Shallow foundations of a house versus the deep foundations of a skyscraper. A foundation (or, more commonly, base) is the element of an architectural structure which connects it to the ground, and transfers loads from the structure to the ground. Foundations are generally considered either shallow or deep. Foundation engineering is the application of soil mechanics and rock mechanics (Geotechnical engineering) in the design of foundation elements of structures. The simplest foundation, a padstone. Latvian Ethnographic Open Air Museum Buildings and structures have a long history of being built with wood in contact with the ground. Post in ground construction may technically have no foundation. Timber pilings were used on soft or wet ground even below stone or masonry walls. In marine construction and bridge building a crisscross of timbers or steel beams in concrete is called grillage. Perhaps the simplest foundation is the padstone, a single stone which both spreads the weight on the ground and raises the timber off the ground. Staddle stones are a specific type of padstone. Dry stone and stones laid in mortar to build foundations are common in many parts of the world. Dry laid stone foundations may have been painted with mortar after construction. Sometimes the top, visible course of stone is hewn, quarried stones. Besides using mortar, stones can also be put in a gabion. One disadvantage is that if using regular steel rebars, the gabion would last much less long than when using mortar (due to rusting). Using weathering steel rebars could reduce this disadvantage somewhat. Rubble trench foundations are a shallow trench filled with rubble or stones. These foundations extend below the frost line and may have a drain pipe which helps groundwater drain away. They are suitable for soils with a capacity of more than 10 tonnes/m² (2,000 pounds per square foot). Main article: Shallow foundation Play media Shallow foundation construction example Shallow foundations, often called footings, are usually embedded about a metre or so into soil. One common type is the spread footing which consists of strips or pads of concrete (or other materials) which extend below the frost line and transfer the weight from walls and columns to the soil or bedrock. Another common type of shallow foundation is the slab-on-grade foundation where the weight of the structure is transferred to the soil through a concrete slab placed at the surface. Slab-on-grade foundations can be reinforced mat slabs, which range from 25 cm to several meters thick, depending on the size of the building, or post-tensioned slabs, which are typically at least 20 cm for houses, and thicker for heavier structures. Main article: Deep foundation A deep foundation is used to transfer the load of a structure down through the upper weak layer of topsoil to the stronger layer of subsoil below. There are different types of deep footings including impact driven piles, drilled shafts, caissons, helical piles, geo-piers and earth stabilized columns. The naming conventions for different types of footings vary between different engineers. Historically, piles were wood, later steel, reinforced concrete, and pre-tensioned concrete. Main article: Monopile foundation A monopile foundation is a type of deep foundation which uses a single, generally large-diameter, structural element embedded into the earth to support all the loads (weight, wind, etc.) of a large above-surface structure. A large number of monopile foundations have been utilized in recent years for economically constructing fixed-bottom offshore wind farms in shallow-water subsea locations. For example, a single wind farm off the coast of England went online in 2008 with over 100 turbines, each mounted on a 4.74-meter-diameter monopile footing in ocean depths up to 16 metres of water. Inadequate foundations in muddy soils below sea level caused these houses in the Netherlands to subside. Foundations are designed to have an adequate load capacity depending on the type of subsoil supporting the foundation by a geotechnical engineer, and the footing itself may be designed structurally by a structural engineer. The primary design concerns are settlement and bearing capacity. When considering settlement, total settlement and differential settlement is normally considered. Differential settlement is when one part of a foundation settles more than another part. This can cause problems to the structure which the foundation is supporting. Expansive clay soils can also cause problems.
