Questions and answers

Advantages of monolithic housing construction: What does it mean- “a monolithic house”?

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The basic principle is known to everyone: the formwork and reinforcement is established first. Then the construction is poured with concrete. Then reinforcement fittings follow formwork again… the process is repeated many times.

The quality of the construction works is determined by factors such as a concrete class, the level of personnel’s qualification, and the formworks plays an important role as well. The world’s leading manufacturers of formwork compete in Kazakhstan’s construction market for the right to supply high-quality products: panel and tunnel formwork for all kinds of monolithic buildings. Unfortunately, the advantage of foreign designs to the Kazakh counterparts is still obvious. Some increase in the value of the property cost through the use of foreign materials can be attributed to the cons of monolithic buildings.

Panel formwork allows working in a fast pace, constructing buildings of some standardized blocks. Similarly, tunnel formworks allows the architect not to limit his imagination by straight lines only and embody the most challenging prototype ideas, working with forms and capacities. Of course, this means that a monolithic house built in this way will be classified as luxury real estate.

There are 2 main varieties of solid concrete: pure monolithic and prefabricated monolithic. Advantages of monolithic homes of the second category is that the weight of such structure is significantly lower than that of pure monolithic one, which allows the use of lighter-weight options of the foundation, and, consequently, saving time and money. Chosen this variant supporting structure is constructed of monolithic concrete, while the external walls are made from other building materials – mostly brick.

Talking about the pros and cons of monolithic buildings it is impossible to ignore such an important topic as the service life of the structures. The apparent advantage of cast-in-place houses is a longer, compared to brick, life – at least 200 years against a maximum one hundred and fifty.

Another advantage of monolithic housing construction is the absence of the shell and core fit-out. Walls, floors and ceilings in monolithic buildings are usually quite smooth and even flat. However, unlike the panel ones, monolithic houses have no wall wiring or ready-built sanitary blocks – all communications are set in place in the course of construction and the subsequent finishing. And here is some more information for those interested in cons of monolithic buildings.

So, one of the most debated issues is the audibility in monolithic houses. In fact, due to solid supporting structures the sound of punch from the top floor will be easily heard on the first floor. Therefore, living in newly built concrete house when repair is not completed in 90% of the flats is a serious test of the tenants’ nervous systems. If it is possible put on the move for 2-3 months, when most of the apartments will be finished. Domestic audibility in the monolithic houses (when the noisy works with walls and ceilings are completed) is pretty low.

On forums where the cons and pros of monolithic buildings are discussed, one can often come across information that such building does not breathe, but it says about the engineering and architectural deficiencies rather than the insolvency of the construction method. After all, a well-designed ventilation system eliminates this problem.

Monolithic walls:

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Concrete monolithic walls with a large scale are commonly used in modern construction works. Erection of monolithic walls has become topical due to innovative technologies in the production of concrete, broad variety of formworks and diverse ways of monolithic construction.

Today construction of prefabricated houses is no longer relevant, as producing concrete elements in the factory and assembling them at the construction site is economically unprofitable and the resulting design is not similar to a monolithic building. The experts note that the panel construction accomplished from pre-fabricated pieces with specific parameters, does not allow erecting buildings of different form and design, which does not meet the requirements of modern construction (today’s customers prefer semicircular form or level drop). It is a monolithic wall that provides great options in terms of design, and allows you to create even a wavy wall.

The monolithic construction transforms the building in a single block, working as a three-dimensional structure, having no use for up/down alignment of wall supporting structures. The construction as if consists of cells that are integrated into a single system.

Walling of low-rise buildings is done by means of monolithic concrete panel or by assembled panel formwork. Construction of monolithic walls has some particular features of the technology.

First, the requirements to the quality of the formworks are quite strict. Only perfectly shaped panels tightly integrated into a single design that is in turn reinforced with back side rods made of various materials are permitted to be applied. The role of rods can be played by metal clutches, or wooden cover strips.

In the course of construction of cast-in-place walls, wall formwork is adjusted to one wall only, or sometimes on the whole perimeter of the walls. Panels up to 2-4 m and with a height of 50-80 cm are made from ship-lapped and tightly fitted stack of planks (with thickness of 30-40 mm) and connected with the outside at a distance of 1-1, 5 m by 80 x 80 mm cross-sectioned wooden strips. There are also available ready-to-use monolithic planks. Attaching the wall panels, they are pulled together with metal rods (long bolts adjusted with washers on both ends). When the formwork is removed, the rods are backed out to be used again in further construction. At the top these boards are fastened either by wooden strips, or by the same metal rods.

Monolithic and solid walls are constructed differently; it all depends on the thickness and height, reinforcement type, formwork type, ways of concrete running and the method of its sealing. The most common type is a layer-by-layer concreting. The monolithic walls are concreted by layers with a height of 30 to 50 cm. Spud vibrators are used to seal the works.

