Cement screed, or as it is also called “traditional screed,” is rightfully considered the most reliable and economical in terms of monetary costs. It is very often used in premises for various purposes, for example: in apartments, country houses, cafes, offices, shops, garages and so on. The basis of such a cement-sand screed is a dry mixture (sand concrete) M-150 or M-300. How much of this mixture is needed for the screed? Calculation of sand concrete for floor screed presented below.
Calculation of mixture for floor screed
First of all, it is necessary to measure the room. By using laser level and tape measures, we measure the entire room and see where there are differences. We calculate how many m2 we need to make, then we count all the building materials needed for the work. It is especially important to correctly calculate the amount of dry mixture required.
Example:
We need to make a screed in a room with an area of 25 m2 thick 5 cm
.
On 1 m2 with thickness 1 cm goes away approximately 22 kg mixtures.
Multiply 5 cm screeds on 22 kg mixtures (5 x 22 = 110). Means 110 kg will weigh 1 m2 our 5 cm screed.
Now 25 m2 multiply by 110 kg mixtures (25 x 110 = 2,750). Means 2 750
kg a screed of 5 cm will weigh on an area of 25 m2.
Next 2 750
kg divided by the weight of the bag of dry mixture (2,750 kg: 50 kg = 55). Means 55
bags of mixture weighing 50 kg we'll need it.
The rest of the material is easily calculated based on the floor area.
To install the screed we will need:
- Profile for beacons;
- Dry mixture M-150 or M-300;
- Primer or concrete contact;
- Reinforcing mesh (used on a loose basis);
- Edge tape;
- Vapor barrier film (on the second or third day, you need to pour water on the screed and cover it with film for 7 days). The process can be repeated again.
Note that a higher grade of mixture indicates that the mixture contains more cement. Pure cement is marked M-500. Therefore, the higher the brand of dry mixture, the stronger the screed will be.
The cement-based sand screed hardens (gains strength) within 30 days, during which time only tiles can be laid on it, the rest of the floor coverings can be installed after 30 days. The fact is that the moisture that is in the screed will be absorbed and ruin the coating. If the thickness of the screed is more than 5 cm, then we recommend using expanded clay for the bottom layer. It is lightweight and allows you to remove total weight screeds, therefore, the load on the floor slab will be reduced.
When sand concrete for floor screed and other materials have been calculated and delivered to the site, the master begins work. First of all, the floor slab is prepared for pouring the screed, that is, it is cleared of all kinds of debris and primed. When the primer dries, attach it to the wall edge tape, it is needed to relieve the tension of the screed. We install beacons with a pre-measured height. If it is necessary to use reinforcing mesh, it must be raised and secured just below the center of the floor screed itself.
Prepare the mixture: 10 kg of dry mixture should be poured into 0.8 - 1.3 l clean water and stir until homogeneous mass no lumps construction mixer. The resulting mixture must be used within 1 hour.
Pour the prepared mixture and pull it together with an even strip along the beacons until the room is completely filled. 2-3 days after pouring the screed, it must be spilled with water and covered with film. Let the screed stand for 30 days and the screed is ready for further use!
One of the main types of construction repair work are cement screeds that can serve different purposes and are structurally very different from each other.
But for all of them, the main main parameter is the consumption of cement for the screed.
Scheme cement screed floor: 1 - Base, 2 - Sand layer, 3-4 - Layers, 5 - Concrete screed, 6 - Tile adhesive, 7 - Tiles, 8 - Separating edge layer.
Main functions and types of screeds
Let's start by looking at the main functions of the screed
- leveling the surface under flooring(parquet, linoleum, laminate);
- improving the heat and sound insulation properties of the ceiling: absorption of household, impact, air noise and insulation of floors;
- concealment of pipelines and utilities;
- distribution of heat energy in floors with built-in heating;
- giving coatings a given slope.
- by design: single-layer (one layer for the entire thickness) and multi-layer (includes heat-, hydro- and sound-proofing layers);
- by composition: cement-sand, concrete, self-leveling synthetic resins and mosaic (on top concrete screed), gypsum;
- according to the method of fastening to the ceiling: bonded screeds (directly bonded to the base), on a separating layer (additional waterproofing layer) and “floating” (laid on top of heat and sound insulating material).
