In some cases (for example, if the metal-roofing system is being arranged over the old soft tiles), this is possible. However, it must be understood that a spoiled base can begin to rot and, thereby, provoke the failure of a new layer. This is why we would not recommend stacking new materials on top of old ones. It is better to remove the damaged building material and completely complete the required work, as required by the technology.
As practice shows, the overwhelming number of roofs in ordinary private houses are erected in such a way that for the installation of an additional insulating layer it is not necessary to disassemble the roofing base. If we talk about multi-apartment buildings, then the situation is different: since surfacing is used in multi-storey buildings, insulation becomes impossible.
If there is damage to individual structural elements, then only these parts can be replaced. In this case, the area of damage should not exceed 35%. For larger problems, it is worth making a complete replacement of the rafter system.
Urgent repair is required in case of a serious violation of the tightness of the coating: it may be required when a part of the roof is torn off, water leaks during precipitation, delamination, rupture or swelling of the roofing material.
We provide the following warranty periods:
- soft roof: 5 years
- metal roof: 3 years
- roll and bitumen coatings: 3 years
- polymer shingles and rebated covering: 6 years.
Any leak is a problem that requires careful and timely repair. First, it is important to correctly determine the cause of the leak. Secondly, with self-repair, there is a risk of damaging the serviceable elements that are nearby. If you are not a specialist in roofing work, we recommend calling a master who will not only fix the problem, but also provide a guarantee for his services.
In order to accurately determine the cause of the appearance of water, an examination is necessary, which will be carried out by a specialist. You can independently determine what is the cause of the appearance of moisture by the following signs:
- if a leak occurs in the roof, water begins to drip in the warm season after rain, and in the cold season with sunny weather and a sharp warming.
- when condensate accumulates, moisture appears constantly and practically does not depend on weather conditions.
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Perhaps, many residents of apartment buildings faced such a problem as leakage, as well as insufficiently reliable roof condition. In one row, such disadvantages as poor-quality coating, collapsing roofs in an old house, etc. That is why the overhaul of the roof of an apartment building is one of the most pressing issues for many residents.
Very often, many citizens, when seeking help from various authorities dealing with the maintenance of houses, are faced with their complete inaction, as a result of which the collection of funds for the repair of the roof in an apartment building is carried out independently.
However, before contacting such bodies and paying for the services of roofing specialists, it is necessary to understand the very reason. Next, we will talk about what types of roofs exist in apartment buildings, as well as the problems arising in connection with them and ways to solve them.
Types of roofing in apartment buildings
Since there are several types of roofs in multi-storey buildings, it is important to understand the features of each of them, since repair work can vary greatly.
According to the design and shape, the roofs are divided into:
- single-slope (with different inclined angle);
- gable;
- multi-slope;
- sloping (standard flat roofs);
- complex (more typical for modern buildings than for old houses).
The roof structure includes an outer covering and a support from the inside (this can be a rafter system or a reinforced concrete slab). Also mandatory elements are the drainage system, as well as layers of insulation and waterproofing. One way or another, when performing a major overhaul of the roof of an apartment building, it is imperative to take into account all the design features of the roof.
Roof repair methods
It is customary to divide work on the restoration of the roofs of buildings with many apartments into two large groups: current, or temporary, and capital, or complete.
So, the current repair of the roof of an apartment building is carried out if any defects in the roofing system are found. Very often, all work comes down to replacing the old and damaged roofing, which usually is roofing material, with a new one, eliminating the cracks and cracks that have appeared. Based on the need, the new coating can be laid in one or two layers. Upon completion of the repair work, all seams and joints of the roofing sheet are completely sealed with special substances.
In terms of finance, this type of repair is not too expensive, therefore it is more common. However, there is another type of current repair, when it is not necessary to lay a new roofing sheet. In the place of the defect, after the preliminary cut, the edges are bent, and the inner space is carefully cleaned. Then it is dried with the help and treated with a layer of construction mastic, both the coating and its base. The edges are returned to their place, after which they must be pressed tightly against each other, waiting for full adhesion.
Places with developed rot are completely cut out, the roof is cleaned. All defective places are filled with the same mastic, and then a new piece is glued to the treated place close to the old material. Of course, this method of repair is far from the highest quality, but nowadays it is quite common, especially on the roofs of old houses.
