes: Everything You Need to Know Explained Simply
1293:
505:
He furthermore claimed anyone could build one of his designs irrespective of skill or ability for only $ 50.
3203:
2968:
1504:
885:
1120:
from the initial excavation and be used for the grass roof and to place as the topmost layer on the berm.
642:
stress. But if you bury the house in the dirt, you can shake the tub without stressing the house as much.
3125:
2629:
1275:
17:
2646:
980:. Earthships classically use rammed earth tire walls, which are labor-intensive but recycle used tires.
977:
3120:
3049:
3044:
3019:
1265:
840:
The soil type is one of the essential factors during site planning. The soil needs to provide adequate
1213:"The Underground House" in Great Ormside, Cumbria. Two storey earth shelter built in a disused quarry.
1020:
The roof of an earth shelter may not be covered by earth (earth berm only), or the roof may support a
299:). Possibly the most well known examples of modern earth sheltering in the English-speaking world are
3228:
3151:
1181:
241:
2182:
2084:
1646:
3223:
2945:
1519:
1936:
2905:
2694:
1725:
161:
3130:
1558:
1289:
253:
3014:
2953:
1450:
1338:
973:
961:
749:
389:
2102:
The earth-sheltered solar greenhouse book: how to build an energy-free year-round greenhouse
1609:
Demonstrating the Viability and Growing Acceptability of Earth-Sheltered Buildings in the UK
465:
which pulls air with a fan or convection from a nearly constant temperature air into buried
3208:
3110:
3094:
3089:
1249:
1220:
538:
451:
316:
2232:
Mechanical and Electrical Equipment for Buildings. Walter T. Grondzik, Alison G. Kwok 2014
1798:. (Newark: Univ. of Delaware Press, 1988); and David Douglas DeBord and Thomas R. Dunbar,
8:
3084:
3079:
2999:
2963:
2744:
1575:
1534:
1509:
1494:
1042:
796:
756:
466:
363:
359:
533:, meaning that it stores heat and releases it again slowly. Compacted soil is more of a
3039:
2921:
2662:
2466:
2276:
2215:
1397:
1259:
1207:
543:
534:
517:
Diagram showing effect of thermal mass and insulation in an earth sheltered structure.
383:
248:
Arthur Quarmby finished an earth sheltered building in Holme, England in 1975. Named "
2864:
2619:
2423:
2413:
2329:
2301:
2264:
2254:
2188:
2115:
2105:
2058:
2048:
1996:
1986:
1912:
1887:
1877:
1829:
1803:
1783:
1761:
1751:
1685:
1489:
1230:
1038:
957:
513:
84:
2141:
Passive annual heat storage: Improving the design of earth shelters. John Hait. 2013
650:
Roof covering is done using the excavated material, in which plants can be planted.
3146:
3054:
2916:
2911:
2880:
2859:
2824:
2764:
1415:
1175:
965:
869:
841:
710:
249:
179:
2442:
624:
Such houses can also be built as terraced structures on a slope in hilly terrain.
3177:
2900:
2651:
2641:
1906:
1823:
1679:
1615:
1237:
1185:
1149:
960:) wall construction in earth shelters have been used successfully. These include
499:
462:
312:
237:
97:
83:
Earth sheltering became relatively popular after the mid-1970s, especially among
1800:
Earth-Sheltered Landscapes: Site Considerations for Earth-Sheltered Environments
123:"The use of earth cover to moderate and improve living conditions in buildings."
3059:
3034:
3029:
3024:
2839:
1566:
1384:
1269:
1037:
of pitch at least 1:12 to promote drainage. The roofs of Earthships tend to be
1030:
685:
563:
194:
105:
2624:
2000:
566:
is the time taken for the minimum external temperature to reach the interior.
3192:
3004:
2890:
2844:
2819:
2804:
2799:
2298:
Chinese earth-sheltered dwellings: indigenous lessons for modern urban design
2268:
2119:
2062:
1891:
1765:
1529:
1524:
1090:
984:
857:
776:
425:
346:
308:
268:
2510:
2427:
600:
landscape, earth-sheltered houses drastically reduce the demand for lumber.
2994:
2854:
2328:. Tianjin: Huazhong University of Science & Technology Press Co., Ltd.
1570:
1499:
1445:
1323:
1103:
969:
772:
530:
292:
272:
221:
101:
77:
42:
2634:
311:(PassivHaus) energy performance standard applied to above grade airtight,
73:) against the walls, on the roof, or that is entirely buried underground.
3172:
3064:
3009:
2926:
2809:
1539:
1420:
1143:
1055:
877:
578:
551:
264:
209:
154:
120:"Homes that have been built underground, either partially or completely."
2086:
Earth Sheltered Buildings Construction Activity And Research In The U.S.
763:
building requires minimal finishing and significantly less maintenance.
437:
Passive annual heat storage is a building concept theorized to create a
263:
Other notable proponents of earth sheltering active in this era include
108:) are not usually considered as earth shelters as they are above ground.
1514:
1430:
1297:
1283:
1196:
1034:
1021:
407:
202:
190:
31:
1178:, West Yorkshire. The first modern earth sheltered building in the UK.
