How to build a low-rise house and save on material and costs? Choose beamed ceilings during construction. They are usually cheaper, and their delivery and installation will not be a big deal. Beams overlap perform quite a lot of functions. First of all, they act as a stiffness diaphragm in the horizontal section of the house, thereby ensuring its strength and stability.
Wooden joists
Today they are extremely popular in conventional housing construction and are used for the construction of wooden and frame buildings. There is only one big “but”: their length is limited, so the interfloor distance cannot exceed 5 m, for the attic - 6 m. Typically, beams are made from coniferous and deciduous trees. The design of the floor is nothing more than the beams themselves, the coast, the insulation and the floor itself.
Basement and basement structures
The main requirement for such an overlap is good strength. Since in this case the beams will serve as the basis of the floor, they must, accordingly, withstand heavy loads.
If there is a garage or a huge basement under the ground floor, it is better to build a wooden floor not on wooden, but on metal beams. This is due to the fact that the floor beams made of wood are subject to decay and are not always able to withstand heavy loads. You can also reduce the distance between the beams.
Attic floor
The design principle of the attic floor can be independent or serve as a continuation of the roof itself, i.e. be a component of the rafter system. A more rational first option, since it is maintainable. In addition, it is he who provides the best sound insulation. To do this, beams are selected and stacked in compliance with certain requirements. First of all, all the beams of the attic floor should be only of dried wood, best of all coniferous species (pine, spruce, larch).
So that they do not bend, they are laid apart from each other at a distance of 1 meter or even closer. The attic floor beam, which has an aspect ratio of 7: 5, is considered the most durable in bending.
Interfloor overlap
The design feature is the “two in one” effect: on the one hand, the floor beams are lags for the floor, and at the same time, on the other, they are the support for the ceiling. As a rule, the space between them is filled with special heat and sound insulating materials, with the indispensable use of vapor barrier. The threshold at the very bottom is finished with drywall, and from above it is pulled by the floorboard.
Wooden floor beams come in several forms, each of which has its own advantages.
Solid wood beams
For their production, an array of solid wood is used. To date, interfloor ceilings on such beams are carried out using a solid tree exclusively with a small span (up to 5 meters).
Glued wooden beams
Such wood floor beams do not have overall restrictions, since the production technology provided allows them to be made quite long.
Due to the increased strength, glued beams are used in cases where it is necessary to withstand a large load on the ceiling.
Advantages of glued beams:
• good strength;
• the probability of blocking considerable spans;
• ease of installation;
• low weight;
• long service life;
• has no deformation;
• good fire safety.
The greatest length of the provided beam is 20 meters.
Since such floor beams have a smooth surface, they are often not sewn up from the bottom, and they therefore remain open, organizing a fairly fashionable interior design in the room.
Cross section of wooden beams
As practice has shown, the cross-section of such beams has a rather significant effect on the ability to withstand the load. As a result of this, it is necessary to preliminarily calculate the section of this material.
Floor beams can have a rectangular, square or circular cross section.
Logs can be used as interfloor beams in wooden houses for design purposes.
We calculate the wooden floor
The distance between the wooden beams is determined by:
- Firstly, the probable loads.
The load, as a rule, can be constant: the mass of the ceiling, the mass of partitions between rooms or the mass of the rafter system. And plus to this - a variable: it becomes equal to 150 kg / m sq. (in accordance with SNiP 2.01.07-85 “Loads and influences”). The so-called variable loads include a lot of furniture, all kinds of equipment, just things that are in people's homes.
Since it is quite difficult to take into account all the possible loads, it is necessary to plan the overlap with a supply of fortress. Professionals advise adding 30-40 percent.
- Secondly, stiffness or standard deflection.
For any type of material, GOST defines its own stiffness limits. Nevertheless, the calculation formula is the same: comparing the absolute size of the deflection with the size of the beam.
Calculation of floor beams
The process of calculating wooden floor beams is quite laborious. In addition to the fact that you need to choose the right distance between them, you should also correctly determine the cross section itself. For these purposes, the amount of deflection at a certain load for a given section is preliminarily calculated. If this indicator exceeds the permissible norm, then the floor beam is taken with a large cross section.
As a rule, the calculation of wooden beams is carried out according to the formula. However, you can also use a specially created calculator for calculating the provided overlap materials. It allows you to take into account all aspects without bothering yourself with the search for information and the calculation itself.
If the beams are folded together, they will carry the load twice as much, and if folded on top of each other, they will withstand the load about four times as much.
Metal Beams
The second popular variety of floor beams is metal. Their advantages: they are durable, reliable, have a small thickness, and, therefore, save space. The bearing component of the provided material is the rolling profile. There are 3 varieties: corners, channel and I-beams. Lightweight concrete inserts or the so-called lightweight reinforced concrete slabs are used as a filler between them, and plus wooden panels. The main advantage of metal beams is that the span is 4-6 meters or more. And their disadvantages are that metal floor beams are very susceptible to corrosion and have reduced heat and sound insulation, however, typical felt can help with this.
Calculation of metal floor beams
It should be noted that the calculation (formulas) is the same for all types of beams. In this case, the size of the possible moment of resistance, as a rule, is checked according to a special reference book or calculated on a special calculator of floor beams, you can easily find it in the global network.
Floor beams: price
It is extremely difficult to say so right away that this type of beam will cost just that much. You need to understand that the price is compiled, not only on the basis of the material (in particular, it is wood or metal). Its formation is influenced by their size, as well as by the manufacturer. The minimum cost of a wooden beam is 219 rubles. for m / p.