- What is it: definition of the concept of MLF
- Advantages and disadvantages
- Scope of use
- What soils are used
- Table for frame and wooden heated houses
- Foundations without deepening frame and wooden unheated houses
- Types of MZLF for home
- The device of a shallow strip foundation
- Shallow strip foundation: laying depth
- Arrangement of a pillow
- Instructions for the correct MLF
- Preliminary stage: trench
- Reinforcement and reinforcement
- Fill in the solution
- Completion of work
The type of base differs in that its deepening occurs at a distance of 30-70 cm relative to the ground level. This is the best option for most small private house projects, suitable for almost any type of land. On such a base, you can easily build walls from high-quality Ytong aerated blocks. Shallow strip foundation is a technology that has its own advantages and disadvantages. We will talk in more detail about all the nuances of work on this system in this article..
What is it: definition of the concept of MLF
The main distinguishing advantage of this option is its simplicity and cost-effectiveness. The only difference from the classical method of pouring a concrete base is that the deepening takes place over a short distance. This means that the structure will be entirely above the soil freezing zone. With this approach, the trench will have to be dug several times less deep than with the usual construction method. This allows you to significantly save both on the remuneration of workers and special equipment, and on the purchase of the necessary building materials..
Even without the use of construction equipment, you can manually dig a recess for a shallow strip foundation for a house. This is very useful in situations where it is not possible to deliver large machines to the construction site. You can also do it yourself by pouring concrete solution after preparing and strengthening the base. But it is worth paying attention to the fact that before choosing this method, you should carefully calculate the loads to which the building support will be subjected. If the pressure is significant, then you should think about choosing a more stable structure..
Advantages and disadvantages
There are definitely a lot of significant advantages of using the MZLF technology:
Optimization of labor costs. This includes reducing the cost of digging a trench.
Reduction of the final price of building materials, which will be required several times less.
Most of the tasks can be done by hand, which is very convenient for people building a house on their own..
At a relatively low cost, the result is a fairly robust and reliable design. Of course, taking into account the competent calculation of loads and drawing up a detailed work plan.
But at the same time, there are some significant disadvantages that you need to know:
On loose and heaving soils, it is imperative to create a drainage system.
A thorough geological check should be carried out to determine soil properties that may cause instability in the future..
MLF foundation is suitable for low-rise buildings. The weight that can withstand such a base is limited, and this must be taken into account.
Note that any of the alternative methods is also sensitive to the area with which soil the construction will be carried out. Therefore, the main negative point in choosing a shallow concrete tape is the weight limitation.
Scope of use
As we wrote above, the technology is most widespread in the private construction of small low-rise buildings. Due to the ease of installation, many people decide to erect buildings on their own. All this has a beneficial effect on the budget, which is much more modest than when pouring a conventional base. If the construction of massive and heavy buildings is planned, then the shallow tape may not be suitable in terms of parameters. To understand the relevance of the technology in your case, it is necessary to make careful calculations of potential loads. This will avoid mistakes and ensure the durability of the entire structure..
What soils are used
The method we are telling you about is suitable for use on various types of soil. Practically on any of the common land in our country, you can fill in such a base. All recommendations that apply to classic concrete tapes will also apply to lightweight shallow subfloors. Regardless of the level of moisture in the ground, and its composition, you can start construction by pouring a shallow strip foundation. Once again, we will emphasize that it is important to do all theoretical calculations before starting work. Even a small mistake at an early stage can lead to quite serious consequences in the future, up to the complete destruction of the building. Let’s consider in more detail the requirements for the base, on different soils.
Houses made of aerated concrete for medium and heavily weathered (table)
If you plan to create a small private building using high-quality Itong aerated concrete as the main material, then the following parameters from the table below must be observed (these are recommendations, since these parameters require a design justification, taking into account the geology of a particular site).
|One||Clay + sand||MEDIUM||60||thirty||Sandy |
|B or D||2|
|Two||Clay||Sand + Crushed stone||one|
|One||Clay + sand||STRONG||60||fifty||Sandy |
|Two||Clay||100||40||Sand + Crushed stone||four|
|A or D|
If we use the data for the arrangement of houses with wooden floors, then the stability of the housing will be even greater than it should be according to the standards. However, frame houses are less stable than stone (aerated concrete) houses. Accordingly, the table can be applied to this type of structure..
