In the process of erecting any building with your own hands, the most important stage is the competent and high-quality installation of the foundation. This also applies to rubble base, which has high strength and reliability. So that mistakes in the construction of the foundation do not cause cracks on the walls and heat loss from the heated rooms, some nuances should be taken into account.
What is rubble stone
Fragments of natural rocks of specific dimensions and shapes are usually called rubble stones.
The rubble stone is the debris of various natural rocks
They are formed during the production of crushed stone during fractionation. In most cases, sorting and crushing complexes are used for production. However, quite often the stone is also taken manually, so the cost of such a stone is very different.
Given the diversity of species, rocks and groups of similar stones, it can be used in private and industrial construction, architecture, and landscape design. In addition, rubble stone has excellent characteristics in terms of environmental friendliness.
In order for the foundation of this material to be of high quality and durable, you should choose the right stone.
For the foundation device, you can use stones that meet the following criteria:
- The dimensions of the stone should be approximately equal to 20x25 cm. Too large stones will reduce the strength of the foundation, and the use of small stones will increase the consumption of cement mixture.
- Stone with noticeable cracks can adversely affect the integrity of the surface, especially some time after the start of operation.
- Contaminated material does not adhere well to the building mixture, but this nuance can be corrected. To do this, you need to wet the stone immediately before pouring the concrete solution.
- It is necessary to check the material used for strength. This is done with an ordinary hammer. If a stone crumbles during an impact with an instrument, this indicates its poor quality. If the stone remains intact and makes a loud sound when struck, then the cobblestone is suitable for making the base.
Careful selection of stones improves the waterproofing of the building and extends the life of the foundation.
Quarry stone base
The construction of rubble stones has practically no differences from its counterparts in concrete. The base is in the form of a tape or on poles. The base can be stepped, gradually expanding or have the same width in all parts. However, unlike reinforced concrete foundations that can work on bending, a foundation made of rubble stones will only absorb compression loads.
In order for the base not to be destroyed by compressive loads, it will be necessary to supplement the laying of the buta with a reinforced concrete structure. For example, a reinforced concrete belt can be arranged on top of the masonry from buta.
Foundation made of rubble stone, supplemented with reinforced concrete belt
You can also make reinforced one-piece pillow for support, on which the rubble base will be made in the future.
By the method of manufacturing the structure, one can distinguish:
- The rubble foundation. It is carried out on a masonry mixture of individual stones, which must be adjusted to each other. This method is often used in individual construction. Despite the fact that the complexity of the work is high, the cost of materials will be minimal. First of all, the soil is compacted with crushed stone, then rubble stones are adjusted to each other and fixed with a solution. In this case, the formwork can not be used.
The rubble stones are laid on the masonry mortar. Formwork can not be used
- The base of rubble stones by pouring. In this case, the soil is compacted with crushed stone, formwork is installed, after which the rubble stones are placed on the building mixture.
The soil needs to be compacted with crushed stone, then install the formwork and put rubble stones on the mortar
- Concrete base. It is made of cast concrete with the addition of large inclusions (concrete with rubble stones). It will be necessary to compact the soil with crushed stone, and then pour a special mixture, which contains rubble stones. Between the fill layers, fittings should be installed.
The base of butobeton, which is poured into the formwork and reinforced with reinforcement
A concrete base has the following advantages:
- The manufacture of the base can be done independently on any soil.
- The structure will be strong, so it is possible to erect multi-story buildings on it. The total load should be calculated when designing the house, so that in the process of constructing the foundation it was possible to take into account the weight of the entire building.
- For construction work related to the manufacture of concrete base, you do not need to have special skills and large equipment. All work can be performed even by a person who has superficial knowledge in the field of construction work.
- Natural stones have high resistance to low temperatures, floods and groundwater. This parameter allows you to build this foundation on almost any soil.
- Rubble stone is relatively inexpensive, so it is often used by private developers. However, do not forget that if your region does not have such stones, then their cost can increase several times due to delivery.
The disadvantage of this base is that the foundation may freeze during the cold season. To exclude negative consequences, it will be necessary to lay the material for thermal insulation from the outside of the base during the construction process. Only in this way can heat be saved in the building.
