Planning the construction of a car storage space is always a balance between the desire to save money and the need to ensure reliable protection of the equipment. The thickness of the walls in the garage is one of the key parameters that directly affects heat loss, structural stability and the final cost of the project. An error in calculations at the design stage can lead to freezing of the room in winter or, conversely, to unreasonably high costs for materials that will not provide a noticeable effect.
Many novice developers rely on the experience of neighbors or general recommendations, forgetting that climatic conditions and the type of material used dictate their own strict rules. SNiP and modern building codes clearly regulate the requirements for enclosing structures depending on the region. In this article we will analyze in detail what the thickness of the walls should be for different materials in order for the garage to remain dry, warm and durable.
It is important to understand that the dimensions of the building are not the only factor. The bearing capacity of the foundation, the type of roof and even the presence of an inspection hole require an individual approach to choosing the width of the masonry. For central Russia, the minimum permissible thickness of a brick wall without insulation is considered to be 510 mm (two bricks), however, with the use of modern heat insulators, this parameter can be significantly reduced. Let's look at all the nuances in more detail.
Factors influencing the choice of wall thickness
Before purchasing materials, it is necessary to conduct a thorough analysis of the operating conditions of the future building. Climate zone plays a decisive role: if in the southern regions one can limit oneself to thinner walls, then in Siberia or the Urals, saving on the width of the masonry will lead to constant heat loss. The engineering calculation takes into account not only the air temperature, but also the wind rose, humidity level and the depth of soil freezing.
The second important aspect is material of execution. Brick, aerated concrete, expanded clay block or corrugated sheet have completely different indicators of thermal conductivity and strength. For example, a 200 mm thick aerated concrete wall can retain heat as effectively as a 500 mm brick wall, but its load-bearing capacity will be lower, which requires an armored belt.
It is also worth considering the functional purpose of the room. Will it be just a “cold” box for summer storage or a full-fledged workshop with heating? Heated garage requires more serious thermal insulation, otherwise energy costs will be unreasonably high.
- 🌡️ Climatic conditions of the region and temperature changes throughout the year.
- 🧱 Type of building material chosen and its thermal conductivity.
- 🔥 Presence or absence of an indoor heating system.
- 💰 Construction budget and availability of specific materials in the region.
Thickness standards for brick walls
Brick remains one of the most popular materials due to its durability and fire safety. However, it has high thermal conductivity, which dictates certain requirements for the thickness of the masonry. Standard single brick has dimensions of 250×120×65 mm, and it is its length that is often taken into account when calculating the width of the wall.
For an unheated garage that serves as a shed or light parking lot, half-brick masonry (120 mm) is acceptable. But such a design requires the presence of powerful support pillars made of brick or concrete, located in increments of 3-4 meters, otherwise the wind load can destroy the building. For a permanent building, even without heating, one brick (250 mm) is considered the minimum.
⚠️ Attention: Laying garage walls in half a brick (120 mm) without frequent support pillars is prohibited by building regulations for buildings more than 2 meters high due to the risk of collapse under its own weight and the influence of wind.
If you are planning heated garage, then the requirements change radically. According to thermal engineering calculations, a brick wall must have a thickness of 510 mm (two bricks) or more in order to meet energy efficiency standards. An alternative to thickening the wall is to use a multilayer structure: a load-bearing layer of 250 mm plus a layer of effective insulation (mineral wool or polystyrene foam) and cladding.
When building walls, it is important to control the quality of the mortar and the dressing of the seams. Cement-sand mortar should be plastic, but not too liquid so that the brick does not “float”. Particular attention is paid to corners and junctions where the load is distributed unevenly.
☑️ Quality control of brickwork
Calculation of the thickness of walls made of foam blocks and aerated concrete
Cellular concrete (foam concrete, aerated concrete) has conquered the market due to its excellent thermal insulation properties and large block dimensions, which speeds up construction. Wall thickness of such materials can be significantly less than brick while maintaining the same thermal characteristics. The standard block width is most often 200, 300 or 400 mm.
