What can be done with foam concrete

Sane-minded people have long understood that building a house, and even more so on an individual project, is an expensive and troublesome business. And every year, calculating labor savings, we realize with bitterness that construction will have to be postponed indefinitely. Today, a medium-sized wooden house (six by six meters) will cost about $ 5,000, and a brick one is even more expensive. And this option – no fancy, no tricky planning and even without finishing!

Meanwhile, houses can be built not only from bricks, logs or timber. There is material that reduces the cost of construction by about one and a half to two times and has many other advantages. It is called foam concrete. In the West, they have been building from it a long time ago. And we, as usual, think, scratch in the back of our heads and doubt. But in vain! It is foam concrete that could give many of us a roof over our heads in the truest sense of the word.

About what is not in dictionaries

Alas, nothing was said about this material in the encyclopedic dictionary. How so? Just in case, I read everything that was said simply about “concrete”. It turned out that it is “one of the most important building materials, which is obtained as a result of the hardening of a compacted mixture of a binder, water, aggregates and, in some cases, additives. Depending on the bulk density, concretes are subdivided into especially heavy, heavy, light and very light. By the type of binding agent, concretes are cement, silicate, gypsum, asphalt concrete, polymer concrete, etc. “.

Not a word about foam concrete. Maybe it’s some kind of special concrete with the addition of special foam? Just what kind of foam is it, how does it affect construction costs and what properties does it give to the material? It is not clear yet.

Several hours of wandering among the exhibition stands also did not bring clarity. One thing became obvious: here you can find anything you want – tiles, porcelain stoneware, bricks, shingles … Foam concrete was not offered. None of the sellers could answer my questions anything concrete and intelligible …

Then I had to go to the Central Scientific Design Bureau (TsNKB). There, as it turned out, they have been working on the creation of installations for the production of foam concrete for several years. They certainly know everything about him.

A bit of history. Oddly enough, foam concrete is not an achievement of modern super-technologies. This material appeared in Russia almost seventy years ago. In the 30s, a Soviet scientist, experimental builder Bryushkov (his name, alas, was lost in the annals of history) added a soap root to the cement mortar – a plant that lives in Central Asia and forms foam. As a result, a new building material appeared – foam concrete. And that’s it! Later, specialists began to actively mix cement with chemical additives – foaming or gas-forming substances (aluminum powder, glue rosin solution, etc.). On the basis of these developments, Russia began to produce building materials from foam concrete – blocks, partitions, wall panels, which in their thermal insulation properties exceeded brick and heavy concrete by 3-5 times..

Pumice or chocolate?


And here it is – foam concrete (on the left – with sand additives, on the right – with polystyrene additives)

They knew everything. And they said that foam concrete is an ordinary cement mortar, which is mixed with a small amount of additives, pore-forming agents. They are also called surfactants (surfactants) and, by the way, are widely used in the production of washing powders and shampoos. So foam concrete and all kinds of detergents are in a sense, relatives, albeit distant.

In appearance, foam concrete turned out to be a rather ugly gray material, externally resembling pumice, and “internally” – porous chocolate. The fact is that as a result of foaming, the concrete mass is filled with air bubbles and acquires a cellular structure. And this, in turn, makes the material lightweight: it is no coincidence that experts classify foam concrete as lightweight aerated concrete. The same quality gives the material additional sound and heat insulation properties. So, despite its nondescript, foam concrete is a very wonderful thing..

But with us – as always! Despite the obvious advantages of the new material, foam concrete has not taken root in Russia. There are several reasons for this: there were no high-quality foaming agents, good units for the production of foam and other equipment. Therefore, our builders continued to use traditional “Russian” materials – bricks and wooden beams. Cellular lightweight concrete was simply forgotten.

And they would hardly have remembered if one circumstance had not formed, moreover, on a national scale.

Second birth


Styling options for foam concrete:
1 – roof or floor;
2 – laying in a fixed formwork (outside – brickwork, inside – drywall or fiberboard, foam concrete is poured between them);
3 – laying in a removable formwork

It happened a few years ago. Russian experts, following the decree of the Ministry of Construction of the Russian Federation, conducted research on heat conservation in residential buildings. It was required to find out whether it is possible to somehow save fuel and energy resources? And to everyone’s surprise, it was found that traditional building materials (the same brick or ordinary concrete) have a very low level of thermal protection. Therefore, the state, and we, its citizens, have to spend a lot of money on heating – by the most conservative estimates, two to three times more than in developed countries. As usual, to begin with, the slogan was put forward: “Energy saving is the first priority”, and the builders were given a “wise” order “to increase the thickness of the enclosing structures made of traditional materials”.