2940:
2834:
2754:
2248:
1475:
1460:
1455:
1440:
1425:
1279:
1073:
300:
217:
175:
2251:
Erd- und Höhlenhäuser von Peter Vetsch = Earth and cave architecture
2895:
2849:
2789:
2779:
2769:
2749:
2739:
2723:
2045:
Earth-sheltered houses: how to build an affordable underground home
1319:
1162:
845:
677:
296:
276:
213:
198:
2565:
905:(or perhaps northeast) to moderate the temperature extremes. Just
546:, meaning, it reduces the rate of temperature flowing through it.
3156:
3074:
2794:
2759:
1552:
1470:
1272:, was a subterranean dwelling known for its architectural design.
1216:
1189:
1078:
1012:
898:
865:
681:
494:
He claimed he would provide a built-in greenhouse in the design.
371:
166:
2657:
577:
As a result of the increased thermal mass of the structure, the
201:. Another historical example of in-hill earth shelters would be
2936:
2885:
2814:
2718:
2713:
2216:"BGS Reference and research reports - Ground source heat pumps"
1410:
1146:, South Australia. Mining town with many underground "dugouts".
853:
470:
150:
137:
2488:
2089:
International Society for Rock Mechanics and Rock Engineering.
429:
of shading device, is used to block out an excess solar gain.
37:
2784:
1562:
1085:
902:
780:
367:
66:
2829:
2708:
1435:
1203:
861:
849:
342:
186:
117:"A residence with an earth covering for its roof or walls."
70:
2350:"Earthship buildings are fire resistant, not a total loss"
2605:
Wade, Herb, Jeffrey Cook, Ken Labs, and Steve Selkowitz.
2153:
Green Building Advisor: Can we live happlily underground?
1555:—site of "Earth House" designed by architect Paolo Soleri
450:
Another design aimed at passive seasonal energy storage,
2692:
2598:
The Underground Space Center University of Minnesota.
228:
earth-sheltered homes have been in use for centuries.
2602:
Van Nostrand Reinhold Company, ed. 1978 and ed. 1979.
2300:. Honolulu: University of Hawaii Press. p. 178.
1871:
406:
construction design from the 1980s of Japan, coined '
2625:
StocktonUnderground : An Owner-Builder Approach
1374:
884:
the rooftop is recommended. An interceptor drainage
612:
795:Despite large windows (usually facing south in the
476:
2607:Passive Solar: Subdivisions, windows, underground.
2562:Hydrophobic Concrete Sheds Waterproofing Membrane'
2489:"Terra-Dome Corporation - Earth Sheltered Housing"
1231:https://www.rightmove.co.uk/properties/100082459#/
766:
2609:Kansas City: American Solar Energy Society, 1983.
1794:(Honolulu: Univ. of Hawaii Press, 1992); Golany,
3190:
542:many different plants, thereby acting more like
189:, dating back some 5,000 years, can be found at
2078:
2076:
2074:
2072:
1937:"Chinese Earth Shelter Dwellings: By Paul Long"
1782:(London: Bloomsbury Publishing, 2013), 112–17.
901:nearest the equator is north-facing toward the
537:than an insulator. Soil is stated as having an
27:House partially or entirely surrounded by earth
2620:Appropedia article on Earth-Sheltered Building
2574:New York: Wan Nostrand Reinhold Company, 1985.
2249:P Vetsch, E Wagner, C Schubert-Weller (1994).
1904:
1821:
1748:Earth Sheltered Housing Principles in Practice
1673:
1671:
1669:
1667:
1665:
1663:
1661:
1659:
1657:
1655:
1062:water is able to penetrate through it easily.
508:
432:
2678:
2570:Debord, David Douglas, and Thomas R. Dunbar.
2244:
2242:
2240:
2238:
2176:
2174:
2172:
2170:
2168:
2166:
2164:
2162:
2160:
1976:
1974:
1972:
1970:
1968:
1966:
1964:
1093:textile in corners and changes in direction.
653:
2374:"Going underground - A Cumbrian perspective"
2367:
2365:
2363:
2319:
2317:
2281:: CS1 maint: multiple names: authors list (
2069:
1867:
1865:
1741:
1739:
1604:
1602:
1600:
1598:
1596:
1594:
1592:
1219:, Pembrokeshire. Built for former Labour MP
529:Due to its density, compacted earth acts as
256:as the "first underground house" in the UK.
2401:
2137:
2135:
2133:
2131:
2129:
2082:
2038:
2036:
2034:
2032:
2030:
1983:Passive solar architecture pocket reference
1863:
1861:
1859:
1857:
1855:
1853:
1851:
1849:
1847:
1845:
1652:
1642:
1640:
1638:
1636:
1634:
1632:
1630:
1628:
1626:
1624:
670:
418:
216:). When Europeans colonized North America,
2685:
2671:
2523:
2481:
2235:
2157:
2093:
2028:
2026:
2024:
2022:
2020:
2018:
2016:
2014:
2012:
2010:
1961:
1817:
1815:
1719:
1717:
1715:
1713:
1711:
1709:
1707:
1705:
1703:
1701:
1677:
826:
594:
2407:
2360:
2314:
1736:
1589:
1199:, UK designed by Patrick Kennedy-Sanigar.
457:
41:An earth sheltered house in Switzerland (
30:For Iron Age underground structures, see
2180:
2126:
2099:
1980:
1842:
1745:
1621:
1353:Underground World Home exhibit, New York
1161:Lättenstrasse estate ("Earth Homes") in
1011:
810:
790:
636:
512:
454:is sometimes applied to earth shelters.