And the overhaul of the roof of an apartment building is a complete rework of the roof. The old coating is removed from it, after which a fresh screed is poured and a new roofing carpet is laid in two layers. Such repairs should be trusted only by specialists, since during the work the interior decoration of the apartments on the upper floors may be damaged.
If the roof is leaking in an apartment building, then this may be the result of improperly performed work. The main work during the overhaul consists in fusing roofing material with a special gas burner (read: ""). The underside of the roof carpet is heated from below, after which the material is gently pressed against the base of the roof. It is very important to control the temperature of the fire, as its incorrect value can lead to the destruction of the material. It is necessary to lay the coating according to the overlap principle, and all seams must be treated with construction sealant.
Factors of roof leaks in apartment buildings
There is only one way to avoid leaks - by overhauling the roof. The causes of these unpleasant defects can be very different, but most often they appear after heavy rains or during the period of massive melting of the snow cover.
So, the reasons for roof leaks in apartment buildings can be the following:
Roof leak detection
Before submitting an application for overhaul, it is necessary to clearly identify the location that is damaged. Most often, for this, the place of leakage is compared and already along it there is a source of damage on the roof. It is very easy to do this on soft bituminous roofs - air bubbles form in the place of the defect.
In this case, the carpet should be replaced completely, and the required place should be well dried. It is not worth doing these work on your own; it is better to entrust the work to specialists. But if you wish, detailed descriptions of the entire course of work with video and photos can always be found in our articles on roofs and their repair.
Sometimes it happens that the problem of leaks on pitched roofs can also be complicated by rotting wooden rafter legs. With this outcome, not only the roofing is usually subject to replacement, but also individual structural elements.
Fusion roofs
As it has already become clear, the essence of the overhaul is reduced to the installation of the deposited materials. According to the existing standards, scheduled repairs with the replacement (if necessary) of individual sections of the coating should be carried out by special services twice a year.
The whole process consists in fusing roofing material and other overlapping materials with a gas burner. Such repairs should be carried out for flat roofs, which are the majority today (read: ""). Such material is resistant to moisture, temperature extremes, as well as direct UV rays.
What to do if the roof is leaking, in detail on the video:
Pitched roof repair process
Pitched roofs are usually covered with a different material. Often these are sheets of metal treated with zinc or simply painted. Repair work in this case consists in finding damaged elements of the coating, their competent replacement and monitoring the condition of the roof base under the coating. To do this, the material must be removed and the necessary work carried out to restore the system of rafters and battens, as well as the base itself, which is located under the covering.
Sometimes it is impossible not to perform such an important part of the work as replacing the waterproofing layer and installing additional high-quality insulation. If the damage is insignificant, you can simply patch and seal all joints with sealant.
Any cracks and crevices should be filled with polyurethane based sealant and covered with special polyurethane plasters. It is important that the damaged area to be repaired be degreased and primed prior to all work. After the completion of the restoration, it is customary to cover the roof with a paint specially designed for a particular roof, the functions of which are to give the coating greater strength and increase the operational life.
Flat roofs are often used in the construction of modern high-rise buildings, administrative and industrial buildings, in suburban construction. In the latter case, they are most popular when creating low-rise buildings or outbuildings.
Basic requirements for flat roofs
Increased roof strength is very important in regions with heavy snowfall. During winter periods, it will have to withstand a significant load as a result of the formation of a thick layer of ice and snow. This indicator is very important in the case of creating an exploited roof.
A flat roof must perform the functions of reliable protection against rain and melt water and have a sufficient slope so that precipitation does not linger on it.
The structure should not deteriorate under the influence of severe frosts and scorching rays of the sun, sudden temperature changes and strong hail.
It should do an excellent job of insulating function.
All materials used in the construction of the roof must be fireproof.
Pros and cons of flat roofs
Pros:
- Flat structures have a much smaller area than pitched ones, which makes it possible to significantly save on materials and during construction and installation work.
- The smaller footprint helps to optimize costs.
- It is possible to cope with the construction of such roofs in a shorter time than with the device of pitched roofs, since all the required materials can be located in the immediate vicinity - literally at the feet.
- Due to the same feature, maintenance and repair work is simplified: their implementation on a flat horizontal surface is greatly simplified.
- On flat roofs, it is convenient to carry out installation and necessary service work that requires the use of special equipment: solar panels, air conditioning systems, antennas, etc.
