Building a garage is not just about erecting walls, but creating a reliable shelter for your car, where thermal insulation, strength and durability are important. Modern. building-blocks (gas concrete, foam concrete, ceramzitoconcrete) have become an excellent alternative to traditional brick due to their size and thermal characteristics. However, to the budget did not get out of control, and the materials were enough exactly for the entire cycle of work without unnecessary residues, a competent preliminary calculation is necessary.
Mistakes in the planning phase can lead to the fact that you have to buy additional material, which may differ in shade, or, conversely, take tons of excess stone to the landfill. Precisely. masonry It allows you to optimize logistics and purchase the right amount of adhesive composition. In this article, we will analyze all the stages of calculations, from choosing the type of block to taking into account window openings.
⚠️ Never round the number of blocks down “just in case.” When cutting material and fighting during transportation, there can be a critical shortage, and the purchase of small volume is often impossible or impractical.
The choice of the type of blocks and their impact on calculations
Before you take on the calculator, you need to clearly determine what material will be built walls. The market offers gas-concretewhich are highly accurate geometry, and foam-concreteIt often has variations in size. Also popular. ceramsiteIt is very strong, but requires additional insulation.
The size of the products directly affects the final figure in the estimate. The standard size for wall blocks is 600×300×200 mm, however, manufacturers can produce products with parameters 625×250×250 mm or other variations.
For the garage, most often choose a material with a density of D500 to D700, which provides a balance between load-bearing capacity and thermal insulation. If you plan a second floor or a heavy roof made of concrete slabs, the calculation should be carried out taking into account the bearing capacity of the selected brand.
Basic calculation method: volumetric approach
The most common way to determine the need for material is to calculate the total volume of walls. You need to know the perimeter of the future structure, the height of the walls and the thickness of the masonry. The formula is simple: multiply the length, height and thickness of each wall, summarize the results and subtract the volume of window and door openings.
Consider an example of calculation for a standard garage of 6×4 meters with a wall height of 3 meters. The perimeter of the building will be 20 meters. If we use a block with a thickness of 200 mm (0.2 m), then the total volume of the walls without deducting the openings will be equal to: 20 m × 3 m × 0.2 m = 12 m3. This is a “dirty” volume, from which the voids must be excluded.
After obtaining a net volume of masonry, it is divided by the volume of one block. For example, if one block has dimensions of 0.6×0.3×0.2 m, its volume is 0.036 m3. Dividing 12 m3 into 0.036 m3, we get about 333 pieces. However, this method does not take into account the thickness of the seams and possible trimming, so a margin is necessarily added to the result.
Accuracy of measurements - the key to success. Do not rely on approximate data from the project, it is better to double-check the dimensions on the site, since the foundation can be filled with deviations. Use a laser rangefinder or roulette to remove actual dimensions.
Size calculation: an alternative method
The second popular method is based on the calculation of the area of the walls. This approach is convenient when the blocks are sold with pallets indicating the area that can be laid out from a single pallet. First, the total area of all walls is calculated: the length of the perimeter is multiplied by the height. For our example (garage 6×4 m, height 3 m) the area will be 60 m2.
Then it is necessary to determine how many blocks are contained in 1 m2 of masonry at the selected wall thickness. For a 600×300×200 mm block with half-block masonry (wall thickness 200 mm), the side facet area is 0.6×0.2 = 0.12 m2. Accordingly, in one square meter of the wall will fit 1 / 0.12 ≈ 8.33 blocks.
Multiplying the total area of the walls (net of openings) by the number of blocks in the square, you get the desired number. This method is often used by foremen for quick evaluation, as it allows you to visually estimate the number of rows and vertical seams.
When calculating the area of the walls, always subtract the area of all openings (gates, wickets, windows, ventilation), even if they are small. This will save up to 5-10% of the budget on materials.
Accounting for window and door openings
The garage is not a deaf box, it will necessarily have a gate, often a gate, perhaps a window for natural lighting and vents. Ignoring these elements will lead to the purchase of excess material, which will lie on the site for years, taking up space.
Standard garage doors have dimensions of approximately 2.5×2.2 m (area 5.5 m2). If you add a window of 1×1 m (1 m2) and ventilation, then from the total area of the walls you need to subtract at least 7-8 m2. In terms of blocks, this is about 60-70 pieces, which is almost a whole pallet.
It is important to consider not only the main gaps, but also armopository. If the top of the walls is planned to pour monolithic reinforced concrete belt, the upper row of blocks is either not laid at all, or a U-block is used, which works as a non-removable formwork. The volume of the armopod should also be subtracted from the total amount of wall material.
| Type of element | Standard dimensions (m) | Area (m2) | Saving blocks (pc, approximately) |
|---|---|---|---|
| The door is swinging | 2.5 × 2.2 | 5.5 | 45-50 |
| Standard window | 1.0 × 1.0 | 1.0 | 8-9 |
| Gateway at the gate | 0.9 × 2.0 | 1.8 | 15 |
| Ventilation duct | 0.2 × 0.2 | 0.04 | 1 (under trimming) |
Technological stocks and combat during transportation
No calculation will be complete without taking into account the stock ratio. Cellular concrete blocks - the material is fragile, and chipped corners during unloading or trimming are inevitable. Experienced builders recommend laying an extra 5% to the estimated volume for aerated concrete and up to 10% for foam concrete, which often has the worst geometry.