Frame and wooden heated houses (table)
|Number of storeys||Base width (cm.) |
(frame / wooden)
(thickness in cm.)
|MEDIUM||One||40 cm / 30 cm||20 cm||B or C||2|
|Three||40 cm |
|Three||40 cm / 50 cm |
Foundations without deepening frame and wooden unheated houses
|Base width (cm.) |
(log / squared)
(thickness in cm.)
|MEDIUM||One||30 cm / 20 cm||60cm. / 70cm||D||3|
|Two||50cm. / 60cm.|
|Three||40cm. / 50cm.|
|STRONG||One||70cm. / 80cm||four|
|Two||60cm. / 70cm|
|Three||50cm. / 60cm|
Shallow foundation for a house: types
Today, the following types are most common:
Monolith is a reinforced concrete structure filled with a homogeneous mass. This type has high strength characteristics..
Precast – consisting of different parts, such as concrete blocks, bricks, etc. Has less resistance to stress, however, due to the absence of the need to use a solution, it is sometimes the best solution.
Combined – pouring with a concrete layer in combination with other elements.
In most cases, the choice of builders stops at the first method due to the highest indicators of resistance to external pressure..
The device of a shallow strip foundation
In short, MZLF is a filling (or consisting of blocks) tape on a sand substrate (in some cases, in combination with crushed stone). It protrudes about half of its height above ground level. What width to equip the recess under the base depends on whether there will be a side backfill made of material that cuts off the structure from the effects of water. A layer of waterproofing material is also installed in the upper plane, which does not allow moisture to damage the concrete over time..
Shallow strip foundation: laying depth
It mainly depends on the location of the object. The depth of the embedment of the tape is selected depending on the climatic zone in which the construction is carried out. Even taking into account the fact that the level of freezing of the ground is located much lower than the MZLF, the influence of this factor still has a very strong effect on the strength of the building. Therefore, simply ignoring these features will not work. In most cases, you have to dig at a distance from half a meter to one and a half meters. Depending on how high the freezing point of the soil is, a higher or lower level is selected..
Shallow foundations: arrangement of a pillow
An important element for the overall structural strength of a building is a backing made of materials that act as drainage and help the tape withstand the effects of heaving. This is often a homogeneous sand layer (thickness from 0.2 m), or a combined backfill in combination with crushed stone. In the second case, each of the layers has a thickness of 0.1 m. with additional sanding at the very top. The main secret of a high-quality result is the maximum compaction of the material. This work is carried out using special equipment. You can understand that the density is sufficient by whether traces remain after a person stands on top.
Correct shallow strip foundation: instructions
It is important to comply with all technical standards and regulations for construction work at all stages of the MZLF installation. It is necessary to strictly act according to the recommended order of actions, not skipping a single step. All this technology has been tested by many generations of builders, so we strongly do not recommend doing amateur performances. Below we will take a closer look at the main steps..
Preliminary stage: trench
After a detailed plan has been drawn up, you can proceed to the implementation of the project. First, remove the top layer of earth so that the remaining surface is level horizontally. Special attention is paid to this, because if the level is lost, then the construction can end in failure. After that, the site is marked on the site of the future house. With the help of pegs driven into the ground and stretched ropes, the outlines of a place for deepening appear. This is how we marked the boundaries of the trench that we will dig.
In the process of digging itself, be sure to clean up the corners and all intersections. The bottom is made relatively flat so that its line runs parallel to the ground. Further technology of a shallow strip foundation involves the creation of a cushion of sand (and crushed stone, if necessary) at the bottom. We described above how to do it correctly. We remind you that after pouring out the fraction, it should be tamped tightly. When the substrate is ready, its surface must be covered with an insulating material. It can be geotextile, roofing felt, or pouring a thin layer of concrete.
