How to make the overlap between floors

There are 3 types of ceilings for houses of different heights:

  • basement (basement, bottom);
  • attic (upper);
  • interfloor.

Any of them consists of 2 structural elements: supports (beams) and plating (flooring). Depending on the purpose of wooden floors for their devices use different materials. Since they are all made of wood, installation work can be done by hand, without involving complicated lifting equipment.

  How to make the overlap between floors

Wooden floors can be built only if the width of the span between the structural elements of the building is no more than 8 m.

Beam selection criteria

The following materials are used as supporting elements:

  • solid timber;
  • knocked down boards;
  • peeled logs.

The standard cross-section of the beams is 150/150 mm or 20/150 mm for timber, 140/240 or 5/20 mm for boards. You can use glued laminated timber. In bending strength, it is not inferior to the whole, and often surpasses it. Any material chosen for the construction of wooden floors must be well dried and free from flaws in the form of cracks, knots and wormholes.

Logs are chosen by tapping on them with an ax butt. The tree should make a clear and sonorous sound. It is recommended to use coniferous varieties of wood, as they work on bending much better than hardwood. The length of the beams must be such that it is possible to lay the support in the sockets for the purpose in the walls.

Requirements for wooden floors

  • the design must be strong and perfectly withstand the anticipated load;
  • all elements of the floor in a wooden house should be designed for a service life that corresponds to the planned period of operation of the building;
  • interfloor overlappings should provide for the presence of heat and sound insulating component.

Calculation of the estimated load

Before starting work, perform calculations that help determine the required cross-section of the beams, the step between them, the amount of lumber. For this purpose, either they use special programs, or they are guided by standard indicators. They are:

  1. For flights whose width does not exceed 2200 mm, take beams with a section of 75×100 mm.
  2. For spans of 3200 mm – with a section of 100×175 mm or 125×200 mm.
  3. For spans with a width of 500 mm – beams section 50×225 mm.

The supports are laid in increments of not less than 60 cm. If the beams have a large section, the distance between them is increased to 1 m. Installation of the floor starts from one of the short walls of the house. Bars (logs) must be laid perpendicular to the long walls.

The technology of installation of floors made of wood

To perform the work will require the following tools:

  • ax;
  • a circular saw;
  • hacksaw;
  • hammer;
  • screwdriver;
  • screws and nails;
  • plane;
  • waterproofing and heat-insulating materials;
  • building level not less than 80 cm long.
  1. When building walls in their upper part form special openings or recesses for the beams. Before starting work, these nests are cleaned of dust and debris and lay waterproofing material in them. Most often use roofing material. If the walls are made of brick, the nests can be treated with bitumen or mastics based on it.
  2. The ends of the beams coated with bitumen.
  3. Lay support in previously prepared openings.

If the structure is made of wood, the beams cut into the upper crown. There is such a way of fastening the supporting elements to the wall as a dovetail. It is used in houses built from a log or a bar. This connection method is simple and reliable. Metal brackets are required to fix the beams.

Warming of interfloor overlappings from the massif

Wood floors in the house are mounted according to the following rules:

  • the timber laid in the nest must be no less than 4 cm from the recess walls;
  • beams should be located at a distance of 40-50 cm from the chimney;
  • every 3-4 beams attached to the wall with anchors;
  • the space between the timber and the walls of the nest is filled with tow or glass wool.

The installation scheme of interfloor overlappings provides for the device of heat and sound insulation. Therefore, the gaps remaining after the installation of the beams are filled with polyurethane foam.

Flooring technology

Depending on the location of the observer, wooden floors between floors can be either a floor or a ceiling of a room. To the device of a floor special requirements. Before proceeding with the installation of the flooring, each beam is hemmed on both sides with cranial bars of 40×40 cm or 50×50 cm.

They will serve as a support for the subfloor. Similarly, you can do with the device flooring, forming a ceiling. But the technology of installation of this structural element has no special requirements for performing such work.

The device overlap on wooden beams

The device of overlapping on wooden beams begins with the attachment to the bottom of the supports of unplaned planks with a thickness of 15 mm. They will subsequently serve as a draft ceiling. The waterproofing material is placed on top of the flooring in the filing process: roofing material, a special membrane or dense polyethylene. On it – insulation.

Mount the lining of the upper part of the ceiling on the wooden beams. Boards fasten nails or screws. Knowing the sequence of work, they are easy to do with your own hands. The overlap of the house should be a sealed, durable, high-quality insulated construction. This element of the building is experiencing the greatest weight loads; therefore, only high-quality materials are selected for its device.

The advantages of wood floors

Installation of wooden elements of the building does not require the involvement of construction machinery and hired labor. In this way, it compares favorably with the laying of heavy concrete slabs. Moreover, such an interfloor overlap in a wooden house in the presence of a second floor or attic is the only right decision.