Another disadvantage is the high complexity of the work. Stones that will be used for masonry will need to be processed and sorted manually. This significantly limits the use of bases made of similar material. It is advantageous to construct such structures only for small buildings.
Processing a buty cane is a time-consuming process, which is a significant drawback of the foundation of this material
The concrete foundation is also made of large stones, which are mounted on a compacted surface. Depending on the soil, the base from buta can either be made using formwork, or located directly in a pit with sheer partitions. Most often, boulders up to 35 cm in size are used. These can be fragments of the following rocks:
- other rocks that have similar properties.
A concrete base differs from a concrete base in that it is made from the same mixture from which concrete is made. However, instead of crushed stone, a brick fight or rubble stone is added to the composition of the solution. It is necessary to lay the concrete base in layers - first a layer of the mixture with a thickness of 10 cm, after which the filler is 17–20 cm thick, etc.
Scheme of a concrete foundation with a designation of the elements used
You will need to arrange a sand pillow, which will make it possible to evenly distribute the loads from the building. It is important to pay attention to the composition of the soil. If the soil is able to filter groundwater well, then adding soil will remove excess moisture from under the base and remove some of the load from the main building.
However, if the structure is located on clay soil, which practically does not filter water, the backfill should be minimal. You can also abandon its device so that a pocket is not created in which moisture can begin to accumulate, washing away the soil. In winter, this can lead to an increase in heaving.
In the process of building a foundation made of rubble stone, you can encounter the following difficulties:
- Acquisition of finished stones in processed form. If it is not possible to pick up sandstone from the nearest quarry and process it manually, then the stone will need to be delivered to the construction site. He is quite loose, so delivery may be difficult. Accordingly, it is advisable to erect such a foundation in territories that are located close to deposits of building stone. If there are no deposits, then the cost of the purchase and delivery of the material will be substantial.
- Safety regulations. The rubble stone has a large weight, and there are sharp parts on its surface, so work with it should be done with care so as not to get hurt.
- Stone distribution and trench filling. To build the foundation, you need to have a large number of stones of various sizes and shapes, so you will have to first organize their reserves.
- You can make the foundation exclusively in the warm season, otherwise the concrete solution will not be able to dry. After a few years, due to the weight of the walls, the mixture may sag, as a result, cracks will appear in the bearing walls. This may result in the destruction of the main building.
Ribbed rubble base
The standard tape base from buta is made 1.6 m high, and a reinforcement belt is installed in the upper part. If a high-quality sand cushion with drainage or a durable arm belt is made, then the height can be reduced.
The base of the buta is usually laid below the depth of freezing. Concrete must be grade M300 or higher. The base must be placed at least 30 cm above the soil level. A base will be located above.
The scheme of the tape rubble foundation with the designation of all elements
The base is erected from rubble stones or a variety of buta - limestone, which is mined in quarries. It is important to skirting, this process allows you to grind the material so that it is weighing up to 30 kg. Cobblestone can be broken as follows:
- Using a marker and a ruler, mark the necessary dimensions.
- You need to evenly stretch the cord and press into a piece of chalk with an incision. Then, at the designated points on the cobblestone, pull the cord and release. Due to the impact on the boulder, the chalk will leave an imprint.
- On the mark made, you need to install a chisel and drive the tool 3-4 cm into stone. For hammering, you can use a hammer. Shocks should be elbow.
Cobblestone can also be split along the seam, which can form naturally. To do this, a chisel should be installed in the seam, and then move it along the crack with a hammer. To identify a crack, you need to find a depression or kink of a dark color.
Concrete foundation: construction technology
The base of concrete is built in several stages:
- Digging a trench and installing formwork.
- The device cushions of masonry mortar and reinforcing bars with a height of 30 cm
- Installation on the pillow of the base of buta.
Before installation, the boulders should be moistened in a liquid so that they retain moisture and can better adhere to the masonry mortar.
The rubble stone is placed with a gap of 3-5 cm. It is not allowed to mount boulders close to each other.
The long side of the cobblestone is called a spoon, and the short side is called a poke. Each row contains pokes that alternate with spoons. This is the masonry technology.