160:
144:
136:
36:
2371:
2007:
1930:
1928:
1898:
1812:
1802:(NY: Van Nostrand Reinhold, 1985), 11.
1698:
956:Several different methods of external (
445:
14:
3191:
2440:
2295:
2210:
2208:
2206:
2204:
2184:The $ 50 and Up Underground House Book
1723:
260:planned for 1986 in Minneapolis, USA.
2666:
2588:University of Washington Press, 2005.
2579:The Handbook of Earth Shelter Design.
1780:Vernacular Buildings: A Global Survey
1202:There are 2 earthships in the UK, at
1016:Meshed metal stretch net construction
924:
603:
231:
2323:
1925:
1876:. Texas A & M University Press.
1796:Earth-Sheltered Dwellings in Tunisia
771:Problems of water seepage, internal
728:
2201:
2042:
802:
562:(or temperature amplitude factor).
141:Mandan lodge, North Dakota. c. 1908
24:
3070:Naples underground geothermal zone
2647:Earth houses by Vetsch Architektur
2548:The Ecology of Building Materials.
627:
585:
25:
3240:
2613:
1792:Chinese Earth-Sheltered Dwellings
1169:
743:
696:
613:Landscape protection and land use
320:make earth shelters more common.
2564:Concrete Products, January 2006.
2557:Vermont: Garden Way, Inc., 1980.
1934:
1377:
1358:
1346:
1337:Earth Sheltered rest area along
1330:
1311:
1243:
1048:
691:
645:
477:Comparison with standard housing
132:
2600:Earth Sheltered Housing Design.
2517:
2503:
2459:
2434:
2342:
2289:
2226:
2144:
1943:
1684:. Atlantic Publishing Company.
1561:—works commonly referred to as
818:
767:Moisture and indoor air quality
439:year-round constant temperature
413:
282:
220:("soddies") were common on the
3116:Forestiere Underground Gardens
2979:Underground mining (soft rock)
2974:Underground mining (hard rock)
2959:Subsurface utility engineering
1872:LL Boyer, WT Grondzik (1987).
1772:
1292:, was a home designed for the
1256:Forestiere Underground Gardens
1155:
1114:
942:
521:-axis represents temperature;
400:
377:
185:One of the oldest examples of
149:"The interior of the hut of a
13:
1:
2540:
2467:""Earth-Sheltered Buildings""
1911:. Shelter Publications, Inc.
1828:. Shelter Publications, Inc.
1123:
1096:
933:
913:sides embedded in the earth.
662:
481:
90:
3219:Semi-subterranean structures
2969:Underground mine ventilation
2635:An Earth Sheltered Directory
2372:P Reddy (July–August 2003).
2326:Earth Sheltered Architecture
2222:. British Geological Survey.
1505:Energy-efficient landscaping
1184:, a community of 5 homes in
1137:
714:collapse after a few years.
65:, is a structure (usually a
7:
3126:Underground House Las Vegas
2572:Earth Sheltered Landscapes.
2555:The Underground House Book.
2511:"Hockerton Housing Project"
2187:. Mole Publishing Company.
1370:
1365:Underground House Las Vegas
1282:is based on the designs of
1276:Underground House Las Vegas
1132:
509:Passive heating and cooling
433:Passive annual heat storage
10:
3245:
3121:Underground House Colorado
3050:Underground City, Montreal
3045:Underground City (Beijing)
2550:Architectural Press, 2000.
2443:""Earth-Sheltered Houses""
1730:www.sustainablebuild.co.uk
1726:"Underground Construction"
1578:—inventor of the Earthship
1304:
1294:1964 New York World's Fair
1266:Underground House Colorado
654:Nuclear bomb survivability
381:
352:
165:Turf house in Sænautasel,
127:
29:
3165:
3152:Hockerton Housing Project
3139:
3103:
2987:
2935:
2873:
2732:
2701:
2693:Man-made and man-related
2586:Toward a New Regionalism.
1905:L Kahn; B Easton (2010).
1822:L Kahn; B Easton (1990).
1182:Hockerton Housing Project
831:
719:
676:significant basis of the
336:
252:," It is recorded in the
242:back-to-the-land movement
3166:Earth shelters Australia
2946:underground construction
2593:Understanding Buildings.
2491:. Terra-Dome Corporation
2253:(in German). A. Niggli.
1874:Earth shelter technology
1582:
1520:Hurricane-proof building
951:
671:Architectural aesthetics
419:Active and passive solar
327:
2906:Missile launch facility
2296:Gideon, Golany (1992).
1951:"Earth-sheltered Homes"
1007:
976:, poured concrete, and
964:(either conventionally
827:Design and construction
595:Natural resource saving
3131:Underground World Home
2652:Self-heating eco-house
2630:Earth-Sheltered Houses
2043:Roy, Robert L (2006).
1647:Earth Sheltered Houses
1559:Earl Young (architect)
1318:Earth house estate in
1290:Underground World Home
1017:
893:shelter construction.
864:can be susceptible to
680:concept. For example,
526:
458:Earth tube ventilation
267:, Rob Roy, John Hait,
254:Guinness World Records
170:
158:
142:
46:
3020:Kőbánya cellar system
3015:Houston tunnel system
2954:Rock-cut architecture
2324:Jing, Qi min (1988).
