- What is the technology
- Why monolithic sandwich technology is considered the most reliable and durable
- Foundation and walls of the basement
- Basement (foundation) slab
- Foundation walls
How to choose a technology for the construction of a reliable capital foundation of a building that will stand for a hundred years? What do you need to know about reinforcing composite structures? How to build a reinforced concrete foundation without precast formwork with your own hands? This will be discussed in our article..
The debate about the “best” material for walls and generally about advanced construction technologies is endless – each of them is good in its own way. We bring to your attention a combined technology using simple materials, which will provide structural strength, thermal insulation and good appearance..
Capital stone construction is suitable for those who decide to settle seriously and permanently in the suburbs. It cannot be called cheap and fast, but the result will last at least 100 years..
What is the technology
The principle of constructing warm, reliable and massive walls is quite simple – a fixed stone formwork with internal filling and reinforcement. The secret lies in the nuances – what to make the formwork from, what and how to reinforce and what solution to use as filling. When choosing filling materials and constructing the wall section, the principle of the overlap is decisive.
Why monolithic sandwich technology is considered the most reliable and durable
Each of the structural elements individually has specific features:
- Reinforced concrete with the best strength indicators requires an additional stage – insulation. The second important disadvantage is the inevitable cost of formwork. At the same time, the main factor of its strength – the combination of reinforcement and concrete – provides the structure with a service life of up to 100 years (unprotected).
- Solid red brick and sandstone (“savage”) – record holders for weather resistance and “vitality” of masonry elements. A single brick can last up to 300 years – ancient fortresses are excellent proof of this. But its disadvantage is a weak bunch of individual stones with each other when constructing a thin (0.5 brick) wall. Only a layer of mortar holds the brick plane. In thicker walls (from 1 brick), the structure is held by static forces (weight).
- Insulation, if mounted with an additional “wet” or “dry” layer, is not a load-bearing layer, but, on the contrary, completely transfers the load to the wall structure.
So, the tasks, having solved which, we get the optimal combination:
- Protection (insulation) of reinforced concrete and the entire wall – on both sides the monolithic layer is lined with brick (stone).
- Reducing the cost of formwork – formwork of walls and foundations is completely absent (not counting the flanging of the slab and armopoyas).
- Reinforcement of the seam and the bond of individual elements of the masonry – the wall filler based on cement mortar will adhere to the seams of the masonry, while completely connecting the stone plane along the inner surface of the stone formwork.
- Apply insulation in such a way that it works in the structure.
The addition of granulated slag and fine gravel to the solution will reduce the strength of reinforced concrete, which will be compensated for by the outer walls – they will keep the shape of the wall. In this case, the additives will reduce the thermal conductivity by a factor of 3–3.5. Instead of granulated slag, it is quite possible to use expanded clay, vermiculite or a foam ball.
The complexity of the perception of the entire technology as a whole lies in its unusualness and apparent complexity. In fact, such a stone house will be cheaper and easier than a completely brick or reinforced concrete frame..
Foundation and walls of the basement
Despite the use of lightweight aggregate in the walls, the foundation for such a house will need a reliable foundation. Moreover, a zealous owner will certainly want to use the underground space for a workshop, warehouse, garage or cellar. The thickness of the foundation walls for any sandwich construction should be equal to the thickness of the building walls. So the load will be evenly distributed over the entire area of the horizontal cut. The foundation walls themselves are also recommended to be made using a multi-layer technology in order to use full-fledged reinforced concrete and not waste time and money on the installation and dismantling of the formwork.
Council. We recommend using factory concrete M200 B15 for filling the walls of the foundation.
Basement or basement construction consists of three stages – slab, walls and ceiling. We will consider the first two elements as they remain the same, while the floor slab can vary, and we will try to cover all possible material combinations..
Basement (foundation) slab
1. Excavation work – an excerpt from the pit. The dimensions of the pit should exceed the dimensions of the house by 80-100 cm.