When laying, use a sledgehammer, hammer or other similar tools. The thickness of the masonry is generally 60–70 cm. For plasticity, a small amount of clay can be added to the mixture.
Technologies for installing stone can be as follows:
- "Under the bracket";
- "Under the scapula";
- "Under the fill."
Types of rubble masonry: a - “under the scapula”; b - under the "bracket"; in - in formwork
“Under the shoulder” boulders are placed like this:
- On a previously prepared surface, lay a series of pokes dry.
- It is necessary to ram the stone and fill the voids with crushed stones.
- Next, fill the masonry mortar.
- Lay out the spoon row with the longer side. The thickness of the first two rows should be 30 cm or less. Cobblestones must be selected so that the rows are almost the same in height. To check, you need to install beacons with a cord.
In the process of masonry, it is necessary to ensure that the cobbles do not touch each other anywhere without a building mixture. The need to install the formwork is determined on the basis of how smooth the walls of the base should be for further finishing.
To build such a foundation yourself, you will need to prepare:
- a shovel;
- rubble stone;
- Shank with a sharp end;
- a hammer;
- roulette wheel;
- wood shields;
- racks for fixing parts;
- crushed stone;
- roofing material;
- nails or screws;
- building level.
Masonry for pouring should be carried out in the formwork. In the process of laying, you need to use a vibration seal. Using this tool, you can increase structural strength by 40%.
Vibro-compactor allows to increase the strength of the base made of rubble stone
Stones do not need to be carefully selected. Masonry sequence:
- The trench and foundation are being prepared, which need to be covered with coarse sand and compacted.
- Masonry of a row of rows is carried out. Then crushed stone is poured and the surface is poured with a building mixture.
- One more row is laid - spoonful. The seams between the stones are filled with rubble. The stones are compacted and compacted.
Work should be carried out as usual, but at the end it is necessary to cover the surface with a plastic composition with a cone draft of up to 5 cm. The layer should be 50-60 cm. The mixture should be compacted with a vibrator until it completely penetrates the masonry rows.
Masonry "under the bracket" requires the selection of stones of the same height. To do this, use the template. It is important to regularly check the location of the bases and corners of the masonry. This can be done using the level. You should also ensure that the cobblestones do not move during the laying process. The laying is carried out with dressing of seams.
For such a base, the ideal dimensions of the stone are 20x30 cm. The size is calculated by the following formula: cobblestone width = 1/3 of the base width.
The concrete base for a private house is built on the same principle as the foundations of other types. It is only important to observe a certain sequence of actions. The first step is to complete the preparation work:
- It is important to determine the type of soil. It can be sandy, rocky, marshy, etc. It is also necessary to determine the depth of soil freezing in a particular region.
- The construction site must be cleaned of debris. Trees and bushes should be cut down, and then remove the turf. The surface must be leveled to the maximum. To do this, in elevated areas you need to remove the soil, and in the lower - to add. Further, uniform distribution is performed. A layer of land needs to be tamped.
You will need to clean the area from debris, and then level it
- The next step is to do the markup. Pegs should be placed on the territory in the corners of the future building. Between them you need to pull a rope or cord. This will be the outer boundary of the foundation. In the process of marking from time to time, you should check the sides, as well as the diagonals of the building, with a tape measure. They must match.
First of all, in the corners of the future building, you need to arrange the pegs, and then pull the rope between them
- Using a manual method or using technology, you will need to dig a trench for the foundation around the perimeter. The width should be chosen on the basis of the estimated, in addition, you need to add a small volume for the installation of formwork and insulation boards.
You can dig a trench manually or using large equipment
- If in the process of digging a hole below the freezing depth groundwater will occur, a drainage system must be set up.
If underground water occurs when digging a pit, a drainage system must be set up.
- When the pit is ready, a sand pillow with a maximum thickness of 10 cm should be arranged at its bottom. The pillow will need to be moistened and tamped.
The sand pillow needs to be moistened and tamped
- Sand cushion covered with roofing material. At this stage, you will need to horizontally waterproof the masonry from the buta.