This step requires wood planks. Necessarily with a flat surface and a thickness of at least 2 cm. A dense shield is assembled from them, the edge of which protrudes slightly above the surface. It is important to make an impenetrable plane so that the solution cannot flow through them. If cracks and gaps are still formed, then they can be eliminated with patches or tow.
Reinforcement and reinforcement
Concrete is not a stable material when exposed to prolonged tensile loads. It can withstand pressure perfectly, but the impact of axial force can destroy the integrity of the structure. To minimize the risk of deformation of the base, it is reinforced with special rolled metal before pouring. Reinforcement occurs by creating a kind of skeleton inside a concrete tape, all the parts of which are firmly connected to each other. MZLF for a house without such hardening will be so susceptible to cracks and delamination that you may not even have time to lay out the walls. Therefore, this stage is considered mandatory. The knitting technology of the elements deserves special attention. At different parts of the foundation, the technique for joining parts may differ. Somewhere welding is permissible, but in other places it is necessary to tie the rods so that the structure retains a certain mobility and plasticity under force..
Fill in the solution
After you have prepared the formwork and installed the reinforcing frame, you should begin the process of concreting the base. The foundation (shallow tape) is poured without long breaks in one stage. If it is not possible to do everything in one day, then get ready for the fact that in the future, crevices may form between the layers. This can lead to a fatal result, up to destruction..
The first step is to cast the inner perimeter, and only then work with the outer. The mortar is fed at regular intervals so that the formwork fills evenly and smoothly. It is strictly forbidden to carry out the process of pouring concrete into one place and disperse it around the entire perimeter. Thus, maximum strength is achieved at any point. Then a process of vibrating concrete is required. If you do not carry it out, you can significantly lose strength. After the solution is poured, the surface should be protected from exposure to sunlight. To avoid cracks, the plane is periodically watered for several days. The first three days at least once every 4-5 hours. The next week the watering interval is increased to 8 hours.
The formwork is dismantled after 10-12 days, and the construction can be started when the brand strength is set. Since its solution will reach earlier than a month, and it can be checked using a non-destructive method, it is not always necessary to wait to continue construction. However, in general, haste in this matter can lead to negative consequences that will be hidden from view until the end of the construction. But after a while they will make themselves felt, which will unpleasantly surprise the owners of the house.
How to make a shallow strip foundation: waterproofing
In modern construction, there are two types of waterproofing technologies. Each of which is aimed at protecting a specific area of the MZLF.
Often it consists of several layers of roofing material, which are treated with bitumen-based mastic. The solution is placed between two sheets of material, and holds them together. This layer cake is laid both on the pillow and on the finished surface of the tape.
This is the treatment of the side planes of the base, which protects them from the effects of excess moisture. For this, various impregnations, coatings, or gluing materials are used. Recently, the most widespread are special impregnating solutions, which guarantee good adhesion and excellent results. It is important not to neglect such an important step as the installation of waterproofing, because the durability of the entire structure directly depends on this..
If the project includes the arrangement of the basement, then the insulation cannot be neglected. It is also worth doing it when building a house in harsh climatic conditions with cold winters and high humidity. The technology involves the use of such types of heat insulators as:
These materials have proven themselves not only in terms of heat retention, but also as excellent waterproofing products..
Completion of work
In the end, a few more manipulations are required. First of all, the sinuses are covered with absorbing fractions (sand, etc.). The operation should be performed both internally and externally. The second stage is to fill in the blind area, which does not allow water to enter the trench, it is recommended to insulate it. All sediments flowing down it are discharged into a special drainage system. There is no need to skip these steps so that all work does not come to naught due to moisture ingress.
In this article, we have analyzed in detail what a shallow strip foundation is. We hope that the information will be useful for those who want to build a house with their own hands. However, we will give a little advice. In practice, the difference in the cost of the work of hired people and the cost of erecting a building on their own is quite insignificant. If you count each of your working hours and set a price for it, it will not be so profitable to do the construction yourself. It is also worth considering that without proper experience there is a chance to make a mistake, and even more go into the negative. Before making a decision, we recommend that you familiarize yourself with our service for finding construction crews, compare the cost of services, and draw conclusions.