Do-it-yourself cement-sand floor screed: device, which cement is better to use

A practical and affordable way to level floors and provide a sturdy foundation for different flooring materials is to create a cement-sand floor screed. Learning this skill will help you save time and money when remodeling a room or a whole house. While the process may initially seem overwhelming, it is completely doable to accomplish professional results on your own with the correct help and resources.

Selecting the appropriate type of cement is one of the most important choices when creating a cement-sand screed. The attributes and qualities of the cement will

Features and advantages

A square meter of cement screed with a thickness of one centimeter weighs, on average, 16 to 20 kilograms. Expanded clay or polystyrene screeds have a maximum weight of eighteen kilograms; self-leveling screeds with self-leveling mixtures show an indicator of sixteen kilograms.

A cement-sand floor screed is the best choice when subfloor differences are three centimeters or greater. When the layer is positioned on top of an additional layer—typically a combination of sand and expanded clay—that serves as moisture- and heat-resistant barrier, the screed can either be unbound (floating) or bound and securely bonded to the base.

The cement-sand screed can have varying thicknesses. The region can support up to 300 kg of weight on average. Steel rods or mesh are used to reinforce the screed in order to improve its strength indicator and capacity to support varying loads. The frame is either positioned atop the enlarging layer of clay or fastened to plasterboard sheets using unique fasteners.

Because of its porous structure, sand-cement screed is capable of absorbing moisture. As a result, the layer inside the building needs to be waterproofed with bitumen mastic or insulated with a specific membrane.

It is quite feasible to arrange a floor screed entirely with your hands. The most important thing is to follow the guidelines and make any necessary preliminary calculations. The screed takes on a rich gray tint after it has solidified and reached its maximum strength.

The layer needs to be thick and even. If there are surface cracks or chips, it indicates that the component proportion was not followed, the pouring technique was not used, or the drying guidelines for the screed were not followed.

• High-quality leveling – for any type of decorative coating.
• Durability – the service life of a concrete floor is on average 50 years.
• The ability to disguise communications inside the screed – sewer, water pipes, wires, “warm floor” system, etc.d.
• Strength – the screed can withstand any load from furniture, equipment, etc.d.
• Good sound insulation – the screed almost does not conduct sound, and if also with a layer of sound insulation, the effect is magnificent.
• Thermal insulation – the minimum thickness of the screed itself retains heat well, but if necessary, you can lay a layer of thermal insulation, providing the best characteristics.
• Minimal shrinkage – provided that the cement for the screed was chosen of high quality, and the mixing was done correctly with the correct proportions.
• Really low price – if compared with alternative methods of flooring.

Among the drawbacks of sand-cement screeds are the following: heavy weight (based on layer thickness) and significant pressure on the ceiling; an extended drying period (approximately one month), the challenge of achieving an exact level surface with your hands (though you can apply a self-leveling mixture on top); and a labor-intensive and lengthy pouring process.

With careful planning and the use of a screed device, you can smooth out most of the imperfections and produce a strong, long-lasting, smooth floor that is ready for additional finishing.

Types of cement screeds

There are numerous ways to use cement-sand mortar to create floors. You can alter the component ratios, add different plasticizers and additives, select a polymer-cement screed to create 3D-looking floors, etc. However, there are two primary kinds of screed arrangements: floating and bound/unbound screeds.

When pouring a layer up to 4 centimeters thick, the bound type cement screed device is used. In this instance, the floor and walls combine to form a single monolithic base. The rough base needs to be ready, with cracks sealed and big holes, bumps, and pits removed. It is possible for minor flaws to remain that differ by up to three centimeters.

To improve adhesion, it is advisable to brush a metal surface over the base prior to making a bound type cement floor screed. Pouring consistency should be similar to sour cream; it solidifies 20 minutes after it is laid. Large sections are gradually poured. Up to forty days pass while the screed dries, preserving the humidity and temperature beneath the film.

Mounting an unbound screed on an already perfect surface is recommended. Moisture should not seep into the base. When laying this kind of screed, the layer may be five centimeters or greater. Neither primer nor adhesion-boosting techniques are used prior to pouring.

When a layer of five to eight centimeters needs to be created, floating screed is put in place. Since various materials, including heat and waterproofing, are installed between the layers, cementing does not require the screed to come into contact with the subfloor. Fiber is added to the solution and reinforcing meshes are typically used to increase layer strength and prevent crack propagation.

