Reinforcement of concrete floors, screed: sequence and materials

Reinforcement is an important step in making concrete floors sturdy and long-lasting. Determining the appropriate materials and method for strengthening your concrete floors and screed can be crucial when building a new structure or remodeling an old one. Your floors will be able to withstand normal wear and tear and the test of time thanks to this process.

First and foremost, selecting the appropriate materials for reinforcement is crucial. To add extra strength, steel rebar or mesh are typically utilized. These substances aid in the even distribution of weights and guard against concrete floor cracking, a frequent problem. The floor’s intended use and the weight it must support determine which reinforcements to use.

The order in which the reinforcement is applied is also important. Usually, the procedure starts with the subfloor being ready and a moisture barrier being installed. The reinforcing materials are then positioned and fastened after that. After careful finishing, the concrete is finally poured over the top. To guarantee the stability and longevity of the floor, each step must be completed accurately.

By knowing these fundamentals, you can make sure that your concrete floors are sturdy and long-lasting. You can build a long-lasting floor by using high-quality materials and adhering to the correct procedure. You’ll be well on your way to a successful concrete floor reinforcement if you keep these pointers in mind while you organize and carry out your project.

When is reinforcement necessary?

Although it is not always done, there are situations in which reinforcing concrete floors is both essential and entirely justified. In residential buildings, reinforced concrete floor slabs are leveled by a screed, which is a 4–8 cm thick layer of sand-cement mortar. Most of the loads that cause deformation are placed on the slabs.

However, surface reinforcement is needed if thermal insulation material—such as foam plastic, mineral sheets, or extruded polystyrene foam—is applied to the floors. Additionally, amplification cannot be prevented in homes near fireplaces, stoves, or heavy objects.

When a concrete screed needs to be reinforced:

• If the project involves a floating screed – with a loose backing, for thermal and waterproofing.
• When laying a floor on soil that can swell (especially if there is an expanded clay insulating layer).
• In underfloor heating systems, where the coating must easily withstand temperature changes.
• In industrial buildings – in areas with increased loads, under heavy equipment, etc..
• Any screed thicker than 5 centimeters must be reinforced.

Sorts of screeds made of reinforced concrete based on their purpose:

• Multilayer – includes gaskets for sound, water, and heat insulation
• Rough – reinforcement of a concrete floor on the ground
• Construction – poured onto a floor slab
• Leveling – poured onto a rough layer, becoming the base of a floor covering or underfloor heating

Reinforcement is most appropriate for self-leveling floors, multilayer and rough screed installations, and situations where a smaller mortar layer is required. Since it would be very difficult to calculate and design everything on your own, they typically enlist the help of design firms, lone experts, or at the very least set guidelines and standards.

The following materials are used today to reinforce floors beneath concrete: fiberglass meshes, steel wire or reinforcing meshes, fiber (from basalt, polypropylene, glass, or metal), and polymer meshes.

Metal screed meshes

The mesh is used where construction technology is observed, where heavy partitions and internal load-bearing walls rest on their foundation. It is composed of wire that complies with GOST 8478 (wire diameter 5 millimeters, cells 10 by 10 or 20 by 20 centimeters). It is employed to create multi-layer screeds on the floor and to fortify the coating in the garage, kitchen, and hallway.

Twisted wire or welding can be used to create the mesh. Reinforcement with a diameter greater than 6 millimeters can be welded. The strongest meshes are made of metal, and they can reinforce screeds up to eight centimeters thick. As with frame reinforcement, sheets are dispersed throughout the whole thickness of the solution. After installation, they are filled with concrete and raised to a height of roughly 2-3 centimeters. If there are insulating layers beneath the screed layer, the mesh is spaced out at the edges by three to five centimeters and they are not fastened to the walls.

Ready-made material is readily available for purchase; it just needs to be arranged in strips on the ground and tied. The cost of the work is not significantly higher than that of using wire for reinforcement, since the mesh is created separately while the work is being done. However, there are far more time savings and reliability benefits.