- When creating a flat structure, you can get additional meters of usable area and use them as a recreation area, sports ground, or arrange a flower garden, garden. Currently, it is possible to cover the roof with paving stones or paving slabs using special technologies. The roof paved with high-quality tiles, combined with garden furniture, a green area, a gazebo will be an ideal place for a family vacation.
Minuses:
- with heavy snowfalls, a snow mass will accumulate on the surface, which, with the onset of melting, often leads to the formation of leaks;
- often there is a need to use gutters;
- in the cold season there is a risk of freezing of the internal drain;
- the drainage system is often clogged;
- a mandatory requirement is mechanical cleaning of the surface from the snow mass;
- you need periodic monitoring of the condition of the insulation to prevent it from wetting;
- from time to time it is necessary to check the integrity of the coating.
Types of flat roofs
There are four main types of flat structures:
Operated roofs
Their peculiarity lies in the need to create a rigid foundation - otherwise it will not be possible to preserve the integrity of the waterproofing layer. The base is a screed based on concrete or corrugated board, which is necessary to create a certain slope for water drainage. The thermal insulation material used in the construction of an exploited roof will be subjected to significant static and dynamic loads and must have a sufficient level of compressive strength. With a slight stiffness of the insulation on top, a cement screed device will be required.
Unused roofs
With the device of this type, there is no need to create a rigid base in order to lay the material for waterproofing. Hard insulation is not needed either. For further maintenance of the roof, bridges or ladders are arranged, the function of which is to evenly distribute the loads over the roofing surface. The construction of unexploited flat roofs will cost much less, but they will not last as long as the operated ones.
Traditional roofs
The structure of traditional types of roofs provides for the location of a layer of waterproofing material above the thermal insulation. The base for the roof is a slab of reinforced concrete, and the drainage of water from the roofing surface is carried out by creating an inclined screed made of expanded clay concrete.
Inversion roofs
Inversion roofs have practically solved the problem of leakage - the main disadvantage of flat structures. In them, the thermal insulation is located above the waterproofing carpet, not under it. This technique helps to protect the layer of waterproofing material from the destructive effects of solar ultraviolet radiation, sudden temperature fluctuations, the process of freezing and subsequent thawing.
Compared to other types of roofs, inversion is more durable.
In addition, it is distinguished by increased functionality: you can arrange a lawn on it, make tiled masonry. The optimal angle of inclination of such roofs is considered to be from 3 to 5 degrees.
Features of the device
The main subtleties of the construction of flat roofs are as follows:
- The vapor barrier is arranged by means of a bitumen-polymer membrane reinforced with fiberglass. Another option is to lay the vapor barrier film over the screed.
- At the edges of the roof, a layer of vapor barrier material is wound vertically so that its height is greater than the height of the insulation layer, after which the seams are sealed.
- Insulation is laid above the vapor barrier (in the case of a traditional roof).
- A protective carpet is laid over the insulation, which is made of waterproofing materials with a bitumen base.
- If expanded clay is used as insulation, a cement screed must be made under it. Waterproofing is laid in two layers on it.
- When installing light structures, for which significant loads are not provided, it is necessary to glue the waterproofing sheet along the entire roofing perimeter.
Mounting
A flat roof cannot be arranged strictly horizontally - a minimum slope of at least 5 degrees must be observed. This requirement is due to the need to ensure the descent of rainwater and snow from the roofing surface. Another important point: it is necessary that the slope is created not only by the coating, but mainly due to the correct execution of expanded clay or slag filling. Even if the slope angle reaches 10 degrees, this will not interfere with the uniform laying of the thermal insulation material.
Lightweight flat roofs
When constructing such roofs, the work is divided into several stages.
As a result of the work done, a warm and rather reliable flat-type roof is obtained: in section, it resembles a multi-layer cake based on several components.
Solid roof device
When creating floors of this type, expanded clay is best suited as an insulating material. The minimum thickness of its layer should be 10 cm. Above the laid expanded clay, it is necessary to perform a cement-sand screed with a thickness of 40 to 50 mm. To ensure greater strength, a reinforcing mesh is placed in its middle layer. Such a measure is necessary to preserve the integrity of the coating while people are on it while carrying out repairs, maintenance, etc. In addition, it is these roofs that are optimal as a base for a pool or recreation area.
The manufacture of beams of such structures is most often carried out on the basis of a metal channel, since parts made of wood will not withstand significant loads.
