Foundation for a log house
The foundation for a log house should provide reliable and durable support for a wooden house and at the same time become a barrier to the penetration of the negative influences of the soil foundation. For a wooden house, it is important that the size of the foundation for the log house does not extend beyond the perimeter of the building (this is not economically profitable). Overhanging logs outside the foundation of a log house can create unexpected stress centers in the walls, which will lead to the destruction of the load-bearing structures of the house, so the optimal size of the log base is important. The question that remains is which foundation is best for a log house.
Online foundation calculator
To find out the approximate cost of various types of foundations, use the following calculator:
Concrete strip
The strip foundation for a wooden house is one of the most beloved by our compatriots and, perhaps, the most reliable. Its width is the same around the entire perimeter, and leaves 50 cm “plus” to the width of the walls.
It is divided into three subspecies: deep, shallow and non-buried. Deeply buried is designed for “difficult” conditions: in the presence of basement premises (garage, basement), multi-story buildings, heaving soil on the site, large freezing depth. It is designed to hold the building stably even when weather conditions change and the ground moves. It is believed that such a base should be buried at least 200 mm lower than the freezing depth (the values for a certain latitude are known and can be easily recognized from the reference book).
Classic strip foundation for a wooden house Source tr.decorexpro.com
If the soil allows, then for the construction of low-rise wooden houses, a shallow foundation is most often used - it is buried to a depth of about 500-700 mm, which, although less than the freezing depth, is quite enough to support a light-weight house. And, of course, it will cost much less than a deep-seated belt one.
In the case of very light buildings (sheds or utility rooms), you can get by with a shallow foundation. This type of foundation can be made of concrete or brick, stone or blocks.
A relative novelty on the construction market is a foundation made of permanent formwork, which consists of ready-made elements that are combined into blocks, and then concrete is poured into them.
A non-buried foundation is essentially a plinth on a sand cushion. Source postroim-svoi-dom.ru
The production time for any strip foundation is about a month, since after pouring it is necessary to wait a certain time until the concrete reaches its design strength.
Slab concrete monolithic
A slab foundation is simply a large concrete slab. This is a good choice for heaving and mobile soils, since the slab base has the ability to move along with the soil when it shifts. You should not think that the house will move around the site - moving soil means displacements of a couple of centimeters per year, but even such values can cause cracks to appear on the walls when using a strip base.
Making a monolithic foundation cannot be called an easy task - in terms of installation time, they are approximately equal to those of a strip foundation. It also requires clearing the site, deepening it, pouring concrete - and, given the harsh conditions, some experts ask for a grade no lower than M400, in principle, given the cost, you can get by with M150, but these are very minimal requirements. A big problem is also the uniform drying of the slab surface (a large area dries poorly, and it will take a long time to dry completely and begin the next stage of work). It will also be necessary to arrange a sand cushion for cement, a blind area on the finished foundation and waterproofing (as a means of protecting concrete from water - film or special compounds).
Ready slab foundation Source stroidom-shop.ru
Pile: steel screw or concrete driven
A pile foundation for a wooden house is a good choice for a site where there are problems with groundwater, and, in addition, the site itself has unevenness, the leveling of which will require significant effort. Proper calculation of the pile field makes such a foundation reliable and stable. In addition, the cost of a pile foundation is significantly lower than a concrete one, and installation is carried out in one day.
The main disadvantage is that with a pile foundation it will not be possible to create a basement or ground floor in the house. Auxiliary buildings on the same foundation as the piles are undesirable - due to the elevation above the ground. Entering a garage, for example, will not be very practical.
conclusions
Which type of foundation should be preferred for a log house?
From all of the above, the following conclusions can be drawn:
- A columnar foundation is not suitable for a full-fledged wooden house. It is intended only for light wooden structures of a small area, bathhouses, verandas, as well as supports for porches and gazebos.
- The recessed strip foundation is designed for multi-story heavy structures and is redundant for log houses.
- It turns out that the most suitable foundations for a wooden house will be shallow strip and pile-strip foundations. These types of foundations are reliable and durable. Which one is preferable depends on the specific geological conditions of your site.