Using the proper materials and techniques when reinforcing concrete floors and screed is essential to guaranteeing its strength and durability. The fundamentals of reinforcing concrete floors will be covered in this article, including how to choose and apply reinforcing materials like mesh and rebar. Knowing the right procedure and methods can have a significant impact on the longevity and general performance of your flooring. Understanding these fundamentals will enable you to build a strong, long-lasting foundation whether you’re working with experts or taking on a do-it-yourself project.

Reinforcement for strengthening the screed

Typically, the rod frame is arranged in two layers, resulting in a solid map of rods with a diameter ranging from 6 to 40 millimeters. The coating’s thickness shouldn’t be more than eight centimeters. This method of reinforcing floors is typically used on crushed stone, soil, or expanded clay.

Spot welding or twisting wire with a unique hook for knitting reinforcement is used to join the rods. Reinforcement class A400 with a diameter that matches the loads is recommended. Steel wire reinforcement with a diameter of 8–12 millimeters is typically used for welding or twisting rods. The dimensions of the cells range from 5 by 5 centimeters to 25 by 25 centimeters, contingent upon the standards and conditions factored into the computations.

Sequence of flooring

Prior to anything else, the guidelines for creating a concrete reinforcing screed must be taken into account; otherwise, the coating will not be of superior quality. Regardless of the materials chosen, the operational features, or the calculations, they are required.

Guidelines for working on floors that need strengthening:

1. The material must be spread using supports on the base of the construction site prior to pouring (fiber is an exception).

2. In order to prevent the reinforcement from obstructing the pouring process, the concrete must be distributed freely.

3. Good adhesion is required for concrete and reinforcing materials; they should not be stained with oily textures.

4. To shield the reinforcement frame from oxidation, decay, corrosion, and damage from outside factors, the mortar layer needs to completely encase it.

The workflow for laying a floor is as follows:

• Surface preparation – removal of debris, dirt, dust.
• When arranging an old concrete surface – expansion of cracks and crevices, cleaning, elimination by pouring liquid solution.
• Preparation of materials for laying waterproofing, sound and heat insulation, installation.
• Marking the floor level on the walls with a water level.
• Laying out plastic clamps closer to the base of the slab or making a lining of mortar so that the reinforcement takes the correct position in the concrete layer. If the reinforcement is not welded or tied, then it is laid on chair clamps.
• Laying a mesh with an overlap of 1-2 cells or a created frame.
• Installation of beacons (slats, boards, guides for plaster) at a distance of 10-20 centimeters less than the length of the rule.
• Pouring the mortar.
• Removing the beacons after the screed has set, sealing the holes with mortar.

To prevent uneven drying, it is recommended to water the screed for a few days and cover it with a polyethylene film during the drying process.

Non-metallic materials for reinforcing floors

Non-metallic materials are often used for concrete screed reinforcement. It applies to self-leveling and warm floors in residential buildings, eateries, workplaces, and other public areas where there aren’t any heavy loads. The material is not as strong as its metal equivalent, but given the substantial cost savings and lack of detrimental effects, this decision is frequently well-justified.

The primary benefits of plastic products are:

• Low weight, convenient and cheap transportation, simple storage.
• Ease and speed of preparation, installation.
• High level of elasticity, tensile strength during shrinkage of the building, protection against cracks.
• Resistance to corrosion, various external influences.
• Low price.

Regarding the mesh, there are no essential distinctions between the applications of polymer and metal meshes. It is sufficient to create a minimum thickness layer of concrete, place a sheet on top, add beacons, and then pour concrete for plastic products; no additional fastening with supports is needed.

Fiberglass mesh

Only after being impregnated with polymer dispersions, which shield the concrete’s thickness from the alkaline environment’s influence, is the material used. Glass threads made of aluminoborosilicate are used as reinforcement. The properties, performance characteristics, and application scope are comparable to those of plastic products. However, because the critical indicator for fiberglass is the threshold of +150 C, it is not advised to use it in areas where there is a risk of fire.

Typically, they select an openwork woven mesh with square cells measuring 4-6 centimeters. SSDor-300 and SSM-95 are not impregnation-coated; however, SSDor-330 and SSP-95 are. Since alkali can corrode fiberglass over a five-year period, the mesh used for reinforcing concrete is not used without impregnation.

