Construction of a house using monolithic sandwich technology

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How to use bricks as formwork for reinforced concrete? How to lighten and at the same time insulate concrete so that it retains its bearing capacity? Is it possible to combine structural elements with finishing? In this article, we will show you how to build walls using monolithic sandwich technology..

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In the previous article, we talked about why this construction technology can be considered “eternal”, and also considered the construction of the foundation step by step. Now we will consider the device of floors and the construction of walls.

Overlapping

There can be three fundamentally different options – monolithic, factory (slab) or beams. The order of work will also differ.

Monolithic floor

By far the most reliable and constructively justified option. At the same time, it is the most time consuming and has limitations on the length of the span – 4.5 m. The positive factor is that a separate armored belt is not required. A separate article will be devoted to concreting the floor. Here we will simply outline the basic principles of connecting walls with floors..

Operating procedure

1. We install floor formwork on the forest or inventory racks-jacks. We lay out the plane with plywood or other material. We expose the formwork to the horizon.

2. We bend horizontally the reinforcement of the wall outlets so that the outer rod falls on the lower mesh.

3. Bend all the outer rods of the perimeter contour through one. As a result, all internal rods and external ones through one remain not bent (vertical).

4. We connect the bent rods with rods of working reinforcement A3 16 mm.

5. Add solid rods between them so that we get even cells 150×150 mm.

6. Install the limiters of the protective layer of the lower mesh and internal limiters of the frame (“frogs”).

Note. Adequate thickness of the floor slab of a residential building when using factory concrete is 160–180 mm. We do not recommend making it thicker, since this will add non-working mass.

7. Bend the inner rods horizontally so that they fall on the upper mesh.

8. We knit the upper mesh similarly to the lower.

9. We install the sides of the formwork around the perimeter on dowels “quick installation” or in another way.

10. We align and strengthen the sides, checking the geometry.

11. We install boxes (pipes) of technological openings and embedded parts.

12. We concreting the floor with factory concrete M200 B15.

We are building an

Attention! The laid slab must be kept for at least 28 days before dismantling the formwork.

Prefabricated slab – factory slab

In this case, the location of the basement walls will be dictated by the length of the product..

Benefits:

  • does not require formwork;
  • installation takes 1–2 days;
  • work can be continued immediately after installation;
  • factory quality concrete.

Disadvantages:

  • almost complete absence of a bond with the walls;
  • slabs should be joined along the axes of the walls;
  • you will need an armored belt on all walls;
  • significant expenses for transport and installation with the involvement of technology.

Operating procedure

1. We arrange an armored belt. The armopoyas beam must have a reinforcement with a thickness of 100 mm (the distance from the rod to the rod is not more than 100 mm). Its thickness is 300 mm. Factory concrete М200 В15.

2. Lay hollow-core slabs (for example, PK-60-15.8) on the armopoyas using a truck crane.

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3. Close up cracks, cavities, sinuses. We plug the holes of the voids.

4. We drill two rows of holes along the axis of the walls with a pitch of 150 mm and install vertical rods in them for further reinforcement of the walls.

The option with a factory floor device is applicable in any version of stone construction.

Overlapping on beams

A very common type, more suitable for a lightweight option for overlapping the second floor. Beams can be wooden, metal or glued.

Operating procedure

1. The beams are pre-treated with antiseptics, fire retardants. We recommend to additionally open the ends of the beams with a primer.

2. Along the armored belt we lay out the beams with a given pitch (usually 550–600 mm along the inner planes – based on the width of the sound insulation sheet) and temporarily fix them together with slats.

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Attention! The row of end faces of the beams should be located along the axis of the outer row of bricks.

Cutting off excess vertical rods.

3. Key point. On the sides and on top of the supporting part of the beams, we fix 15–20 mm foam plastic. This will simplify dismantling in the event of a major overhaul with a possible replacement of the ceiling.

4. Install the outer and inner flanges.

5. We lay the longitudinal reinforcement bars with a step of 100 mm and tie them up with transverse bars.

6. Concreting the beams. Concrete placement level – 80 mm from the upper plane of the beams.

With such a device, vertical rods must be left for subsequent connection with the walls. This is the key to structural strength. By connecting all elements of the building with a strong reinforcing mesh, we use the main advantage of reinforced concrete. Similarly, all other overlaps are tripled..