"Toolshed" redirects here. For the Tool demo album, see 72826. "Bike shed" redirects here. For bike-shedding, see law of triviality. A rural shed Modern secure bike sheds Garden shed with gambrel roof A shed is typically a simple, single-storey roofed structure in a back garden or on an allotment that is used for storage, hobbies, or as a workshop. Sheds vary considerably in the complexity of their construction and their size, from small open-sided tin-roofed structures to large wood-framed sheds with shingled roofs, windows, and electrical outlets. Sheds used on farms or in industry can be large structures. The main types of shed construction are metal sheathing over a metal frame, plastic sheathing and frame, all-wood construction (the roof may be asphalt shingled or sheathed in tin), and vinyl-sided sheds built over a wooden frame. A culture of shed enthusiasts exists in several countries for people who enjoy building sheds and spending time in them for relaxation. In Australia and New Zealand there are magazines called The Shed, an association for shed hobbyists (the Australian Men's Shed Association), and a book entitled Men and Sheds. Depending on the region and type of use, a shed may also be called an "outhouse", "outbuilding" or "shack". The simplest and least-expensive sheds are available in kit form. These kits are designed for regular people to be able to assemble themselves using commonly available tools (e.g., screwdriver). Both shed kits and DIY (do-it-yourself) plans are available for wooden and plastic sheds. Sheds are used to store home and garden tools and equipment such as lawn tractors, and gardening supplies. In addition, sheds can be used to store items that are not suitable for indoor storage, such as petrol (gasoline), pesticides, or herbicides. For homes with small gardens or modest storage needs, there are several types of very small sheds. The sheds not only use less ground area but also have a low profile less likely to obstruct the view or clash with the landscaping. A metal garden shed made with sheets of galvanized steel over a steel frame These small sheds include corner sheds, which fit into a corner (3 ft tall × 3 wide × 2 deep, or 0.91 m × 0.91 m × 0.61 m), vertical sheds (5 ft × 3 ft × 4 ft deep, or 1.52 m × 0.91 m × 1.22 m), horizontal sheds (3 ft × 5 ft × 4 ft or 0.91 m × 1.52 m × 1.22 m), and tool sheds. When a shed is used for tool storage, shelves and hooks are often used to maximize the storage space. Gambrel-style roofed sheds (sometimes called baby barns), which resemble a Dutch-style barn, have a high sloping roofline which increases storage space in the "loft" area. Some Gambrel-styles have no loft and offer the advantage of reduced overall height. Another style of small shed is the saltbox-style shed. Many sheds have either a pent or apex roof shape. A pent shed features a single roof section which is angled downwards to let rainwater run off, with more headroom at the front than the back. This is a simple, practical design that will fit particularly well next to a wall or fence. It is also usually lower than the typical apex shed, so could be a better choice if there are any height restrictions. A pent shed may be free-standing or attached to a wall (when it is known, unsurprisingly, as a wall shed). An apex shed has a pointed roof in an inverted V shape similar to the roof line of many houses. Two roof sections meet at a ridge in the middle, providing more headroom in the centre than at the sides. This type is generally regarded as a more attractive and traditional design, and may be preferable if the shed is going to be visible from the house.  A twist on the standard apex shape is the reverse apex shed. In this design, the door is set in a side wall instead of the front. The main advantage of the reverse apex design is that the door opens into the widest part of the shed instead of the narrowest, so it's easier to reach into all areas to retrieve or store equipment.  A tall shed with windows and a shingled roof Larger, more-expensive sheds are typically constructed of wood and include features typically found in house construction, such as windows, a shingled roof, and electrical outlets. Larger sheds provide more space for engaging in hobbies such as gardening, small engine repair, or tinkering. Some sheds have small porches or include furniture, which allows them to be used for relaxation purposes. In some cases, teleworkers and homeworkers in general who live in mild climates use small to medium-sized wooden garden sheds as outdoor offices. There is a growing industry in providing "off the peg" garden offices to cater for this demand, particularly in the UK but also in the US. Shed owners can customize wooden sheds to match the features (e.g., siding, trim, etc.) of the main house. A number of decorative options can be added to sheds, such as dormers, shutters, flowerboxes, finials, and weathervanes. As well, practical options can be added such as benches, ramps, ventilation systems (e.g., in cases where a swimming pool heater is installed in a shed), and electric lighting. Sheds designed for gardening, called "potting sheds", often feature windows or skylights for illumination, ventilation grilles, and a potter's bench for mixing soil and re-potting plants. "Bicycle shed" redirects here. For "the bicycle shed effect", see Law of triviality. A bike shed The main types of shed construction are metal sheathing over a metal frame, plastic sheathing and frame, all-wood construction (wood frame, wood siding and wood roof), and vinyl-sided sheds built over a wooden frame. Each type has various advantages and disadvantages that a homeowner has to consider. For example, while metal sheds are fire and termite-resistant, they can rust over time, or be severely damaged by high winds or heavy snow loads. Wood sheds are easier to modify or customize than plastic or metal, because carpentry tools and basic carpentry skills are more readily available. Vinyl-sided, wood-framed sheds blend the strength of a wood frame with the maintenance-free aspect of vinyl siding (it does not need to be painted or varnished). The International Building Code (IBC) defines a shed as a building or structure of an accessory character; it classifies them under utility and miscellaneous group U (Chapter 3 Section 312). A corrugated iron shed Metal sheds made from thin sheet metal sheathing (galvanized steel, aluminium, or corrugated iron) attached to a metal frame. Metal sheds are a good choice when long-term strength and resistance to fire, rot, or termites is desired. However, metal sheds may rust over time, particularly if they are constructed from steel that is not galvanized. Be aware that concrete is highly corrosive so care needs to be taken when assembling your shed to avoid contact with the outside panels. As well, some types of metal sheds that have thin walls are easily dented, which may makes some types of thin metal sheds a poor choice for vandal-prone areas or for high-traffic activities such as small businesses. In cold climates, metal sheds with thin walls need to have snow and ice cleared from the roof, because the thin metal may be damaged by a heavy accumulation. Since thin metal sheds weigh much less than wood or PVC plastic sheds, thin metal sheds are more at risk of being damaged by heavy winds. To prevent wind damage, thin metal sheds should be attached to a concrete foundation with screws. In countries where the climate is generally mild, such as Australia, very large metal sheds are used for many types of industry. Corrugated metal sheds may be better able to withstand wind and snow loads, as the corrugated shape makes the metal stronger than flat tin. Lifetime brand blow-molded plastic sheds Plastic shed kits utilizing heavy molded plastics such as PVC and polyethylene may be less expensive than sheet-metal sheds. PVC resins and high-impact, UV light-resistant polyethylene make plastic outdoor sheds stronger, lighter, more durable, and more resistant to denting and chipping than wood, and tend to be more stable. Plastic shed kits sided with vinyl are typically among the least-expensive types of shed construction. Higher-quality sheds use UV-resistant plastic and powder-coated metal frames. Many plastic sheds are modular to allow for easy extensions, peg-boards, shelving, attic-storage, windows, skylights, and other accessories to be added later, if these additions are purchased from the manufacturer. Plastic sheds are not susceptible to termite or wood-boring insect damage, and they require little maintenance. Being rot-proof they do not need to have preservative applied. This makes them preferable in climates where the weather can be changeable, such as the United Kingdom. Unlike wooden or metal sheds, which often require a permit to build, in many areas, plastic sheds do not. However, this is something property owners will need to verify. A call to your council/town's planning or building code office can provide information on permits. Domestic wooden sheds. Example of wood storage shed from US cedar shed builder. Wooden sheds have a natural look that can blend in well with garden environments. Despite the strength of wood, over time, untreated and neglected wood can rot, split, warp or become susceptible to mold and mildew, so wood sheds should be treated for protection with stain and varnish. Wood sheds need regular maintenance. This includes keeping plant matter and debris from piling up beside the walls and on the roof, and occasional rot-proofing with preservative. Sheds are sometimes also re-stained or varnished at times for aesthetic and wood protection reasons. Fire and, in some regions, termite attack are also potential problems. Stains and preservatives can be applied to wood