Recommendation points
- Foam concrete
- Benefits
- disadvantages
- Myths and misconceptions
- Aerated concrete
- Benefits
- disadvantages
- Myths and misconceptions
- We count and compare
- Consumption of plaster mixture
- Cost of plaster solutions
- Plastering cost
- Bricklayer service cost
- Wall material cost
- The cost of the binder mixture and the consumption of wall materials
In this article we will answer a very important and topical question: what is more profitable to build a house from? Give preference to cheap foam concrete or “splurge” on more expensive and high-quality aerated concrete. Our calculations will surely surprise you.
“What should we build a house?” – this is the question that a modern developer is thinking more and more often. And today, when aerated concrete materials such as foam concrete and aerated concrete claim the place of the main structural material for the construction of cottages, it is often difficult for even an experienced builder to make the best choice..
Looking ahead, I will say that if the work is done correctly without violating construction technologies, the difference in the final cost of the finished wall will be insignificant. First, let’s figure out what foam and aerated concrete are, and what is the fundamental difference between them.
Foam concrete
Foam concrete is a product of foaming of a sand-cement mortar. Numerous air bubbles define the structure of the material as cellular. All pore cells are closed – isolated from each other.
Benefits
Cheapness
The cost of a cube of foam concrete, depending on the manufacturer, is 1600–4000 rubles. For the estimated cost of the material, we take the average price – 2300 rubles / cubic meter. A similar volume of bricks will cost about 3200 rubles. And this despite the fact that for the construction of a wall with the same thermal conductivity of a brick, several times more will be required.
Thermal insulation indicators
With a foam block density of 500-800 kg / m3 its thermal conductivity will be 0.12–0.21 W / (m? K), respectively. For example: a brickwork has a thermal conductivity of about 0.6 W / (m? K), which is 3-5 times higher than that of a wall made of aerated concrete.
Ease of installation
Since foam concrete blocks have a relatively small actual weight with significant dimensions, it is quite easy to erect a wall from it, which, ultimately, has a positive effect on the cost of laying it.
disadvantages
Low bearing capacity
With a material density of 500 kg / m3, its strength is only 13 kg / cm2. With an increase in density, thermal insulation qualities are lost. So at a density of 900 kg / m3 bearing capacity increases to an acceptable 35 kg / cm2, but the thermal conductivity also increases to 0.24 W / (m? K), which depreciates the main advantage of this material – low thermal conductivity.
Bad geometry
If you look at things realistically, and not through the prism of advertising PR, then the geometric shape of domestic foam concrete is very far from ideal. Whether it is the human factor or the equipment purchased “for inexpensive” is to blame, but the fact remains. True, there is high-quality foam concrete, which can really be laid on glue, but, unfortunately, the price of such material is not much lower than that of aerated concrete and is about 3000-3500 rubles per cubic meter.
Inhomogeneous structure
The density of the gas bubbles and their size in foam concrete cannot be calculated. Remember how foam rises in a glass of beer, here is the same effect, so cold bridges are also possible, that is, areas whose thermal conductivity is much higher than the average declared.
The risk of buying low-quality material
Relatively inexpensive equipment for the production of foam concrete and simple technology made it possible to produce this wall material in “handicraft” conditions, without strict control over the quality of the products. It was these grief-Kulibins that discredited foam concrete in the post-Soviet building materials market.
Myths and misconceptions
- “Foam concrete does not” breathe “, as it has an isolated cellular structure”.
Foam concrete perfectly “breathes”, since gas exchange does not depend on open or closed pores. The key criterion here is the density of the molecular structure and the total thickness of the material..
- “To build a house, a 30–40 centimeter wall made of foam concrete with a density of 500–600 kg / m is enough3“.
From the point of view of thermal insulation, 40 cm thick walls made of material with a thermal conductivity of 0.12 W / (m? K) will certainly be enough for the most severe Russian winter, but the bearing capacity of foam concrete of the above density is so small that it simply cannot withstand the load imposed on it. More durable brands of foam concrete will have too high thermal conductivity. The optimal solution is a wall cake with a thickness of 600 mm, consisting of a load-bearing row of foam blocks with a density of 800-900 kg / m3 and insulation – foam concrete with a density of 400-500 kg / m3.