- You should not skimp on geological surveys - their results will show exactly what type of foundation is suitable for your site. Often this knowledge saves up to 50% of the cost of the foundation, and will also allow you to be 100% confident in the correct type of foundation.
- Shallow strip foundations are more popular due to their efficiency and ease of installation. It can be successfully used for a house made of rounded logs and a wooden cottage on slightly heaving soils or with additional insulation.
- The tape-pile method has a fairly high cost; it is a fairly new method and is not used very often in construction.
In order to decide which foundation is better in each specific case, the entire set of factors should be taken into account, such as the area and weight of the building, the nature of the soil, the region of residence, etc.
Video description
What are the pros and cons of a pile screw foundation? Is it possible to make a high-quality foundation for little money? Watch in this video:
Pile foundation - screw and concrete Source stroy-dom-pravilno.ru
See also: Catalog of wooden house projects presented at the Low-Rise Country exhibition.
Log house
A log house is the walls of a house made of solid logs. In the corners of a wooden house, logs are connected into so-called crowns. At the bottom of the log, a piece of wood is cut out the width of the transverse diameter of the log. Wooden elements in the corners of the house form locking systems that do not require additional strengthening. This confirms the popular expression - to build a house without a single nail.
Such houses are most often built in areas where timber is available to consumers at a low price. Such places include Central, Eastern Siberia and the Far East. Although it is worth noting that the popularity of building private houses from solid wooden elements has increased widely in all regions of our country.
The low specific gravity, excellent thermal insulation qualities, durability and environmental friendliness of wood are an undeniable advantage over other building materials.
Video description
What are the features of concrete driven piles? We'll talk about pile foundations in our video:
Columnar: brick, block or concrete
Columnar foundations do exist as a separate type of foundation, but it must be noted right away that they cannot be used for the construction of a residential building.
In general, this is an inexpensive and easily erected foundation, which is a hole 50-70 cm deep, at the bottom of which sand and crushed stone cushions are laid, on top of which the pillar itself is built.
The methods for making “pillars” are completely different - bricks, pouring concrete into formwork, asbestos pipes, ready-made blocks. As with any technology that uses concrete, care should be taken to ensure that sand cushions, formwork and reinforcement are installed when making the bases on site.
Columnar foundation poured and made of blocks Source nauka-i-religia.ru
The distance between the pillars, regardless of unevenness, should not be more than 1.5-2 m; in addition, pillars must be present at the corners of the building and at the intersections and junctions of walls. Columnar foundations are installed almost everywhere, with the exception of floating areas (areas completely unsuitable for construction), using special device technologies - for example, TISE, where the pillars “expand” at the bottom, giving additional strength to the structure. But even when using this technology, you should also take care of additional insulation and waterproofing, and this work must be performed together with the construction of the walls (that is, the places where the pillars adjoin the walls are processed together).
Considering that columnar foundations are suitable exclusively for ultra-light buildings - gazebos and the like, it can be argued that they do not have many disadvantages. But in any case, such foundations are not suitable for complex soils - loose, with a large freezing depth.
No specialist would use such a foundation for a residential building. In addition, it is strongly recommended not to experiment with such a foundation when building a house through the efforts of “gray” construction crews, who do not care what they build, because they do not bear warranty obligations.
If the soil is even slightly mobile or susceptible to heaving (and usually it is), then eliminating the consequences will cost a pretty penny.
Incorrect use of a columnar foundation - the work will have to be redone Source stroy-dom-pravilno.ru
See also: Catalog of companies that specialize in foundation repair and design.
Slab foundation structures
Slab foundations are direct successors to a solid monolithic grillage. Determining the size of a slab foundation for a log house is not difficult. If a 6x6 house is planned to be placed on a solid foundation, then the dimensions of the slab will be similar. It is important to fit within the perimeter of the house, and a small protrusion beyond the outer boundaries of the wall structures will not interfere with the work of the foundation - 5-10 centimeters of reserve will be enough. It is not recommended to leave the wall overhang, since it is important to rest the entire wall base on the edge of the foundation. The depth of the slab foundation is another important dimension.
Insulation of a slab foundation is a very important stage, since it often serves as both a support and a ceiling for the first floor. Whatever insulation is chosen, it will not affect the dimensions of the foundation in plan - the vertical size of a slab foundation is calculated based on the load-bearing part, without taking into account the insulation and protective structures.
