Building a garage is not just about building walls, but about creating a reliable “home” for your car that will protect it from weather conditions, temperature changes and potential thefts. In the modern construction industry piece wall materials have long pushed traditional red brick into the background, offering higher construction speed and excellent thermal insulation characteristics. The correct choice of material at the design stage allows you to save a significant part of the budget and reduce the work time by several times.
Today the market offers many options, each of which has its own unique physical and mechanical properties and areas of application. Aerated concrete, foam concrete, expanded clay concrete, cinder blocks — it’s quite difficult to understand this diversity without preparation. In this article, we will analyze in detail the advantages and disadvantages of each type of block, calculate the required wall thickness and consider the nuances of installation technology so that your garage will last for decades.
Criteria for choosing material for garage walls
When designing a box for a car, not only the price per cubic meter of material is of paramount importance, but also its ability to retain heat and withstand loads. Compressive strength determines whether it will be possible to support heavy floors or a roof truss system on the walls without additional reinforcing belts. For one-story buildings, low-density blocks are often sufficient, but if you are planning a second floor or attic, the load-bearing capacity requirements increase sharply.
The second critical parameter is thermal conductivity. The garage, especially if you plan to spend time in it or store cold-sensitive materials, should hold heat well. However, here lies an important nuance: many lightweight concretes are highly hygroscopic, that is, the ability to absorb moisture. A wet wall instantly loses its heat-insulating properties and begins to freeze.
⚠️ Attention: Never leave walls made of cellular concrete (aerated concrete, foam concrete) without external finishing for the winter period. Having been saturated with autumn rains, by frost they can become saturated with water and, when frozen, collapse from the inside.
It is also worth considering the geometric accuracy of the products. If you plan to lay the blocks on a special glue with a thin seam, the size variation should not exceed 1-2 mm. For masonry on cement mortar, tolerances may be wider, but this will increase the consumption of the mixture and create cold bridges. Row reinforcement and corners is a mandatory requirement for all types of blocks to compensate for low bending strength and prevent cracks from occurring during foundation shrinkage.
Aerated concrete and foam concrete: lightweight cellular concrete
These two materials are often confused, but their production technology and final properties differ significantly. Aerated concrete It is produced in a factory using the autoclave hardening method, which provides it with ideal geometry and a uniform pore structure. Thanks to this, the blocks can be laid on a thin layer of special glue, which minimizes heat loss through the seams. The density of the material varies, but for garages the D400-D500 brands are most often used, which combine sufficient load-bearing capacity and low thermal conductivity.
Foam concrete, in turn, are often made in an artisanal way by pouring the liquid mixture into molds, where it hardens naturally. This leads to the fact that the geometry of the blocks can “walk”, and large voids or, conversely, areas without pores can be found inside. However, foam concrete is cheaper to produce and, as a rule, costs less than aerated concrete. It is less hygroscopic, but requires mandatory application of plaster or cladding due to its unpresentable appearance and uneven structure.
Both materials are classified as fireproof and environmentally friendly. They are easy to saw with a regular hacksaw, which simplifies the laying of communications and gating walls for wiring. However, to attach heavy shelves or gate equipment to such walls, it is necessary to use special chemical anchors or dowels for cellular concrete, since a regular plastic dowel will simply fall out of the loose structure.
When purchasing aerated concrete, be sure to request a quality certificate and check the packaging. The blocks should be shrink-wrapped to protect them from moisture during transportation and storage.
Expanded clay concrete blocks: the golden mean
Expanded clay concrete is concrete in which expanded clay - baked clay - is used as a filler. This makes the material heavier and stronger compared to aerated concrete, but at the same time it retains good thermal insulation properties. Frost resistance Expanded clay concrete is significantly higher, which makes it an ideal choice for unheated garages where sudden temperature changes and condensation are possible.
Blocks can be solid or hollow. For the construction of load-bearing walls of a one-story garage, four-hollow blocks are excellent, as they are lighter than their solid counterparts and retain heat better. Solid options are used for basements or foundations, as well as for places where fastening of heavy equipment is required. An important feature is the rough surface, which provides excellent adhesion to the cement mortar.
Unlike aerated concrete, expanded clay concrete blocks are less demanding on the type of foundation, but still require a reliable foundation. They do not shrink as strongly as cellular concrete and are less likely to crack. However, when cutting they can crumble, so when working with them it is recommended to use a grinder with a diamond blade or a special machine for cutting blocks to get a smooth end.
Why is expanded clay concrete better for a garage?
Expanded clay concrete blocks have better sound insulation and higher load-bearing capacity compared to aerated concrete of similar density. They are not as afraid of moisture as aerated concrete, and it is easier to secure heavy gates or tire racks in them without the use of complex chemicals.
Cinder blocks: budget classics
A cinder block is, in fact, a concrete stone in which the filler is slag (waste from metallurgical production), broken bricks, ash or sawdust. It is one of the cheapest materials on the market, making it extremely popular for the construction of outbuildings. However, there is an important nuance here: environmental friendliness. If a block is made from blast furnace slag without proper curing, it may release harmful substances. Therefore, it is rarely used for residential construction, but for a garage it is an acceptable option, provided that the exterior finish is of high quality.