Another requirement for the construction of operated roofs is the sufficient thickness and strength of the walls of the house.
Methods for the device of flat structures
There are several basic ways to create flat roofs:
- By installing concrete floor slabs. Such work can be done in a fairly short time, but special lifting equipment will be required. The use of this method involves the implementation of insulation. The material can be installed both inside and outside.
- Using metal channels or double-tee beams, on top of which boards must be laid: their thickness should be 25-40 mm. A layer of expanded clay is poured on top, then a concrete screed is created.
- The overlap is created by means of monolithic concreting. This requires a heavy-duty formwork with thick supports. The supports are fastened together with jumpers. This type of overlap also needs to be insulated.
- With the help of large ceramic blocks: they are laid on top of metal beams. These blocks replace wood flooring. The main advantage of this method is the use of ceramics, which are characterized by increased mechanical strength, moisture resistance and excellent sound and heat insulating properties. Large-sized ceramic blocks do not need additional insulation: when using them, you can limit yourself to such a measure as creating a concrete screed.
CONCLUSIONS:
- Flat roofs are often used in the construction of modern multi-storey buildings, administrative and industrial buildings, in suburban construction.
- Flat structures must have increased strength - especially when there is a large amount of rainfall.
- Flat roofs have a much smaller area than pitched roofs, which makes it possible to significantly save on materials and during construction and installation work.
- The main disadvantage of such roofs is that with heavy snowfalls, a snow mass accumulates on the surface, often leading to the formation of leaks.
- Flat roofs can be exploited, unexploited, traditional and inverted.
- Inversion roofs have practically solved the problem of leakage - the main disadvantage of flat structures.
- A flat roof cannot be arranged strictly horizontally - a minimum slope of at least 5 degrees must be observed for precipitation to disappear.
- The construction of lightweight flat roofs is fundamentally different from the process of construction of solid roofs.
- There are several ways to create flat roofs.
In the video, you can see how to organize drainage from a flat roof using the Rockwool non-combustible insulation system.
Flat roofs are made with load-bearing prefabricated or monolithic reinforced concrete structures. Such roofs are designed flat (with a slope of up to 5%) in three main versions - attic, non-attic or exploited.
Attic roof
Attic roof is the main type of roofing in residential buildings of mass construction.Attic roof
Sheerless in massive public and industrial buildings. An attic roof is allowed to be used in residential buildings with a height of no more than four floors, being built in a temperate climate, as well as in limited areas of the coatings of multi-storey buildings - above the engine rooms of elevators, loggias, bay windows, above the volumes of lobbies, vestibules and low-rise non-residential extensions protruding from the plane of the facades (trade, household service, etc.). In turn, the attic roof structure is sometimes used in multi-storey public buildings when their structural and planning parameters coincide with the parameters of residential buildings, which allows the use of prefabricated reinforced concrete products for roofs corresponding to them.Operated roof
An exploitable roof is installed over attic or non-attic roofs in custom-built buildings. It can be installed over the entire building or in selected areas of the coverage.The type of drainage from a reinforced concrete roof is chosen during design, depending on the purpose of the object, its number of storeys and location in the building.
In residential buildings of medium and high storey, an internal drainage system is used, in low-rise buildings - it is allowed to use an external organized drainage system when placing buildings with an indented horizontal projection of the edge of 1.5 m or more from the red building line, and unorganized - in low-rise buildings located inside the quarter. In all cases of the use of an unorganized drainage system, visors are provided over the entrances to buildings and balconies.
With an internal drain in residential buildings, one water intake funnel is provided for the planning section, but at least two per building.
With an external organized drainage system, the placement and cross-section of drainpipes is assigned the same as for pitched roofs.
Waterproofing of reinforced concrete roofs is designed depending on their type. For non-attic structures, as a rule, roll-up waterproofing coatings are used (with the exception of attic roofs of a separate structure).
Waterproofing of attic and separate attic roofs is carried out in the following of three ways: the first (traditional) - the device of a multilayer carpet from roll waterproofing materials; the second - by painting with waterproofing mastics (organosilicon or others), which, together with waterproof concrete of the roofing panel, provide the protective functions of the coating; the third is the use of prestressed roofing panels of high-grade concrete for waterproofing, providing waterproofing of the roof without painting with mastics.
According to the adopted method of waterproofing, the requirements for the characteristics of concrete of roofing panels change (Table 20.2).