2. Preparation, drainage. The pit is filled with sand or crushed stone over the entire area with a thickness of 200–250 mm and carefully rammed with vibrating rammers. If necessary, drainage channels are arranged.
3. Key point. Roll waterproofing is laid on top – euro-roofing material or another. Waterproofing must be reliable – then the basement will be dry.
4. Foundations. The entire area under the future building is concreted with a layer of 50–60 mm. This is done for the convenience of further work..
5. Basement floor slab. It will be 250 mm thick with two-layer reinforcement:
- We break the platform under the slab using dowels and fittings, pull the cords.
- Key moment. Checking the diagonals, right angles. Correct the breakdown if necessary.
- We knit the first mesh of the frame. Armature A3 16 mm with an equal cell of 150 mm. It is allowed to lay insulation (expanded polystyrene plates M35) only under flat.
- If the basement has a pool, sauna, shower room, bathroom, you can lay a 50 mm sewer pipe in the body of the stove. However, it should not pass under the walls..
- At the installation site of the walls, there must be reinforcement reinforcement – add one solid rod to each cell along the entire length of the wall.
- Set the stops for the first and second mesh of the wireframe. Distance between meshes 150 mm.
- We knit the second frame mirror to the first, observing the rule of reinforcement under the walls. Key point – cells of both grids must not match.
- We knit U-shaped elements into the frame under the walls with a pitch of 150 mm so that the free outlets are located vertically.
- We expose the flanging and once again check the geometry of the building. The basement slab may go beyond the boundaries of the walls, but the resulting step must be reinforced.
- Concreting the basement slab with factory concrete. Cover the stove with a “blanket”.
After placing the concrete, at least 3 days must pass for the cement to set. It is advisable to withstand 7 days before starting the next stage.
At this stage, the thickness of the walls of the house is laid, which will “grow” from the walls of the foundation. The section size is determined by the outer edges, regardless of the difference in filling volumes. Both formwork walls of the foundation are laid out in half a brick.
1. We knit a vertical mesh:
- We impose vertical rods on the outlets of U-shaped elements with a length exceeding the height of the basement by 600-700 mm.
- We set the corners vertically in level, tying the slopes from the reinforcement at the corners.
- In places of openings, we install boxes in such a way that masonry can be laid along their planes. Under the lintels of the internal openings, we start a clip – two corners with a length equal to the width of the opening plus 600 mm. A mesh or rods are welded between them. The result is a combined concrete lintel frame.
- We tie horizontal rods to the vertical rods, observing the separation of the cells and the distance between the grids. Vertical bars above the floor level of the future overlap must remain free.
Note.The distance between the grids is a key dimension that remains unchanged over the entire height of the wall and is laid by the U-shaped elements of the basement slab. The size of this distance is determined by the selected building technology. Passing solid rods through all the elements of the building, the reinforcement ties them together.
- We install reinforcements (additional rods) in the corners, along the lower part of the wall, in the upper part of the wall, framing the opening.
- We install limiters of the “sun” type.
2. We lay out the brick sides of the walls of the foundation.
For this work, it is possible to use used red solid bricks. It is better to prepare the solution on M500 cement. Masonry is carried out in the usual way, the seams are rubbed from the outside for maximum bunch of bricks together.
An important key point. Every 3 rows, be sure to tie both walls with a masonry mesh with a cell of 100–150 mm. At the edges, it must be bent in the manner of a hook so that the adhesion between the walls is maximum.
Attention! Do not use a dense mesh (50×50 mm) – it will be difficult to vibrate the mixture.
The walls of the foundation are best concreted every 1.5 m, that is, twice. To fill the sinuses, we also recommend using factory concrete M200 B15. After placing concrete in the walls, external waterproofing of the walls should be done and the sinuses of the pit should be filled without tamping.
In the next article we will tell you how to arrange floors and erect walls of a building..