If we consider the question of how to make the floor on the second floor, it is necessary to first decide what functions it will perform? If this is an attic space and will only be used for storing various things, then in this case the difference is only in the coating - it is enough to use rough boards as flooring. The cross-section of the beams can also be reduced, since the loads in the attic will be significantly less than in the room that is used as a living room. Such a floor will be much cheaper and will allow you to move safely. As for other operations for insulation, steam and moisture protection, they must be performed regardless of the operating conditions of the floor.
Floor types
Interfloor floors in a house are usually made of wood or concrete. In both cases, the work is quite complex and requires the necessary knowledge. It should be remembered that a rush or an attempt to save money on this design can lead to sad consequences and costly alterations. For this reason, if the overlap of the second floor is supposed to be carried out independently, it is necessary to draw up a detailed work plan, determine the materials and their quantity.
When choosing a material, one should take into account the main technical characteristics that the floor should have.
Primarily:
- must be sufficiently strong and safe to operate;
- meet all technical requirements;
- have protection against decay and fire;
- provide heat retention and sound insulation.
Of course, you should not overload the floor with unnecessary structures, but at the same time it must meet all operational requirements.
Wooden floors
Regardless of the initial plans for the construction of a house, in any case, ceiling beams are present and, as a rule, they must be strong enough if the house is assembled according to all the rules.
The construction of the floor of the second floor should be started with these beams. If the house is under construction and the project plans to use the second floor, it should be remembered that the size of the beams depends on the size of the span.
For example:
- section of the beam is 75 × 100 mm with a span of 2200 mm;
- 100 × 175 mm or 125 × 200 mm with a span of 3200 mm
Sometimes boards are used that are stitched together, forming an imitation of a bar. But, as practice shows, in most cases, beams are used with dimensions of 150 × 150 mm or 200 × 200 mm. The direction of laying the beams is chosen in the direction of the smallest distance between the walls. The ends of the beam must rest on the wall at least 90 mm. It is recommended to use pine beams, since materials from this type of wood are light enough, but at the same time they can withstand heavy loads. In this case, the tree must be completely dry and of good quality.
The installation of the timber is carried out in pre-prepared recesses in the brickwork or also in the timber. It should be remembered that the beams must be treated with appropriate protective compounds before installation. If the part rests on a brick wall, waterproofing materials must be laid in the places where the wood contacts the brick. If the house is wooden, it is recommended to lay tow or other material with the same properties in the recess in the wall where the beam will be installed.
Next, a rough floor is nailed to the beams, which at the same time serves as a rough ceiling. If, for some reason, the parts are laid at a short distance, there are attempts to save money on a rough board, and a finishing ceiling is immediately nailed to the beams. This should not be done, since the material used for fine filing is not always able to withstand the stresses that arise after the installation of insulation and protective components.
There is another option for installing a sub-floor. To the beams on both sides along the entire length, a bar of 40 × 50 mm or 50 × 50 mm is attached, and already on these bars a sub-floor is mounted in a size corresponding to the width between the beams.
A less common method is to make grooves in the beams into which the sub-floor boards are installed. With this option, the size of the timber must be selected taking into account the size of these grooves.
After laying the roughing board, a thermal protective film should be laid (any type of this material is used). The film is laid between the beams so that its edges overlap the part itself. It is advisable to secure the film with a stapler. It should be remembered that the film is laid with the smooth side up, and the rough side down. Otherwise, it will not be able to carry out its functions. In this case, roofing material or simply rasters made of clay and sand can be used as cheap materials.
After the film is laid, the insulation is laid. Various materials can be used as it. The most common is mineral wool. As for this product, regardless of advertising promises and advice from knowledgeable specialists, it must be remembered that it is made on the basis of fiberglass, phenolic resins are the binding element. In any case, fumes will be present, and microscopic dust as well. In some cases, the space between the beams is covered with expanded clay, slag, sawdust, or foam is laid. If it is necessary to provide increased sound insulation, it is advisable to use penofol and sand. A layer of foam foam is placed in the space between the beams and covered with a layer of sand of about 5 cm.
