The organization of a quality entry into the territory of a private home is a critical stage of improvement, which is often underestimated until the first serious problems with the arrival of a car. Rightly done. screed provides not only comfortable movement of the vehicle, but also protects the underflood space from flooding with groundwater, and also prevents soil erosion under the foundation of the structure. Errors made at the stage of preparation of the base or selection of the concrete brand can lead to the formation of cracks after the first winter, which will require expensive and time-consuming repairs of the entire structure of the entry group.
In this article, we will analyze in detail the technological process of creating a durable concrete site, paying special attention to the nuances that are silent in construction stores. You will learn how to correctly calculate the thickness of the layer, why you need a compensation tape and why saving on the reinforcement frame in this case is absolutely not justified. Competent approach lintel And the entry group will allow you to forget about the puddles and dirt at the gates for years to come.
Before starting to purchase materials, it is necessary to conduct a thorough analysis of the soil and determine the level of groundwater, since the choice of the type of foundation for screed directly depends on this. If the soil is thick, then a simple pouring of concrete on the ground without preparation can lead to deformation of the plate in winter due to the forces of frost burrowing. That is why the preparatory stage takes up to half of the entire time of work, and it is absolutely impossible to neglect it.
Calculation of materials and preparation of the basis
The first step in any construction is an accurate calculation, which will avoid a situation where concrete ends in the middle of the process, and it is no longer possible to continue pouring due to the formation of a cold seam. For a standard 3-meter wide and 4-5-meter long entry, you will need to determine the exact volume of concrete, sand and crushed stone, taking into account the shrinkage of the mixture and possible losses during transportation. Concrete calculation It is produced according to the formula of the volume of the parallelepiped, but always a reserve of 5-10% should be laid in case of irregularities of the base or unforeseen circumstances.
The quality of the base directly affects the service life of the entire structure, so removing the fertile soil layer is a mandatory requirement. The plant layer contains organic matter, which over time bends, forming voids under the concrete slab, which inevitably leads to its sagging and cracking. The depth of the excavation depends on the type of soil and the planned thickness of the pillow, but usually ranges from 20 to 30 centimeters, which allows you to place all the necessary layers of the design cake.
⚠️ Warning: Never leave a fertile layer under a concrete platform, as organics will rot in 2-3 years, forming voids that will lead to the destruction of the screed under the weight of the car.
To strengthen the design and prevent slipping of the edges of the site, it is necessary to install formwork from a trimmed board or plywood treated with a hydrophobiser. Boards are fixed with pegs from the outside with a step of no more than 50-70 centimeters, so that the pressure of the concrete mixture does not squeeze the sides and does not violate the geometry of the product. Before pouring, the inner surface of the formwork is desirable to lay a plastic film, which will facilitate its dismantling and save the lumber for further use.
Technology of creating cushions and waterproofing
After the excavation of the soil, a multilayer cushion is formed, which takes on the load from the car and distributes it to the ground, preventing deformation of the upper layer. The first layer is laid geotextiles with a density of at least 200 g / m2, which separates the soil and bulk materials, preventing their mixing and siltation of the drainage layer. On the textiles is poured a layer of large crushed fraction 20-40 mm thick about 10-15 centimeters, which is carefully trampled vibrating or hand-tramming to the state of monolithic coating.
On top of the rubble is a layer of sand, preferably river or washed quarry, which fills the voids between the stones and creates a flat platform for laying insulation or reinforcement. The sand is shed with water and is also subjected to intense tamping until the footprints no longer remain on the surface. Tamming the base This is a critical process, as any remaining void will eventually lead to local failure of the concrete slab.
Waterproofing is performed using rolled bitumen materials or a dense polyethylene film with a thickness of at least 200 microns, the joints of which are glued with tape with overlapping at least 15 centimeters. The edges of waterproofing should go on the sides of the formwork, creating a kind of trough that will not allow cement milk to go into the ground and ensure proper hydration of concrete. In some cases, especially with high groundwater levels, it is recommended to use floatable waterproofing, which creates a more reliable barrier to moisture.
