Concrete screed

For many construction projects, concrete screed is a necessary component because it offers a level, smooth surface for flooring and other uses. It serves as a sturdy foundation, guaranteeing the resilience and lifespan of the finished floor covering—whether it be carpet, wood, or tile. Gaining an understanding of the fundamentals of concrete screed will enable you to complete your construction project with a superior finish.

A mixture of cement, sand, and water is poured over a concrete slab and leveled. This process is known as screeding. By using this method, a smooth, level surface that can be tailored to different thicknesses based on the requirements of the project is produced. Concrete screed is a popular material for both residential and commercial buildings because of its versatility.

Concrete screed comes in a variety of forms, each with special qualities and uses. The conventional method of applying sand and cement screed is very popular due to its dependability and simplicity. As an alternative, self-leveling screed ensures a perfectly level surface by allowing the material to flow and settle naturally, saving labor. Fast-drying screeds also minimize downtime by enabling faster project completion.

Effective planning and implementation are essential for a screeding project’s success. This include leveling the substrate with the proper tools, adjusting the mixture ratios, and cleaning the substrate. By paying close attention to details, common problems like cracks, uneven surfaces, and weak spots can be avoided during the screeding process.

Learning the craft of concrete screeding can significantly improve the caliber of your construction projects, regardless of your experience level as a contractor or as a do-it-yourselfer. You can produce long-lasting, smooth surfaces with the appropriate skills and knowledge. Examine the different facets of concrete screed to guarantee that the foundation of your upcoming project is strong.

What is a screed?

A screed serves as the flooring’s foundation. It is the finish of the floor base, which is typically made of interfloor slabs, and is typically composed of concrete mortar. The goal of the screed

• creation of a flat base for installing the floor covering;
• evenly distribute loads;
• adjustment of floor slopes;
• make the floor more durable for static and dynamic loads.

Concrete floor screed is referred to as "wet" screed because it is poured with a liquid composition.

The type of mixture to be used will depend on what will be the final floor covering. Using a cement-sand composition is more practical when fill is created by hand. It doesn’t require any specialized knowledge or manufacturing equipment to use. When merely the base needs to be leveled and the coating needs to be replaced, leveling mixtures are appropriate for aesthetic repairs.

Types of concrete screed

Concrete screed classification according to type:

• Knitted – the solution is poured directly onto the base, which is previously covered with a deep penetrating primer. Thanks to this, adhesion to the surface increases, which provides resistance to heavy loads.
• With a separating layer – the pouring technology provides for the laying of a waterproofing layer. The minimum thickness of such a screed is 3 cm. The advantage of this type is that with improved waterproofing, the strength of the concrete does not suffer.
• With insulating glass – for cases when it is necessary to provide greater insulating properties. For example, when laying warm floors. Another name for this type is "floating" screed. The disadvantage of using is the loss of floor strength, it deteriorates from dynamic loads. Among the advantages, it is necessary to note good insulation indicators.

An essential flooring layer, concrete screed offers a level, smooth surface for final floor coverings like carpet or tiles. Because it guarantees longevity, steadiness, and balanced weight distribution, it is crucial for both residential and commercial structures. A flawless, long-lasting floor can be achieved with an understanding of the various types of screeds, their applications, and the correct installation techniques. Everything you need to know about concrete screed will be covered in this article, from its advantages to useful advice for a flawless installation.

Types of concrete screed

With reinforcing mesh

The most common type of screed is concrete. It is built using a metal mesh that has 4-5 cm-long cells covering it. Place mesh over low supports that are installed all over the floor. Strength and wear resistance are boosted by this. Among the drawbacks of using it are the following:

• due to the metal"s susceptibility to corrosion, the mesh will gradually deteriorate, the concrete screed may delaminate, which adversely affects the service properties. This process takes many years, so the prevalence of the method has not decreased;
• When shrinking in concrete, cracks may form.

Fiber screed

Fiber fiber has only lately started to be utilized in the installation of concrete screeds, owing to the ongoing advancements in construction technologies. Rather than being placed in a reinforced mesh, it is in a concrete solution. It is a thin, synthetic material composed of polymer granules called microfiber.

Fibre increases the concrete’s plasticity and resistance to cracking. One benefit is that using this material is less expensive and easier to use than using metal mesh six times per square meter. Additionally, keep in mind the benefits of the reinforcement effect. Strict adherence to calculations and proportions when using the material is one of the drawbacks. An error will reduce concrete to crumbs.

Thickness and weight of concrete screed

While pouring the screed, the weight and thickness of the concrete layer must be ascertained first. This parameter is dependent on the type of flooring that is intended, the materials used for the solution, and whether the concrete is laid on the insulation layer or the floor panels.

There are various types of insulation: either loose or solid, the concrete layer needs to be thicker than 40 mm and reinforced with fiber or metal mesh.

