- №1.Foundation types by type
- №2.Foundation types of construction
- № 3.Ribbon foundation for a private house
- №4.Slab foundation for a private house
- №5.Column foundation for private house
- №6.Pile foundation for a private house
- №7.What is important to consider when choosing the type of foundation?
The foundation is the foundation of the house, and it is not a figure of speech at all. On how correctly chosen the type of foundation and how it is executed, depends on the durability of the building. The crooked houses and the cracked walls of the dacha only once again convince of the increased responsibility of the work associated with the design and construction of the foundation. The first thing that anyone who starts to build should do is to choose the type of foundation of a private house, and for this it is necessary to take into account a lot of factors and know the key features of all types of bases.
№1.Foundation types according to the type of assembly
Depending on whether factory elements are used in construction, or all of them are formed directly on the site, the foundations are divided into:
- monolithic .For their manufacture, formwork is being settled into which a concrete solution is poured;
- prefabricated monolithic is obtained when concrete is filled with finished constituent elements;
- prefabricated foundations are constructed from factory-made concrete products.
Naturally, monolithic foundations are much stronger than prefabricated monolithic and, especially, prefabricated ones, but they require more time and effort for the construction.
№2.Foundation Types by
Design All foundations used in private construction can be divided into four groups:
- strip foundations is a solid sheet of reinforced concrete( much less often of brick), which is laid under all the bearing walls of the house and has the appearance of a closed contour or tape,where the name came from. The most common type;
- slab foundations are also called “floating”, they are a solid monolithic concrete slab that allows you to most evenly distribute the load;
- , columnar foundations, as the name suggests, are a system of pillars made of concrete, brick, stone, less often wood, and located at a uniform distance from each other at the locations of the bearing walls and corners of the future house. The pillars for reliability are united by a grillage( a frame that connects all the pillars), but they can do without it. This kind of foundation is suitable for small light houses;
- The pile foundations consist of pillars that are screwed in or driven into the ground( pillars of the columnar foundation are installed in the pits) at a relatively large depth. Piles can be reinforced or metal, used on loose and heaving soils.
The choice of the type of foundation for a house depends on the height and dimensions of the house, the materials of the walls and floors, as well as the type of soil, the level of frost penetration, the depth of groundwater, the presence of underground utilities, and the need to equip the basement.
№3.Ribbon foundation for a private house
The most common type of foundation in the construction of a private house is considered to be tape. It is a tape or frame of concrete, which is laid under the bearing walls. A sand-gravel pad is formed under the concrete, which allows you to more evenly distribute the load on the soil and eliminates the need to conduct more serious soil preparation before laying the foundation. Sand-gravel pad plays the role of drainage and protects against groundwater. Foundation requires waterproofing and insulation work.
The main advantages of the strip footing include:
- the ability to withstand decent loads, so it is used in the construction of both relatively light wooden houses, and 2- and 3-storey brick buildings;
- the ability to use such a foundation for arranging the basement;
- can be any form of strip footing( except for prefabricated structures);
- minimum amount of earthworks.
- labor input;
- need for specialized equipment( at least, concrete mixers, and for arranging a prefabricated structure - a crane).
Tape foundations are of two fundamentally different types:
monolithic strip foundations are formed by arranging formwork, installing reinforcement and pouring sand-concrete or concrete mix. It can be of any shape, and due to its integrity, excellent thermal and waterproofing qualities as well as strength are ensured.
prefabricated strip foundations are made from prefabricated reinforced concrete blocks, which greatly simplifies and speeds up installation. Some parts are bonded with reinforced cement, the construction is inferior in monolithic strength, and is its main minus - insufficient waterproofing at the junction of the blocks, which in areas with elevated groundwater levels and in wetlands can lead to such a foundation. Much less frequently, prefabricated foundations build up made of bricks, but their service life is less than that of concrete.
Separately, should be provided with the intermittent strip foundation , which is laid not with a solid line, but with separate sections, but clearly under the supporting elements. This design allows you to save money when building lightweight buildings.