According to the method of passage and release of exhaust ventilation air through the structure, attic roofs with a cold, warm and open attic are distinguished. For each of these structures, any of the above described waterproofing methods can be applied in the design. Thus, the construction of an attic reinforced concrete roof has six main design options (Fig.20.13):
- A - with a cold attic and roll roofing;
- B - the same, with no roll;
- B - with a warm attic and roll roofing;
- G - the same, with no roll;
- D - with an open attic and a roll roof;
- E - the same, with no roll.
- Zh - separate ventilated (with a roofing panel and an attic floor) structure with a roll roof
- And - the same, with a rollless roof
- K - combined three-layer panel structure
- L - combined multilayer building fabrication
Attic roof structures consist of covering panels (roofing panels and trays), attic floors, supporting structures for trays and roofing panels, external fascia elements (Fig. 20.15). The height of the through passage in the attic space must be at least 1.6 m. Local depressions up to 1.2 m outside the through passage are allowed.
Attic roofs with a cold and open attic (construction types A, B, D, E) contain an insulated attic floor, non-insulated thin-walled ribbed reinforced concrete roofing, tray and frieze panels, in which holes are provided for ventilation of the attic space. The area of ventilation openings on each longitudinal side of the facade is assigned in climatic regions I and II at 0.002 of the attic area, in regions III and IV - up to 0.02.
The dimensions of the supply and exhaust openings in the frieze panels of open attics are assumed to be significantly large according to the results of calculating the ventilation of the attic space.
Ventilation blocks and shafts traverse the cold loft roofs, expelling the air mixture into the open space above the roof.
Roof structures with a warm attic (type C and D) are insulated roofing, tray and frieze panels, non-insulated attic floor and supporting structures of roofing and tray panels (Fig. 20.16). Since the warm attic serves as an air collection chamber for the building's exhaust ventilation system, the ventilation blocks and shafts are terminated in the attic space with 0.6 m high headers without crossing the roof. Fascia panels are designed blind (without ventilation holes). These panels in some areas can be translucent (for natural lighting of the attic), but not folding. In the central zone of the warm attic, a common exhaust shaft (one per planning section) is arranged with a height of 4.5 m from the upper plane of the attic floor.
Roof structures with an open attic (types D and E) are similar in composition to structures with a cold attic, but ventilation structures do not cross it, breaking off at a height of 0.6 m from the surface of the attic floor, as in roofs with a warm attic.
Roofs with inclined frieze panels and vertical frieze panels of gable shape, echoing the traditional forms of mansard roofs, became a peculiar architectural variant of the construction of reinforced concrete attic roofs of multi-storey buildings. This option can be applied with both cold and warm attic roofs (fig. 20.17).
Roofing panels for rollless roofs with a cold and open attic, as well as separate attic roofs are solved in the same way. These are thin-walled (slab thickness 40mm) ribbed reinforced concrete slabs. The butt edges of the panels and their abutments to vertical structures crossing the roof (lift shafts, ventilation units, etc.) are equipped with 300 mm high ribs. The joints are protected with slats (or overlapped) and sealed.
The drainage trough-shaped trays are made of waterproof concrete with a bottom thickness of 80 mm and a rib height of 350 mm, a width of at least 900 mm.
Roof panels and roof trays with a warm attic are designed in two or three layers. The top layer is made of frost-resistant concrete with a thickness of at least 40 mm.
The structure of a separate attic roof (type I) contains the same structural elements as the attic roof with a cold attic, but due to the fact that its airspace has a low height (up to 0.6 m), the solution of supporting structures is simplified - they can serve as separate reinforced concrete bars.
Three-layer panels of combined roofs (type K) are manufactured in a single technological cycle or assembled at the factory from two thin-walled ribbed plates and an insulation between them.
With an almost threefold increase in the regulatory requirements for the resistance to heat transfer of external enclosing structures, the use of the most industrial and economical construction of the combined roof (as well as warm attics) from single-layer lightweight concrete panels has ceased, as they have lost economic profitability.
Traditional combined roofs of construction production (type L) are erected by sequential laying on the building along the overlap (made of monolithic or prefabricated reinforced concrete) of the upper floor of the vapor barrier layer, filling along the slope, thermal insulation layer, leveling screed and multilayer roll carpet. Design L is the most labor-intensive and has the worst performance. Its use should be as limited as possible.