1649:page on Lowimpact.org
1339:Interstate 77 in Ohio
1015:
985:waterproofing barrier
978:pressure-treated wood
811:Limited escape routes
791:Limited natural light
750:life-cycle assessment
637:Earthquake protection
516:
317:zero carbon buildings
164:
148:
140:
40:
3214:Sustainable building
3199:Building engineering
3095:Subterranean fiction
3090:Subterranean warfare
2595:The MIT Press, 1984.
2581:Dolphin Books, 1982.
2383:(16). Archived from
2356:. 12 September 2018.
2083:RL Sterling (1980).
1790:; Gideon S. Golany,
1221:Bob Marshall-Andrews
1041:, classically using
968:or surface-bonded),
860:potential. Sand and
452:annualized geo solar
446:Annualized geo solar
153:Chief": aquatint by
3204:Energy conservation
3085:Subterranean Toledo
3080:Subterranean London
3000:Caves of Maastricht
2964:Tunnel construction
2745:Burial vault (tomb)
2530:www.telegraph.co.uk
2526:"A buried treasure"
2524:S Lonsdale (2005).
2412:. Pelican Pub. Co.
1750:. Springer Verlag.
1732:. SustainableBuild.
1678:R McConkey (2011).
1576:Michael E. Reynolds
1535:Radiation shielding
1510:Energy conservation
1495:Earth cooling tubes
1206:, Scotland and the
797:Northern Hemisphere
757:Reinforced concrete
467:Earth cooling tubes
364:Southern Hemisphere
360:Northern Hemisphere
3040:Underground living
2922:Underground hangar
2654:by Veljko Milković
2640:2013-08-01 at the
2408:L Wampler (2003).
1614:2019-01-23 at the
1398:Underground living
1260:Fresno, California
1236:2021-01-24 at the
1208:Earthship Brighton
1165:, by Peter Vetsch.
1018:
925:Building materials
604:Biological effects
544:thermal insulation
527:
384:Underground living
232:1970s–1980s heyday
171:
159:
143:
59:earth bermed house
47:
3186:
3185:
3140:Earth shelters UK
3111:Bill Gates' house
3104:Earth shelters US
2874:Military features
2865:Ventilation shaft
2733:Civilian features
2584:Miller, David E.
2410:Underground homes
2335:978-7-5308-0526-8
2307:978-0-8248-1369-7
2181:M Oehler (1981).
2100:M Oehler (2007).
1981:D Thorpe (2018).
1955:Mother Earth News
1746:M Terman (2012).
1490:Daylight basement
1250:Bill Gates' house
729:Design complexity
711:opportunity costs
535:conductor of heat
362:and north in the
85:environmentalists
63:underground house
53:, also called an
16:(Redirected from
3236:
3229:Earth structures
3147:Underhill, Holme
3055:Mine exploration
2917:Underground base
2912:Scallywag bunker
2881:Air raid shelter
2860:Smuggling tunnel
2825:Underground city
2765:Dugout (shelter)
2702:Natural features
2687:
2680:
2673:
2664:
2663:
2577:Edelhart, Mike.
2534:
2533:
2521:
2515:
2514:
2507:
2501:
2500:
2498:
2496:
2485:
2479:
2478:
2476:
2474:
2463:
2457:
2456:
2454:
2452:
2447:
2438:
2432:
2431:
2405:
2399:
2398:
2396:
2395:
2389:
2378:
2369:
2358:
2357:
2346:
2340:
2339:
2321:
2312:
2311:
2293:
2287:
2286:
2280:
2272:
2246:
2233:
2230:
2224:
2223:
2212:
2199:
2198:
2178:
2155:
2148:
2142:
2139:
2124:
2123:
2104:. Mole Pub. Co.
2097:
2091:
2090:
2080:
2067:
2066:
2040:
2005:
2004:
1978:
1959:
1958:
1947:
1941:
1940:
1932:
1923:
1922:
1902:
1896:
1895:
1869:
1840:
1839:
1819:
1810:
1776:
1770:
1769:
1743:
1734:
1733:
1721:
1696:
1695:
1675:
1650:
1644:
1619:
1618:. J Harral, 2012
1606:
1466:Souterrain house
1387:
1382:
1381:
1380:
1362:
1350:
1334:
1315:
1195:"The Burrow" in
1176:Underhill, Holme
974:cordwood masonry
870:capillary action
842:bearing capacity
803:Risk of collapse
424:application for
98:earth structures
21:
3244:
3243:
3239:
3238:
3237:
3235:
3234:
3233:
3224:Passive cooling
3189:
3188:
3187:
3182:
3178:Lightning Ridge
3161:
3135:
3099:
2983:
2944:
2931:
2901:Fallout shelter
2869:
2728:
2697:
2691:
2658:Earth Homes Now
2642:Wayback Machine
2616:
2560:De Mars, John.
2553:Campbell, Stu.
2543:
2538:
2537:
2522:
2518:
2509:
2508:
2504:
2494:
2492:
2487:
2486:
2482:
2472:
2470:
2465:
2464:
2460:
2450:
2448:
2445:
2439:
2435:
2420:
2406:
2402:
2393:
2391:
2387:
2376:
2370:
2361:
2354:Pangea Builders
2348:
2347:
2343:
2336:
2322:
2315:
2308:
2294:
2290:
2274:
2273:
2261:
2247:
2236:
2231:
2227:
2214:
2213:
2202:
2195:
2179:
2158:
2149:
2145:
2140:
2127:
2112:
2098:
2094:
2081:
2070:
2055:
2047:. New Society.