Despite its significant thickness, floating (including reinforced) screed does not imply an excessive amount of weight because it is poured using a technique known as semi-dry technology, in which the solution is mixed with a smaller amount of water than a liquid mixture, giving the surface a structure more akin to wet sand.

Proportions of cement and sand

The type of screed, anticipated requirements, loads, and operating conditions are taken into consideration when determining the cement grade, component composition, and proportions. Sand and cement are the principal ingredients. Typically, M200 concrete—which is made by mixing three parts sand with one part M500 cement—is enough to pour the floor in an apartment. Approximately one liter of water is added for every kilogram of cement, or until the ideal consistency is reached.

Thickness and calculation of the floor screed

Cement, sand, and water make up the straightforward and constant composition of cement-sand mortar. The approximate calculations are provided below; they may vary based on the grade of cement used and the necessary floor specifications.

A cubic meter of mortar can weigh up to two thousand kilograms. A cubic meter of the mixture typically contains 1300 kg of sand and 450 kg of cement. Twenty kilograms of solution are needed for a screed one centimeter thick, which translates to 4.5 and 13 kilograms of component consumption, respectively.

You can purchase a ready-made dry mix if you prefer not to mix concrete by hand and worry about the type of cement required, the proportions of the ingredients, etc. It will cost more than if you prepared the solution yourself, but the end product will be of excellent quality, with standards defining the final coating’s parameters and properties.

Apart from cement, the proper sand selection is crucial, devoid of any impurities like dust, silt, or clay that could weaken the future screed layer’s strength. They often use cleaned river sand, though quarry sand will be used in dire circumstances.

A primer needs to be purchased in order to fill a standard screed; the amount needed is approximately 350 milliliters per square meter of surface. The strength and dependability of the screed will be ensured by the primer’s ability to guarantee excellent base and mortar adhesion.

Dry building mixtures

DIY Ready-made dry mixes can be used to make cement floor screed. Their primary benefit is that the proportions of the components included in the composition don’t need to be calculated, which leads to excellent results and the stability of the characteristics. The mixture is prepared by the manufacturer; the master’s job is to determine how much of the mixture is needed to complete the task and mix the solution on location while adding water.

Dry building mixtures are also simple to prepare, dense, and plastic; they are also comfortable to work with. As a result of the addition of different additives, plasticizers, etc., they frequently exhibit improved characteristics. All you have to do is refer to the instructions regarding mixture consumption, purchase the necessary quantity of bags (25–50 kg), add water as directed, and get to work.

The market provides blends for both semi-dry and dry technology screed production. Because of its elasticity, the polish mixture makes work easier and is frequently used in civil and industrial construction to build new structures and restore ones that are already in place.

Self-leveling screed mixtures are highly common; all you have to do is pour the mixture onto the surface, and it will spread flawlessly and evenly. Nevertheless, it is not as strong as dry mixtures reinforced with metal fiber and does not guarantee high strength. The self-leveling mixture option works best in residential buildings with low floor loads. Here too, lightweight concrete mixtures are employed.

A wide variety of dry mixes made in the United States and other countries are available on the market today. Because of the extensive selection, selecting an option will not be difficult, even for fairly specific requirements. Although the cement used for floor screeds generally has specific characteristics, ready-made mixtures can have quite different effects because different ingredients are added to them.

One of the greatest producers in the market, the German company Knauf, offers a product similar to this in the form of the KNAUF UBO mixture. Because CSP has a density that is four to five times higher than traditional concrete, this is a great choice for its preparation. Because the screed is temperature-resistant, it is ideal for installing underfloor heating systems. thanks to the addition of polyethylene modifiers to the composition, offers good sound insulation.

About five kilograms of mixture are needed to fill one square meter. And given the floor’s outstanding performance qualities and ease of installation, this decision is justified for pouring in a residential area.

DIY cement screed

It’s important to thoroughly examine every step of the process before cementing the floor. The base must first be ready for pouring, and only then should the screed be laid. Each stage requires sufficient attention because they are all significant.

Preparatory work

Marking the future screed is the first step in establishing the layer’s height and evenness. It is best to use a laser or regular construction level for this. Laser aids in the accurate installation of beacons, ensuring quicker mixture leveling and superior outcomes.

After positioning the laser level on the base and projecting the beam, the horizon line is found. Subsequently, a parallel line is further marked 30 centimeters from the wall using the same step, and portions of the solution are arranged along it, with a profile placed on top. Special beacons are compatible with the clamps. After that, the mixture is equalized by using the profile or beacons. However, a number of significant tasks must be finished first.