The material is characterized by high density and strength, but very poor thermal insulation. A garage made of pure cinder block will be cold, akin to metal, if additional insulation is not provided. In addition, cinder blocks often have unstable geometries and wide variations in weight, which require the skilled hand of a mason and the use of a thick layer of mortar to level the rows.
Despite the disadvantages, cinder block has excellent fire resistance and does not rot. It is resistant to rodents, which is important if the garage is located near fields or warehouses. With proper reinforcement and installation of a reinforced concrete belt under the roof, cinder block walls can withstand even heavy reinforced concrete floors.
Comparison table of characteristics
To systematize the information and facilitate the choice, we present a comparison of the main parameters of the materials under consideration. Please note that figures may vary depending on the specific manufacturer and production technology.
| Parameter | Aerated concrete | Expanded clay concrete | cinder block |
|---|---|---|---|
| Density (kg/m³) | 400-600 | 700-1200 | 1000-1400 |
| Thermal conductivity (W/m*K) | 0.10-0.15 | 0.25-0.40 | 0.35-0.50 |
| Frost resistance (cycles) | 35-50 | 50-75 | 25-50 |
| Water absorption (%) | Up to 25% | 10-15% | Up to 20% |
| Price per m³ (relatively) | High | Average | Low |
From the table it is clear that aerated concrete is a leader in thermal insulation, which allows you to build thinner walls without losing energy efficiency. Expanded clay concrete wins in strength and frost resistance, and cinder block – in price, but loses in environmental friendliness and warmth.
Masonry technology and important nuances
The construction process begins with preparing the foundation. For blocks of any type it is necessary strip foundation or a monolithic slab, the upper plane of which must be perfectly aligned with the horizon. The first row of blocks is always laid on a cement-sand mortar, which makes it possible to compensate for uneven foundations. All subsequent rows (for aerated concrete and foam blocks) can be laid on special glue.
The most important design element is armored belt. Since block materials do not work well in tension, a reinforced concrete belt must be poured under the Mauerlat (roof support). It evenly distributes the load from the roof to the walls and prevents cracks from occurring. Without this element, the rafter system can push through the walls or cause their deformation.
☑️ Checklist before starting masonry
The masonry is carried out with bandaging of the seams: the vertical seam of the next row should fall in the middle of the block of the previous row. This ensures the solidity of the wall. Every 3-4 rows (or according to the design) a basalt or fiberglass mesh or reinforcing bars are placed in the grooves in the seams. The corners of the building are laid out first and serve as beacons for tensioning the mooring cord.
⚠️ Attention: Do not use regular cement mortar with a thick seam for laying aerated concrete. This will create powerful cold bridges, and the wall will freeze at the seams, negating all the thermal insulation properties of the block.
Calculation of quantity and cost of materials
For an accurate calculation, you need to know the perimeter of the garage, the height of the walls and the sizes of window and door openings. The standard size of a wall block is often 600x300x200 mm. The volume of one such block is 0.036 m³. By dividing the total volume of the walls (minus openings) by the volume of one block, you will get an approximate number of pieces. Always add 5-10% for fight and trimmings.
The cost consists not only of the price of the blocks, but also of the cost of glue (or mortar), fittings and labor. A cheap block may require a more expensive foundation and mandatory insulation, which will ultimately be more expensive than construction from more expensive but warm aerated concrete. Also consider logistics: delivery of heavy expanded clay concrete will cost more than light aerated concrete.
Savings on the foundation when using lightweight blocks (aerated concrete) can be up to 30% of the total construction cost, since the load on the foundation is reduced.
Don't forget about hidden costs: cutting tools (hacksaws, wall chasers), glue containers, levels and trowels. If you hire a team, check whether the price includes laying the armored belt and installing lintels over the openings, since these are labor-intensive processes.
How to calculate the number of blocks for a 6x4 meter garage?
For a 6x4 meter garage, the perimeter is 20 meters. With a wall height of 2.5 meters, the wall area is 50 m². We subtract the area of the gate (for example, 2.5x2.2 = 5.5 m²) and get 44.5 m². With a wall thickness of 0.3 m, the volume of the masonry will be 13.35 m³. Divide by the volume of one block (0.036 m³) and we get approximately 371 blocks. We add 5% for the battle - the final figure is about 390 pieces.
Is it necessary to insulate a garage made of blocks?
If the garage is heated, this is a must. Aerated concrete with a thickness of 300-400 mm may not require additional insulation in central Russia, but expanded clay concrete and cinder block require a layer of insulation (mineral wool or polystyrene foam) 50-100 mm thick for a comfortable temperature.
What adhesive is best for aerated concrete?
Use only specialized adhesive mixtures with low thermal conductivity. They allow you to make a seam with a thickness of 1-3 mm. The cement mortar creates a 10-15 mm seam, which dramatically increases heat loss.