By the way, in the old days, a mixture of earth with oak leaves was also used as sound insulation - this is the cheapest way. In any case, it should be borne in mind that the insulation layer must be at least 50 mm, otherwise it will not perform its functions. If the premises of the second floor will be constantly heated and used as residential, insulation in the interfloor overlap can be excluded (it is enough to provide good sound insulation).
The next step is to lay another layer of film that acts as a vapor barrier. It can be laid directly on the insulation, but it is better if there is a small space between the insulation and the film. Therefore, the film is attached directly to the beams.
After all the operations, laying the floor on the second floor begins. For installation, an edged board without a groove is used if the floor is supposed to be further covered with chipboard or other slabs. Ideally, use floorboards with a groove. In this case, they fit tightly, without any gaps.
In order to save material, in some cases, the boards are laid directly on the beams. But ideally, bars with a section of 50 × 50 mm should be laid on the beams at a distance equal to the distance of the beams, and the floor should be laid on them.
Concrete slab
Another construction of the second floor is the installation of the floor on concrete. If the floor has already been installed, an alignment must be made. Those. the base is screed with a liquid solution, while fiber is added to the solution to give strength.
When the screed is ready, proceed to the installation of the floor itself. Compared to hardwood flooring, a solid concrete slab is a stronger and more durable option.
Installation should begin with marking, having previously determined what the height of the floors of the second floor will be in order to install the formwork. Direct installation of formwork is a rather laborious and crucial moment. It must be placed completely horizontally. The uprights that will support the entire structure must be strong enough to support the weight of the concrete while it cures.
After the formwork is installed according to all calculations, reinforcement begins. For these purposes, reinforcement rods with a cross section of 12 mm are used. They must be tied together in such a way that you get squares. It is desirable that the size of the square is about 20 cm.
It is better to fill the floor with concrete in one step: this will ensure the uniformity of the structure and higher performance. To prepare concrete, it will be enough to use cement of the M400 brand, which is mixed with sand and fine gravel in a ratio of 1: 3. After pouring, air is removed from the concrete (a construction vibrator is suitable for this operation).
With a perfectly even screed, the final floor covering can be installed directly on the concrete, having previously laid a waterproofing material and a leveling base, which will also serve as a shock-absorbing cushion. In some cases, logs are laid between the concrete screed and the boards to create either additional insulation or sound insulation. In this case, it is necessary to set the logs according to the level and provide good waterproofing between them and the concrete base. Further laying of the floorboards is carried out in the usual way. Those. a board is attached to the logs, and, if necessary, other coatings are attached to it, depending on the interior.
And if the bathroom?
If on the second floor it is planned to arrange a bathroom and toilet, it is necessary to provide space for communications, in particular, a sewer drain and pipes for water, before pouring the concrete floor. If the floor covering of the second floor is made of wood, it is necessary to take into account the loads that will act at the location of the bathroom.
The bathtub weighs about 200 kg, and the weight will double when filled with water. Accordingly, the normal load on timber floors must be doubled. One of the solutions is to increase the size of the cross-section of the beams, and reduce the distance between them in the place of the intended bathroom. Particular attention should be paid to moisture removal and additional protection of wood in order to exclude the formation of mold and, as a result, rotting of wooden structures.
It is better to use a board on the floor from larch, elm or alder, since these types of wood, being in a humid environment, only become stronger and more durable. If a shower is provided in the bathroom, it will be necessary to drain water, as a rule, in this case, a drain with a dry locking element is used. Installation must be carried out in such a way that all the water that falls on the floor of the shower room leaves through the drain. Waterproofing materials must be highly adhesive and have sufficient elasticity.
Additional work during installation
A common problem is squeaking wooden floors. As a rule, this happens because the boards are attached to nails, and they loosen over time, thereby forming gaps between the boards and the logs, which is the cause of the squeak. To avoid this in the future, it is recommended to use screws instead of nails when laying the flooring.