Fig. 20.14, it is obvious that any of the attic roofs is a multi-layer structure, including a load-bearing reinforced concrete slab, vapor barrier, heat insulation and waterproofing (with a special prefabricated or monolithic base for it) layers. At the same time, it is traditional to place a waterproofing layer on top, which leads (with a non-ventilated roof structure) to a decrease in the durability of the waterproofing carpet under the influence of solar radiation and the pressure of vaporous moisture accumulating under the carpet.
To increase the durability of roof waterproofing, a variant of an inversion structure has been developed and is being implemented - with the location of the waterproofing layer directly on the supporting plate under the thermal insulation layer (Fig. 20.18).
Changing the location of the thermal and waterproofing layers, in addition to increasing the durability of the roof, creates a number of additional economic and technological advantages. The inversion structure is less massive, since there is no need to arrange a special base for the roof in the form of a cement-sand screed over the insulation: the base for the waterproofing carpet is the bearing plate of the covering. Thanks to this arrangement of the carpet, the need for a para-insulating layer is eliminated - a rolled carpet combines the functions of vapor and waterproofing.
Accordingly, the cost and labor costs are reduced, since the design and implementation of the joints of inversion roofs is simpler than that of traditional ones (Figure 20.19). The fact that inversion roofs have so far received relatively limited use in domestic construction is associated with the requirements for the physical and technical properties of insulation in such structures. With a low coefficient of thermal conductivity 1 3, compressive strength 0.25-0.5 MPa, daily water absorption in% by volume 0.1-0.2, be microporous and have a closed pore structure. The insulation must be hydrophobic, not swell or shrink, and have the required mechanical strength. In practice, the possibility of expanding the introduction of inversion structures is formed with the start of production of domestic extrusion polystyrene foam boards "Penolex", and, accordingly, a decrease in the volume of exports of similar heaters.
Operated roof-terraces are arranged over warm and cold attic roofs, over technical attics, and sometimes over combined roofs (Fig. 20.20). The latter option is especially often used in buildings with terraced ledges in its volumetric form. The floor of roof-terraces is designed flat or with a slope of no more than 1.5%, and the roof surface under it is designed with a slope of at least 3%. For the roof, the most durable materials are taken (for example, waterproofing). The number of layers of rolled carpet is taken one more than with an unexploited roof. A layer of hot mastic antiseptic with herbicides is applied to the surface of the carpet. They protect the carpet from the germination of plant roots from seeds and spores carried onto the roof by the wind. When constructing an exploited roof on an inverted combined structure, this role is played by a filtering synthetic canvas located under the ballast and drainage gravel layer. The floor of the roof terrace is made of stone or concrete slabs, sometimes tiled with ceramic tiles. Floor slabs are laid loosely over the gravel drainage layer.
Five-storey panel houses series 1-464
Large-panel 4-5-storey residential buildings of the series of standard projects 1-464 are the most common prefabricated buildings of the first generation. The basis for the solution of the houses of the series under consideration is a cross-wall structural system.
The main load-bearing frame of buildings is transverse reinforced concrete walls located with a pitch of 3.2 and 2.6 m, due to which houses of this type were called houses with a "narrow" spacing of transverse load-bearing walls. Reinforced concrete floor slabs of "room size" are supported on them. They also rest on the outer and inner longitudinal walls, which take part of the vertical load, while ensuring the longitudinal stiffness of the building.
Floor slabs laid at 3.2m steps are designed and function as supported along the contour. Since all interior walls separating the rooms bear the load from the floors and overlying floors, it is impossible to move these walls and thereby change the width of the rooms. For the same reason, it is impossible to remove the outer walls in a step of 3.2 m, without ensuring the support of the floor slab along the short outer wall.
The outer walls are made of three-layer panels, consisting of two reinforced concrete shells and a layer of insulation between them, or single-layer panels (made of lightweight concrete). Internal load-bearing walls 12cm thick and floor slabs 10cm thick are solid-section reinforced concrete flooring. Roof - combined with a rolled soft roof or attic rafter with a corrugated asbestos cement roof.
When redeveloping houses of the 1-464 series, it becomes necessary to construct new or expand existing openings in the transverse walls. This is possible to a limited extent, but requires confirmation by calculations.
When modernizing a building, floor slabs cannot be dismantled. However, during the superstructure of the building, the floor slabs above the existing fifth floor can be partially dismantled. The device of new openings in them is possible, but with large sizes of such openings, it may be necessary to reinforce the floor.