In each of these types, the consumption varies depending on the selected brand of binding material, its quantity per unit of solution, and the technology for preparing the mixture. Failure to comply with certain regulatory rules and instructions in these matters can lead to delamination of the mixture, cracks on the surface, loss of large pieces of screed and the formation of voids.
Calculation algorithm
By building regulations for screed in kilograms is produced per cubic m (1m3) of solution. Sometimes it is more convenient to calculate the amount of binding material per cubic meter of sand. To count total number mixture, you need to know the total need for solution (in cubic meters) for work surface. Let's look at the screed using examples.
- 1 m3 of solution. Single-layer cement-sand screed. Recommended brand of mortar M200 (cement/sand ratio 1:3);
- for 1 m3 of M200 mixture, according to the standard (see table), 410 kg of M500 cement is required;
- let the surface area be 12 m2, and the thickness of the screed be 30 mm. Calculation of the volume of the solution (multiply the surface area by the thickness): 12 * 0.03 = 0.36 m3;
- cement consumption: 410 * 0.36 = 147.6 kg, or 3 bags of 50 kg (regular packaging). This quantity is one part;
- calculation of sand and water. To receive ready mixture add 3 parts of sand (3 * 147.6 = 442.8 kg - 9 bags of 50 kg) and 0.5 parts of water (147.6 * 0.2 = 73.8 l - 7.5 buckets);
Add water to the well-mixed dry mixture in small portions, constantly stirring the solution with a trowel, spatula or shovel. So, for a room with an area of 12 m2 and a screed 3 cm thick, we will need 3 bags of M500 cement, 9 bags of sand and 7.5 buckets of water. Cement standards for various brands of mortar can always be found either in the instructions supplied with the cement on the packaging or bags upon purchase, or on the Internet pages in the codes of practice of the joint venture “Preparation and use of mortars” (see table).
When using concrete, fillers are added to the known components cement, sand, water: crushed stone, gravel or lime paste in various proportions and the calculation is made according to the specified algorithm.
Note that to improve waterproofing, sand and cement for screeds are used together with bitumen paper, roofing felt or polyethylene film (no more than 300 microns thick). Increased strength is provided by cement for screeds laid on a reinforcing mesh with cells of 100 * 100 and 150 * 150 mm, and good soundproofing properties are provided by the following materials: mineral wool, polystyrene foam, polystyrene, polyurethane, laid first on the subfloor.
Floor screed consumption per 1 sq.m of material, as a rule, it is necessary to calculate using specialized construction equipment.
Cooking process cement-sand mixture requires precise adherence to the proportions of all necessary components. To make the solution you need:
- Cement. It is recommended to use Portland cement M500 d0 or M500 D20
- Washed or sifted coarse sand without large inclusions and various kinds of residues. It is advisable to use sand with a fraction of 2.5-3mm.
- Water . It is not recommended to take from unverified sources due to possible contamination domestic wastewater and small natural particles. Ideal option- non-chlorinated from the well.
- Fiber fiber . The approximate calculation is 40 grams per 1 square meter mortar 50 mm thick.
- Initially Cement and sand are mixed together in proportions from 1/4.5 to 1/6 (depending on the requirement for brand strength), after which water with fiber fiber is added to the dry mixture in portions.
How to calculate material consumption for a semi-dry floor screed
The calculation of floor screed, cement, sand and fiberglass is carried out in the following way:
- Per 1 square meter with a thickness of 50 mm, on average we need 15 kg of cement, 0.065 m3 of coarse sand, 2-3 liters of water and 35-40 grams of fiberglass.
- Accordingly, if you have an object with an area 100m2, then for installing a semi-dry screed with a thickness 5cm you will need 100 * 15 = 1500 kg of cement (30 bags of 50 kg each), 0.065 * 100 = 6.5 m3 of sand, 35 * 100 = 3500 g or 3.5 kg of fiberglass. It is also worth taking into account the cost of plastic film and damper tape.
