Each house must have a solid foundation, which transfers the load from its weight to the ground. Houses made of timber are resistant to deformations and relatively small masses. This feature slightly reduces the requirements for supporting structures for them. In ancient times chopped log huts were put on large stones or even on decks of larch. Today we have the choice of several types of structures.
- 1 Factors for choosing the type of foundation
- 2 How does the foundation affect the choice of the foundation
- 3 In which case to use this or that type of foundation
Factors for choosing the type of foundation
The stronger and more reliable the support, the better, but the excessive massiveness is unnecessary costs, which are not always justified.
What is the best foundation for a house made of timber, depends on many factors:
Weights and structure of the structure.
Type of soil, its hardness, heaving, stability of behavior when wet.
The level of groundwater, the amount of precipitation, seasonal fluctuations in humidity, relief.
Presence of basement, availability of materials, economic calculations.
How does the foundation affect the choice of the foundation
Before deciding which foundation to choose for a house of timber, you should study the properties of the soil in the construction site. Here, the bearing capacity, mobility, heaving is important. The structure of the base is divided into several types.
Rock and clastic soils
Bases in the form of a rock or a dense mound of solid debris have the highest load-carrying capacity, and their behavior is practically independent of moisture and groundwater level. They work well ribbon and columnar shallow and undeveloped foundations. In these soils it is very difficult, and it is often impossible to arrange a basement under the house.
Soils with a high sand content refer to stable and reliable grounds for the house. Good drainage qualities of sand practically exclude frost whipping, except for cases of flooding above the freezing level. With a consistently low groundwater table, any type of foundation can be used. With seasonal podtaplivanii the best choice will be pile or columnar, with the deepening of the sole below the depth of freezing.
Clay soil in a dry state has a bearing capacity comparable to a stone. But its properties change drastically when moistened. In addition, it has the property of punching during freezing. If the groundwater does not approach close to the base of the basement, and the surface layers are protected from precipitation and flood waters, then any foundations are equally effective on clay, provided that measures are taken against frost heaving.
If it is possible to raise groundwater or floods, it is better to put the house on a monolithic slab of reinforced concrete. If at the same time there is a dense breed at accessible depth, which can serve as a support, it is possible to make a pile foundation with a rigid strapping, which turns the pile field into a single structure.
In which case to use this or that type of foundation
There are different types of foundations. Each of them has its own area of greatest efficiency.
Constructively this is the simplest foundation. It is located under all supporting walls and has the form of a continuous tape. Due to its large footprint, it has a high bearing capacity and can be used for heavy walls and structures.
In terms of the depth of the basement, the band foundations are divided into undeveloped, buried and shallow depths. The buried foundations are used under heavy structures and laid below the freezing level of the soil in order to exclude the influence of frost heaving on the sole. A deep strip foundation forms the walls for basements and semi-basements.
For light structures, such as one-two-story wooden houses, such a structure is justified, only in the case of a basement or basement under the building. A light structure, supported by deep soil layers, gives too little load to the base, which in some cases can cause loss of stability. Particularly strong influence of lateral and tangential forces of frost heave on heaving grounds.
In rural housing construction, shallow foundations are often used. Under them, trenches up to 0.5 m deep are laid, a pillow of drainage materials is placed - large and gravel sand, gravel, gravel, carefully compacted and a stone or concrete supporting "tape" is placed on top of it. This design is much cheaper both in terms of materials and labor costs. The drainage pillow compensates for vertical frost heave, and lateral and tangential loads are insignificant because of the small area of contact between the lateral surface and the ground.
Belt foundations are used on any sufficiently stable bases. Do not use them on weak, heavily watered and underflooded soils.
The pillar foundation is a series of pillars of stone, brick or concrete, connected by grillage.
This design allows to save material and reduce the amount of excavation work. But because of the technical complexity of the device grillage, significant savings are obtained only with a sufficient vertical size of the foundation, which achieves a large difference in the volume of materials compared to the tape type. The lower strapping of the timber house takes on the function of distributing the load to the posts. This partially removes the problem of grillage and extends the range of economic advantages of columnar supports.
It is possible to build a foundation foundation on clay soils, to the depth of freezing, if it is planned to build a house without a foundation. If, due to soil properties, climatic and hydro-geological conditions, the foundation is laid to a great depth - 1.5 m and more, then the complexity of the construction of the columns sharply increases. Here we enter the field of effectiveness of pile foundations.
A screw pile is one of the types of piles used in construction. For private construction, screw piles are best suited because they do not require heavy special equipment for their installation. Depending on the diameter and depth of the dive, each pile can be installed by forces of 2-3 people, or with a compact power plant, which is easy to deliver to the construction site.
Screw piles are perfectly kept on weak and waterlogged soils. They are insensitive to frost whipping, and the ease of their immersion allows the structure to be supported on deep, dense layers.
The foundation on screw piles can be used on clay and sandy grounds, with the proximity of groundwater, in the flooded areas, on the shore of the reservoir, on the coastal shoal. The only limitation for them is rocky and coarse clastic soils.
Plate foundation - a rigid monolithic slab of reinforced concrete. Such a plate has a very large area of support, so it can maintain stability even on the weakest soils.
With a correctly designed penetration, such a foundation is called floating because its load-bearing capacity does not depend on the hardness of the substrate. The load created by the weight of the structure is balanced by the pressure of the soil, even in the plastic state.
Under the timber house, it is advisable to use such a foundation on loam with a high level of groundwater, as well as unstable sandy loamy soils.
To choose the best foundation for a house from a bar, it is necessary to take into account all factors, including a height difference in terms of the house, the possibility of shifts and landslides in the adjacent territory. Based on the above descriptions of foundations and foundations, general recommendations can be made.
- On a clastic and rocky ground, the timber house should be placed on a strip or columnar, unshadowed or shallow foundation.
- On the sandy base - on the columnar low-depth, and if you need a basement, then on the tape.
- On the clay soil it is necessary to use columnar with a depth below the freezing level or pile. Tape - for the cellar.
- On a weak base, dusty or waterlogged it is better to use a slab foundation.
When building on a steep slope, you need to take into account the lateral pressure of the soil on the poles and walls. Any soil, except for rock, behaves like a liquid for large periods of time. He seeks to push out buried structures, and those standing on a slope - to overturn. On the steep slope, screw piles show the greatest stability, as they have a developed anchor section, a rigid strapping and a relatively thin trunk.
Choosing a foundation for a house is a task for professionals. And yet, you can and should be guided in this matter. I hope this article helps to avoid blunders.