sheds to prevent damage to the wood caused by exposure to rain, damp ground, UV light, harsh climatic conditions, fungal attack and wood-boring insects. If a coloured preservative oil or stain is used, a wooden shed can either be made to stand out as a feature within a garden, or to blend in with its surroundings. Red cedar coloured stain is popular. Some types of wood, such as cedar, are more naturally resistant to water damage. When looking for a wooden shed, it is important to understand the difference between the two types of preservative used in their manufacture. The timber will have been treated in one of two ways: dip treatment and pressure treatment. Dip-treated sheds are made from components that are lowered into a tank of preservative before the panels are assembled. This is a quick and simple process which keeps costs down and encourages manufacturers to produce a wide variety, making dip-treated sheds the most popular and affordable type on the market. They are easily recognisable by their golden brown colour, which is due to a dye added to the preservative. Most manufacturers offer a 10-year anti-rot guarantee on dip-treated sheds, but they have to be re-coated every year or two.  Pressure-treated sheds are made from timber planks which have had the moisture sucked out of them under vacuum conditions in a special cylinder. A powerful preservative is then forced into the wood at high pressure until it is absorbed deep into the grain, becoming an integral part of the timber. This provides excellent protection against the weather - so much so that manufacturers generally give a 15-year anti-rot guarantee. These sheds are usually distinguished by a pale green tinge which will fade eventually to a silvery grey. Although pressure-treated sheds tend to be more expensive than dip-treated ones, their big advantage is that they won't need any further preservative treatment during the guarantee period, saving owners time and money.  One advantage of using wood sheds over metal versions is that it is easier to modify them by adding windows, doors, shelving, or exterior trim (etc.) because wood can be cut and drilled using commonly available tools, whereas a plastic or metal shed requires specialized tools. Some homeowners may prefer wood sheds because wood is a renewable resource. An Amish-style vinyl-sided shed Vinyl-sided sheds are typically built with standard wood framing construction and oriented strand board (OSB) on the walls covered with standard vinyl siding. The vinyl siding protects the OSB wood and the frame from moisture from rain and snow. Vinyl-sided sheds never need to be painted, and are maintenance-free. They are stronger than plastic or metal sheds, and are usually built to conform with the local building codes. They offer good value for money because they hold up in all weather, including winters with heavy snowfall, as they use a strong wooden frame and the OSB panels have stronger structural support than thin metal or PVC siding or roofs. Metal, plastic and resin sheds are cheaper, but they cannot handle the weight of snow in winter (roofs may cave in). Vinyl sheds also offer more colour options. In the early and middle years of the 20th century, many garden sheds and domestic garages were made of asbestos-cement sheets supported on a very light angle-iron frame. Concerns about safety led to the practice being discontinued, but they were cheap and long-lasting, and many can still be seen in British gardens. Advice on continued use or disposal is available. Since 2013 garden sheds have been available in the UK made from TPR - a sustainable alternative to concrete. They are typically coated in a marine gelcoat and are far stronger and more durable than traditional sheds. A shed made from TPR became the first Secured by Design-approved shed in 2014 A shed near Sydney, Australia In Australia and New Zealand the term shed can be used to refer to any building that is not a residence and which may be open at the ends or sides, or both. Australia's passion for sheds is documented in Mark Thomson's Blokes and Sheds (1998). Jim Hopkins' similarly titled Blokes & Sheds (1998), with photographer Julie Riley Hopkins, profiles amateur inventors from across New Zealand. Hopkins and Riley followed up that book with Inventions from the Shed (1999) and a 5-part film documentary series with the same name. Gordon Thorburn also examined the shed proclivity in his book Men and Sheds (2002), as did Gareth Jones in Shed Men (2004). Recently, "Men's Sheds" have become common in Australia. In New Zealand, the bi-monthly magazine The Shed appeals to the culture of "blokes" who do woodwork or metalwork DIY projects in their sheds. The Australian Men's Shed Association is one organisation that has been set