In the series under consideration, the balconies are placed in a step of 3.2 m. Balcony reinforced concrete slabs 10cm thick and 90cm wide are mounted according to two schemes. In the initial period of construction, they rested on the outer wall and were held in the design position by two metal rods, which, passing through the joint between the outer walls, were attached to the end of the inner wall panel. In later projects, this decision was abandoned and, calculating the balcony slab as a console supported on the outer wall, they connected it to the floor slab using welded embedded elements.
Five-storey panel houses series 1-468
Typical designs of residential buildings series 1-468 were originally developed at the Institute "Gostroyproekt", since 1961 - at TsNIIEPzhilishcha.
The load-bearing frame of the houses of this series is the transverse load-bearing walls, located in the plan with a step of 3 and 6 m, due to which, unlike the houses of the 1-464 series, the houses of this structural system are called houses with a "mixed" step of the transverse load-bearing walls.
The most common representative of this series of houses is a five-story, four-section residential building. In it, the external wall panels are made of autoclaved aerated concrete or lightweight concrete, and hollow-core reinforced concrete floors rest on transverse load-bearing reinforced concrete walls. The longitudinal walls of the building are self-supporting. The roofs of such houses were erected in two versions: combined with a roll covering and an attic rafter with a roof made of corrugated asbestos-cement sheets.
The main advantage of the houses in this series is that the floor panels do not rest on the longitudinal walls of the building. Therefore, these walls, in addition to individual sections of the inner wall adjacent to the stairwells and ensuring the longitudinal stability of the building, can be dismantled in some places. It is this circumstance that, when modernizing such buildings, opens up wide opportunities for eliminating the disadvantages of the layout of existing apartments by adding additional volumes to the building. The construction of new and expansion of existing openings in the load-bearing transverse walls is possible only with the confirmation of the calculation and strengthening of the "contours" of the openings.
5-storey panel houses series 1-335
Five-storey residential buildings of the series of standard projects 1-335 are representatives of the frame-panel constructive system. Typical designs of this series were initially developed by the team of authors of the Leningrad design bureau, and then were continued at the LenZNIIEP institute.
The structural scheme of the house is a so-called "incomplete" frame, which consists of one row of reinforced concrete columns located on the middle longitudinal axis of the building with a pitch of 3.2 and 2.6 m and reinforced concrete crossbars located across the building and resting on one side of reinforced concrete columns and, on the other hand, on metal support tables embedded in the body of load-bearing external wall panels. Reinforced concrete floor slabs of "room size" are laid on the crossbars, designed to be supported on two long sides. The columns are connected to each other by girders that ensure the longitudinal rigidity of the building.
In the houses of the system under consideration, load-bearing external walls were used mainly layered. They have an outer layer in the form of a reinforced concrete ribbed "shell" and an inner (insulating) layer of foam concrete 26 cm thick, the surface of which is plastered from the side of the premises. There are no internal load-bearing walls in these houses, with the exception of stiffening diaphragms, which are the intersectional walls of the stairwells.
With the same sizes and steps of houses of different series in houses of the frame-panel system, the principle of "free planning" can be fully implemented. The presence of crossbars under the floor slabs can be considered as a certain disadvantage that impedes the traditional formation of the interior of living rooms.
A modification of this structural system was the introduction of two more rows of columns into it - at the outer walls of the building to support the crossbars on them. Such houses are called “full frame houses”. In them, the external walls are self-supporting and can be dismantled during reconstruction.
Five-storey brick houses series 1-447
The series 1-447 includes standard projects of 4-5 storey brick residential buildings with three longitudinal load-bearing walls. The load-bearing frame of the houses of the series under consideration are three longitudinal load-bearing walls and transverse brick walls - external end walls and internal ones, between which the staircases are located. Transverse brick walls act as stiffening diaphragms. All other walls (intra-apartment and inter-apartment) are non-bearing.
The ceilings are made in the form of hollow-core reinforced concrete slabs, supported by their short sides on longitudinal brick walls. The most loaded is the middle wall, on which the floor panels are supported on both sides. In the outer longitudinal walls, openings can be increased only by eliminating the window sill while maintaining the existing piers. The jumpers over the windows should also be preserved. In the end walls of the building during reconstruction, it is possible to arrange openings.
Possible dismantling of partitions in series 1-447