In this way you can protect any volume at any thickness and, as practice shows, this is the most best option calculation.
If it is necessary to add a plasticizer, Superplast is added at the rate of 50 ml per 1 sq.m.
To determine the readiness of the solution, it is necessary to squeeze a small amount of the mixture in your hand; if during the compression process a small amount of moisture is formed, but a strong lump is obtained, then the solution is prepared correctly and is ready for screeding.
If you are making a semi-dry floor screed with sand concrete M-300, then the calculation of the amount of sand concrete will be as follows:
Necessary multiply the area of the object by the thickness of the layer, multiply by 18 and divide by the weight of the bag. For example, if you have an apartment of 50 m2 and the middle layer of semi-dry screed is 6 cm, then the calculation will be as follows 50m2*6cm*18/40kg = 135m, but since the bags are constantly not filled, our advice is not to divide by 40kg, and by 38kg. It’s better to have a little more than to run out and buy it later!
Sand concrete consumption calculator for floor screed
Repair is a costly business, and you don’t want to overpay for materials that will later turn out to be unnecessary. Not all people turn to professionals for help when carrying out repair work. And when a person, without proper education and experience, gets down to business, difficulties may arise.
Why do you need an online calculator?
When replacing the floor covering, before starting work, it is necessary to screed the floor. The durability of the floor covering depends on the quality of the screed. As a rule, the screed is made from a solution of sand and cement mixed with water. A thin layer of mortar is designed to protect thermal insulation and sound insulation from the weight of objects installed on the floor.
To save money cash, you need an accurate calculation of the initial amount of materials to prepare the solution.
An online calculator for calculating sand concrete and other materials for floor screed is designed to correctly calculate the proportions of cement, sand and water. With its help it is easy to prepare a solution that will not be affected mechanical damage and temperature changes, and will fully comply with the necessary requirements for the quality of the mixture.
How does an online calculator work?
Quantity calculation Knauf mixtures, expanded clay and cement are produced using several formulas, but they are difficult to use and errors can be made in the calculations. It is much more convenient and easier to use a special online calculator to calculate the consumption of materials per 1 m2 for floor screed.
To calculate correct proportion, you need to know several parameters: the length of the room, the width of the room and the height of the screed. The length and width can be measured using a tape measure. How to determine the required height?
According to SNiP rules, the minimum screed height should be 40 mm. But for different types Underfloor heating has its own nuances. So, for electric heating the thickness should be 50 mm, and for water heating - at least 70 mm. At the same time, to fill the floor in rooms that do not require thermal insulation, it will be enough to fill a screed with a height of 30 mm.
Having determined all the parameters in meters, you need to enter them in special form and click the “calculate” button.
The required values for cement, sand and water will appear on the screen, when mixed, you can obtain the ideal solution for pouring floors. The amount of cement and sand is indicated in kilograms, and the amount of water is indicated in liters.
Thus, by taking the specified amount of materials, you can prepare a solution for the screed without spending extra money and saving time.
In order to level the floor as best as possible, use. And some kind of floor covering is applied on top of it. To avoid excess consumption of material, it is necessary to make certain calculations that will help save a lot of money. But not many people know how to calculate a floor screed.
Solution distribution
In order for the calculation to be correct, it is necessary to take into account all the features of the screed, so we will consider them. The solution with which the rough layer will be poured must be distributed over the entire surface of the room in such a way that it is ideal. After all, the base is often made not only with defects, but also at the wrong angle.
Here you need to know that after the solution has completely dried, its volume can decrease significantly. And also unpleasant surprises may arise in the form of uneven drying. This can cause the floor to crack and begin to peel off. But this process can be changed. To do this, many professionals generously moisten the damaged areas with water.
For use, the thickness should be 40 mm, for use - 50 mm, and for water - from 70 to 100 mm. So take this factor into account when making calculations.
Based on the rules of SNiP, the minimum height of the filling solution should be 40 mm, but those that do not require increased heat, for example, a pantry, hallway and the like. In these rooms, you can reduce the height of the base to 30 mm, but not lower, otherwise the strength and durability will leave much to be desired.