Also, there may be a creak on a concrete base. In this case, the reason may be the gaps between the joists and the concrete base. You should not rush or be lazy, you need to install the logs in such a way that they fit snugly on the concrete. If you ignore the recommendations, in the future you will need complex reworking of the floor, which is not always possible.
Another nuance that must be considered during installation is the staircase to the second floor. In this case, everything depends on how the premises of the second floor will be used. If it is just an attic space, a small hatch will suffice. If the room is to be residential, the staircase should be large, and the parameters depend on the interior and the type of staircase itself. But in either case, the size should be convenient for use, regardless of how often it will be used or not.
Another of the openings that must be provided for during the installation of the interfloor overlap is the opening for the chimney. If the ceiling is concrete, it will be enough to mount the opening to the size of the chimney. Wooden floors have their own nuances. The stove and, accordingly, the chimney is a source of possible ignition, and for this reason it is necessary to worry about fire safety. The opening in this case should be larger than the size of the chimney itself.
So, as it is clear in the end, in any case, strict adherence to all technical recommendations will make it possible to make a high-quality and durable floor on the second floor.
Requirements for the floors of the second floor, popular flooring designs and materials for them, installation technology in wooden and brick houses.
The content of the article:
Floor installation on the second floor is a flooring structure with an attractive appearance and good performance. The construction assembly technology depends on the floor plan and the purpose of the premises at the first level. The types of floors on the second floor and the features of assembly work will be discussed in this article.
The main types of floors on the second floor
The design of the floors on the second floor depends on several factors, the main one being the method of forming the interfloor overlap. If the base is wooden, the flooring is laid on beams or joists. In the case of using reinforced concrete slabs, the material is placed on the logs.
Here are the characteristics of the main types of floors for the second floor of the house:
- Floors on beams... In this design, the flooring is mounted directly on the logs holding the floor. Supporting structures (beams) are the foundation of the floor, its load-bearing elements. The work is carried out during the construction phase of the entire building. The shape of the bar can be different - rectangular, round, square. Blanks for beams are sold untreated and require preliminary finishing before laying in a regular place, which increases the installation time. Strength elements made of rough wood have advantages over logs - they are cheaper and more resistant to stress. But the structure has poor sound insulation, because the profiles are placed in the frame part of the building.
- Log floors... Lags are necessary to obtain high quality flooring in floor structures. In wooden houses, these elements are laid directly on the load-bearing beams. The workpieces have a rectangular cross-section of standard dimensions and do not require pre-processing. Installation of floors on joists is quick due to precise dimensions and smooth surfaces. During operation, the flooring is insulated from the walls and power profiles, which makes it possible to increase the heat and sound insulation of the room. Among the disadvantages can be noted a decrease in the distance between the floorboards and the ceiling after assembly of the structure and the high cost of the material.
- ... Concrete floor slabs on the second floor can withstand a much higher load than wooden ones; heavy structures can be mounted on them. The boards are supported by logs that can be installed on a pre-leveled surface or on technological spacers. As a heater, you can use the most environmentally friendly high-quality insulator - expanded clay. It has a significant weight, therefore it is not used in wooden structures.
Requirements for the floors of the rooms of a multi-level house
The floor of the second floor must meet the following requirements:
- Have maximum rigidity and minimum deflection. The overlap must withstand its own weight and load from furniture, household appliances, people, etc.
- The design is simple and in line with construction technologies.
- The materials used are not afraid of moisture, have a long service life, and are resistant to abrasion.
- The flooring is made in a fireproof design, and its fire resistance limit corresponds to the permissible values for this material. For unprotected wooden floors, this value is less than 15 minutes.
- The slab has good sound insulation and complies with special standards for residential premises.
- If the temperature difference on different floors is more than 10 degrees, the floor must be insulated.
- The load-bearing capacity of the flooring corresponds to the operational load of the entire building.
- The appearance of the floor should be attractive and consistent with the style of the room.