Its simplicity of use, light weight, resistance to water and temperature changes, and ability to be worked with without the need for extra tools or personnel all contribute to its popularity. The mesh’s primary functions are to strengthen the coating and prevent shrinkage cracks from forming.

Fiberglass

At the preparation stage, bulk fibers are added to the solution to remove microcracks and cracks. Although fiber increases the floor’s resistance to impact, it does not lessen the load on deflection and tension. Fiber is an even distribution of tiny, evenly spaced reinforcing fibers that enhance the properties of the screed. These fibers are typically 6–20 millimeters long, though metal fibers can reach lengths of up to 60 millimeters.

Fiber is composed of fiberglass, metal, basalt, and polypropylene. Fiberglass or polypropylene are used where it is important not to load the screed; metal is used for floors with heavy traffic; and basalt is used for coatings that are subjected to the influence of aggressive substances and complex atmospheric factors.

In order to mix the solution, combine the fiber with all of the dry ingredients and mix in a concrete mixer for up to five minutes, allowing the fibers to crumple and disperse evenly throughout the composition. The solution can then be used right away in the work by pouring it along the beacons after adding water and mixing for an additional ten minutes.

The primary benefits of the material include its lighter reinforcement technology, ability to combine with other materials to achieve the best results, protection against shrinkage-induced cracks, strengthening of the entire layer, increased resistance to abrasion and sudden temperature changes, increased water and frost resistance, and stronger overall layer.

Steel reinforcement

Offers the longest-lasting finish, appropriate for industrial workshops, warehouses, and roof boxes. Larger steel rods are used less frequently; the mesh is tied from rods that have a diameter of 8 to 12 millimeters. Although the parameter can change, cells are typically made with dimensions of 100 by 100 millimeters. After the grid is delivered, it is welded or wire-tied at the location and a layer of reinforcement is poured underneath.

During the building design phase, the diameter of the rods and the size of the cells are calculated with an emphasis on the loads and technological features of the structure, as well as its resistance to both static and dynamic effects.

Composite reinforcement

When in agreement with the developer, used in a manner akin to steel meshes, primarily in semi-dry and dry screeds. The composite reinforcement is a very easy-to-work-with material that is long-lasting, corrosion-resistant, and easily delivered to the construction site. increases the strength and flexibility of the structure while lowering the weight of the floors.

Ready-made meshes

A wide variety of meshes produced under production conditions are available. The most widely used materials are composite, steel, fiberglass, etc. Purchasing a prefabricated product offers several benefits, including the ability to compute its parameters and properties instantly, use it in compliance with building codes, and save time and effort compared to producing a mesh by hand using rods. The total expense is not that much more.

The most chosen choices are:

Metal

Steel wire with a diameter of 2.5–6 millimeters is used to make the mesh; cell sizes range from 6 to 20 centimeters. The material is stronger the smaller the cell size. supplied in sheets (diameter greater than 3 millimeters) and rolls (diameter up to 3 millimeters).

Principal benefits include: superior tensile strength, strong binding, resistance to temperature fluctuations, extended service life, total protection against stretching-related cracks, and enhanced floor load-bearing capacity.

Plastic

Up to eight centimeters of screed reinforcement are provided by the material, which is lightweight, elastic, and soft. Such a mesh will bend, but unlike metal, it won’t rip the floor if the building shrinks unevenly. Used in locations where there is little load because of its poor tensile strength. Comes in rolls that can be easily cut with regular scissors and is resistant to deterioration and rust.

Principal benefits include: radio frequency transmission, elasticity, chemical inertness, ease of installation and transportation, and light weight.

Fiberglass

For material to be resistant to alkali, it must be impregnated with cells measuring up to 6 millimeters. Plastic-like operational features are present.

Rod reinforcement

Steel rods of grades A400 or A500 or composite reinforcement (basalt fiber, carbon fiber, fiberglass, etc.) are used to make reinforced concrete flooring. The rods are inserted into the frame, welded, and/or further fastened with a construction wire mesh. polymer

The rods need to be full size, free of corrosion and significant rust damage, and precisely meet the required physical specifications.