An important parameter of the quality of the wooden elements of the building is the absence of cold bridges. If sheet materials are used for insulation (foam plastic, mineral wool plates), the sheets are trimmed strictly according to the size of the openings between the beams. If the construction of wood floors between floors involves the use of bulk or fibrous materials, it is necessary to ensure that all the gaps are filled.

It is extremely important to provide high quality vapor permeability. Therefore, when laying on polyethylene insulation, and not on a special vapor-permeable membrane, gaps are left. The installation of the wooden flooring is completed with the finishing flooring and finishing works.

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    Construction of wooden floors between floors: detailed construction technology

    In the construction of private low-rise houses of wood, concrete blocks or bricks between the floors most often erected wooden floors. These structures, in comparison with alternative concrete slabs, have several advantages. Wooden floors do not overload the walls, during installation do not require the involvement of lifting equipment. In addition, they have high strength, durability and reasonable price. Installation of such ceilings is quite simple, so many home masters perform it independently.

    Floor structure

    The basis of the wooden floor is beams, which are held on the bearing walls and serve as a kind of “foundation” for the rest of the structural elements. Since the beams in the operation of overlap will bear the full load, especially attention should be paid to their proper calculation.

    For beams, they usually use massive or glued laminated timber, logs, and sometimes – boards (single or fastened with nails or staples in thickness). For overlappings, it is desirable to use softwood bars (pines, larch), which are distinguished by high bending strength. Hardwood parallel bars work much more flexurally and can deform under load.

    Draft boards (OSB, plywood) are fastened to the ceiling beams on both sides, on top of which we sew the front cover. Sometimes the floor of the second floor is laid on the logs, which are fixed on the beams.

    It is worth remembering that the wooden ceiling on the side of the first floor will be the ceiling, and on the side of the second floor (attic, attic) – the floor. Therefore, the upper part of the floor is sheathed with flooring materials: a sheet piling, laminate, linoleum, carpet, etc. The lower part (ceiling) – clapboard, drywall, plastic panels, etc.

    Due to the presence of the beams, a space is formed between the draft boards. It is used to add overlap to additional properties. Depending on the purpose of the second floor, between the joists of the ceiling lay insulating or soundproof materials, protected from moisture by waterproofing or vapor barrier.

    In the event that the second floor is an uninhabited attic that will not be heated, thermal insulation is necessarily put into the construction of the ceiling. For example, basalt wool (Rockwool, Parock), glass wool (Isover, Ursa), foam, etc. Under the insulating layer (from the side of the first heated floor) put a vapor barrier film (asphalt, polyethylene and polypropylene films).

    If EPPS, which does not absorb water vapor, was used as thermal insulation, the vapor barrier film from the “cake” can be excluded. Over heat-insulating or sound-proof materials absorbing and capable to deteriorate from moisture, lay a layer of a waterproofing film. In the event that during finishing the possibility of atmospheric moisture in the attic was excluded, the insulation could not be protected by waterproofing.

    If the second floor is planned as a heated and living space, then the “cake” of the floor does not need additional thermal insulation. However, in order to reduce the impact of noise that will occur when people move along the overlap, a sound-proof layer is placed between the beams (usually the usual heat-insulating materials are used).

    For example, basalt wool (Rockwool, Parock), glass wool (Isover, Ursa), foam plastic, sound-absorbing ZIPP panels, sound-proof membranes (Tecsound), etc. When using materials capable of absorbing water vapor (basalt wool, glass wool), a vapor barrier film is placed between the ground floor and the sound insulator, and waterproofing is placed over the sound insulator.

    Beam fastening to the wall

    Floor beams can be connected to walls in several ways.

    In brick or lumber houses, the ends of the beams are slid into grooves (“jacks”). If bars or logs are used, the depth of the beams in the walls should be at least 150 mm, if the boards – at least 100 mm.

    Parts of the beams in contact with the walls of the “nest” are waterproofed, wrapping them with two layers of roofing material. The ends of the beams are cut at 60 ° and left uninsulated. to ensure the free breathing of wood.

    When placed in the “nest”, between the beam and the wall (from all sides), ventilation gaps of 30-50 mm are left, which are filled with thermal insulation (tow, mineral wool). The beam is supported on the base of the groove through an antiseptic and hydro-insulated wooden plank with a thickness of 30-40 mm. The sides of the groove can be filled with rubble or covered with cement mortar for 4-6 cm. Each fifth beam is additionally fastened to the wall using an anchor.

    In wooden houses beams are buried in the grooves of the walls not less than 70 mm. To prevent squeaks, waterproofing materials are laid between the walls of the groove and the beam. In some cases, the beams cut into the walls, making dovetail joints, etc.