For a garage that will not be heated constantly, a 200 mm wide block would be the best choice. This is enough for the structure to retain heat longer than a metal garage and not freeze instantly. However, if you are planning frequent visits in winter or installing a boiler, it is better to choose a 300 mm block or additionally insulate a 200 mm wall.
The main feature of aerated concrete is its brittleness to fracture and low load-bearing capacity under point loads. Therefore, even if the thickness of the wall can withstand the load from the roof, the device is critically important reinforced belt along the top of the walls. This will distribute the weight of the rafter system and prevent cracks from occurring.
Unlike brick, cellular concrete blocks require special glue or foam for masonry, which allows for minimal seams (1-3 mm). This reduces the number of “cold bridges”. However, the material is hygroscopic, so external finishing is required to protect it from moisture.
- 🏗️ 200 mm wide blocks are suitable for unheated garages.
- 🔨 An armored belt under the Mauerlat is required to distribute the load.
- 💧 Mandatory hydrophobic facade protection is required.
- 📉 Low weight of the structure allows you to save on the foundation.
Why can’t an aerated block be placed on cement mortar?
Using a thick layer of cement mortar to lay aerated concrete blocks creates wide seams that act as powerful cold bridges. The thermal conductivity of the solution is 3-4 times higher than that of the block itself, which negates its energy-saving properties. Use only special glue.
Frame structures and metal garages
Frame garages and buildings made of metal profiles are a separate category, where the concept of “wall thickness” is transformed into “sandwich panel thickness”. Here the load-bearing function is performed by a metal frame, and the walls only enclose the space. The standard thickness of sandwich panels varies from 50 to 200 mm.
For seasonal use (spring-autumn), a panel 50-80 mm thick filled with mineral wool or expanded polystyrene is sufficient. If the garage will be used as a workshop all year round, the thickness of the enclosing structures should be at least 100-150 mm. Metal garages (“shells”) without insulation have a wall thickness of only 1-2 mm, which makes them unsuitable for comfortable living inside in cold weather.
The advantage of frame technology is the ability to lay any thickness of insulation inside the frame. You can make a 200mm thick wall by filling it with cheap foam and get excellent insulation at a relatively low cost. However, such walls have low sound insulation and require high-quality vapor barrier.
⚠️ Attention: When building a frame garage, use only non-flammable insulation (stone wool) if welding work is planned inside. Expanded polystyrene and polystyrene foam emit toxic substances when burned and can cause a fire to quickly spread.
An important element of a metal garage is anti-corrosion treatment. Even thick walls of sandwich panels can suffer if the tightness of the joints is broken. Waterproofing foundation and correct installation of the basement flashing are more important here than in brick buildings.
When installing sandwich panels, do not overtighten the screws. The cap should fit tightly to the metal, but not deform the surface of the panel, otherwise corrosion will begin at the attachment point.
Comparison of thermal conductivity of materials
To finally determine the thickness of the walls, it is necessary to compare the thermal conductivity of various materials. This coefficient shows how much heat the material transmits. The lower it is, the “warmer” the wall is with less thickness. Below is a table that will help you navigate your choice.
| Material | Thermal conductivity coefficient (W/m K) | Optimal thickness for middle strip (mm) | Do you need insulation? |
|---|---|---|---|
| Ceramic brick | 0.5 - 0.7 | 510 - 640 | Preferably |
| Aerated concrete (D400) | 0.1 - 0.12 | 300 - 400 | Not necessary |
| Expanded clay concrete | 0.2 - 0.4 | 400 - 500 | Yes |
| Sandwich panel (mineral wool) | 0.04 | 100 - 150 | No (built-in) |
| Wooden beam | 0.15 | 150 - 200 | Yes (for winter) |
From the table it is clear that aerated concrete and modern sandwich panels beats brick in terms of heat conservation. However, brick wins in heat accumulation: it cools down for a long time, smoothing out temperature changes. For a garage where the car sits for a long time, temperature stability is more important, so brick walls are often more practical than thin, but quickly cooling frame walls.