Aerated concrete
Aerated concrete is an artificial stone with a porous structure. Micropores 1–3 mm in size communicating with each other are evenly distributed throughout the material.
Benefits
Fake diamond
Aerated concrete is inherently artificial stone, not just concrete. With the same density, it will be many times stronger than other cellular concrete.
Good geometry
Since gas blocks are made by cutting a solid aerated concrete slab, and not by pouring into molds with questionable geometry, all block dimensions are respected with a tolerance of up to a millimeter. As a result – the ability to lay on thin-glue.
Adhesion
Due to its porous, rather than homogeneous structure, aerated concrete is easily processed with finishing materials.
disadvantages
Price
Yes, it is the price that initially scares people away from aerated concrete, who do not understand well the technology of construction processes. After all, it’s hard to believe that you can save money by buying such an expensive material..
The need for waterproofing
Of course, even Soviet scientists proved that despite its spongy structure, aerated concrete is not afraid of precipitation and even in winter it will not “tear” from the destructive effects of frozen moisture. But the appearance of such a “wet” building will be terrible. So you can’t do without facade plaster, siding or the same porcelain stoneware.
Myths and misconceptions
- “The aerated concrete masonry is so even that it is quite possible to do without plastering”.
Yes, from aerated concrete, laid on glue, indeed, with certain skills, a perfectly flat wall is obtained. But you still need to plaster it!
Firstly, a wall just laid out of blocks is very breathable – no matter how you fill the seams, there will still be flaws.
Secondly, aerated concrete putty gives cracks, which, as a rule, repeat the outlines of the wall blocks. That is why plaster is reinforced with a facade mesh.
- “It is very expensive to lay aerated concrete on glue”.
And again delusion. Let’s not be unfounded and just use elementary mathematics.
The manufacturer specifies in the norms one bag of adhesive mixture per one cube of aerated concrete blocks.
Let’s discard advertising and put in a more realistic consumption: one and a half bags (37 kg) per one meter of cubic wall material. This, at a price of glue 6.50 rubles. per kilogram, it comes out about 240 rubles. That is, the cost of the glue mixture when laying a cubic meter of gas blocks will be about 240 rubles.
Now let’s see what the masonry will cost us when buying a cement mortar.
Even if we just open the tables and take these values, then the consumption of the sand-cement mixture per cubic meter of masonry will be 0.22 m3, that at an average price of 2500 rubles. per cube will be 550 rubles. Obviously, the glue will cost us half the price..
We count and compare
And now let’s try to find out from what it is financially more profitable to build a house? For comparison, let’s take a square meter of a wall made of foam concrete and a similar volume of aerated concrete structure. For greater clarity, we will take into account the different types of plaster materials used on the wall.
Consumption of plaster mixture
The aerated concrete wall, due to the better geometry of the material, turns out to be perfectly flat, so that the thickness of the plaster will be equal to the section of the lighthouse profile ± 1 mm. Total, an average of 7 mm. For each millimeter of a square meter of machine plaster, 1 kg of the mixture is consumed, that is, we get 7 kg of the plaster mixture per square meter of the aerated concrete wall. In the case of using lime plaster, by multiplying the square by the thickness, we find the volume of the plaster “cake”, it will be equal to 0.007 m3.
The situation is different on a foam concrete wall. Since the geometry of the material is far from perfect, the wall is not too even. Typically, the thickness of the plaster layer is about 3 centimeters. That is, the consumption of the mixture for machine plastering and the use of lime mortar will be 30 kg and 0.03 m3 respectively.
Cost of plaster solutions
The market price of PM-75, which is used for machine plastering, is 240–250 rubles. This is about 8 rubles. per kilogram of mixture. The price of a lime mortar is on average 2500 rubles. per cube.
Plastering cost
Different teams estimate the cost of their services differently, but the average picture will be as follows: machine plaster with a layer of up to 1 cm about 340 rubles, up to 3 cm – 360 rubles. Handwork is estimated at 450 rubles per square meter.