In those cases, , when there is a weak soil under the strip foundation, its base must be expanded, and this is done by forming , resulting in a stepped design: the main load will be placed on the wide part( sole).It is also possible to form the foundation of the in the form of the trapezoid : the lower wide part will become the main support. If the groundwater is located at a shallow depth, it is recommended to use concrete of special grades and additionally protect it with bitumen mastic.
As is clear from the above, the strip foundation can be built from the following materials:
- reinforced concrete structures provide the greatest strength and durability, relatively cheap, but time consuming;
- butto-concrete structures are distinguished by the presence of large particles of gravel, bricks, and boulders in the concrete solution. Bypasses inexpensive, able to withstand decent loads;
- The brick foundation is actually ordinary brickwork, but recessed into the ground. Such a base is used when there is no possibility to build a monolithic concrete foundation, it can withstand the weight of houses up to five floors.
The foundations of the foundations are divided into:
- shallow ( depth 50-70 cm) - an option for poorly lush soils, i.e.those that are little exposed to frost heaving;
- , deep-laid are laid at a depth of 20-30 cm below the level of soil freezing. Used for the construction of heavy structures and in places with complex soil.
№4.The slab foundation for a private house
The slab foundation equips the in areas with loose, heaving and mobile soil. Monolithic concrete slab, located under the entire future structure, prevents the negative effects of soil movement and allows you to evenly distribute the load of the house on the soil. Under the action of soil swelling, this type of foundation can evenly rise and fall again( therefore, it is called floating ) - cracks in its construction and the supporting walls of the house do not appear.
The slab foundation is made of several layers:
- sand and gravel pad;
- layer of insulation:
- concrete with reinforcing framework.
The thickness of the main concrete layer varies from 30 to 100 cm, only monolithic constructions are used, so the concrete is prepared and poured into the formwork on site. In rare cases, ready-made concrete precast slabs are used, but this method is allowed only for the construction of small light buildings, since the strength of such a foundation is not very high.
The sand-gravel layer is used to level the base, sometimes it is replaced by concrete of low strength. It is imperative to use a waterproofing material when organizing such a foundation. If it is necessary to build a large house, an expansion joint is recommended to be made on the concrete monolith. expansion joints - the foundation is simply cut into smaller pieces. This helps prevent cracking.
Pros of the slab foundation:
- uniform load distribution of load-bearing structures on the foundation;
- sufficient strength, ability to transfer vertical and horizontal deformations;
- for areas with weak soil types is actually the only option to organize a strong foundation;
- for the floor does not need additional floor slabs, and with high-quality insulation, such a foundation can even be used as a subfloor.
- inability to equip the basement;
- high cost, it is the most expensive of all types of foundations for the home, so its use is justified only in areas with loose soil;
- need a smooth terrain, otherwise the site must be properly planned.
№5.Pillar Foundation for an
Private House For light wooden and frame houses, a pillar foundation is ideal, which is distinguished by in relative simplicity in arrangement and for a small outlay. Such a foundation is a privilege of plots with normal soil, but if the foundation is laid at a depth below groundwater, it can also be used on heaving soils.
Columnar foundation consists of equally spaced pillars, recessed into the ground. Poles can be :
- concrete with reinforcement;
The strongest are concrete and concrete, they can withstand severe loads, brick pillars are inferior to them, and wooden can be used only as a base for small wooden buildings( barn, bath, etc.).Columns to increase strength and reduce mobility from above can be connected by strapping beams of reinforced concrete.
It is recommended to equip a sand layer with a thickness of about 50 cm under the column foundation - it will prevent swelling. The pillars are installed at a distance of 2-3 m from each other along the contour of the house, in the corners of the building and at the locations of the bearing partitions. Pillar foundation can be:
- monolithic .All the supports are made on site, reinforced concrete or butobeton and wooden formwork are used;
- assembly. For its construction using concrete pillars produced in the factory. They are installed on special “glass pads” with a thickness of about 0.15 m.