When choosing a material, you should also consider the cost of delivery and labor. A thick brick wall will require a powerful foundation, which increases the total estimate by 20-30%. Lightweight walls made of aerated concrete allow the use of a pile-screw or shallow strip foundation, which is significantly cheaper.
The choice of wall thickness is a compromise between the thermal conductivity of the material and its load-bearing capacity. It is often more profitable to make a thinner wall from an effective material and insulate it than to fence a meter-long brickwork.
Typical mistakes when building garage walls
The most common mistake is skimping on the foundation when choosing heavy materials. The owners build walls with two bricks on a weak foundation, which leads to the appearance of cracks already in the first winter. Foundation deformation inevitably pulls the walls along with it, and no amount of masonry thickness will save you from destruction if the base “floats”.
The second mistake is the lack of waterproofing between the foundation and the first row of masonry. The capillary rise of moisture from concrete destroys the lower rows of bricks or blocks. Be sure to use roofing felt or bitumen mastic on the foundation section before starting to lay the walls.
The third mistake is ignoring expansion joints. If the garage is long (more than 6-8 meters), expansion joints must be installed in the brick or block masonry, otherwise seasonal expansion of the material will lead to chaotic cracking of the walls in the middle.
⚠️ Attention: Regulatory requirements and prices for building materials may change. Before starting construction, be sure to check the current SNiP for your region and check the cost of materials with local suppliers, as logistics can significantly affect the budget.
Ventilation is also often forgotten. Sealed walls without vents create the effect of a thermos, but with moisture. Condensation on the walls and car is a direct path to corrosion. The thickness of the walls should allow the installation of ventilation ducts or provide for the presence of supply and exhaust openings.
What is an expansion joint and how to make it?
An expansion joint is a gap in the masonry filled with a material (mineral wool, sealant) that allows two parts of the building to move independently of each other when the temperature changes. It is made by tearing apart the masonry and installing two end surfaces with insulation laid between them.
FAQ: Frequently asked questions
Is it possible to make garage walls 250 mm thick (one brick) for year-round use?
Technically, it is possible to build, but operating such a garage in winter with heating will be extremely expensive. A 250 mm wall without additional insulation will freeze, condensation will form on the internal walls, and the heat will evaporate instantly. For winter use, such a wall must be additionally insulated (with mineral wool or polystyrene foam) with a layer of at least 50-100 mm.
What is the minimum thickness of an aerated block wall allowed by law?
According to building codes, for one-story outbuildings (which include a garage), the minimum thickness of load-bearing walls made of cellular concrete is usually 200 mm (when using blocks with a strength grade of at least B2.5). However, for two-story garages or when using a heavy roof, the thickness may be required more, which should be confirmed by calculation.
Do I need to reinforce garage walls made of foam blocks?
Yes, reinforcement is necessary. The first row is laid on the mortar and must be reinforced, and every 3-4 row is laid with reinforcing mesh or rods. This prevents the appearance of cracks during shrinkage and increases the fracture strength of the structure.
Does the thickness of the walls affect the need to obtain a building permit?
The thickness of the walls itself is not a criterion for obtaining permission. A garage is classified as an auxiliary building, and if it is not used for commercial purposes and is located on its own site, permission is usually not required (provided the setbacks from the boundaries are observed). However, the capital nature of the structure (foundation, wall material) affects its cadastral registration.
What is better for a garage: a brick wall or a thin one with insulation?
From the point of view of heating engineering and economy, the option “thin load-bearing wall + insulation” is more profitable. It allows you to reduce the load on the foundation and saves usable space inside the garage. A brick wall of 2-3 bricks without insulation is an overconsumption of materials and a loss of internal space for the same thermal efficiency.