But this, as usual, only complicated the situation – construction became more than twice as expensive.

Later, another interesting document appeared – the Decree of the President of the Russian Federation “On the development of the federal target program” Own House “. This program provided for the development of the production of new types of building materials, which should, in turn, reduce the cost of construction.

It was then that the experts remembered our “native” foam concrete. “From above” was followed by another strict directive – to increase the production of building materials (primarily from aerated concrete) and create technological installations for their manufacture. In general, to improve the “new” invention of 70 years ago.

After this state upheaval, the foam concrete was again subjected to careful analysis and a number of tests were carried out. For the experiment, two walls were laid out – one of bricks, the other of foam concrete. And what happened? To keep the same warmth in the room, the brick wall must be five times thicker than aerated concrete! Thus, even a layman understands that the construction of a brick house will accordingly take five times more. Which certainly makes brick construction quite expensive. In order to somehow solve this problem and at least slightly reduce the thickness of the brick walls, builders from time immemorial have made heat and sound insulation “layers” of mineral wool or expanded polystyrene plates in brickwork. But this is also a double-edged sword: it turned out that mineral wool quickly absorbs water, and polystyrene foam is flammable and toxic.

And what about foam concrete? Foam concrete owes its positive technical properties to its internal cellular structure, reminiscent of porous chocolate. Moreover, each air cavity, like a submarine compartment, is hermetically sealed from neighboring cells. As a result, water does not seep inside.

But still, this is not the main thing. Due to all the same cellular pores, foam concrete is a good heat and sound insulator: in a house made of foam concrete it is warm in winter, cool in summer and quiet at any time of the year. Walls and partitions made of foam concrete perfectly tolerate temperature changes. They “breathe” and do not sweat. The microclimate in foam concrete buildings is the same as in wooden houses. Moreover, this material is environmentally friendly and fireproof: it is made of cement and sand, and therefore, there is simply nothing to burn.

All this is certainly interesting and important. But I was worried about something else: is it possible to build a house from foam concrete and how to do it? TsNKB employees explained that foam concrete is suitable for all types of construction: both public and private. Moreover, those wishing to have their own house can get by with “little blood” both in terms of finances and in terms of time. Only the appropriate equipment is required. Here you need to add the main thing: this equipment is not cheap – about 7 thousand dollars. Most likely, such a price will discourage the summer resident from any desire to build a house from foam concrete. But there is no need to despair: there is a way out of this situation – you need to find a company that has an installation for the preparation of foam concrete. Its employees will come to the site, bring the equipment and start building the house. If you still want to acquire your own equipment, then it will be more profitable to “chip in” with your neighbors and buy the installation in a club.

Math calculations


If funds are not enough, you can build a house from foam concrete in parts

In general, foam concrete cannot be prepared without a special unit, which means that nothing can be built. Now is the time to do the calculations to determine how much a foam concrete house will cost us. We will proceed from the fact that we are building walls for a house, for example, measuring 6 x 6 m.

First of all, you should decide on an architectural solution. Let’s say you have selected a project. What’s next? As you know, building a house begins with laying the foundation. The pleasure at the present time is not cheap – you need to pay about $ 2000. After the workers make the foundation and it “settles down”, you can start building.

To do this, you need to buy “raw materials” (cement and sand), pump water from the well and invite a team of workers with a foam concrete plant. As a result, everything about everything will take somewhere between $ 2000 – $ 2500 (construction materials plus work). Add here $ 2,000 for the foundation. Thus, a house made of foam concrete, built by the method of monolithic removable formwork, will cost about $ 4000 – 4500, and a house made of ready-made blocks – 1.5-2 times more. This amount is in any case less than the price for building a brick and even a wooden house. In addition, it is quite possible to build in parts: first the walls, then the partitions, then the roof. By the way, nails can be driven into foam concrete, it is very easy to paint and even saw with a regular hacksaw. So the wall can be reduced by simply cutting it off. Let me remind you that if you decide to use a monolithic installation with permanent formwork, or if you decide to lay down a house from ready-made foam concrete blocks, the construction price will increase significantly. So before making a decision, it is worth weighing all the pros and cons.

