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Often during the repair process it is required to install partitions, and more and more often aerated concrete (gas silicate) is used for this. It is lightweight – it weighs several times less than a brick, the walls fold quickly. Therefore, aerated concrete partitions are installed in apartments and houses, regardless of what the load-bearing walls are made of.
Thickness of aerated concrete partitions
For the construction of partitions inside the premises, special gas silicate blocks are produced, which have a smaller thickness. The standard thickness of partition blocks is 100-150 mm. You can find non-standard in 75 mm and 175 mm. The width and height remain the same:
- width 600 mm and 625 mm;
- height 200 mm, 250 mm, 300 mm.
The brand of aerated concrete blocks must be at least D 400. This is the minimum density that can be used to build partitions up to 3 meters high. Optimal – D500. You can also take denser ones – grades D 600, but their cost will be higher, but they have a better bearing capacity: it will be possible to hang objects on the wall using special anchors.
Without experience, it is almost impossible to determine the brand of aerated concrete. You can “by eye” see the difference between the heat-insulating blocks density. D300 and wall D600, but between 500 and 600 it is difficult to catch.
The only available control method is weighing. Data on the size, volume and weight of aerated concrete partition blocks are given in the table.
The thickness of aerated concrete partitions is selected according to several factors. The first is whether it is a load-bearing wall or not. If the wall is bearing, in a good way, a calculation of the bearing capacity is required. In real life, they are made the same width as the outer load-bearing walls. Basically – from wall blocks 200 mm wide with reinforcement through 3-4 rows, like for external walls. If the partition is not load-bearing, use the second parameter: height.
- With a height of up to 3 meters, blocks of 100 mm wide are used;
- from 3 m to 5 m – the thickness of the block is already taken 200 mm.
More precisely, you can choose the thickness of the block according to the table. It takes into account factors such as the presence of an interface with the upper floor and the length of the partition.
Device and features
If aerated concrete partitions are installed in the process of repairing and redevelopment of apartments or houses, you must first apply markings. The line is upholstered around the entire perimeter: on the floor, ceiling, walls. The easiest way to do this is with a laser plane builder. If it doesn’t exist, it’s better to start with a stream:
- A line is marked on the ceiling (two points on opposite walls). Between them, a masking cord is pulled, dyed with blue or some other coloring dry substance. With his help beat off the line.
- The lines on the ceiling are transferred to the floor with a plumb line.
- Then the lines on the floor and ceiling are connected, drawing verticals along the walls. If everything is done correctly, they should be strictly vertical.
The next step in the construction of aerated concrete partitions is the waterproofing of the base. The floor is cleaned of debris and dust, waterproofing roll material is laid (any: film, roofing material, waterproofing, etc.) or coated with bituminous mastics.
Vibration damping strips
To reduce the possibility of crack formation and improve soundproofing characteristics, a vibration damping strip is spread on top. These are materials with many small air bubbles:
- hard mineral wool – mineral wool cardboard;
- polystyrene foam of high density, but small thickness;
- soft fiberboard.
The first row of blocks is laid on this strip with glue. Glue thickness – 2-5 mm, consumption at a thickness of 1 mm 30 kg / m3. Further, the construction of partitions takes place according to the same technology as the load-bearing walls. Read more about the technology of laying aerated concrete walls here.
On short spans – up to 3 meters – reinforcement is not done at all. On longer ones, a reinforcing polymer mesh, a perforated metal strip, as in the photo, etc. are laid.
Wall connection
To ensure connection with adjacent walls at the stage of laying, flexible connections are laid in the seams – these are thin metal perforated plates or T-shaped anchors. They are installed in every 3rd row.
If a gas silicate partition is placed in a building where such connections are not provided, they can be fixed on the wall by bending in the form of the letter “G”, leading one part into the seam.
When using anchors, the connection with the wall is rigid, which in this case is not very good: a rigid rod from vibrations (wind, for example) can destroy the adjacent adhesive and the body of the block. As a result, the junction strength will be zero. When using flexible links, all these phenomena will not affect the blocks so much. As a result, the bond strength will be higher.
To prevent the formation of cracks in the corners, between the wall and the partition, a damper seam is made. It can be thin foam, mineral wool, special damper tape, which is used when laying underfloor heating and other materials. To exclude the “suction” of moisture through these seams, they are treated with steam after laying.notpermeable sealant.
Openings in gas silicate partitions
Since the partitions are not load-bearing, the load will not be transferred to them. Therefore, there is no need to lay standard reinforced concrete beams above the doors or make a full-fledged jumper, as in load-bearing walls. For a standard doorway of 60-80 cm, two corners can be laid, which will serve as a support for the overlying blocks. Another thing is that the corner should protrude beyond the opening by 30-50 cm. If the opening is wider, a channel may be required.
In the photo, to reinforce the opening of a standard door, two metal corners were used (on the right), in the opening on the left, a channel was walled up, under which the grooves in the blocks were selected.
If the opening is not wide, and there are only two blocks in it, it is advisable to pick them up so that the seam is almost in the middle of the opening. So you get a more stable opening. Although, when laying on corners or a channel, this is not a table that matters: the bearing capacity is more than enough.
So that the metal does not bend while the glue dries, the openings are reinforced. In narrow openings, it is enough to nail boards; in wide openings, a supporting structure resting on the floor may be required (fold a column of blocks under the middle of the opening).
Another option on how to reinforce a doorway into aerated concrete partitions is to make a reinforced tape from reinforcement and glue / mortar. A flat board is stuffed strictly horizontally into the opening, nailing it to the walls with nails. Sidewalls are nailed / screwed on the sides, which will hold the solution.
A mortar is laid on top of the board, three bars of class A-III reinforcement with a diameter of 12 mm are placed in it. Partition blocks are placed on top, as usual, following the displacement of the seams. The formwork is removed after 3-4 days, when the cement “grabs”.
Last row – adjoining the ceiling
Since the floor slabs can sag under loads, the height of the partition is calculated so that it does not reach the ceiling by 20 mm. If necessary, the blocks of the upper row are sawn. The resulting expansion gap can be sealed with damping material: the same mineral wool cardboard, for example. With this option, sounds from the upper floor will be less heard. An easier option is to moisten the seam with water and fill it with mounting foam.
Sound insulation of aerated concrete
Although the sellers of gas silicate blocks talk about high rates of sound insulation, they greatly exaggerate. Even a standard block with a thickness of 200 mm conducts sounds and noises well, and even thinner partition blocks even more so.
According to the norms, the sound resistance of partitions should not be lower than 43 dB, but it is better if it is higher than 50 dB. This will give you silence.
To have an idea of how “noisy” the gas silicate blocks are, we present a table with standard indicators of the sound resistance of blocks of different density and different thicknesses.
As you can see at the block, 100 mm thick, it falls short of the lowest requirement. Therefore, when finishing aerated concrete, it is possible to increase the thickness of the finishing layer in order to “reach out” to the standard. If normal sound insulation is required, the walls are additionally sheathed with mineral wool. This material is not soundproofing, but reduces noise by about 50%. As a result, sounds are almost inaudible. The best indicators have specialized soundproof materials, but when choosing them, you need to look at the vapor permeability characteristics so as not to lock moisture inside the gas silicate.
If you need absolutely “quiet” walls, experts advise installing two thin partitions with a distance of 60-90 mm, which is filled with sound-absorbing material.