The choice of materials for the floors of the second floor
The construction of the floors of the second floor consists of the following main elements: base, rough coating, heat and sound insulation, waterproofing. The choice of materials depends on the load on the coating and the conditions in which it will be used.
Power beams for floor mounting
Decking profiles are most often made from coniferous trees - pine or larch, which have a high bending strength. Hardwood planks may bend after a load is applied. When purchasing, make sure that the samples are free of knots, cracks, rot and other defects.
Before making the floor on the second floor, determine the load capacity and dimensions of the logs. For the calculation, you can use simple computer programs or apply ready-made proven designs.
The shape of the deck can be different - rectangular, round, square. The classic version of the power beam is a beam 140-240 mm high and 50-160 mm wide. The section size depends on the load, the span size and the step between the products. The beams are laid along a short span with a maximum length of 6 m. The optimal length of the supporting structures is 4 m.
Logs for floors of residential premises must withstand a load of 350-400 kg / m2, for non-residential unexploited ones - 200 kg / m2. If there is a concentrated load, for example from a bath or boiler, special calculations are performed.
A longer product will sag under its own weight and lead to deformation of the structure. If necessary, supports are mounted on the ground floor that support the ceiling structure.
Instead of supports, you can use reinforced beams (purlins) on which other beams are supported. The ratio of the height of the purlin to the length of the span should be 1:20. For example, for a span of 5 m, choose a support with a height of 200-225 mm and a thickness of 80-150 mm.
On construction markets, glued rectangular girders and I-beams made of logs and planks are sold. In the first variant, the profiles rest on the upper part of the purlin. When using an I-beam, the decks are placed on the lower shelf of the product, reducing the height of the structure.
Lags for creating flooring
They are made from coniferous trees, in which the material is soft, easily processed, inexpensive. You can use bars of the second or third grade with a moisture content of up to 18%. Stronger oak or hardwood specimens, but are considered elite materials and are expensive.
The beam should be rectangular, and its width is 1.5-2 times less than the height. Profiles with such proportions withstand the greatest load. Products with a cross-sectional area of 75x150 mm are popular.
The section of the lags depends on the distance between the beams and is calculated according to special tables. If the span is intermediate, choose large logs.
The product of the required thickness can be made independently by connecting two boards together. If the height is less than the width, the product is placed on the edge.
Choose the height of the timber 3-4 mm more than the thickness of the protective layer so that there is space for ventilation under the flooring.
Insulators for floor installation
For heat and sound insulation, roll or block materials (basalt wool, glass wool, foam) are used. The protective layer is laid with a thickness of 50 to 200 mm, depending on the height of the floors of the second floor.
It consists of several levels:
- The lower part of the ceiling is protected from moisture with a vapor barrier film (glassine, polyethylene sheets).
- For sound insulation, you can use conventional heat-insulating coatings made of basalt wool or glass wool with a density of 40-45 kg / m 3. A greater effect can be achieved when laying special materials such as "noisy".
- If the ground floor is cold, the floors are insulated with basalt wool, glass wool or foam. The temperature of the outer floor covering should differ from the temperature in the room by no more than 2 degrees. The ideal way to keep the room warm is to use mineral wool. Also for these purposes, foam plastic, expanded clay, sawdust are used.
- Cover the "pie" with waterproofing material.
- The flooring in the nursery must be environmentally friendly and have impact sound insulation.
- If there is a shower room, bathroom, pool on the ground floor, be sure to build a moisture protection.
- Waterproofing is not required when using EPS insulation.
- If the structure does not get water from above, the moisture-proof film can not be laid over the insulation.
- The floor in heated rooms located above the living quarters need not be insulated, but sound insulation is required.
Lumber for the floor on the second floor
Choose the type of wood for the platform depending on the operating load of the floor. Pine, fir and spruce lumber, which is not recommended for use, for example, in the corridor, is laid in little-visited rooms. Solid oak and hardwood can be laid in any room, but they are expensive. It is better to make alder and aspen floors in nurseries and bedrooms.
The choice of lumber grade depends on the finish, financial capabilities and other factors:
- The first grade materials are usually varnished and used as finishing materials.
