What should be the layers and thickness of a concrete floor in a garage??

Planning ahead and paying close attention to detail are essential when building a concrete floor in your garage. To guarantee longevity and optimal performance, the appropriate layering and thickness are essential. Whether you’re building a new garage or remodeling an old one, knowing these components will help you get the best results.

Finding out which layers are required for a solid concrete floor is the first step. Every layer has a distinct function, such as offering stability or moisture protection. Together, these layers form a foundation that is strong enough to support cars and not crack over time.

Next, the concrete’s actual thickness is crucial. If it’s too thin, it might not be able to support large loads; if it’s too thick, pouring it can be costly and time-consuming. Finding the ideal balance is essential for a garage floor that is both economical and useful.

We’ll walk you through the necessary layers and suggested thickness for a concrete garage floor in this post. You can make sure your garage floor is durable and able to withstand regular use by adhering to these guidelines.

Regulatory regulation

A garage floor screed is an essential component that acts as both an enclosing element and a load-bearing base for leveling the floor slab’s surface prior to laying the finished floor. You must become familiar with the standards before pouring the floor. The following regulations in effect in the Russian Federation set requirements for concrete wet or semi-dry screed:

• SP 29.13330.201.1 Floors.
• GOST 13087-2018. Concrete. Methods for determining abrasion.
• SP 71.13330.2017. Insulating and finishing coatings.
• SP 63.13330.2018. Concrete and reinforced concrete structures.
• GOST 31489-2012. Garage equipment. Safety requirements and control methods.

Based on the above-mentioned documents, each production company that manufactures ready-mixed floor screed or sand concrete creates its own specifications. Every batch of goods has all of its prototypes tested in compliance with regulations. The manufacturer then receives a certificate of conformity, which attests to the product’s high quality, based on the protocols.

Layers of concrete screed

Depending on where it is installed and the technology needed for the finishing coat, the garage floor or parking area’s concrete or sand-cement screed consists of the following primary layers and structural components:

• The thoroughbred ground soil, either a reinforced concrete floor slab, in the case of a screed in a multi -storey heated or cold parking.
• Aligning screed of skinny class concrete no more than B7.5, designed to fix the subsequent layers that increase the operational characteristics of the supporting and enclosing structure.
• Technomast type coating waterproofing, which simultaneously serves the hydrovition with the interrefck and other layers of the enclosing structure, ensuring its energy efficiency and moisture resistance.
• Vapor barrier from a polymer membrane with a thickness of up to 80 – 120 μm, which prevents the formation of condensate from a heated room.
• Adhesive waterproofing designed to protect adjacent rooms from accidental leaks, as well as the garage space during a seasonal rise in groundwater levels.
• Thermal insulation boards made of extruded polystyrene foam with a density of 35 kg/m 3 or more, which are laid on top of waterproofing with “locking” fixation and subsequent installation of polyurethane foam at the joints.
• Reinforcing mesh made of steel or composite rods with a cell from 50 x 50 mm to 200 x 200 mm, ensuring normal operation of the structure in tension or bending.
• Concrete or cement-sand screed of the required thickness, which serves as a reliable base for the final coating of the garage floor.
• A thin layer of self-leveling floor with polymer additives 5–10 mm thick, which is necessary to reduce the porosity coefficient of the base and level the surface of the cement-sand mixture for the installation of a finishing coating, usually self-leveling mastic with abrasives or porcelain tiles.
• In some cases, grinding, grouting or ironing of the cement-sand screed is allowed, provided that cement grade no less than M400 or M500 was used in its manufacture, as well as polymer additives – epoxy resins and water repellents.

The final number of layers in a screed made of concrete or cement-sand mixture is determined by the specifications of the design documentation, in addition to factors like the room’s operational needs and the type of technology being used in the designated space.

For a garage’s concrete floor to be functional and long-lasting, the proper layers and thickness must be used. For drainage and a sturdy foundation, the base layer should be composed of crushed stone or compacted gravel. A layer of sand sits on top of this and aids in producing a level, smooth surface. To support the weight of automobiles and prevent cracking, the concrete itself needs to be at least 4 inches thick. It is advised to include rebar or wire mesh in the concrete for added strength. And last, a sealer can shield the surface from wear and stains.

What parameters should be?

