How to make a reinforced belt for floor slabs with your own hands

Here at "All about concrete," we’ll look at useful hints and methods for dealing with one of the most basic building materials. This post will go over how to make a reinforced belt for floor slabs, which is an essential step in guaranteeing the durability and structural integrity of concrete floors.

When building floor slabs, reinforcing belts are essential for distributing stress and preventing cracks, particularly in locations that are vulnerable to seismic activity or large loads. These belts are made up of beams of reinforced concrete that go around the slab’s perimeter, adding strength and stability.

With the correct equipment and supplies, any do-it-yourself enthusiast can complete the several essential steps involved in creating a reinforced belt. By taking these actions, you can improve the resilience of your building project overall and increase the longevity of your floor slabs.

At "All about concrete," we’re committed to providing our readers with useful information that they can use right away on their projects. The ability to create reinforced belts for floor slabs is a valuable skill that improves the quality and performance of your concrete structures, regardless of your experience level as a contractor or as a do-it-yourselfer.

To reinforce a belt for floor slabs: 1. Measure and mark where the belt will go around the slab perimeter.
2. Dig a trench around the slab to the required depth and width. 3. Place a layer of gravel or crushed stone at the bottom of the trench for drainage.
4. Install a grid of reinforcing bars (rebar) in the trench, ensuring they are securely tied together. 5. Pour concrete into the trench, covering the rebar completely and smoothing the surface.
6. Allow the concrete to cure according to manufacturer"s instructions. 7. Once cured, the reinforced belt will provide added strength and stability to the floor slab.

Reinforced belt design

To even out the loads caused by the weight of the roof and the interfloor panels on the capital walls, a monolithic belt is built beneath the floor slabs (their end plane). By doing this, the load from the floor slabs can be distributed as best as possible, resulting in the strength of the entire structure.

Planning the structure includes:

  • Determining the structural type
  • Selection of the optimal reinforcement diameter, mesh pitch, number of layers – the power should be greater, the less durable the materials used in the masonry of the walls (for example, for lightweight floor slabs, you can take a not very powerful belt)
  • Calculation of sizes in accordance with the area, structural features
  • Determining the thickness of the armored belt – usually equal to the thickness of the walls

Depending on its intended usage, the armoured belt can be:

1. Girder: a support for the foundation built in a specific trench at a depth determined by the building’s weight, number of stories, dimensions, and other features.

2. Plinth: a structure under every load-bearing wall that distributes the weight across the foundation; it is 20–40 centimeters high, equal in width to the thickness of the walls, reinforced with 12 millimeters, and waterproofed.

3. After every floor, the interstory reinforced belt for the floor slabs is installed. This reinforces the walls and increases their rigidity, preventing travel and deformations and distributing the load evenly.

4. Unloading: this process takes place beneath the roof, makes it easier to construct a rafter system, secures the Mauerlat to the wall, smoothes them horizontally, and evenly distributes the weight of the roof around the perimeter to prevent point load.

From which armopo is made

It is vital to consider both the design itself and the preparatory work in light of this issue. Formwork will be required during the preparatory phase. Strict wood is used to create unique shields for collapsible formwork, and polystyrene is typically used to create stationary designs. The materials used in this project need to be carefully chosen in order to guarantee the formwork structure’s tightness and rigidity.

The following materials are used to carry out reinforcement with reinforcement:

1) Cement grade M400 or higher is used to mix the concrete mortar. The reinforcing mesh-containing formwork frame is filled with mortar. As the concrete dries, it forms a power circuit around the capital walls’ periphery that can support different kinds of loads.

Sand, crushed stone, and cement are combined in a standard recipe to make mortar. Concreting is done all at once, and to ensure that there are no air pockets in the slab, vibratory compaction is required.

2) Corrugated-surfaced steel rods measuring 8 to 10 millimeters in diameter. After being cut to the proper length, the rods are knotted together into a stiff frame using specialized knitting wire. Typically, the structure consists of four longitudinal rods that are connected by transverse wire segments that are six millimeters in diameter and of the appropriate size. Square cells are used to create the mesh, and their size is determined by computations and the diameter of the reinforcement that is used.

Height and thickness armored belts

A reinforced belt with square sections typically has a height and thickness that are equal. Rectangular structures are based on the 1.6-times height over width assumption.

The grillage should be between 30 and 50 centimeters high; in soft, unstable soil, this can be increased to 80 or even 100 centimeters. Under the basement floor slabs, the reinforced belt should be 20–40 centimeters high, with an interfloor of roughly 40 centimeters.

The width of the structure’s load-bearing walls and the thickness of the reinforcing contour should match. However, in certain instances, the technology permits you to decrease the belt’s thickness, taking 0.7–0.8 wall thickness into account (if thick, lightweight blocks are used in building construction).

When it is necessary to strengthen building structures with a reinforced belt

To increase the strength of load-bearing walls, create a level base for installing interfloor panels, distribute different types of loads uniformly, prevent wall deformation, lessen the negative effects of external factors on the building, ensure maximum structural stability, and increase the safety margin, an armored belt may be required.