- Second-grade sawn timber is colored.
- Boards of the third grade are covered with linoleum on top or used in back rooms.
- The finishing coating is made from ordinary boards, plywood, OSB. To obtain a flat surface, it is better to use tongue-and-groove material.
- The top layer can also improve the soundproofing of the room if solid board materials such as DSP are used.
- The tongue-and-groove boards adhere tightly to each other and also do not allow extraneous sounds to pass through.
- The moisture content of the workpieces should not exceed 12%, otherwise, after drying, large gaps appear between the floorboards.
- Please check the product for defects before purchasing. The surfaces of the beams must be parallel, otherwise it will be very difficult to ensure horizontal alignment.
Installation of the second floor floor on load-bearing beams
The scaffold is laid on the interfloor profiles during the construction phase of the building. The end result depends not only on the topcoat, but also to a large extent on the installation of the load-bearing elements on the walls.
Installation of timber on walls
The flooring is attached to the load-bearing beams that form the interfloor overlap, without intermediate elements. Floor works on the second floor are performed in the following sequence:
- Cover the beams with antiseptics and flame retardants.
- Make openings in the walls for the beams. If the partitions are brick or concrete, grooves (nests) are made. In log structures, provide for recesses at least 150 mm deep (for beams) or at least 100 mm (for planks). The step between the openings should be within 0.6-1 m.
- The first log is placed at a distance of at least 50 mm from the wall, the rest - evenly between the extreme elements.
- Decks can be attached to the wall in other ways. For example, if you cut the dovetail grooves in the partition, and make projections of the same shape in the log. Another option is to pre-fix the corners or brackets to the walls with self-tapping screws or anchors and put the beams on them. The latter method allows you to quickly create an overlap, but in operation, the connection is not very reliable.
- Cut the ends of the profiles at an angle of 60 degrees.
- Cover the ends of the decks that lie on the walls with bitumen and wrap with two layers of roofing material for waterproofing. Do not insulate the cut ends, they must remain in this form for ventilation.
- Prepare trim boards with a thickness of 30-40 mm, saturate with waterproofers and antiseptics. Place the samples on the bottom of the beam grooves.
- Lower the beams onto the planks and leave gaps between them and the walls of 30-50 mm on all sides.
- Check the horizontal level of the bar with a level. If necessary, make wooden blocks of different thicknesses, grease them with resin and dry them.
- Place spacers under the edge of the timber and eliminate the slope.
- Put all the lumber in place in the same way.
- Check the location of the upper surfaces of all products in the same horizontal plane using a building level. Correct slopes if necessary.
- Fill the gaps between the wood and the wall with mineral wool or tow to prevent cold air from entering. Fix every fifth sample to the wall with anchors.
Assembling the floor structure
The order of assembly of the floor structure and its fastening is carried out in the following sequence:
- Fasten the 50x50mm Skull Bars flush with the lower base of the bar.
- Place the subfloor elements on them and fix them from the side of the first floor with self-tapping screws. When installing, check the horizontalness of the bottom deck.
- To protect against damp fumes, lay glassine or plastic wrap on the floor. They are laid on top of the logs with an overlap with an overlap of 10 cm and fastened with a stapler. Glue the joints with construction tape.
- Place a roll or panel insulation material on top of the vapor barrier. Check that there are no gaps on the floor. When installed in two layers, the slabs must overlap the joints of the lower row.
- Cover the insulation with plastic wrap, seal all the gaps between the material and the base.
- After installing the insulation, subfloor boards are laid on the power elements. The material of the platform depends on the topcoat. For example, linoleum or a parquet board is laid on plywood 10-12 mm thick.
- Laying the floor on the second floor ends after making holes in the corners of the room for ventilation of the underfloor space.
Laying the floor of the second floor on logs
The construction of flooring and joists is used in rooms with high ceilings, because the bars raise the flooring. It can be installed at any stage of construction, even in a residential building.