Video: DIY floor screed installation
If you want to increase, then you will need to fill twice. The first layer is 20 mm, the second - more than 20. Insulation or material that promotes sound insulation is placed between such a screed, and a special film is placed on top of them.
Compound
The components and consistency of the solution should also be calculated in advance. The composition includes not only cement, water and sand, but also various additives that perform specific functions. Although most often they are used to reduce the cost of expensive cement.
For example, polystyrene in granules or expanded clay, which also has insulating properties, can be added to the solution. Whatever filler you choose, always expect that percentage filler to cement will be 50% to 50%. Only in relation to cement, and not to other components of the solution.
Level determination
First of all, in order to screed the floor, it is necessary to set the zero level. An ordinary water or laser device will help with this: a level. You will need to move it around the perimeter of the room, while fixing it with marks, which you will subsequently need to connect with lines. This is how the horizontal plane is revealed.
From the line, that is the same zero level, measure the distance. Write down all the indicators and determine the maximum height. Yes, most small value will mean the highest point and, accordingly, vice versa.
Based on these data, you must calculate the height of the screed. For example, the highest height is 1 cm, and the lowest is 0.7, which means the difference between them (1-0.7 = 0.3) will be the average thickness that needs to be taken into account. The layer will be 3 cm, which means 3+0.3=3.3. In total, you buy the mixture at the rate of 3.3 cm per width.
How to calculate the amount of sweep for a floor screed
Each package of the finished mixture must indicate the average consumption, which should be used as a guide. Let's say you need to fill 20 mm of base for the entire volume, the consumption is 2 kg/m² with a thickness of 1 mm. It follows from this that you need to multiply 20 by 2, which turns out to be 40 kg per 1 m². Next, we calculate the amount of mixture per room area: 40 × 20 (area) = 800 kg. Typically, dry mixtures are packaged in bags of 50 or 25 kg, so we divide 800 by 50 (25) and get 16 (32) bags.
Consumption
Method one
In fact, it is quite simple and to implement it you need to adhere to certain formulas. For example, you need to make a screed in a room of 20 m², and the base should have a thickness of 25 mm. You need 20×0.25=0.5m³ of solution.
Since cement is mixed with sand in a ratio of 1:3, we can calculate the amount of each. To do this, we divide 0.5 by 4, we get 0.125, which we multiply by 3. As a result, it turns out that we need 0.125 cubic meters of cement and 0.375 cubic meters of sand.
If you are confused by the formula in cubic meters, you can convert this to kilograms. Knowing that 1m³ of cement is equal to 1300 kg, we get the following result: 0.125×1300=162.5 kg of cement.
Now you know how to make the calculations correctly, just keep in mind that when the solution is diluted and when it dries, it decreases slightly in volume, so buy the material with a small margin.
Method two
There is another calculation method. To do this, you need to calculate the amount of dry cement mixture. In general, the average density of cement screed is 1800 kg/m³, so if you don’t need to add fillers, then calculating this is as easy as shelling pears.
The area of the room must be multiplied by the thickness of the layer. Then, when the volume is determined, calculate the required dry weight of the solution.
If you add filler, then subtract the amount of additive from the total volume, and then convert it to dry weight.
If there are differences
IN modern world, many people use different ones in one room, and in this case it is worth thinking about ensuring that there are not too large differences during installation. Therefore, it is very important to calculate where the joints will be so that the floor is on the same level. After all, you must agree that the thickness of tiles differs from laminate, linoleum, and so on.
In order to avoid this, you need to correctly calculate the floor screed. Let's say mastic, glue, plywood and parquet are used, and for ceramic tiles just the glue and the tile itself. That is, the thickness is completely different.
We do the calculation in the following way:
- Parquet - 15 mm, glue - 1 mm, plywood - 10 mm and mastic - 2 mm. In total, it turns out to be 28 mm.
- The tile is 10 mm and the adhesive is 5 mm. This is equal to 15 mm.
- Further, 28-15 = 13 mm, which means that at the junction of two materials the difference should be 13 mm.
Experts with extensive experience in this matter still advise adding a couple more millimeters, since practice shows that during the process, it may rise a little. If this happens, you can level the tiles.