Wall material Aerated concrete Foam concrete Type of plastering work machine plaster lime plaster machine plaster lime plaster Consumption of plaster mixture per 1 m2, (kg, m3) 7 0.007 thirty 0.03 Price 1 kg, 1 m3 plaster mix, rub. 8 2500 8 2500 Cost 1 m2 plastering works, rub. 340 450 360 450 The total cost of the plaster “cake”, rub. 396 467.5 600 525 These data clearly show that when using more expensive, but higher quality aerated concrete, we save about 100 rubles. on each “square” of plaster. For plastering surfaces with a plaster layer thickness of more than 3 cm, it is more advantageous to use a lime mortar.
Bricklayer service cost
The cost of laying gas and foam concrete is the same and averages 1,500 rubles per cubic meter of wall. However, as we found out above, the thickness of the aerated concrete wall is 40 cm, while for a full-fledged load-bearing foam concrete wall, this figure is at least 60 cm. This implies a different volume of wall material used on one “square” of the finished wall made of different materials: aerated concrete 0.4 m3, foam concrete 0.6 m3.
Wall material cost
When calculating the cost of gas blocks, we will take products of the YTONG trademark as a basis, since they can serve as an example of high-quality aerated concrete. Unfortunately, the quality of domestic materials still leaves much to be desired, and only discredits this wonderful building material.
The cost of YTONG gas blocks is about 4420 rubles / m3. As a basis, when calculating the cost of foam concrete, we will take the average domestic block worth 2300 rubles / m3. We deliberately missed the more expensive and high-quality foam concrete, since its price is not much lower than the price of aerated concrete blocks, moreover, the quality of the latter, a priori, will always be higher.
The cost of the binder mixture and the consumption of wall materials
According to tabular data for laying 1 m3 walls made of blocks with dimensions of 625x250x300 mm, 0.22 m is required3 cement-sand mortar and, accordingly, 0.78 m3 wall blocks.
For laying aerated concrete blocks 625x250x400 mm, 37 kg of glue is needed, which is 0.07% of the wall volume. At the same time, the market value of the cement-sand mortar is 2500 rubles, and the cost of a kilogram of glue is 6.50 rubles.
Based on these data, we get:
Wall material Aerated concrete Foam concrete Cost 1 m3 masonry, rub. 1500 1500 Volume 1 m2 walls, m3 0,4 0.6 Wall material consumption per 1 m3 masonry, m3 0.93 0.78 Cost 1 m3 wall material, rub. 4420 2300 Cost 1 m3, 1 kg of binder solution, rub. 6.5 2500 Solution consumption per 1 m3 masonry, (kg, m3) 37.5 0.22 Total cost of the wall, rub. 2,341.74 2,306.40 As you can see, the choice of wall material practically did not affect the final cost of the wall itself. The best physical and technical indicators of aerated concrete ultimately leveled the price advantage of cheaper foam concrete, leaving behind all its advantages.
The final table looks like this:
Wall material Aerated concrete Foam concrete Type of plastering work machine plaster lime plaster machine plaster lime plaster Consumption of plaster mixture per 1 m2, (kg, m3) 7 0.007 thirty 0.03 Price 1 kg, 1 m3 plaster mix, rub. 8 2500 8 2500 Cost 1 m2 plastering works, rub. 340 450 360 450 Cost 1 m3 masonry, rub. 1500 1500 1500 1500 Volume 1 m2 walls, m3 0,4 0,4 0.6 0.6 Wall material consumption per 1 m3 masonry, m3 0.93 0.93 0.78 0.78 Cost 1 m3 wall material, rub. 4420 4420 2300 2300 Cost 1 m3, 1 kg of binder solution, rub. 6.5 6.5 2500 2500 Solution consumption per 1 m3 masonry, (kg, m3) 37.5 37.5 0.22 0.22 The total cost of the plastered wall, rub. 2 737.74 2 809.24 2,906.40 2831.40
I’m quite curious to know, for those who are experienced or knowledgeable in construction, which material would be a better choice for building a house: foam concrete or aerated concrete? Both seem to have their advantages, such as foam concrete’s thermal insulation and fire resistance, and aerated concrete’s durability and strength. But I wonder if one outweighs the other in terms of cost effectiveness, sustainability, or ease of construction. Any insights or comparisons between these two options would be greatly appreciated!