When is the creation of a reinforced concrete belt required?

  • In multi-story construction, where it is prescribed by building codes
  • When erecting walls from porous materials (aerated concrete, cinder block), which can be crushed and destroyed
  • If construction is carried out on weak soils and there is a possibility of subsidence, a monolithic belt will act as a screed and will not allow cracks to appear
  • When the foundation is shallow or made of prefabricated blocks
  • The house is being built in a seismically active zone

If the foundation is poured below the freezing point of the soil and the capital walls are constructed using brick or block with good strength characteristics, then installing a reinforced concrete belt may not be necessary. In other situations, the reinforcement contour becomes a required component of the structure, negating the need for a reinforced concrete belt beneath a monolithic floor.

Reinforced belt under precast and monolithic reinforced concrete floors

Here the contour greatly increases the load-bearing capacity of walls constructed from cellularly structured blocks, removing issues brought on by the porosity and instability of the concrete to deformations. By distributing the loads from the roof and interfloor ceilings evenly, the reinforced belt helps to reduce local forces that frequently result in cracks.

Furthermore, by strengthening the structure in this way, the masonry’s service life is greatly extended, the effects of abrupt temperature changes are mitigated, and the building box is shielded from cracking. It is crucial that concrete and reinforcement combine to form a single power contour that unites the building box and floor slabs.

In this post, we walk you through the process of making a reinforced belt for floor slabs with easy-to-follow step-by-step directions. For concrete floor structures to be stronger and to distribute loads evenly, reinforced belts are essential. We go over the necessary supplies, equipment, and useful advice to guarantee that your reinforced belt is strong and adequately supports your concrete floor, making this a useful do-it-yourself project for anyone wishing to hone their construction abilities. Does this thesis statement need any improvement or clarification?

We are preparing to make a reinforced belt under the floor slabs: building materials and tools

In order to pour a monolithic reinforcing belt, the following materials must be measured, purchased, and assembled: polyethylene film (which seals the formwork), plywood and planed boards (or polystyrene in sheets) for the formwork, all the materials for the concrete mortar (gravel or crushed stone, cement, sand), steel reinforcement for the structure itself and knitting wire for its assembly.

Equipment that might be required for the task:

  • Concrete mixer for preparing concrete mix
  • Hand hook for tying reinforcement
  • Angle grinder + metal circle for cutting steel rods
  • Plumb line + building level for measurements
  • Device for bending reinforcement – if larger diameter rods are used

Technology of constructing a reinforced belt (main stages)

  • Preparing the base, cutting blanks for the formwork structure
  • Assembling the formwork from the selected material
  • Cutting rods in accordance with the specified dimensions and in the required quantity
  • Assembling the frame – tying the rods with wire
  • Preparing the concrete solution
  • Filling the formwork with solution – in one go is desirable, tamping with a vibrator or manually to remove air pockets
  • Watering the concrete with water using the spray method to avoid the appearance of microcracks
  • Dismantling the formwork after the concrete has hardened

This material can also be used to make belts for brick-built homes. As the walls are being laid, the outline is created, and the design fits the building’s characteristics. Formwork does not need to be formed for the brick belt because the reinforcement is positioned directly on the brick. If a grid is to be used, sheets with a rod thickness of at least 5 millimeters must be selected.

What materials can be used for formwork

Formwork creation is the first step, which entails strengthening the armored belt beneath the floor slabs. The thickness is roughly thirty centimeters, and the width matches the wall’s dimensions. Planed wood, typically two centimeters thick, is used. The boards are fastened with self-tapping screws five centimeters before the top of the wall, and reinforcement is added every 100 centimeters or more frequently.

Either strips or threaded studs are used to secure the side edging. The boards need to be hermetically and firmly fastened horizontally in accordance with the level.

Additionally, they employ moisture-resistant plywood that has been impregnated with leftover oil to make installation easier. The most common material used for heat-insulated formwork arrangements is extruded polystyrene slabs.

Installation of reinforcement

The process of installing reinforced concrete strip follows a specific order: rods are cut first, then they are positioned along the formwork on clamps or pads, tied with wire (this is the bottom layer), transverse rods are installed on top of them, and the top layer is secured. The components are then secured using threaded studs or wire.

Ribbed rods with a 12 mm diameter are typically used, and a parallelepiped or ladder is assembled using them. Nonetheless, it is preferable to use 12 for the first layer, 6 for the second, and 10 for the transverse fastening. It is possible to weld the transverse frame’s center and edges as well as to tie the entire volume of rods.

The frame needs to be recessed several centimeters into the concrete solution; the indentation from the edges is five centimeters. Knitting wire can have a very small diameter because its thickness greatly increases the time and resources required to complete the task, without compromising the strength of the internal or external structures it supports.

When the mesh is ready on both sides, it is laid out and the edges and center are welded together to form a frame with a square or rectangular cross-section. It is preferable to complete this stage of work inside the formwork to avoid having to move the part, which has a noticeable large weight, later.