If you plan on complex architectural forms, bay windows or non-standard corners, the number of pruning will increase. In such cases, the stock should be increased to 10-12%. Also, the stock is necessary in case a part of the material is defective already in the masonry process (for example, internal voids or cracks).
⚠️ Note: When buying blocks, pay attention to the packaging. The material on the pallets should be covered with film. Wet block heavier than dry, and if you bring moisture-filled material, its weight may exceed the load capacity of the manipulator, which will lead to additional unloading costs.
It is also worth considering. seam-thickness. When using cement-sand solution, the seams can reach 10-15 mm, which “eats” the volume of masonry. When using a special glue for gas blocks, the seams are only 2-3 mm, and the effect of the solution on the volume is minimal.
☑️ Check before ordering blocks
Calculation of related materials: glue and fittings
In addition to the blocks themselves, it is necessary to calculate the amount of adhesive composition. The consumption of glue depends on the geometry of the block. For ideal aerated concrete, the flow rate is about 25 kg (1 bag) per 1 m3 of masonry at a seam of 2-3 mm. If the geometry is broken and you have to put it on the solution, the flow rate of the mixture increases by 4-5 times.
We must also not forget about reinforcement. Every 3-4 rows of masonry must be laid with a rebar with a diameter of 8 mm or use a basalt mesh. This prevents the appearance of cracks when the foundation shrinks. For a garage, two rows of reinforcements are usually enough: the first is above the windows and doors (liners), the second is under the mauerlat or armoposse.
To calculate the reinforcement, you need to know the perimeter of the walls and the number of rows to be reinforced. If the garage is 6×4 m, the perimeter is 20 m. Two rows of reinforcement (bottom and top of the openings) will need 40 linear meters of reinforcement plus overlapping on the corners. Don’t forget to buy a groove if you’re going to make grooves for the fittings inside the block.
The secret to saving on glue
If you buy blocks with imperfect geometry, do not try to plant them on a thin layer of glue, hoping to align the row. Use a cement solution for the first row to bring out the perfect horizontal, and then go to the glue, compensating for the unevenness of the blocks with the thickness of the seam.
Summary estimates and frequent errors
The final stage is to bring all the data into a single table. Errors are most often caused by inattention to units of measurement. Builders talk in cubes, sellers can count as pallets, and you can think in pieces. Always bring all values to a common denominator before payment.
A common mistake is to (forget) take into account the cap. Blocks cannot be placed directly on the foundation, a waterproofing layer is needed and often several rows of full-body brick or concrete, especially if the floor in the garage is below ground level. These series are considered separately.
And many people forget about it. need for delivery by a manipulator. Pallet with blocks weighs from 800 kg to 1 ton. If you do not have the opportunity to accept and unload such weight manually or by machinery, you will have to hire unloaders, which is an additional expense item.
⚠️ Note: Do not store blocks on the ground without a substrate. The porous material instantly absorbs moisture from the soil, which reduces its thermal insulation properties and can lead to the destruction of the structure when frozen. Always keep the pallets on a level ground.
The correct calculation of blocks for the garage includes: the volume of walls minus the opening, plus 5-10% of the reserve for combat, plus consumables (glue, fittings).
How to calculate the number of blocks if the walls are different thicknesses?
If the garage has partitions inside or extensions with a different wall thickness, the calculation is carried out separately for each section. Calculate the volume of the outer walls (e.g., 300 mm) and inner partitions (100 or 200 mm) independently using the appropriate dimensions of the blocks for each thickness, and then summarize the results.
Should we consider the seams when calculating the number of blocks in a cube?
In the volumetric method (dividing the total volume of walls by the volume of one block), the seams are already taken into account indirectly, since we take the full volume of masonry. However, if you count piece by piece, the theoretical number of blocks of 1 m2 (for example, 8.33 pcs) does not take into account the seam. In practice, the same 5% of the stock is added to this number, which covers the volume of seams and trimming.
Can I use used blocks for the garage?
Theoretically, it is possible, but the savings will be questionable. Used blocks often have chips, remnants of an old solution and disturbed geometry. Cleaning and leveling them will require more glue and time. For a garage, where sealing and the absence of cold bridges are important, it is better to use a new material, albeit a lower grade of strength, but whole.
What is the reserve to take on the battle: 5% or 10%?
For aerated concrete of autoclave production, which has an ideal geometry and is supplied in shrink film, 5% is enough. For foam concrete, which often pricks when unloading with forks, or if delivery is planned for a long distance on bad roads, safely take 10%. The remains of entire blocks can always be used for outbuildings.