2041:
2008:
1993:
1979:
1962:
1957:. October 2006.
1949:
1948:
1944:
1933:
1926:
1919:
1903:
1899:
1884:
1870:
1843:
1836:
1820:
1813:
1777:
1773:
1758:
1744:
1737:
1724:J Gray (2019).
1722:
1699:
1692:
1676:
1653:
1645:
1622:
1616:Wayback Machine
1607:
1590:
1585:
1567:mushroom houses
1544:
1480:
1383:
1378:
1376:
1373:
1366:
1363:
1354:
1351:
1342:
1335:
1326:
1316:
1307:
1246:
1238:Wayback Machine
1186:Nottinghamshire
1172:
1158:
1150:Lightning Ridge
1140:
1135:
1126:
1117:
1099:
1051:
1010:
954:
945:
936:
927:
834:
829:
821:
813:
805:
793:
769:
746:
731:
699:
694:
673:
665:
656:
648:
639:
630:
628:Fire protection
615:
606:
597:
588:
586:Wind protection
511:
484:
479:
463:Passive cooling
460:
448:
435:
421:
416:
403:
386:
380:
370:(north) in the
366:), towards the
355:
339:
330:
285:
238:1973 Oil Crisis
234:
135:
130:
93:
35:
28:
23:
22:
15:
12:
11:
5:
3242:
3232:
3231:
3226:
3221:
3216:
3211:
3206:
3201:
3184:
3183:
3181:
3180:
3175:
3169:
3167:
3163:
3162:
3160:
3159:
3154:
3149:
3143:
3141:
3137:
3136:
3134:
3133:
3128:
3123:
3118:
3113:
3107:
3105:
3101:
3100:
3098:
3097:
3092:
3087:
3082:
3077:
3072:
3067:
3062:
3060:Mines of Paris
3057:
3052:
3047:
3042:
3037:
3035:Trench warfare
3032:
3030:Tunnel network
3027:
3025:Tunnel warfare
3022:
3017:
3012:
3007:
3002:
2997:
2991:
2989:
2988:Related topics
2985:
2984:
2982:
2981:
2976:
2971:
2966:
2961:
2956:
2950:
2948:
2933:
2932:
2930:
2929:
2924:
2919:
2914:
2909:
2903:
2898:
2893:
2888:
2883:
2877:
2875:
2871:
2870:
2868:
2867:
2862:
2857:
2852:
2847:
2842:
2840:Secret passage
2837:
2832:
2827:
2822:
2817:
2812:
2807:
2802:
2797:
2792:
2787:
2782:
2777:
2772:
2767:
2762:
2757:
2752:
2747:
2742:
2736:
2734:
2730:
2729:
2727:
2726:
2721:
2716:
2711:
2705:
2703:
2699:
2698:
2690:
2689:
2682:
2675:
2667:
2661:
2660:
2655:
2649:
2644:
2632:
2627:
2622:
2615:
2614:External links
2612:
2611:
2610:
2603:
2596:
2591:Reid, Esmond.
2589:
2582:
2575:
2568:
2558:
2551:
2546:Berge, Bjørn.
2542:
2539:
2536:
2535:
2516:
2502:
2480:
2458:
2433:
2418:
2400:
2359:
2341:
2334:
2313:
2306:
2288:
2259:
2234:
2225:
2200:
2193:
2156:
2143:
2125:
2110:
2092:
2068:
2053:
2006:
1991:
1960:
1942:
1924:
1917:
1897:
1882:
1841:
1834:
1811:
1771:
1756:
1735:
1697:
1690:
1651:
1620:
1587:
1586:
1584:
1581:
1580:
1579:
1573:
1556:
1543:
1542:
1537:
1532:
1527:
1522:
1517:
1512:
1507:
1502:
1497:
1492:
1486:
1479:
1478:
1473:
1468:
1463:
1458:
1453:
1448:
1443:
1438:
1433:
1428:
1423:
1418:
1413:
1407:
1401:
1400:
1389:
1388:
1385:Housing portal
1372:
1369:
1368:
1367:
1364:
1357:
1355:
1352:
1345:
1343:
1336:
1329:
1327:
1317:
1310:
1306:
1303:
1302:
1301:
1287:
1273:
1270:Ward, Colorado
1263:
1253:
1245:
1242:
1241:
1240:
1224:
1214:
1211:
1200:
1193:
1179:
1171:
1170:United Kingdom
1168:
1167:
1166:
1157:
1154:
1153:
1152:
1147:
1139:
1136:
1134:
1131:
1125:
1122:
1116:
1113:
1098:
1095:
1050:
1047:
1009:
1006:
962:concrete block
953:
950:
944:
941:
935:
932:
926:
923:
833:
830:
828:
825:
820:
817:
812:
809:
804:
801:
792:
789:
768:
765:
745:
744:Sustainability
742:
730:
727:
698:
697:Financial cost
695:
693:
690:
686:Salt Cathedral
672:
669:
664:
661:
655:
652:
647:
644:
638:
635:
629:
626:
614:
611:
605:
602:
596:
593:
587:
584:
564:Phase shifting
510:
507:
483:
480:
478:
475:
459:
456:
447:
444:
434:
431:
420:
417:
415:
412:
402:
399:
382:Main article:
379:
376:
354:
351:
338:
335:
329:
326:
315:low carbon or
313:superinsulated
284:
281:
233:
230:
195:Orkney Islands
134:
131:
129:
126:
125:
124:
121:
118:
115:
112:
109:
92:
89:
76:Earth acts as
69:) with earth (
26:
9:
6:
4:
3:
2:
3241:
3230:
3227:
3225:
3222:
3220:
3217:
3215:
3212:
3210:
3207:
3205:
3202:
3200:
3197:
3196:
3194:
3179:
3176:
3174:
3171:
3170:
3168:
3164:
3158:
3155:
3153:
3150:
3148:
3145:
3144:
3142:
3138:
3132:
3129:
3127:
3124:
3122:
3119:
3117:
3114:
3112:
3109:
3108:
3106:
3102:
3096:
3093:
3091:
3088:
3086:
3083:
3081:
3078:
3076:
3073:
3071:
3068:
3066:
3063:
3061:
3058:
3056:
3053:
3051:
3048:
3046:
3043:
3041:
3038:
3036:
3033:
3031:
3028:
3026:
3023:
3021:
3018:
3016:
3013:
3011:
3008:
3006:
3005:Civil defense
3003:
3001:
2998:
2996:
2993:
2992:
2990:
2986:
2980:
2977:
2975:
2972:
2970:
2967:
2965:
2962:
2960:
2957:
2955:
2952:
2951:
2949:
2947:
2942:
2938:
2934:
2928:
2925:
2923:
2920:
2918:
2915:
2913:
2910:
2907:
2904:
2902:
2899:
2897:
2894:
2892:
2891:Blast shelter
2889:
2887:
2884:
2882:
2879:
2878:
2876:
2872:
2866:
2863:
2861:
2858:
2856:
2853:
2851:
2848:
2846:
2845:Semi-basement
2843:
2841:
2838:
2836:
2833:
2831:
2828:
2826:
2823:
2821:
2820:Utility vault
2818:
2816:
2813:
2811:
2808:
2806:
2805:Rock-cut tomb
2803:
2801:
2800:Rapid transit
2798:
2796:
2793:
2791:
2788:
2786:
2783:
2781:
2778:
2776:
2775:Earth shelter
2773:
2771:
2768:
2766:
2763:
2761:
2758:
2756:
2753:
2751:
2748:
2746:
2743:
2741:
2738:
2737:
2735:
2731:
2725:
2722:
2720:
2717:
2715:
2712:
2710:
2707:
2706:
2704:
2700:
2696:
2688:
2683:
2681:
2676:
2674:
2669:
2668:
2665:
2659:
2656:
2653:
2650:
2648:
2645:
2643:
2639:
2636:
2633:
2631:
2628:
2626:
2623:
2621:
2618:
2617:
2608:
2604:
2601:
2597:
2594:
2590:
2587:
2583:
2580:
2576:
2573:
2569:
2566:
2563:
2559:
2556:
2552:
2549:
2545:
2544:
2531:
2527:
2520:
2512:
2506:
2490:
2484:
2468:
2462:
2444:
2437:
2429:
2425:
2421:
2419:9780882892733
2415:
2411:
2404:
2390:on 2019-02-03
2386:
2382:
2375:
2368:
2366:
2364:
2355:
2351:
2345:
2337:
2331:
2327:
2320:
2318:
2309:
2303:
2299:
2292:
2284:
2278:
2270:
2266:
2262:
2260:9783721202823
2256:
2252:
2245:
2243:
2241:
2239:
2229:
2221:
2220:www.bgs.ac.uk
2217:
2211:
2209:
2207:
2205:
2196:
2194:9780442273118
2190:
2186:
2185:
2177:
2175:
2173:
2171:
2169:
2167:
2165:
2163:
2161:
2154:
2151:
2147:
2138:
2136:
2134:
2132:
2130:
2121:
2117:
2113:
2111:9780960446407
2107:
2103:
2096:
2088:
2087:
2079:
2077:
2075:
2073:
2064:
2060:
2056:
2054:9780865715219
2050:
2046:
2039:
2037:
2035:
2033:
2031:
2029:
2027:
2025:
2023:
2021:
2019:
2017:
2015:
2013:
2011:
2002:
1998:
1994:
1992:9781138501287
1988:
1985:. Routledge.