Plasticizers are used to pour a cement-sand mortar on uneven floors measuring more than 20 mm. In this instance, a fill of greater than 30 mm is required to reduce the likelihood of cracking. Such a layer ought to be in the thinnest area in this instance.

Sand concrete is poured with a pouring height of 0.1-0.15 meters and used for floors with imperfections up to 60 millimeters. First, expanded clay concrete with 16 cm discrepancies is poured into the holes. As a result, the floor is lighter and costs less because less concrete is used.

Mixtures of dry self-leveling cement are used if the base is relatively flat. This type of screed is referred to as a "layer," and the plant determines how thick it is. The weight of the concrete fill is another crucial factor to consider when laying a floor since it directly influences the supporting components. A load of 3–4 tons per 1 m2 is required by the standards (the project specifies the precise parameter for each building).

How to make a concrete screed?

You have to do some prep work before you can lay concrete by hand. The following instruments are employed by us:

• tape measure;
• high-power drill/hammer drill;
• self-tapping screws;
• shovel;
• levels (2 pieces);
• knife;
• trowel;
• spatula;
• screwdrivers;
• gloves;
• two-meter rules (2 pieces: with a level; regular).

The following supplies are required to lay concrete screed:

• primer: deeply penetrating and increasing adhesion;
• waterproofing agents;
• thermal insulation (for underfloor heating);
• guide corners and fasteners;
• sand concrete mixture.

You must clear the area of dust and debris before pouring the base. Although an industrial vacuum cleaner works best, a standard broom can also be used for cleaning. The preparation is now complete.

Marking

Using a water or laser level, we marked the perimeter of the apartment and set the markers at zero. Placing the laser level in the center allows it to create lines with its beam that are used to place markers around the room’s perimeter. This procedure is simple and quick.

To place marks using a regular water level, you need to put a mark on one of the walls at a height of 1.5 m from the ceiling. We place the water level tube on the mark and lead it to the opposite wall so that the water inside is distributed evenly. To determine the zero level mark, it is necessary to measure the distance from the ceiling to the threshold of the adjacent room in the apartment, while subtracting the thickness of the floor covering.

Installation of guide beacons

Without installing guide elements, a concrete screed cannot be installed. The corners are spaced 1.5 meters apart along the wall in a parallel pattern. We use a pencil to indicate the location for laying. Along this line, holes are drilled and multiple screws are screwed in. They have beacons fixed to them.

Following completion of the task, we measure the beacons’ horizontality and their coincidence with the zero mark. Screws can be tightened to change the height if needed. A cement and sand mixture is used to anchor the corners.

Insulation and primer

Often, layers of insulating materials are used to create a concrete screed. We’ll use the example of a connected screed to examine the procedure. Use a deep penetration primer first. The base needs to be given enough time to dry fully. Use waterproof grout to seal joints and corners, then give it time to dry. Apply adhesive primer after that. Install a reinforced mesh once it has dried, if needed.

Use bulk or molded materials for sound and thermal insulation. Crushed stone, sand, slag pumice, and expanded clay gravel make up the bulk. Molded: cork, rubber, synthetic fiberglass, etc. For thermal insulation, a vapor barrier layer is also applied.

Pouring concrete screed

The base that will be used for pouring determines how much concrete screed is used. Use a big container to mix the concrete. This procedure will be streamlined and expedited by using a mixer and hammer drill. Small amounts of water are added to the dry mixture once it has been poured into the container. The concrete is given a thick, sour cream consistency after mixing.

It is most convenient to do this from the door. Next, you must pour concrete mortar into the floor and tighten it using a metal rule along the guides. Next, give the screed two to three weeks to dry. The concrete base will begin to dry out a few days after pouring; therefore, sawdust must be added and the surface must be moistened to prevent cracks. The sawdust needs to be removed and the floor needs to dry completely after a few days.

Concrete screeds are an essential part of construction because they guarantee stability and longevity while giving flooring a level base. Because of their adaptability, they can be used in both residential and commercial settings.

The ability of concrete screeds to produce a level and smooth surface—a critical component for the installation of different floor coverings—is one of their main advantages. Whether you intend to install hardwood floors, carpets, or tiles, a properly applied screed can greatly improve the flooring’s durability and final finish.

Concrete screeds have practical advantages, but they also have environmental benefits. Their environmental impact can be minimized by mixing them with recycled aggregates, which can be sourced locally. Additionally, because of their longevity, they need to be replaced less frequently, which promotes long-term sustainability in building projects.

Ultimately, the success of your building project can be greatly impacted by your comprehension of the significance and appropriate application of concrete screeds. Concrete screeds can provide a dependable foundation that satisfies both functional and aesthetic needs with proper planning and attention to detail. Putting money into high-quality supplies and knowledgeable installation will guarantee that your floors are sturdy and attractive for many years to come.

Video on the topic

Paving stones or concrete screed. Which is better?

Screed from A to Z. Flat floor. Subtleties of work. All stages.