up involving sheds. A much-loved and frequently restored British shed in Lincolnshire Another magazine called The Shed, a bimonthly PDF magazine produced in the UK, but with a global audience, targets people who work (usually in creative industries) in garden offices, sheds and other shed-like atmospheres. In the UK, people have long enjoyed working in their potting sheds; the slang term "sheddie", to refer to a person enamoured of shed-building, testifies to the place of sheds in UK popular culture. A Usenet Newsgroup "uk.rec.sheds" has long championed this subculture: their lengthy FAQ is a masterly summary of the idea. Shedworking: A lifestyle guide for shedworkers is published at Blogger. Author Gordon Thorburn examined the shed proclivity in his book Men and Sheds, which argues that a "place of retreat" is a "male necessity" which provides men with solace, especially during their retirement. In contrast, in the novel Cold Comfort Farm by Stella Gibbons, Aunt Edna Doom saw "something nasty in the woodshed" and retreated to her bed for half a century. To woodshed, or 'shed, in jazz jargon, is "to shut oneself up, away from the world, and practice long and hard, as in 'going to the woodshed'." The word is recorded in English since 1481, as shadde, possibly a variant of shade. The word shade comes from the Old English word "sceadu", which means "shade, shadow, darkness". The term's P.Gmc. cognate, "skadwo" also means "shady place, protection from glare or heat". The Old English word is spelled in different ways, such as "shadde", "shad" or "shedde", all of which come from an "Old Teutonic/Anglo-Saxon root word for separation or division". The first attested usage of the word, in 1481, was in the sentence, "A yearde in whiche was a shadde where in were six grete dogges". The Anglo Saxon word "shud", which means "cover" may also have been part of the development of the word. In 1440, a "shud" was defined as a "... schudde, hovel, swyne kote or howse of sympyl hyllynge [covering] to kepe yn beestys". A waterside shed in Sweden
A shallow foundation is a type of building foundation that transfers building loads to the earth very near to the surface, rather than to a subsurface layer or a range of depths as does a deep foundation. Shallow foundations include spread footing foundations, mat-slab foundations, slab-on-grade foundations, pad foundations, rubble trench foundations and earthbag foundations. Play media Shallow foundation construction example In ground reinforced concrete foundation in cyclonic area, Northern Australia. In ground reinforced concrete foundation in cyclonic area, Northern Australia. A spread footing foundation, which is typical in residential building, has a wider bottom portion than the load-bearing foundation walls it supports. This wider part "spreads" the weight of the structure over more area for greater stability. The design and layout of spread footings is controlled by several factors, foremost of which is the weight (load) of the structure it must support, penetration of soft near-surface layers, and penetration through near-surface layers likely to change volume due to frost heave or shrink-swell. These foundations are common in residential construction that includes a basement, and in many commercial structures. But for high rise buildings they are not sufficient. A spread footing that changes elevation in a series of vertical steps so that it follows the contours of a sloping site or accommodates changes in soil strata, is called a stepped footing. Mat-slab foundations distribute heavy column and wall loads across the entire building area, to lower the contact pressure compared to conventional spread footings. Mat-slab foundations can be constructed near the ground surface, or at the bottom of basements. In high-rise buildings, mat-slab foundations can be several meters thick, with extensive reinforcing to ensure relatively uniform load transfer. Example of slab on grade foundation Raft slab house foundation in cyclonic area, Northern Australia. Raft slab house foundation in cyclonic area, Northern Australia. Slab-on-grade or floating slab foundations are a structural engineering practice whereby the concrete slab that is to serve as the foundation for the structure is formed from a mold set into the ground. The concrete is then placed into the mold, leaving no space between the ground and the structure. This type of construction is most often seen in warmer climates, where ground freezing and thawing is less of a concern and where there is no need for heat ducting underneath the floor. The advantages of the slab technique are that it is cheap and sturdy, and is considered less vulnerable to termite infestation because there are no hollow spaces or wood channels leading from