After laying the sand cushion, the base must be waterproofed
Frame mounting and pouring process
To fill the concrete, you will definitely need to make the formwork of wood. In this case, the requirements for its strength will be increased. To install the formwork, you must perform the following steps:
- Assemble a structure from battens or plywood. The height of the frame must be at least 250 mm above the soil.
- Install auxiliary fixation struts and spacers around the perimeter of the base, if you plan to make the frame more than 250 mm high.
If the formwork has a height greater than 250 mm, additional racks and struts must be installed
- Pull the rails from the plywood sheet or battens between the bars at the top so that they are not damaged. Parts can be fixed with nails or self-tapping screws.
- Make sure that there are no gaps between the racks and the shields of the frame. Otherwise, the mixture may leak out. To avoid this, you need to cover the walls of the frame with a film of polyethylene or roofing material.
After the formwork is built, you can begin to pour concrete mortar. Sequencing:
- Filling begins with laying a layer of a building mixture with a thickness of about 250 mm. It must be evenly distributed around the perimeter of the pit with a shovel. A shovel is also used to remove air bubbles from the solution. Next, a rubble stone must be drowned in the mixture layer. The size of the cobblestones can be different, however, it should not be more than 1/4 of the width of the structure.
In the process of pouring concrete, stones should be heated in the mixture
- After that, the structure of reinforcing pins is mounted.
To strengthen the foundation, you will need to install a frame of reinforcement
- The first layer of the mixture should dry. The second layer can be applied only after the first has dried. The thickness of this layer should be approximately 250 mm.
- Cobblestones need to be drowned in masonry mortar at a distance of about 50 mm from each other. They should not be in contact with each other. Their upper parts should remain on the surface, without mixture.
Stones should be 50 cm apart
- To strengthen the structure, you will need to install another frame of reinforcing pins.
- Subsequent layers are laid in the same way, however, the last layer should completely hide the sharp parts of the rubble stone. Otherwise, masonry work will be difficult to perform. The thickness of the screed for leveling should be a maximum of 150 mm.
- The top layer of the solution needs to be covered with a film of polyethylene or moistened with water from time to time. This will not allow the concrete mortar to dry quickly and crack. The mixture dries in about 28 days. Complete hardening of concrete will occur in 36 days.
To prevent the concrete from cracking, it must be covered with plastic wrap
The base of concrete should consist of 22–25% of rubble stones and 77–80% of concrete. The advantage of the concrete base over the rubble base is that the structure can be strengthened by a frame of reinforcing pins, which is installed between the stacked layers.
It is important to know: if the base is planned to be placed on heaving soil, then it should have an extension in the lower part. In view of this nuance, formwork should also be made.
DIY rubble base
This type of foundation can be performed in two ways:
The base can be constructed with simultaneous cladding with bricks or blocks of concrete. Facing can be done on one or two sides (for example, if the private house has a basement).
In the first case, work must be done by placing cobblestones in rows. The elements are fastened together with the help of a clay solution. To reduce the thickness of the seam and make compacted laying, boulders should be cut with a buchard or pickaxe. As in the case of brickwork, the dimensions of the structure must be set with a stretched cord or rail.
The base of rubble stones by pouring should be done in the formwork. The sequence of actions is as follows:
Formwork is arranged on the one hand to the entire height of the base, and on the other - by 55-60 cm. In the process of filling the frame needs to be increased.
Unlike concrete, stone should be laid so as to completely fill the space of the frame. There should be no gaps.
In height in one layer there should not be more than one cobblestone.
The laid layer must be shed with a cement mixture so that the formed cracks are filled to the maximum.
- When the whole mixture covers the boot, you can start laying the next cobblestones. Continue until the frame is full.
If the work will be carried out in the pit, then the masonry can be performed as separate sections up to 1 m long, and being in the masonry array. In the first case, the builder should be located in the end part of the structure.
How to lay a base of rubble stones
Stones must be installed so that a dressing is formed. You should select elements with suitable parameters so that they can fully occupy the free space between nearby stones. For fixing, you need to use a cement-sand mixture of consistency of thick sour cream. Cement must be at least M300 grade. Apply the solution with a trowel. Excess mixture must be eliminated, and the seams should be sealed with a seal.
