Monolithic lintels in openings from permanent formwork. Spied on the technology from the pros

On the first floor of my house, all the lintels are made monolithic - both above the windows and in the doorways. Because floor slabs were laid above them on an armored belt. And it turned out that all the walls are load-bearing. The mass is decent, so I think this is a mandatory technical solution. No metal corners under the blocks. The method was spotted on the channel Real Builder in YouTube.

House made of aerated concrete with a density of D500. The attic floor will also be concrete, monolithic using the technology of frequently ribbed floors. Therefore, in the bearing wall of the second floor, I also make monolithic lintels over the doorways. Moreover, there were scraps of reinforcement. There will be factory lintels over the windows. In the fall, I glued the permanent formwork and tied the reinforcement frames:

The frames for the frame were bent on a homemade machine from rods with a diameter of 5 mm. How I glued the permanent formwork (U-blocks), you can see in this video:

Only here shown are U-blocks for 400 mm wide walls. For a wall of 300 mm - I cut plates 5 cm wide on a machine for sawing aerated concrete. To the bottom of the U-block, cut 5 cm plates horizontally from a block 200 mm wide. It turns out a formwork with a width of 5 + 20 + 5 = 30 cm.

I installed props in the openings. The lintel will be continuous for two openings at once.

Raised the formwork, prepared the tool. Because it's still cold outside (especially at night), I don't want to dilute mineral glue. Installation was done on glue-foam for aerated concrete. Only the balloon needs to be heated to room temperature (the balloon was brought warm from the city). There are slight deviations from the width of 300 mm (the width of the cutting part of the blade is lost). But this is compensated by plaster.

Because above the lintels there will be another row of blocks 300 mm wide, then several pieces had to be cut from 400 mm blocks. They were not enough. And I don't want to buy blocks separately. Their price per piece in 1.5 times higher than one pallet. And the blocks still need to be delivered.

Let's move on to filling. This was done on a separate day after the installation of the formwork.

I laid the armored frames on concrete supports and tied them. I made the coasters from the remnants of concrete, pouring egg containers into plastic molds. Prepared a deep vibrator and a spatula for smoothing the surface.

The concrete was made thick, with a plasticizer and the addition of an anti-freeze additive (at night there is still a subzero temperature, although it is the end of April). Crushed pebble concrete. Concrete proportions: 2 buckets of sand, 2 buckets of rubble, 1.5 buckets of cement and an incomplete bucket of water. It turned out about 3 buckets of concrete. To fill the lintel, it took 4 mixes in a concrete mixer. Mandatory vibration with a deep vibrator. It makes no sense to fill in without vibrating.

After every third bucket, he smoothed the surface with a spatula. At the end of the work, I covered it with a film and pressed it with concrete tiles.

Using this technology, lintels from fixed formwork can also be made from wood concrete. But you need a reciprocating saw, or an electric saw with a carbide-tipped chain or such a machine on the ball of this electric saw. It is not difficult to collect, it cuts exactly. But the oil supply is clogged and the chain has to be lubricated by hand after every second sawing. But saving energy with an excellent result is more important.

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