Walls

All sandwich walls have the same principle and differ in thickness and bearing capacity. Any of the above options involves laying out two brick walls as formwork for a grout. The rules for laying out the walls of the formwork are completely identical with the walls of the foundation. In total, we will consider three options for the construction of walls – lightweight, capital and “semi-antique”.

Lightweight version

The brick is laid on the edge. If the subsequent finishing is supposed to be “dry” (frame, insulation plates), then it is better to use white sand-lime brick. With the same parameters of length, width, weight and cost, it has a thickness of 85 mm, which makes laying “on edge” more accurate and convenient. On the other hand, sand-lime brick itself has finishing qualities, but is poorly suited for “wet” surfaces.

1 – plate; 2 – 40 mm limiter; 3 – “frog” limiter 150 mm; 4 – fittings A3 O 16 mm; 5 – mesh 100x100x3 mm

Advantages:

  1. Low brick consumption. An amount equal to the laying of one wall half a brick thick is consumed for the entire wall.
  2. You can use second-hand material, since both planes are not finishing.

Disadvantages:

  1. Relatively low bearing capacity.
  2. At least one more cycle of exterior finishing.

A lightweight wall is suitable for a one-story construction or with a wooden attic.

The optimum filling thickness is 200 mm. Wall thickness 360 mm.

Capital option

1 – plate or armopoyas

Both walls are laid out in half a brick. This approach allows you to combine construction and decoration in the outer wall, if it is made of finishing bricks. Suitable for the construction of any number of storeys.

The optimum filling thickness is from 200 to 400 mm. Whole wall thickness from 450 to 650 mm.

Semi-capital option

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The inner row is placed “on the edge”, and the outer row is placed in half a brick. Exterior finishing is also possible.

The optimum filling thickness is from 200 to 400 mm. Whole wall thickness from 510 to 710 mm.

Antique wall

We are building an 1 – sandstone “savage”

The inner row can be either “on the edge” or in half a brick. The outer row is made of plates or small boulders of sandstone 250-300 mm wide, which gives the walls an exceptional decorative appearance, while maintaining their bearing capacity.

The difficulty in the execution of the “antique” wall lies in the finishing of the armored belt of the upper floor. Its outer border should run approximately in the middle of the finishing row (sandstone) and leave room for finishing masonry.

The optimal filling thickness is from 200 to 800 mm. Whole wall thickness from 535 to 1225 mm.

Other varieties

We are building an 1 – aerated concrete 600x300x100 mm; 2 – laying in one brick

The presented technology is universal, so there can be many options – it all depends on your wishes and imagination. When combining layers, the following rules should be observed:

  1. The horizontal section of the walls should not exceed the section of the foundation.
  2. The percentage of the area of ​​the brick in the cross-section of the walls should not exceed the same indicator of the foundation. Optimally, there should be 25-40% more bricks in the basement walls than in the walls.
  3. The reinforcement must bind the maximum number of elements. This is the main advantage of the technology. When using factory floors, the effect of the monolith is almost completely lost.

Window and doorways

For lining and subsequent concreting of openings, templates (frames) should be made to indicate their boundaries and location. The frames are installed in the design position and serve as beacons for laying and installing lintel frames. Examples of templates for openings

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Attention! When making a template, remember that you will have to remove it after concreting. Provide a way to quickly disassemble.

Overlap of the second floor

Traditionally, the overlap of the second floor is being made lightweight. In our case, all the rules regarding the basement floor work. You can make it beamed.

Roof

Roof structure and roof material do not depend on the application of the described technology.

Wall filling material

At this key point, the bearing capacity and the function of the insulation are combined. The decisive factor here is not the strength of the material in compression, shear or bending. The durability of the building walls determines their ability to evenly distribute the load. If the effort is unbalanced, then sooner or later the load will “gather” in one area, it will not withstand and will crack. That is why such a seemingly insignificant element, like a masonry mesh through three rows, serves as one of the guarantors of the stability of the entire building..

It is better and cheaper to make your own wall filling mixture. In composition, it should be close to the solution from which the cinder block is made – for 2 parts of cement, 1 part of sand, 2 parts of crushed stone of fraction 5–20 and 3-4 parts of granulated slag (granulated slag). The mixture is laid in horizontal layers with vibration.

A house built using the described technology requires a significant investment of time and money. The main material that perceives wear from atmospheric phenomena is finishing brick – it should be carefully selected so that it lasts as long as possible. When the time comes for an exterior renovation, it can be finished in any known way..

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