A mixture of cement and sand should be used to fix the stones.
The cracks between large cobblestones need to be filled with small ones, but this cannot be done too often - in the process of construction work, try to use stones of the same dimensions. To improve the appearance of the masonry, the stones can be brushed.
It should be remembered that the base must be insulated.
The foundation is recommended to be insulated inside and out, otherwise a private house can be cold
To do this, with the help of bitumen, extruded polystyrene foam is glued underground to the parts of the foundation. To facilitate installation during the excavation of the pit and the manufacture of the frame, you need to leave free space.
After the insulation is made, backfilling should be done with soil cleared of stones and construction debris.
Part of the rubble base, which is located above the surface of the soil, is recommended to be done simultaneously with brick lining. Fixing the brick lining with a part above the ground is carried out by laying a row of bricks that need to be laid on a half brick in rubble masonry. This should be done every 5-6 rows.
Facing scheme of rubble base: 1 - insulation, 2 - rubble stone, 3 - brickwork
If during the manufacture of the foundation it is planned to stop work for more than 24 hours, then in order to protect it from drying out in warm weather, the already made part of the base must be watered with water at least 3-4 times a day. You can also cover the base with glassine or polyethylene film.
Proportions of ingredients for masonry mortar
The service life of a private house depends not only on the construction of the base. Of great importance is the building mixture. Properly selected materials for mixing the mortar play an important role in the successful construction of the structure and long-term use of the main building.
To knead the building mixture, you need to prepare:
- cement grade M300 – M500;
- large concrete mixer or tank;
- clean sand from a river or quarry with medium grain;
- a shovel;
- crushed stone with a maximum diameter of 30 mm.
Before pouring, you will need to prepare a concrete mixture and calculate the required amount. The sequence of actions will be as follows:
- In a mixer or concrete mixer, pour cement and sand in a ratio of 1: 3. The elements must be mixed until a homogeneous dry mixture is obtained.
- In small portions, 5 parts of fine gravel should be added to the mixer. It is important to mix until the crushed stone is hidden by cement and sand.
It is necessary to mix until crushed stone is completely hidden by cement
- Add water a little. The density of the mass must be controlled from time to time. Optimal - the consistency of sour cream.
The volume of the mixture depends on the amount of stone. To get an accurate calculation, you should contact the specialists who must investigate the soil in the territory of the construction work. However, there are general provisions in this matter that will determine the approximate volume of the masonry mixture.
The specific gravity of the solution should be approximately 40% of the number of stones. Such an amount will make the foundation more durable.
In each concrete brand, the proportions of the ingredients may vary. To build a one- or two-story building on the base, concrete of the M300 brand is suitable. The grades above should be used for the construction of load-bearing structures with significant loads.
Table: proportions of ingredients depending on the brand of concrete
|Concrete grade||Mass, sand / crushed stone, kg (per cement unit)||Volume, sand / crushed stone, l (per 10 l of cement)||The amount of the finished mixture of 10 l of cement, l|
|M200||2.8 / 4.8||25/42||54|
|M250||2.1 / 3.9||19/34||43|
|M300||1.9 / 3.7||17/32||41|
|M400||1.2 / 2.7||11/24||31|
|M500||1,1 / 2,5||10/22||29th|
The higher the quality of the concrete mortar, the more cement is required and less crushed stone and sand. However, the higher the quality of cement, the lower its costs will be when preparing a mixture for the manufacture of the base.
Before proceeding with the manufacture of the base, you need to calculate the desired volume of the mixture. The amount of solution depends on the dimensions of the formwork. As an example, we will consider a frame 10 m long, 8 m wide and 2 m high. First, the perimeter should be calculated: 2 x 10 + 2 x 8 = 36. Then, the obtained value must be multiplied by the height and width of the casting: 36 x 2 x 0 , 2 = 14.4 m 3 . A more complex foundation will require more careful calculation.
Video: DIY rubble foundation
In the manufacture of concrete base there are no particular difficulties. If you prepare everything you need, then you can easily build such a foundation on your own.