No matter how much or how little modifying additives are used, when installing a screed of heavy-duty, lightweight concrete or a cement-sand mixture, it is important to pay attention to the number of layers and their minimum, ideal, and maximum thickness, which are as follows:

• The minimum thickness of a screed made of heavy concrete or cement-sand mixture without reinforcement must be at least 40 mm. This value is determined by the absence of through shrinkage cracks during hardening of the plastic material.
• The minimum permissible thickness of the screed, subject to the laying of a reinforcing mesh, is from 50 – 60 mm, since the protective layer of reinforcement must be at least 10 – 15 mm from the edge of the structure.
• The optimal thickness of the screed, which achieves the highest strength and other physical and mechanical characteristics of the structure, is from 70 to 100 mm, provided that the reinforcement mesh is laid in the bottom layer. When choosing this parameter, the maximum strength and load-bearing capacity of the structure is achieved when working under external loads.
• The maximum permissible thickness of a wet or semi-dry screed is 150 mm. If it is necessary to exceed this indicator, it is recommended to divide the entire structure into 2 or more layers, waiting for polymerization and partial strength gain of each of them. A thick screed in the garage is arranged if it is necessary to lay utilities under the concrete slab – sewerage, drainage, underfloor heating and other pipe or cable products.
• The thickness of the self-leveling floor over the main screed is from 5 to 25 – 20 mm. This value is due to the high cost of self-leveling material, as well as the average size of defects in a new screed from 5 to 10 mm.
• The insulation thickness ranges from 50 to 100 mm, depending on the thermal design of the structure, as well as the presence of additional requirements for a floating screed, or for ensuring sound insulation of the room.
• The thickness of 1 layer of waterproofing should be no more than 5 mm, 2 layers – 10 mm, respectively.
• The vapor barrier film, together with the coating sealed base, is no more than 1 – 2 mm.
• Protective or leveling screed is usually performed with a thickness of 30 mm.
• A layer-by-layer compacted sand and gravel cushion is also placed under the floors on the ground, the size of which depends on the engineering and geological conditions under the building site, as well as on the requirements of the project. With a high quality supporting base, the thickness of the pillow does not exceed 200 mm. In the case of replacing the base with a deepening of the trough between the foundation walls, the thickness of each layer that is subjected to compaction to a degree of 0.95, should be no more than 250 mm.

In an architectural project, the designer presents a graphical representation of pie sections and floor assemblies, detailing the technical attributes of each layer, the composition of the enclosing structure, and the reasoning behind each new layer’s dimensions.

How to control performance when pouring?

The most crucial factor is the thickness of each screed layer, which needs to be monitored to prevent both the possibility of an automobile entering the box through the gate and violations of the finished floor’s height, which determines the room’s free height. In order to regulate the layers’ thickness and arrangement in a garage floor screed, the subsequent algorithm is necessary:

• Accurate adherence to the detailed design drawings, respecting the height of each layer of screed in the garage.
• Checking the elevation of each layer using a laser level – preparing as-built surveys of critical structures.
• Making marks on the garage wall using a laser level with a preliminary indication of the thickness of the layers.
• Measuring the clear height of the garage after installing the screed, followed by calculating the difference, which allows you to quickly calculate the thickness of the structure at each stage of its construction.

The master runs the risk of incurring unnecessary costs if they fail to regulate the height of the screed overall and each layer individually. This is especially true if they decide to disassemble the building, modify the entry gate, or raise or lower the garage box’s lightweight roof.

Consequences of violating values

When building a garage screed, breaking the layer thickness can have the following unfavorable effects:

• Delamination and destruction of the screed during operation under all existing permanent or temporary loads.
• Risk of capillary suction of moisture from the soil or flooding of adjacent rooms.
• Impossibility of setting a slope for water drainage and organizing a ladder.
• Insufficiently rigid structure when working on an elastic base made of polystyrene foam insulation boards.
• Incorrect operation of the floating screed.
• Insufficient size of the soil cushion, which leads to settlement of the concrete screed under loads and its own weight.
• The presence of defects on the screed due to insufficient thickness of the self-leveling floor layer.
• The occurrence of shrinkage cracks during hardening of the mixture.
• Insufficient protective layer for the reinforcement mesh.

Before installing a garage screed, in addition to carefully adhering to the working design, selecting premium materials, and following the technological map, you should acquaint yourself with master classes from professionals who frequently share their videos in the public domain. This will help you avoid mistakes and the consequences mentioned above.

Useful video

Added details regarding the thickness of the screed:

For longevity and practicality, a garage’s concrete floor needs to be built well. Maintaining the proper layers and thickness will increase the floor’s longevity and offer a stable, secure surface for storage and cars.

To create a sturdy foundation, start with a subbase composed of crushed stone or compacted gravel. This layer needs to be about 4 inches thick in order to guarantee adequate drainage and to avoid settling or shifting.

The next step is to help stop moisture from leaking into the concrete by adding a layer of sand or a vapor barrier. This is an essential step, particularly in regions with high humidity or problems with groundwater.

For standard vehicle use, the concrete layer itself needs to be at least 4 inches thick. For increased strength and durability, think about increasing the thickness to 6 inches if you intend to park heavier cars or equipment.

Steel rebar or wire mesh reinforcement can greatly increase the concrete’s ability to support weight and stave off cracking over time. For best results, this reinforcement should be positioned in the center of the concrete layer.

You can be sure that your garage floor will endure weather and regular use by carefully designing and building each layer. A well-constructed concrete floor is a reliable and long-lasting investment.