- In the load-bearing beams, make grooves for the logs in increments of 30-40 cm. The distances between them depend on the thickness of the rough flooring and the type of topcoat, the values can be found in special tables. For example, if sheet material (plywood or chipboard with a thickness of 16 mm) is used for the rough coating, the distance between the beams along the axes is 30 cm.If boards with a thickness of 20 mm are used, the step is increased to 40 cm.The first opening should be at a distance of 20-30 cm from the wall.
- Place the logs in the cutouts with the smaller side.
- Check the location of the upper surface of the lags in the horizontal plane. Follow the bar pads alignment procedure if necessary.
- Fasten the beams to the strength members with nails or self-tapping screws. In the latter case, holes are pre-made.
- Attach boards or bars to the bottom of the logs to create a rough floor.
- Place plywood or other lumber that can withstand insulation on the supports you have made.
- Cover the prepared substrate with a vapor barrier foil. Seal the joints of individual parts of the film with tape.
- Place heat and sound insulation on the base. Check that there is a gap of 10-15 mm for floor ventilation between the top of the log and the insulation.
- Cover the cake with waterproofing tape and secure with a stapler.
- Lay a finished floor made of plywood, boards or other materials on the logs and finally secure. The edges of the material must necessarily lie on the logs.
Placing the floor of the second floor on a concrete slab
Lags for arranging floors are indispensable if work is planned on concrete floor slabs. The beams are laid in two ways - on a cement screed or on wooden gaskets. The first method involves preliminary leveling of the slab surface to the horizon.
The work is performed in the following sequence:
- Remove any dirt from the stove.
- Seal deep gaps with cement screed, knock down protruding elements.
- Using a hydrostatic level, mark the walls of the room with horizontal marks that will serve as guidelines for the maximum fill of the floor.
- Prepare a sand-cement mortar and fill the floor to the level of the marks on the wall.
- After drying, check the levelness of the surface.
- Before installing the lag, waterproof the base, because concrete absorbs moisture well. The operation is allowed not to be carried out if the ground floor is heated and the building is dry.
- Decide on the orientation of the boards (and, accordingly, the lags) in the room. Unlike wooden floors, on which the beams are placed perpendicular to the load-bearing elements, beams can be fixed on a concrete slab in any position. In hallways, corridors and other rooms with a high operational load, the floorboards are placed along the direction of travel. In living rooms, the boards are placed parallel to the light from the window.
- Place the logs on the foil and secure with anchors to the base.
Fix the wood to the slab with screws and dowels. Place the fasteners next to the spacers. The further procedure for laying insulation and installing a finished floor is similar to assembling a platform on a wooden floor.
How to make the floor on the second floor - watch the video:
Installation of floors on the second floor is not fundamentally different from work on the first. The main problems remain the arrangement of soundproofing of the floor and the strength calculations of the structure. To keep the flooring in operation for as long as possible, follow the advice of our instructions.
One of the elements that can withstand the entire load of the floor is the beam. The integrity and durability of the floor between the floors will depend on how correctly its installation is performed and the calculation of the bearing capacity is made.
The beam, made of wood, remains popular when equipping floors between floors. But they, like any building material, are endowed with their own positive and negative qualities. Consider the characteristics.
The positive characteristics of wooden beams include the following:
- The floor joists are made of wood and are easy to use. Easy and quick to install.
- They have a relatively low weight, which entails a reduction in the overall load on the base of the building.
- They are less expensive than other materials.
- The material for the manufacture is in sufficient quantity.
- They can be quickly replaced if necessary.
- Well suited for the construction of small private houses and cottages that have small spans.
- Wood is an environmentally friendly material.
The disadvantages of this building product include the following:
- They require processing with special fluids that have fire-fighting characteristics and do not allow material to rot.
- Have a limited load.
- The inability to install them in rooms with large spans.
