Table of Contents
The purpose of any owner at construction or reconstruction of country house – to receive as much as possible rooms on the available allotment. For this reason include basement storey, mansard roof and, whenever possible, two or three floors in the house in the project. Irrespective of how many levels of the building are provided in the project, builders should mount overlappings, having chosen suitable option from variety of types.
Requirements to overlappings
As about 20% of all estimate of the house under construction are the share of the cost of this constructional element, it is extremely undesirable to make the wrong choice and to save where it is not necessary to do it. Not to make serious error, it is necessary to understand requirements imposed to overlappings of buildings:
- Durability. This parameter is meant as the payload stated in documentation, that is ability of overlapping to maintain the curb weight and also mass of constructional elements of the building, the equipment, people, furniture. The below there is overlapping, the it has to have bigger durability.
- Rigidity or resistance to deflection. This parameter is directly connected with durability and depends on width of interfloor element. For tree this indicator cannot be more than 0.5-0.7%, and for steel girders is obliged to exceed threshold of 0.25% of aperture width.
- Sound insulation. Is responsible for low noise level in the house, thanks to prevention of distribution of sound waves.
- Heat insulation. Shows extent of heat preservation in rooms.
- Fire resistance. The important indicator in terms of fire safety, is characterized by degree of protection of the room against damage by fire during certain time.
- Mass and dimensional indicators, that is optimum combination of weight and thickness of overlapping.
Classification of overlappings
It should be taken into account that requirements to the specified characteristics can change depending on location of interfloor element. Therefore builders and designers separate overlappings first of all on:
Basement overlappings undertake maximum load. Besides that they have to maintain the weight of partitions and load bearing walls, so for them the considerable mass of operating equipment and decorative elements of the first floor lays down. These are usually all elements of kitchen, fireplace, the fountain, furniture and other parts of interior. Also basement overlapping makes considerable contribution to ensuring rigidity of structure of the house. Considering all these factors, it is also worth remembering that restrictions on weight and thickness of the overlapping practically do not exist, thanks to thorough arrangement on house footing. But it is worth taking care of good heat insulation, vapor barrier and waterproofing, especially if the cellar is not heated.
To socle overlapping of the requirement approximately same, and too there are no restrictions on the curb weight of element.
Interfloor and mansard overlappings are chosen taking into account balance between the curb weight of elements and the loadings maintained by them. Often for achievement of optimum result put up additional load bearing walls, reduce the size of flights or reduce loading. Also as well as with the cellar, it is necessary to consider heating of penthouse to provide sufficient isolation of overlapping. For interfloor overlappings significant role is played by requirements to sound insulation.
Types of overlappings
To satisfy such variety of requirements the construction market offers the huge choice of decisions. Elements on design and the used material differ and are classified as follows:
- Girderless: assembly and monolithic;
- Beam: wooden, metal, steel concrete;
- Brick arch;
From these options the choice, proceeding from the project of the building under construction is carried out.
Very often at construction of the house only wooden decisions as other options it is more expensive, more difficult in installation are considered and sometimes even demand availability of special equipment for mounting. But if to look at problem on the other hand, then the choice of improper overlapping leads further to decrease in its life cycle, frequent repairs and reconstruction of buildings. Therefore it is the best of all when construction elements are chosen not in price parameters, and on the general technical characteristics.
Flat slab floors
- Girderless combined overlappings mount from hollow concrete panels. Carry to their advantages:
1. High rates of durability;
2. Fire resistance;
3. Convenience of mounting;
4. Technological effectiveness;
5. Availability of different standard sizes with restriction longwise in 9 meters.
Mounting of combined overlappings is conducted by means of special equipment that causes certain difficulties.
- Flat monolithic slab floors. Their creation does not require the special order at the plants, to complexity with transportation and lease of special equipment. Works are carried out by underpouring on the prepared horizontal timbering or on professional flooring. Thanks to such technology monolithic overlappings often use for replacement of outdated wooden decisions, especially if it is about basement or socle arrangement of element. Having strengthened the basis, over wooden blank fill in concrete weight, creating monolithic overlapping by the hands. But as all works are conducted at concrete participation, in the course of construction involuntarily there are long breaks about one month until concrete weight completely dries out. Such overlappings usually use as socle or basement construction element. In the form this type of overlappings subdivides into ribbed, beam, plate and with inserts.
- Flat combined and monolithic slab floors. Creation of this construction element allows to integrate technical and technology advantages of two previous types. Assembly monolithic constructions receive by filling of concrete layer in the hollow blocks laid between floor beams. As beams can use practical any including steel concrete, and strength characteristics turn out optimum for the building practically of any height. Thus, combined and monolithic overlappings are:
1. Mounting without participation of special equipment;
2. Profitability – expenses decrease twice;
3. Good speed of work;
4. Work contraction of volume;
5. Lack of timbering during creation of design;
6. Possibility of creation of difficult architectural configurations.
7. Ready overlappings have excellent eco-friendly, adhesive, heat-insulating and sound-proof characteristics.
Joist wooden ceilings. The most widespread decision in country construction, thanks to possibility of carrying out all works as the hands. Besides, builders are involved by availability of materials, good sound-proof and heat-insulating parameters, low cost.
Joist metal ceilings are also widely used for implementation of projects of country housing – usually as socle or basement option. Unlike wood structures they are more reliable and long-lasting, have smaller dimensions at the same parameters of the bearing loadings. But, unfortunately, and they are not deprived of shortcomings: do not differ in good heat-insulating properties and are subject to formation of corrosion. For creation of designs use channels, double tees (normal or wide-shelf) which stack 0.5-1.5 meters with step. Over beams the reinforced non-standard concrete slabs which are usually differing in small standard size are mounted.
Joist steel concrete ceilings differ in big weight that forces to employ special equipment for work. Besides, the foundation load increases, and it needs to be considered during creation of the project. Also steel concrete is characterized by low indicators of sound insulation and heat insulation, badly processed and is labor-consuming when mounting.
Lacunar, arch and tent overlappings
Lacunars and tent panels belong to kinds of ridge panels. They are used for implementation of difficult architectural concepts usually at construction of large objects. At construction of owner-occupied country houses such designs are inexpedient to be applied. Most it is possible to tell also about brick arch overlappings.
Instead of conclusion
At design and construction of the house it is always worth adhering to optimal solutions and to objectively select designs for different stages of construction: monolithic overlappings for the cellar and socle, tree – for penthouse, according to requirements to premises are chosen interfloor elements.
Perhaps, such approach will seem difficult, but only it is so possible to build the house which will be reliable, qualitative and long-lasting.