Are there internal walls made of foam concrete?

There are. This time we talked, so to speak, about the “outer walls”. But it is quite possible to build excellent interior partitions from foam concrete. Moreover, they are much better than walls made of plasterboard or brick. For example, if you need to make redevelopment, then putting a new brick partition is very risky and inconvenient. Risky, because your overlap may simply not be able to withstand such a weight. And it is inconvenient, because in the process of “brick” work there will be a lot of dirt, construction dust and debris.

As for drywall, it is not enough to simply block a room for them – this is not yet a wall. Firstly, special guides are needed, on which two sheets of drywall are fixed parallel to each other. Secondly, between them you still need to lay some kind of soundproofing! And thirdly, it is not recommended to hang anything heavier than a photograph of a beloved dog on such a wall – the wall may simply not withstand a more serious load..

So, foam concrete will successfully fulfill all these tasks: the process of its production is much “cleaner”, and besides, the wall made of this material is light, durable and reliable. Moreover, if you wish, you can even make a headboard (a kind of podium) for the bed out of it, or else, as the designers write, “somehow originally solve the design of the living space”.

Recipe for making foam concrete

The technology for making foam concrete is quite simple and even somewhat resembles the preparation of a pie. First, the “dough” of cement, sand and water is kneaded (and in some cases polystyrene granules are added instead of sand (then the material is lighter). Then the finished foam is added to the homogeneous mass, which makes the foam concrete porous. The “dough” is ready, you can form wall blocks, floor slabs, enclosing structures.

In modern conditions, foam is obtained from a foam concentrate. It is produced industrially. To prepare foam, special equipment is needed, for example, a foam generator or a small-sized installation (see drawing), which not only “whips up” the foam, but also mixes it with cement mortar. By connecting a hose to the installation, you can supply (transport) the ready-made mixture to a house under construction at a height of 20 m and a distance of 40 m. Only two people operate the installation, but the performance is amazing – 1600 – 4000 l / h! The only condition: in order for the foam concrete to turn out to be of high quality, the air temperature during mixing must be at least 10 degrees C..


Installation for the preparation and supply of foam concrete:
1 – mixer; 2 – lattice; 3 – bunker; 4 – gerotor pump; 5 – frame; 6 – foam generator; 7 – vacuum gauge; 8 – control cabinet; 9 – container with foaming agent; 10 – pipeline (hose)

The installation is quite compact: it takes about 2.5 sq.m., it can be easily put into the back of a Gazelle and taken to the construction site. By the way, with its help, you can make foam concrete not only on the street, waiting for the cherished +10 degrees C, but also indoors (if you need to fill, say, the floor or make a partition).

In the manufacture of blocks, monolithic laying is used, in which foam concrete is poured into the formwork, thus obtaining a whole wall, partition, etc. Formwork can be either removable (sliding) or non-removable. For removable formwork, fibreboard is used. They are placed on both sides, foam concrete is poured inside, and then removed. It turns out a flat wall or partition. Moreover, fiberboard is used repeatedly.

With fixed formwork, different options are possible: either brick walls are erected on both sides, and foam concrete is poured between them, or from the outside – brick, and from the inside – fiberboard, drywall, etc. After foam concrete is poured between these two layers, fiberboard can be removed, or it is possible not to remove it – this is a matter of taste. If you nevertheless decide to remove the fiberboard and leave the “foam concrete” surface inside, you can paint it, glue tiles to it, etc..

If you want to make a monolithic installation, the company that carries out the construction will take care of the formwork. But we should not forget that with monolithic laying with fixed formwork (especially if brick walls are erected on both sides), the construction price increases several times. In other words, monolithic installation with removable formwork is cheaper than with non-removable.

Don’t want to mess with monolithic styling? Fold the house from ready-made foam concrete blocks, fastening them with cement mortar. The blocks are sold in specialized stores and construction markets. You can also contact directly the manufacturers of reinforced concrete products – precast concrete factories. The dimensions of foam concrete blocks are different, but, as a rule, these are “bricks” measuring 0.2 x 0.2 x 0.4 m (width x height x length) or 0.2 x 0.3 x 0.6 m, which are sold at a price of 15–20 rubles apiece. And one more thing: if you build a house from ready-made blocks, then it will still cost no less than a brick one.

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