Warm floors

The construction of an integrated heating system requires a reinforced concrete floor. This requirement is based on many years of operating experience and is outlined in SNiPs. Installing a sturdy layer of thermal insulation—typically made of polystyrene foam boards—is necessary for a warm floor. After placing heating components on top of them, mortar is added.

These coatings need to have reinforcing elements (not necessarily with a complex type of reinforcement) that prevent cracks from spreading because they are constantly exposed to temperature changes. In this situation, combined reinforcement using steel or polypropylene mesh is the best option.

Walking on the mesh during pouring

It is not advised to walk on the mesh when pouring the base on the ground or other surfaces because it could cause them to shift. Spacers must be positioned beneath each cell’s third corner in order for the cards to remain perfectly still.

• Make paths – pour concrete in a straight line from one end of the room to the other, fixing the grid.
• Lay boards or boards on top of the frame and gradually rearrange them during the work.
• Tie the mesh and make it rigid enough for walking during the installation of beacons for pouring.

What determines the price of a reinforced concrete floor?

During the work’s design phase, the costs can be estimated beforehand. Numerous variables that are changed in accordance with the objectives established determine the total amount.

What influences the price is:

• The pouring area – the larger, the more expensive the work will be. This factor cannot be influenced, it is constant, except that you can get a discount on completing an order with a very large area.
• The number and quality of layers – is formed based on the operating characteristics of the premises.
• The type of reinforcement – is selected by the customer, must meet the stated requirements.
• The quality of concrete and other materials – the higher, the better. Even if it is more expensive, in the end a good floor will fully cover the costs, since low-quality materials can lead to the need to repeat the process, repairs, other problems.

Step	Description
1. Surface Preparation	Clean the concrete surface to remove any dust, debris, or loose material. This ensures proper adhesion of the screed.
2. Moisture Check	Ensure the concrete is dry enough. Excess moisture can affect the screed’s performance.
3. Apply Primer	Use a primer to enhance the bond between the concrete and the screed. This step is crucial for a strong, long-lasting finish.
4. Install Reinforcement	Lay reinforcement mesh or bars if required. This helps to strengthen the screed and prevent cracking.
5. Mix and Pour Screed	Prepare the screed mixture according to the instructions and pour it over the prepared surface. Spread it evenly.
6. Leveling	Use a screed board or similar tool to level the screed. This ensures a smooth and even surface.
7. Curing	Allow the screed to cure properly. Keep it moist and protected to avoid cracks and ensure it gains strength.
8. Final Check	Once cured, inspect the surface for any imperfections. Address any issues before moving on to finishing or covering.

Knowing the proper procedure and materials to use when reinforcing concrete floors and screeds is crucial for a long-lasting and satisfactory result. There are a few key steps in the process, and each one enhances the flooring system’s overall durability and strength. You can make sure that your concrete floors can withstand damage and stay stable for many years by doing the proper steps.

It’s important to start with the preparation. Prior to placing any reinforcement, make sure the base is clear and level. Selecting the appropriate materials, like mesh or steel rebar, is also crucial. For the best support, these materials need to be positioned and spaced appropriately. By taking this action, you can help keep the concrete from cracking and strengthen its overall structural integrity.

Applying the screed comes next, following the placement of the reinforcement. To achieve an even, smooth surface, a layer of material is spread over the concrete. Using a premium screed mix and making sure it is applied evenly are crucial. This improves the floor’s appearance and provides an additional layer of security.

To sum up, the process of reinforcing concrete floors and screeds is methodical and requires meticulous planning and execution. You can create a strong, long-lasting floor that satisfies your needs by paying close attention to each step and using the appropriate materials. Applying screed correctly and using proper reinforcement are essential for a concrete flooring project to succeed.

Video on the topic

Do-it-yourself floor screed in an apartment. Reinforcement with fiber

APARTMENT RENOVATION. FIRST SCREED OR WALLS? #108

Floors on the ground. Errors. #Floors #Screed #Concrete

Metal road mesh in the floor screed, what is it for, where is it located and at what height

Floor screed from 1 to 5 cm. How to fill it so that it does not fall off.

Floor screed on the ground. Floors on the ground without unnecessary expenses. Is steel reinforcement necessary??