Construction of a log house on a slab
Usually, they tend to make such foundations for a log house prefabricated, and in order to save money, floor slabs are laid on the ground, the dimensions of which depend on the parameters of the material used.
Typically, these are hollow-core floor slabs with a thickness of 220-250 centimeters. If you plan to fill a monolithic slab, you should take a minimum thickness of 30 centimeters.
Concrete works well in compression, but practically cannot withstand tensile loads, so reinforcement is laid - this thickness will ensure uniform distribution of two rows of flat reinforcement frame and leave room for a protective layer of concrete, which should not be less than 1.5 cm.
Pros and cons of a pile-screw foundation
After considering the main types of foundation, it would seem that choosing a pile-screw foundation is the most optimal, however, there are both advantages and disadvantages.
Advantages:
- Installation speed - just determine the freezing depth and order a drill, and literally within a day the piles will be installed;
- Simple process - does not require additional time or money;
- Versatility - good performance of this type of foundation was obtained on all types of soil, including peat;
There are only two disadvantages , but they must be taken into account:
- Calculation complexity - the heavier the building and the more complex its shape, the more careful calculations will be required;
- If a geological examination of the soil was not carried out before installing the pile field, then in the case of loose or peaty soil, a certain percentage of subsidence of the structure is possible - unfortunately, often uneven.
Pile field for a wooden house Source art-stroynn.ru
Screw foundation with channel or beam strapping
If you choose a screw foundation for a wooden house, then after installation you need to decide on the type of strapping, which is divided into beam and channel strapping.
Bonding is a method of stabilizing a foundation of piles after they have already been installed and concreted.
Timber strapping looks good under wooden buildings - bathhouses and houses. The main requirement is that all piles be cut to the same height, but then the frame can play the role of the lower crown of your log house, taking into account that the floor joists are located quite high (at least 2-3 crowns higher).
Tying a pile foundation with timber Source 2gis.ru
A channel (rolled metal in the shape of the letter “P”, if viewed from the side) is used in cases where the alignment of all piles is difficult (for example, there are too many of them), and, in addition, the channel supports heavier structures. It is laid around the entire perimeter and along load-bearing partitions. It will be a little more expensive, because with this technology you will need to order special equipment. The channel can be laid on top of the piles (a more common option) or between them. It is also worth considering that channel tying must be done immediately after the stage of screwing in the piles in order to avoid changes in their position.
Anti-corrosion treatment is carried out after installation of the harness.
Tying a pile foundation with a channel Source korden.org
Criteria for choosing a base
The main criteria are, of course, the condition of the soil and the climatic features of the region:
- Freezing depth - the greater it is, the deeper the foundation should lie;
- Material consumption is also an important criterion;
- Aesthetics – the foundation of the house must be combined with the environment and the building itself;
- Position of the house - if possible, you should choose places away from cliffs and ravines;
- Plinth and its use - is the device planned to be installed in the basement of a garage or other ancillary premises? Depending on the answer to this question, you will need to use a certain type of foundation;
Strip foundation for a bathhouse
Often, a strip foundation is the best choice for building a wooden bathhouse. In addition to the reliability of the design, this option can also be considered from an aesthetic point of view - to play on the contrast of materials.
For the construction of a bathhouse, a shallow strip foundation is recommended - it is quite enough to support a structure that is not too heavy. If the soil is heaving and the freezing is deep (over 1.5 m), you will have to opt for a deep strip foundation.
Carrying out markings on the ground
The process of marking the outer contour of the foundation
Now you can begin marking the area on which you plan to build a dwelling from timber. What tool is needed for this:
- shovel and bayonet;
- pegs;
- rope;
- roulette.
To ensure effective marking, some preparatory work should be done, namely:
- Clear the area of dead wood, grass and stones. You need to clean the place so that it is larger in size than indicated in the plan. That is, both the width and the length protruded beyond the edges of the foundation being built by 0.5 m in all directions. In this case, the marking will be done correctly.
- Remove the top layer of soil to further level the area. The layer thickness should be about 7-10 cm.
- Perform contour markings using pegs installed every 0.3 m from each other. Tie the pegs with rope.