the ground to the structure (assuming wood siding, etc., is not carried all the way to the ground on the outer walls). The disadvantages are the lack of access from below for utility lines, the potential for large heat losses where ground temperatures fall significantly below the interior temperature, and a very low elevation that exposes the building to flood damage in even moderate rains. Remodeling or extending such a structure may also be more difficult. Over the long term, ground settling (or subsidence) may be a problem, as a slab foundation cannot be readily jacked up to compensate; proper soil compaction prior to pour can minimize this. The slab can be decoupled from ground temperatures by insulation, with the concrete poured directly over insulation (for example, extruded polystyrene foam panels), or heating provisions (such as hydronic heating) can be built into the slab (an expensive installation, with associated running expenses). Slab-on-grade foundations are commonly used in areas with expansive clay soil. While elevated structural slabs actually perform better on expansive clays, it is generally accepted by the engineering community that slab-on-grade foundations offer the greatest cost-to-performance ratio for tract homes. Elevated structural slabs are generally only found on custom homes or homes with basements. Copper piping, commonly used to carry natural gas and water, reacts with concrete over a long period, slowly degrading until the pipe fails. This can lead to what is commonly referred to as slab leaks. These occur when pipes begin to leak from within the slab. Signs of a slab leak range from unexplained dampened carpet spots, to drops in water pressure and wet discoloration on exterior foundation walls. Copper pipes must be lagged (that is, insulated) or run through a conduit or plumbed into the building above the slab. Electrical conduits through the slab must be water-tight, as they extend below ground level and can potentially expose wiring to groundwater. A cross section view of a rubble trench foundation The rubble trench foundation, a 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. However, some soil environments (such as particularly expansive or poor load-bearing (< 1 ton/sf) soils) are not suitable for this kind of foundation. A foundation must bear the structural loads imposed upon it and allow proper drainage of ground water to prevent expansion or weakening of soils and frost heaving. While the far more common concrete foundation requires separate measures to ensure good soil drainage, the rubble trench foundation serves both foundation functions at once. To construct a rubble trench foundation a narrow trench is dug down below the frost line. The bottom of the trench would ideally be gently sloped to an outlet. Drainage tile, graded 1:8 to daylight, is then placed at the bottom of the trench in a bed of washed stone protected by filter fabric. The trench is then filled with either screened stone (typically 1-1/2") or recycled rubble. A steel-reinforced concrete daro beam is poured at the surface to provide ground clearance for the structure. If an insulated slab is poured inside the grade beam, the outer surface of the grade beam and the rubble trench must be insulated with rigid XPS foam board, which must be protected above grade from mechanical and UV degradation. The rubble-trench foundation is a relatively simple, low-cost, and environmentally-friendly alternative to a conventional foundation, but may require an engineer's approval if building officials are not familiar with it. Frank Lloyd Wright used them successfully for more than 50 years in the first half of the 20th century, and there is a revival of this style of foundation with the increased interest in green building. The basic construction method begins by digging a trench down to undisturbed mineral subsoil. Rows of woven bags (or tubes) are filled with available material, placed into this trench, compacted with a pounder to around 1/3 thickness of pre-pounded thickness, and form a foundation. Each successive layer has one or more strands of barbed wire placed on top. This digs into the bag's weave to prevent subsequent layers from slipping, and also resists any tendency for the outward expansion of walls. The next row of bags is offset by half a bag's width to form a staggered pattern. These are either pre-filled with material and delivered, or filled in place (often the case with Superadobe). The weight of this earth-filled bag pushes down on the barbed wire strands, locking the bag in place on the row below. The same process continues layer upon layer, forming walls. A roof can be formed by gradually sloping the walls inward to construct a dome. Traditional types of roof can also be made.