Use geotextiles between the soil and the rubble – this will prevent layers from mixing and drainage cushion silting, extending the service life of the entry for decades.
If you have severe frosts in your area, it makes sense to lay a layer of extruded polystyrene (EPPS) 50 mm thick on top of the waterproofing to prevent freezing of the soil under the site. Entry insulation prevents frosty bloating, which can push individual sections of the plate upwards, disrupting the level and integrity of the coating. The sheets of the insulation are laid apart, and the joints between them are also glued, creating a continuous thermal insulation circuit.
Reinforcement and installation of lighthouses
Concrete works perfectly for compression, but is extremely weak in tensile, so reinforcement is an indispensable element of the design, perceiving dynamic loads from the wheels of the car. For reinforcement of the entrance platform, a road grid with a cell of 100x100 mm or 150x150 mm and a rod diameter of 4-5 mm is most often used, however, for severe operating conditions, it is better to weld a frame from a valve with a diameter of 8-10 mm. The grid is laid with overlap in one or two cells and is connected with wire, forming a single plane.
It is critical to provide a protective layer of concrete around the reinforcement, for which the mesh is raised above the base on special plastic clamps or brick linings. Reinforcing frame It should be in the lower third of the thickness of the concrete slab, where the greatest tensile forces occur, but not lie on the ground, otherwise the metal will quickly rust and cease to perform its function. The distance from the reinforcement to the surface of the concrete should be at least 3-4 centimeters on all sides.
To ensure a flat surface and the necessary slope for water runoff, beacons are installed, as which profile pipes, wooden slats or special beacon profiles can be used. Lighthouses are set strictly on the level, taking into account the slope towards the drainage or soil, which is usually 1-2 cm per linear meter. Fixation of lighthouses is made with the help of small heaps of cement-sand mortar, which should completely dry before the start of the main work.
☑️ Preparation for reinforcement
⚠️ Note: Do not use wooden bars or trimming boards to raise the rebar, as they will rot, leaving voids through which moisture and oxygen will flow to the metal.
Preparation of concrete mixture and pouring
The quality of the concrete mixture directly determines the strength and frost resistance of the finished product, so it is strictly forbidden to save on cement or use expired material. For pouring the entrance platform, it is recommended to use concrete brand M300 (B22.5) or M350 (B25)It has sufficient strength to withstand the weight of cars and trucks. When mixing independently, it is important to strictly observe the proportions of the components: 2.4 parts of sand and 4.3 parts of crushed stone are taken for 1 part of the M500 cement.
The pouring process must be continuous to avoid the formation of cold seams, which significantly reduce the monolithic structure and can become points of beginning of destruction. The concrete mixture is unloaded into formwork and evenly distributed by shovels, after which bayoneting or treatment with a depth vibrator is performed to remove air bubbles. Vibration of concrete contributes to the compaction of the mixture and the release of excess air, which makes the structure of the material more dense and waterproof.
The successive alignment rule surface of the concrete is subjected to iron, which can be done in a dry or wet way to increase the wear resistance of the upper layer. With the dry method, a thin layer of pure cement is crumbled on the surface of freshly laid concrete and rubbed with a ironing device, creating a strong crust. The wet method involves rubbing cement milk, which is also effective, but requires more accurate observance of the start time of work.
The Secret to the Perfect Surface
To get a smooth surface without sinks, use a vibrator or long rule with a vibrator attached to it, which simultaneously aligns and compacts the mixture.
Concrete care and dismantling of formwork
Concrete gains its design strength within 28 days, but it is critically important to the first period after pouring, when there is an active evaporation of moisture. If the surface dries too quickly, the cement hydration process will stop and the material will not gain the stated strength, becoming loose and dusty. To prevent this screed should be regularly moistened with water or covered with a plastic film, which will retain moisture inside.