1984:
1977:
1975:
1973:
1971:
1969:
1967:
1965:
1956:
1952:
1946:
1938:
1931:
1929:
1920:
1918:9780936070490
1914:
1910:
1909:
1901:
1893:
1889:
1885:
1883:9780890962732
1879:
1875:
1868:
1866:
1864:
1862:
1860:
1858:
1856:
1854:
1852:
1850:
1848:
1846:
1837:
1835:9780936070117
1831:
1827:
1826:
1818:
1816:
1809:
1805:
1801:
1797:
1793:
1789:
1785:
1781:
1778:Allen Noble,
1775:
1767:
1763:
1759:
1757:9781468466461
1753:
1749:
1742:
1740:
1731:
1727:
1720:
1718:
1716:
1714:
1712:
1710:
1708:
1706:
1704:
1702:
1693:
1691:9781601383730
1687:
1683:
1682:
1674:
1672:
1670:
1668:
1666:
1664:
1662:
1660:
1658:
1656:
1648:
1643:
1641:
1639:
1637:
1635:
1633:
1631:
1629:
1627:
1625:
1617:
1613:
1610:
1605:
1603:
1601:
1599:
1597:
1595:
1593:
1588:
1577:
1574:
1572:
1571:Hobbit houses
1568:
1564:
1560:
1557:
1554:
1551:
1550:
1549:
1548:
1541:
1538:
1536:
1533:
1531:
1530:Passive solar
1528:
1526:
1525:Passive house
1523:
1521:
1518:
1516:
1513:
1511:
1508:
1506:
1503:
1501:
1498:
1496:
1493:
1491:
1488:
1487:
1485:
1484:
1483:Applications:
1477:
1474:
1472:
1469:
1467:
1464:
1462:
1459:
1457:
1454:
1452:
1449:
1447:
1444:
1442:
1439:
1437:
1434:
1432:
1429:
1427:
1424:
1422:
1419:
1417:
1414:
1412:
1409:
1408:
1406:
1405:
1399:
1396:
1395:
1394:
1393:
1386:
1375:
1361:
1356:
1349:
1344:
1340:
1333:
1328:
1325:
1321:
1314:
1309:
1308:
1299:
1296:by architect
1295:
1291:
1288:
1285:
1281:
1277:
1274:
1271:
1267:
1264:
1261:
1257:
1254:
1251:
1248:
1247:
1244:United States
1239:
1235:
1232:
1228:
1225:
1222:
1218:
1215:
1212:
1209:
1205:
1201:
1198:
1194:
1191:
1187:
1183:
1180:
1177:
1174:
1173:
1164:
1160:
1159:
1151:
1148:
1145:
1142:
1141:
1130:
1121:
1112:
1108:
1105:
1094:
1092:
1091:polypropylene
1087:
1082:
1080:
1075:
1071:
1067:
1066:application.
1063:
1059:
1057:
1049:Waterproofing
1046:
1044:
1040:
1036:
1032:
1031:timber framed
1026:
1023:
1014:
1005:
1002:
998:
992:
988:
986:
981:
979:
975:
971:
970:stone masonry
967:
963:
959:
949:
940:
931:
922:
918:
914:
912:
908:
904:
900:
894:
890:
887:
881:
879:
874:
871:
867:
863:
859:
855:
851:
847:
843:
838:
824:
816:
808:
800:
798:
788:
784:
782:
778:
774:
764:
760:
758:
753:
751:
741:
738:
735:
726:
723:
721:
715:
712:
707:
703:
692:Disadvantages
689:
687:
683:
679:
668:
660:
651:
646:Roof planting
643:
634:
625:
622:
618:
610:
601:
592:
583:
580:
575:
571:
567:
565:
559:
555:
553:
547:
545:
540:
536:
532:
524:
520:
515:
506:
503:
501:
495:
492:
488:
474:
472:
468:
464:
455:
453:
443:
440:
430:
427:
426:passive solar
411:
409:
398:
394:
391:
385:
375:
373:
369:
365:
361:
350:
348:
344:
334:
325:
321:
318:
314:
310:
309:Passive House
304:
302:
298:
294:
289:
280:
278:
274:
270:
269:Malcolm Wells
266:
261:
257:
255:
251:
245:
243:
239:
229:
225:
223:
219:
215:
212:' (see also:
211:
206:
204:
200:
197:off northern
196:
192:
188:
183:
181:
177:
168:
163:
156:
152:
147:
139:
133:Early history
122:
119:
116:
113:
110:
107:
103:
99:
95:
94:
88:
86:
81:
79:
74:
72:
68:
64:
60:
56:
52:
51:earth shelter
44:
39:
33:
19:
2995:Cave dweller
2855:Storm cellar
2774:
2606:
2599:
2592:
2585:
2578:
2571:
2561:
2554:
2547:
2529:
2519:
2505:
2493:. Retrieved
2483:
2471:. Retrieved
2461:
2449:. Retrieved
2441:NREL / DOE.
2436:
2409:
2403:
2392:. Retrieved
2385:the original
2380:
2353:
2344:
2325:
2297:
2291:
2250:
2228:
2219:
2183:
2146:
2101:
2095:
2085:
2044:
1982:
1954:
1945:
1935:Long, Paul.
1907:
1900:
1873:
1824:
1799:
1795:
1791:
1779:
1774:
1747:
1729:
1680:
1546:
1545:
1500:Earthscraper
1482:
1481:
1446:Quiggly hole
1403:
1402:
1391:
1390:
1324:Peter Vetsch
1127:
1118:
1109:
1104:polyurethane
1100:
1083:
1072:
1068:
1064:
1060:
1052:
1039:mono-pitched
1027:
1019:
993:
989:
982:
958:load-bearing
955:
946:
937:
928:
919:
915:
910:
906:
895:
891:
882:
875:
839:
835:
822:
819:Legal issues
814:
806:
794:
785:
773:condensation
770:
761:
754:
747:
739:
736:
732:
724:
716:
708:
704:
700:
674:
666:
657:
649:
640:
631:
623:
619:
616:
607:
598:
589:
576:
572:
568:
560:
556:
548:
531:thermal mass
528:
522:
518:
504:
496:
493:
489:
485:
461:
449:
436:
422:
414:Applications
404:
395:
387:
356:
343:earth bermed
340:
331:
322:
305:
293:Peter Vetsch
290:
286:
283:Modern times
279:and others.