Welding is not necessary when assembling the parts into a single mesh; a 20–30 centimeter overlap between each part is sufficient. A building level is used for measurements, and the entire structure must be positioned evenly inside the formwork.

If the reinforcement is placed in other blocks or polystyrene concrete, first the grooves are created using a chaser, then they are dampened, dust-free, and filled with glue or mortar that has been softly mixed. After that, extra adhesive is scraped off and 8 millimeter metal corrugated rods are placed in the grooves to continue the building process.

How to pour concrete

Use concrete mortar and follow these instructions to fill the monolithic frame: After thoroughly mixing the dry ingredients—5 parts gravel, 3 parts sand, and 1 part cement—water is added gradually until a thick solution is achieved.

The necessary volume of the mixture is prepared ahead of time and the stage is completed in one go. In order to fill the formwork, gaps must be filled using a vibrator or rammer, horizontality must be checked with a level, and discrepancies must be eliminated. After that, the surface needs to be carefully planned and covered with polyethylene film.

Periodically misting it with water is required during the hardening process. After the concrete dries in three to five days, slabs can be placed on top of it; for stability, space them 12 centimeters from the walls. Using a nail puller or crowbar, you can remove the formwork once the layer has fully solidified—just make sure not to break it.

Insulation of the armored belt

Since the reinforcement contour conducts heat, the thermal insulation properties will be greatly deteriorated in the absence of appropriate insulation due to the appearance of cold bridges. Insulation is inserted into the remaining recesses after the formwork is disassembled before the work is completed.

Insulation is typically installed along the whole facade at the belt height. Two insulating belts are made along the facade of two-story buildings if there is a belt between the first and second floors, including after the second floor beneath the wall plate.

The most popular brand of foam plastic used is PSB-S 25, which has an 8-centimeter thickness. The height of the insulating contour is determined by adding the height of the reinforcement belt to 15 centimeters. The insulation is fixed at the designated distance below and above the contour lines.

A drip cap is inserted in the upper portion to drain melt and rainwater from the reinforcing contour, thereby extending the durability of the thermal insulation layer. The polyester-coated drip cap is made of galvanized sheet steel and is positioned at an angle from the wall. The upper edge is trained, sealed, and fixed with a step of thirty centimeters after being fixed by drinking over the insulating belt.

The strength and durability of floor slabs are improved by creating a reinforced belt, which is essential for long-term support of heavy loads. You can make sure your concrete floor will endure over time by adhering to these guidelines.

Begin by carefully arranging and measuring the dimensions of your floor slab. To ascertain the precise location and dimensions of the reinforced belt, take precise measurements. By taking this initial step, you can be sure that your reinforcement will offer the best possible support when it’s most needed.

Next, get the supplies ready for the belt reinforcement. This usually consists of formwork to shape the concrete into the required shape, concrete mix, and steel rebars or mesh. To preserve the structural integrity of the rebars, make sure they are clean and free of rust.

Build the formwork around the floor slab’s perimeter, where the reinforced belt is going to be installed. As the concrete sets and takes on the desired shape, the formwork serves as a mold to hold the mixture in place. To guarantee a smooth finish and avoid leaks, firmly fasten the formwork.

As per the earlier designed layout plan, insert the steel rebars or mesh inside the formwork. Rebars should be evenly spaced and fastened in place with wire ties or other supports. The strength required to support the weight and stresses applied to the floor slab will be provided by this reinforcement.

Pour the concrete mixture carefully into the formwork after the reinforcement is in place. Fill the space uniformly, making sure the mixture gets to all of the formwork’s edges and corners with a shovel or concrete mixer. Achieve a dense, solid structure by tapping or vibrating the formwork to remove air bubbles and consolidate the concrete.

As directed by the manufacturer, let the concrete cure and set after pouring. In order to achieve the highest level of strength and durability in your reinforced belt, this curing process is essential. Cover the concrete with damp burlap or plastic sheeting to prevent it from drying out too quickly.

Ultimately, the completed reinforced belt can be seen by carefully removing the formwork once the concrete has completely dried. Examine the surface for flaws and make any necessary corrections or alterations. Now that it has been strengthened, your belt is prepared to sustain the floor slab and endure regular wear and tear.

These instructions will help you build a reinforced belt for floor slabs that will increase their strength and guarantee long-term durability. You can achieve a strong and dependable concrete structure with the aid of these techniques, regardless of whether you’re building a new floor or strengthening an old one.

Video on the topic

Making a reinforced belt on aerated concrete for floor slabs

ARMOPOYAS FOR FLOOR SLABS / ARMOPOYAS AERATED CONCRETE BELT WITH YOUR OWN HANDS / WHY IS ARMOPOYAS NEEDED

THE EASIEST WAY! ARMOPOYAS under floor slabs

Armopoyas under floor slabs. How to properly tie reinforcement. Construction of monolithic sections

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Andrey Ivanov

Experienced civil engineer with more than 20 years of experience. Specializing in the construction of industrial and civil facilities. Author of many publications in professional journals.

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