• Removing the old screed.
• Cleaning the surface from dirt, debris, dust.
• Applying adhesion primer using a roller/brush.
• Filling with a layer of expanded clay and sand (if necessary, thermal insulation is laid), the thickness of which is up to 10 centimeters. Moisturization layer.
• Design, installation of pipes, wires and other communications that are planned to be laid in the screed.

In the event that the number of significant irregularities surpasses the intended thickness of the screed, they must be removed by filling in potholes, capping bumps, sealing cracks, and so on.

Preparation of the mixture

A solution required for the screed is prepared prior to the floor being concretized. Cement-sand mixtures can be obtained in a number of ways: by buying a pre-made dry mixture and mixing it on the spot; by ordering the necessary volume of liquid solution from the plant (which offers this service both in Moscow and the regions); by independently figuring out the component proportions; and by preparing concrete.

If you decide to make the mixture yourself, combine the sand and cement in a 1:3 ratio and add water to achieve the right consistency. After that, the mixture is spread out across the floor, leveled along the beacons, and given time to solidify.

• Laying to the ground with a plastic film, cement and sand are poured on top of it, mixed with a shovel in the direction from the bottom up, trying not to break the shape of the cone.
• Make a hole in the center of the cone, pour water into it and mix everything.
• Continuing to mix the components, add dry mixture along the edges, trying not to disturb the integrity.
• When the mass becomes thick, it is ready for laying, it must be used within 20 minutes.
• Leveling the screed for 1.5 hours.

Use high-grade cement to make a wet cement-sand mixture. Take one-third of a cement bag and replace it with a sand bag, adding water to fill it up to roughly the same level as the binder. Mixing in a 25–30 liter container is the simplest method.

You must maintain control over the mixture’s color while it is being prepared. The solution should be gray; if it is too dark, there is too much cement, and if it is too red, there is too much sand.

Pouring

The room needs to be sealed with damper tape around the perimeter before pouring. This will shield the screed from pressure, moisture, and temperature fluctuations. As the mixture is being laid, one person begins at the angle closest to the door and floods and smoothes the mixture while the other person gets ready for the next section. Pouring at a time at a time base of 30 to 50 centimeters works best (this is the step where the beacons are laid).

Ten centimeters of mixing separates adjacent zones of two fillings. The last performs the strip at the doorway. Half of the strength is acquired after 2-4 days, and the screed hardens in 2-3 hours. The amount of water in the mixture and the thickness of the screed determine how fully it ripens. In typical residential settings, the screed hardens about one centimeter every week on average.

The screed is sprayed with water every day to prevent the upper layer from hardening too quickly while the lower layer is still soft. After pouring, you can align with gliding on wedges for 1.5 hours, during which time the curses that later surfaced are manually strangled.

A mixture of equal parts cement and sand is used to wipe the solution, along with water. Water must be sprayed on the surface liberally before grouting.

Step	Description
1. Preparation	Clean the floor thoroughly, removing any debris or dust. Use a primer to ensure proper adhesion of the screed.
2. Choosing Cement	Opt for Portland cement with a grade of at least 42.5 for better strength and durability.

A cement-sand floor screed can be made easily by many do-it-yourselfers, and it offers a level and sturdy surface suitable for many kinds of flooring. With the correct materials and a few easy steps, you can accomplish professional-quality results without hiring a contractor. Comprehending the entire procedure from start to finish will help guarantee a sturdy, even, and long-lasting screed.

Choosing a high-quality cement is essential when choosing for your screed. Choosing Portland cement with a high strength rating will guarantee that your floor can tolerate regular wear and tear. The right ratio of cement to fine sand results in a strong, smooth screed that can support any type of floor covering, including tiles, hardwood, and laminate.

Keeping an eye on the mixing procedure, the uniformity of

For a long-lasting and smooth finish, selecting the appropriate materials and following the right procedure are essential when making your own cement-sand floor screed. Choosing premium cement that meets your particular requirements is essential to a successful screed, whether it’s for a home or business. Portland cement is usually advised due to its consistency and strength. In order to make a workable mixture that can be evenly spread across the floor surface, the cement, sand, and water are combined. To guarantee a strong foundation for your flooring and prevent cracks and unevenness, careful preparation and leveling are crucial.

Video on the topic

With your own hands. How to save on a screed. How to fill a screed on beacons. LAD.

Cement self-leveling floor