273:Peter Vetsch
262:
258:
246:
235:
226:
222:Great Plains
210:earth lodges
207:
184:
172:
102:rammed earth
82:
78:thermal mass
75:
62:
58:
54:
50:
48:
43:Peter Vetsch
3209:House types
3173:Coober Pedy
3065:Mole people
3010:Coober Pedy
2927:Spider hole
2810:Root cellar
2695:subterranea
2473:15 November
2451:15 November
1547:Proponents:
1540:Root cellar
1421:Earth lodge
1210:in England.
1156:Switzerland
1144:Coober Pedy
1115:Backfilling
1056:EPDM rubber
1035:gable roofs
943:Foundations
878:water table
858:frost heave
633:buildings.
579:thermal lag
552:thermal lag
401:Other types
378:Underground
265:Mike Oehler
155:Karl Bodmer
55:earth house
18:Earth house
3193:Categories
2541:References
2495:29 January
2394:2019-02-02
2001:1032285568
1908:Shelter II
1808:0442218915
1788:0857723391
1515:Green roof
1431:Grubenhaus
1298:Jay Swayze
1284:Jay Swayze
1197:Canterbury
1124:Finishings
1097:Insulation
1022:green roof
934:Excavation
663:Soundproof
482:Advantages
408:Alice City
301:Earthships
218:sod houses
203:Mesa Verde
191:Skara Brae
91:Definition
32:Souterrain
2941:quarrying
2835:Wine cave
2755:Catacombs
2277:cite book
2269:441647358
2120:184985256
2063:959772584
1892:925048286
1766:861213769
1476:Zemlyanka
1461:Sod house
1456:Shabestan
1441:Pit-house
1426:Earthship
1280:Las Vegas
1227:Undermill
1138:Australia
1074:Bentonite
997:Grancrete
250:Underhill
176:pit-house
2896:Casemate
2850:Stepwell
2790:Hypogeum
2780:Erdstall
2770:Dry well
2750:Borehole
2740:Basement
2724:Sinkhole
2638:Archived
2428:58835250
1612:Archived
1451:Rock-cut
1371:See also
1322:made by
1320:Dietikon
1234:Archived
1223:in 1998.
1163:Dietikon
1133:Examples
1081:damage.
966:mortared
903:aphelion
889:drains.
846:drainage
678:arcology
368:aphelion
297:Dietikon
277:Ken Kern
214:Barabara
199:Scotland
3157:Malator
3075:Sapping
2795:Manhole
2760:Dungeon
2381:Ingenia
1825:Shelter
1565:homes,
1553:Cosanti
1471:Yaodong
1392:Topics:
1305:Gallery
1217:Malator
1190:England
1079:termite
1001:Hycrete
907:outside
899:Tropics
866:erosion
682:yaodong
550:termed
539:R-value
500:fallout
372:Tropics
353:In-hill
341:In the
193:in the
187:berming
167:Iceland
128:History
2937:Mining
2908:(silo)
2886:Bunker
2815:Tunnel
2719:Grotto
2714:Cenote
2469:. NCMA
2426:
2416:
2332:
2304:
2267:
2257:
2191:
2118:
2108:
2061:
2051:
1999:
1989:
1915:
1890:
1880:
1832:
1806:
1786:
1764:
1754:
1688:
1416:Dugout
1411:Burdei
1404:Types:
873:soil.
854:gravel
832:Design
471:ASHRAE
390:atrium
337:Bermed
180:dugout
151:Mandan
100:(e.g.
2943:, and
2785:Fogou
2446:(PDF)
2388:(PDF)
2377:(PDF)
1583:Notes
1569:, or
1563:gnome
1341:, USA
1086:epoxy
1043:vigas
952:Walls
886:swale
781:radon
347:grade
328:Types
67:house
61:, or
2830:Well
2709:Cave
2497:2019
2475:2022
2453:2022
2424:OCLC
2414:ISBN
2330:ISBN
2302:ISBN
2283:link
2265:OCLC
2255:ISBN
2189:ISBN
2116:OCLC
2106:ISBN
2059:OCLC
2049:ISBN
1997:OCLC
1987:ISBN
1913:ISBN
1888:OCLC
1878:ISBN
1830:ISBN
1804:ISBN
1784:ISBN
1762:OCLC
1752:ISBN
1686:ISBN
1436:Kiva
1204:Fife
1008:Roof
999:and
911:long
862:clay
852:and
850:sand
844:and
777:mold
720:Roof
236:The
178:and
71:soil
1278:in
1268:in
1258:in
106:cob
104:or
49:An
3195::
2939:,
2528:.
2422:.
2379:.
2362:^
2352:.
2316:^
2279:}}
2275:{{
2263:.
2237:^
2218:.
2203:^
2159:^
2128:^
2114:.
2071:^
2057:.
2009:^
1995:.
1963:^
1953:.
1927:^
1886:.
1844:^
1814:^
1760:.
1738:^
1728:.
1700:^
1654:^
1623:^
1591:^
1188:,
1045:.
1033:,
972:,
473:.
275:,
271:,
224:.
182:.
57:,
45:)
2686:e
2679:t
2672:v
2567:.
2532:.
2513:.
2499:.
2477:.
2455:.
2430:.
2397:.
2338:.
2310:.
2285:)
2271:.
2197:.
2122:.
2065:.
2003:.
1939:.
1921:.
1894:.
1838:.
1768:.
1694:.
1300:.
1286:.
1262:.
1192:.
523:x
519:y
169:.
34:.
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