The number and depth of the pillars are calculated taking into account the type of soil and the structure. If the building is small and light, it is even allowed to use a shallow( this is about half the normative depth) and a non-buried foundation( 40-50 cm).
The advantages of the columnar foundation:
- relative simplicity and low cost of arrangement;
- is ideal for building small houses on stable soils.
- difficulties in arranging basements and underground garages;
- low strength and inability to use on highly mobile soils - the supports can bend over and even tip over, which will result in the deformation of the building.
Pile Foundation for a Private House A pile foundation consists of a system of piles, long pointed poles, which are driven in or screwed into the ground directly or at an angle. The long length of such elements allows using their in areas with weak and loose soil, because they are installed at such a depth to rely on stronger and dense soil layers that do not freeze through in winter. This principle allows the use of a pile foundation even in the most difficult conditions. Top piles are tied with a concrete slab or beam - with a grillage .This type of foundation is used for the construction of wooden, frame, panel and other non-heavy houses, as well as fences on swampy and peaty soils.
Piles can be made of the following materials:
- wood. Used to support light wooden houses, made of pine treated using a special technology;
- reinforced concrete - the most durable material that is suitable for the construction of more or less heavy structures;
- ; metal also has high strength characteristics and is not inferior to reinforced concrete;
- combined piles , usually combine metal and concrete - such strongest bases are suitable even for the most complex marshy soils.
According to the installation technology, the piles are:
- driven are, as a rule, reinforced concrete piles with a pointed end, which are immersed in the ground with the help of special drum sets. Not suitable if there are buildings nearby, as the shock wave can damage them;
- bored involve the preparation of a well, the arrangement of a framework made of rebar in it and pouring it with concrete;
- screw piles are hollow metal rods with blades at one end, can be installed manually or screwed in with specialized equipment. Suitable for soils of any density;
- pushed-in piles are installed with special hydraulic pumps, rarely used in private construction, as the adjacent buildings can be deformed by a shock wave.
Among the main advantages of the pile foundation:
- can be installed on any type of soil, there is no dependence on the water table;
- reducing the amount of concrete consumed;
- reduction in the number of earthworks;
- relative speed of installation.
- the need to use specialized equipment for the transportation and installation of piles;
- relatively high cost.
№7.What is important to consider when choosing the type of foundation?
It is better to entrust the calculations and design of the foundation to specialists, especially if we are talking about a large house with heavy load-bearing walls and floors. If a private house or a small cottage is built on its own and has a small weight, then many prefer to do without detailed calculations, which is not entirely true. To avoid mistakes, it is necessary to take into account a lot of factors, and the basic principles for choosing the type of foundation for the house and its arrangement are considered:
- on strongly heaving soils, the foundation should be equipped with below the soil freezing level. The conditionally non-knocking depth of the basement can be 0.5–1 m;
- The average and maximum depth of soil freezing is variable, and it is not always easy to determine them. Relevant data should be from the organization that owns the land, along with other characteristics of the soil, otherwise you will have to conduct their own research. The most unreliable way is to ask the neighbors in the area, but the ground can be non-uniform, therefore such data is not always accurate;
- the more dense and wet the soil, the more it freezes through during the cold season. The most difficult in this respect - clayey soil, which is not enough that it swells, so also unevenly. The most effective way to prevent possible deformations is to replace complex soil with sand or to equip a sandy pillow;
- sandy ground is considered ideal for building any kind of foundation and building houses made of brick, aerated concrete, foam block and other materials, it is well water permeable, almost does not swell. The rocky grounds of the practically do not swell, do not freeze and do not change their properties under the influence of external factors, but it is difficult to organize the foundation in them due to increased hardness. Clay soils require either arranging a sand pad or using piles;
- if other massive structures are located near the intended construction site, then should be taken into account the total load on the ground;
- on silty and heaving soils it is better not to use a strip and column foundation;
- pile foundation is justified only when other options are not suitable at all - it is expensive in arrangement.
The foundation will last for many years, if you do not forget to also take care of its waterproofing and insulation. Much also depends on the quality of the materials used and the responsibility of those who are building the foundation.