    Also, the beams can be mounted on the wall using metal supports – steel corners, clamps, brackets. They are connected to the walls and beams with self-tapping screws or screws. This mounting option is the fastest and most technologically advanced, but less reliable than when placing beams in the wall slots.

    Calculation of floor beams

    When planning the construction of the floor, first we must calculate the structure of its base, that is, the length of the beams, their number, the optimal cross-section and spacing. This will determine how safe your overlap will be and how much load it can withstand during operation.

    The length of the beams depends on the width of the span, as well as the method of fixing the beams. If the beams are mounted on metal supports, their length will be equal to the width of the span. When embedded into the grooves of the walls, the length of the beams is calculated by summing the span and the depth of the two ends of the beam into the slots.

    Beam position

    The distance between the axes of the beams is kept in the range of 0.6-1 m.

    The calculation of the number of beams is performed as follows: plan to place the extreme beams at a distance of at least 50 mm from the walls. The remaining beams are placed in the span space evenly, in accordance with the selected interval (step).

    Beams can have a rectangular, square, circular, I-section. But the classic version is still a rectangle. Frequently used parameters: height – 140-240 mm, width – 50-160 mm.

    The choice of the beam section depends on its planned loading, span width (along the short side of the room) and the beam placement interval (step).

    The load of the beam is calculated by summing the load of its own weight (for interfloor floors – 190-220 kg / m 2) with the temporary (operational) load (200 kg / m 2). Typically, for existing floors, the load is assumed to be 350-400 kg / m 2. For attic floors that are not operated, you can take a smaller load, up to 200 kg / m 2. Special calculation is necessary if significant concentrated loads are assumed (for example, from a massive bath, pool, boiler, etc.).

    Beams are laid along a short span, the maximum width of which is 6 m. A sagging of the beam is inevitable on a larger span, which will lead to deformation of the structure. However, in this situation there is a way out. To support the beams on a wide span establish columns and supports.

    The beam cross-section directly depends on the span width. The larger the span, the more powerful (and durable) beam you need to choose to overlap. The ideal span for overlapping beams is up to 4 m. If the spans are wider (up to 6 m), then you need to use non-standard beams with an increased section. The height of such beams must be at least 1 / 20-1 / 25 of the span. For example, with a span of 5 m, it is necessary to use beams with a height of 200-225 mm and a thickness of 80-150 mm.

    Of course, it is not necessary to independently perform beam calculations. You can use ready-made tables and diagrams that indicate the dependence of the dimensions of the beams on the perceived load and the width of the span.

    After performing the calculations, you can proceed to the device overlap. Consider the entire technological process, starting with fixing beams on the walls and, finishing, with finishing covering.

    Wood Flooring Technology

    Stage # 1. Installation of floor beams

    Most often, beams are installed with placing them in the grooves of the walls. This option is possible when the installation of the ceiling is under construction at home.

    The installation process in this case is as follows:

    1. Beams covered with antiseptics and flame retardants. This is necessary to reduce the tendency of wooden structures to rot and provide fire safety.

    2. The ends of the beams are cut at an angle of 60 °, dyed them with bitumen mastic and wrapped in roofing paper in 2 layers (for waterproofing). At the same time, the butt should remain open for free water vapor through it.

    3. Begin installation with the installation of two extreme beams, which are placed at a distance of 50 mm from the walls (minimum).

    Bars start in the “nest” at 100-150 mm, leaving the ventilation gap between wood and walls of at least 30-50mm.

    4. To control the horizontal position of the beams, a long board is placed on the edge of the upper plane on the edge, and a bubble level above it. To align the beams on the level, use wooden dies of different thickness, which are placed in the lower part of the groove on the wall. Dies must be pre-treated with bitumen mastic and dried.

    5. To eliminate the creaking of the beam and block the access of cold air, the gap is filled with mineral insulation or tow.

    6. Lay the rest, intermediate beams on the laid control board. The technology of their establishment in the nests of the walls is the same as in the installation of the extreme beams.

    7. Every fifth beam is additionally attached to the wall with an anchor.

    When the house is already built, the installation of beams for flooring is easier to perform with metal supports. In this case, the installation process is as follows:

    1. Beams impregnated with flame retardants and antiseptics.

    2. On the walls, on the same level, in accordance with the calculated step of the beams, supports (angles, clamps, brackets) are fixed. Fastening is performed with screws or screws, screwing them into the holes of the supports.

    3. Beams are laid on supports and fixed with self-tapping screws.

    Stage # 2. Mount cranial bars (if necessary)

    If it is more convenient to lay the “pie” of the floor structure on top, that is, from the second floor side, cranial bars with a cross section of 50×50 mm are filled along the edges of the beams. The lower part of the bars must be flush with the surface of the beams. Cranial bars are necessary in order to lay roll boards, which are a rough basis for the ceiling.