In hot weather, evaporation occurs very intensively, so water the site with water should be every 3-4 hours for the first 3-5 days, preventing drying out of the upper layer. Care for concrete It also includes protection from direct sunlight, which can cause uneven drying and the formation of temperature cracks on the surface. If the weather is windy, the rate of evaporation of moisture also increases, which requires more frequent moisture.
It is possible to remove formwork only after the concrete has gained sufficient strength, usually this happens in 7-10 days at an air temperature of +20 ° C. Early dismantling of the sides can lead to scraping of the edges of the plate, especially if the soil behind the formwork is wet and presses on the structure. After removing the boards, it is also desirable to treat the side faces with a hydrophobizator or bitumen mastic to protect against moisture.
| Parameter | Meaning/Description | Recommendation |
|---|---|---|
| Mark of concrete | M300 (B22.5) - M350 (B25) | Optimal for passenger cars |
| Plate thickness | 100 - 150 mm | Depends on the weight of the technique |
| Slope of the surface | 1.5 - 2 cm by 1 meter | For water runoff |
| Strength-building time | 28 days (100%) | Full load in a month |
Compliance with the temperature and humidity regime in the first 7 days determines 80% of the final strength of your concrete platform.
Deformation seams device
Deformation seams are necessary to compensate for the temperature expansion and compression of concrete, as well as to separate areas with different loads or pouring times. If the screed area in front of the garage exceeds 25-30 square meters or has a complex geometric shape, the presence of seams becomes a mandatory requirement of technology. The absence of such compensators leads to chaotic cracking of concrete in places of greatest tension, spoiling the appearance and reducing the durability of the coating.
The seams are cut with special equipment with a diamond disc 2-3 days after pouring, when the concrete has already hardened, but has not yet gained full strength. The cutting depth should be about one-third the thickness of the plate, and the cutting step depends on the thickness of the concrete and is usually 25-30 times the thickness of the plate. After cutting, the seams are cleaned of dust and filled with sealing materials such as polyurethane or thiocol sealants.
Particular attention should be paid to the seam of the adjoining, which is arranged between the new screed and the foundation of the garage or the existing pavement. This seam prevents stresses from being transferred from the new structure to older structures that may have different precipitation and loading histories. Compensatory seam It is filled with an elastic material that allows structures to move independently of each other without breaking.
⚠️ Note: Do not fill the deformation seams with rigid solutions or mounting foam, as they do not have the necessary elasticity and will lead to chipping of the edges of concrete at temperature deformations.
How do I fill the suture?
The best material to fill the seams is a polyurethane sealant that retains elasticity over a wide temperature range from -40 to +80 degrees Celsius.
Frequently Asked Questions (FAQ)
Can I fill the screed in front of the garage in winter?
Concrete pouring at negative temperatures is possible only with the use of special anti-frost additives and heating methods (thermoelectromates or heat guns). However, for private construction in winter it is better to refrain from concrete work, since the risk of obtaining low-quality, not gaining strength material is extremely high without industrial equipment.
Do I need to make a slant and in which direction?
The slope is necessary to do so that the water does not accumulate at the garage gate and does not flow inside. The direction of the slope should be from the garage gate to the outside, to the site or to the drainage system. The recommended angle of inclination is 1.5-2 cm for each linear meter of the length of the site.
How many days can I drive to a new location?
The car can exert a full load on concrete only after gaining 100% of the design strength, which takes 28 days under normal conditions. A passenger car can be put on the site after 14-20 days, but heavy equipment (trucks, concrete mixers) is better not to let before the end of the full month.
Which rebar is better to use: a net or rods?
For the standard entry of cars, a ready-made welded mesh with a diameter of 4-5 mm with a cell of 100x100 mm is quite enough. If heavy equipment or trucks are expected to arrive, it is recommended to use a knitted frame of reinforcement with a diameter of 10-12 mm in two layers or one powerful layer.