A solid wall, concreted layer by layer, should be not less than 10 cm thick. In order to improve the surface quality and achieve truly homogeneous structure of concrete you need careful vibration and uniformity in the running concrete mixture. Compacting concrete by a vibrator, it is not allowed to touch formworks because vibrations can cause destruction of the previously laid layers.

Monolithic foundation:

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Monolithic foundation in construction industry is considered to be generic. This technique ideally fits to uneven surface (sand, peat bogs). The most essential condition, distinguishing monolithic foundation from all other types, is a concrete slab. It is usually adjusted to the formwork into a single entity.

Foundation of monolithic type is sufficiently resistant to a wide variety of loads, especially to those that occur because of the soil subsidence. The resistance is provided for a large area, thus reducing the pressure on the soil.

Foundations of a monolithic type are characterized by the following:

-solidity;

-high consumption of raw materials;

-high levels of efficiency;

-increased construction terms due to excavation works.

Certainly, all of the above information is difficult to relate to the benefits. However, there is one pretty significant plus – the maximum reliability. And please consider that this is a very serious argument in favour of cast-in-place foundation.

So, this type of foundation requires reinforcement. It’s spread not less than in two layers. The (top) part of the foundation simultaneously performs the functions of the basement. Optimal thickness of the plate is 40 cm, being approx. 10 cm below the ground level.

Monolithic foundation is found above the frost penetration depth only if construction is carried out on sandy or dry soils, with a distance of 50-60 cm from the ground level required for compliance.

There is a belt-type monolithic foundation. Basement construction technology is not too complicated:

1. Break the ground.

2. Run the preliminary work on the sand preparation.

3. Establish drainage around the perimeter of the house; its main function is to protect the basement from ground water.

4. Carry out the 2 layered waterproofing in the footing (a thin layer of concrete).

5. Then put fittings (2 layers) and fill the base slab. A fitting, which sticks out from the slab, strongly connects it to the wall.

6. When the concrete sets enough, connect the frame to the reinforcement. This process is required to be carried out during the construction of cast-in-place foundation. It is important that the distance between the bars of the reinforcement was at the level not more than 30 cm (reinforcement fittings must cover the formwork as well).

8. Concreting of the monolithic foundation. Concrete is poured in layers, each of 15 cm thick, and aligned with a shovel. Compaction of concrete lasts until the water appears at the top. And the last, the surface is to be smooth. To achieve this we often use an ordinary bar, which moves over the formwork planks.

9. Stripping down the formwork is possible only when concreting has been finished long time ago, and concrete is dry.

Monolithic foundation can be of the types as follows:

-reinforced (concrete is poured in one go);

-unreinforced (concrete is poured several times, with the horizontal joints retained).

Sometimes incompetent people argue about the advantages of monolithic and prefabricated foundations. Which one is better and cheaper? At the first glance, assembling prefabricated foundations seems to be more simple, quicker, and cheaper. Actually, prefabricated foundations are 1,5 times more expensive than the monolithic ones. This is primarily due to the fact that prefabricated foundations imply the manual performance of multiple operations.

Cast-in-place works

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It’s no secret that the word “cast-in-place” refers to something whole, indivisible. Most people have witnessed the construction of the houses using specific forms that builders thoroughly filled with reinforced concrete. This technology is used in the construction of monolithic (cast-in-place) structures. This construction technology is today considered as one of the most progressive and forward-looking techniques.

Monolithic works include numerous stages of filling the formwork. The monolithic technology involves the application of monolith forming elements, which are called “form working equipment”. Typically the formwork represents pretty solid panels of various configurations, which are the material for the forms required. Formwork is made for multiple applications. In monolithic constructions, hydraulic machines are generally used. They transport this or that structure to the next phase of construction.

This construction technology allows you to quickly build pretty cheap, monolithic concrete reinforced houses and structures.

The main advantages of the monolith are as follows:

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-Minimum construction time. As practice shows, compared to conventional technology, monolithic construction allows shortening the work term three or four times;

-A significant reduction in construction costs provides relatively low cost monolithic works;

-Monolithic technology allows achieving truly unique indicators of power saving and sound conductivity;

-This construction technology requires no additional preparation of the structure for the fine finishing;

-Cast-in-place construction reduces the overall weight of the structures 15-20% on average (in this case, the comparison is with brick buildings);

-Monolithic technology provides great strength. Monolith has no seams;

-When using this technology the need for construction equipment is minimized;

-Monolithic construction provides great architectural options;

-Monolithic buildings allow using the finishing of coating materials. Both natural and artificial stone finish can be used.

Recently the requirements for the quality and design of reconstructed buildings and facilities have increased significantly. That is why, today, the monolithic works occupied a worthy place among the most modern and reliable technologies.