    It is possible to do without cranial bars if hemming roll boards from below, from the first floor. In this case, they can be mounted directly on the beams, with the help of screws (nails are not suitable, as they are difficult to hammer vertically into the ceiling).

    Stage # 3. Fastening of roll-up boards for a rough ceiling base

    When installing from the side of the second floor, cranking bars are fixed with nails or self-tapping screws to the reel boards (OSB, plywood are possible).

    When attaching the reel from the first floor, the boards are fixed on the beams from below using self-tapping screws. If necessary, lay a thick layer of insulation or sound insulating material between the beams, the option of filing boards from the bottom is preferable. The fact is that the cranial bars “eat up” a part of the inter-gully space, and without their use, the thickness of the overlap can be completely laid with insulating material.

    Stage # 4. Steam insulation (if necessary)

    Vapor barrier is laid in the construction of the ceiling in front of the insulation (which can also perform the functions of a sound insulator) if there is a risk of steam ingress into it or the occurrence of condensate. This happens if the overlap is arranged between floors, the first of which is heated, and the second is not. For example, an unheated attic or attic is set up over the first residential floor. Also, steam can penetrate into the floor insulation from wet rooms on the ground floor, for example, from the kitchen, bathroom, pool, etc.

    The vapor barrier film is laid on top of the ceiling beams. The canvases are overlapped, setting the edges of the previous canvass for a subsequent 10 cm. The joints are glued with construction tape.

    Stage # 5. Device insulation or sound insulation

    Between the beams on top lay slab or roll heat or sound insulators. It is necessary to avoid cracks and voids, materials should fit snugly to the beams. For the same reason, it is undesirable to use pruning, which must be docked with each other.

    In order to reduce the occurrence of impact noise in the ceiling (with a residential upper floor), sound insulation strips with a minimum thickness of 5.5 mm are placed on the upper surface of the beams.

    Stage # 6. Laying waterproofing film

    A waterproofing film is placed on top of the heat or sound insulation layer. It serves to prevent the penetration of moisture from the upper floor to the insulating material. If the upper floor is uninhabited, that is, no one will wash the floors there and the penetration of atmospheric moisture will also be excluded, waterproofing film can not be used.

    The waterproofing film is laid with canvases, overlapped by 10 cm. Joints are glued with adhesive tape to prevent moisture penetration into the structure.

    Stage # 7. Fixing boards (plywood, OSB) for subfloor

    The beams on top sew a rough base for the floor of the second floor. You can use regular boards, OSB or thick plywood. Fastening is carried out with the help of screws or nails.

    Stage # 8. Covering overlapping bottom and top finishing covers

    On top of the draft base, from below and above the ceiling, any suitable materials can be laid. On the upper side of the floor, that is, on the second floor, they arrange laminate, parquet, carpet, linoleum, etc. When arranging non-residential attic floor, draft boards can be left without trim.

    On the bottom surface of the ceiling, which serves as the ceiling for the first floor, ceiling materials are sewn: wooden lining, plastic panels, plasterboard structures, etc.

    Overlap operation

    If the construction used beams with a large margin of safety, laid with a small step, then such an overlap will not need to be repaired for a long time. But nevertheless it is necessary to check beams for durability regularly!

    At damage of beams by insects or as a result of remoistening, their strengthening is carried out. For this, the weakened beam is removed, replaced with a new one, or strengthened with durable boards.

    I have long been thinking about repairing the ceiling on my wing at the dacha, but still my hands will not reach. But here you need to seriously understand – I didn’t quite understand how the beam load is calculated, if there are additional loads. It will be necessary to do this seriously, most likely in the summer.

    Nikolay, without special knowledge from the field of construction, you cannot correctly calculate the beam load. Too many factors and nuances need to be considered when calculating. Believe me, a layman is practically impossible to do. To get started, try to at least determine the type and characteristics of the joists on your wing. Even if you succeed, then at the stage of miscalculation, the work is stalled: formulas are too complex (even their simplified versions). My advice: entrust repairs to professionals.

    Good day.There is a wooden house, I understand everything from the first floor and the floor. We put most likely the market or something like that. Second floor only beams. A question arose with me: do I need to lay down what films? The house is residential, the second floor is residential. Or I put heat insulation between the beams (since I stayed, and of the type of sound insulation), and on top I will type the floor, 35 mm board. It seems, as it seems to me, do not need any films.

    General knowledge does not give an understanding of the approximate calculations of the beam / floor load. A sofa + dresser + table + 6 chairs, well, 10 people = about one and a half tons – this is not a load. another thing if you decide to place a brick warehouse on this floor. )

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