Requirements for floors made of wooden beams
When installing wooden beams, it is imperative to fulfill a number of requirements. Violation or failure to comply with these requirements can lead to negative consequences. Requirements define that:
- it is forbidden to use deciduous tree species for the manufacture of beams. Manufacturing should be carried out only from conifers. Such wood has a significant margin of safety;
- the wood from which the beams are to be made should have a moisture content of no more than 14 percent. If the specified value is exceeded, the beam span may have significant deflection;
- wood must be peeled from bark, treated with a fire-resistant liquid, a solution against pests and fungal diseases. It is forbidden to use wood material that has diseases or defects;
- before the manufacture of beams, it is necessary to provide for a building lift. During operation, it will level out, the floor and ceiling will remain flat;
- alignment of the beams must be carried out by installing sawn timber scraps impregnated in resin under their ends. It is not recommended to undercut the ends of structures;
- in addition to rectangular beams with a calculated cross-section, a solid log can be used. It must be hewn and have a certain diameter. It is much cheaper than using lumber. But, such logs must be stored in a dry place for at least a year before installation.
Calculation of beams made of wood
When planning to mount a wooden floor, you need to calculate the required number of beams and their dimensions.
For this you need:
- know the distance between the walls to which they will be mounted;
- calculate the expected load on the beams after they are installed;
- knowing the indicated values, calculate the size of the section and the step of their installation.
Determination of the size of the beams
The size of the beam is the sum of the total values. These quantities include:
- distance between walls;
- the length of the beam that will be embedded in the depth of the wall.
The span is determined using measuring accessories such as a tape measure. Depending on the material from which the wall is made (wood, concrete, brick, etc.), the depth of the beams will depend.
If the building is brick, then the stock for wooden beams should be more than 10 cm.If the building is built of wood, then specific grooves are made for the beam span for the second floor, which have a depth of 6-10 cm. rafter system, they should be 5-7 cm longer than the span of the building.
Important!
The overlap with wooden beams should be between 2.5 and 4 m. The maximum span length should not exceed six meters. If the overlap exceeds this value, then glued laminated timber structures are installed.
Calculating the load on a wooden beam
The load, like the size of the beams, consists of the sum of several elements. This is the total mass of the span elements and interior details that will be located in the upper floor room. The elements that are included in the overlap between floors include wooden beams, logs, insulation, floor and ceiling coverings, steam and waterproofing. Interior elements include furniture, household appliances. This also includes the possible number of residents who will constantly use the floor. Often, the calculation of loads is carried out by special institutions.
For self-calculation of the bearing capacity, the following scheme is used:
- Overlap of the attic with filing. If mineral wool is used as a heater, then its own load lies within 50 kilograms per square meter. SNiP standards denote a standard load for overlap within 70 kilograms per square meter and a safety factor for it with a factor of 1.3. The total load is calculated simply: 70 kg x 1.3 + 50 kg = 130 kilograms per square meter.
- The insulation is not mineral wool, but material with a large weight. Or thick boards were used for filing. In this case, the standard load increases to 150 kilograms per square meter. Accordingly, the total load will change: 150 kg x 1.3 + 50 kg = 245 kilograms per square meter.
- For the attic, the standard load will be 350 kg per square meter.
- For beams that perform the function of overlapping between the first floor and the second, the standard is 400 kg per square meter.
Calculation of the size of the section and the step of installation of beams
Having decided on the size of the load that will fall on the beam and, having counted its length, you can calculate the installation step and the size of the section (or diameter). These values are related to each other and are designated according to established standards:
- The cross-section of the beams is in the ratio of width to height, like 1 to 1.4. Depending on the load, the beam should have a width of 5 to 20 cm and a height of 10 to 30 cm. the exact dimensions of the section depending on the length and the expected loads.
- When calculating the cross-section, it is necessary to take into account that the greatest deflection of the floor beams between the floor and the attic should not be more than 1/200, and between the lower and second floors should not exceed 1/350.
- The installation of beams is carried out with a step that lies in the range from 30 to 120 cm. Basically, the step of laying the floor is used every 60, 80, 100 cm. Often, the step is chosen according to the size of the insulation material. If the building is frame, then the step is carried out taking into account the location of the frames.
What are lags and the benefits of using them
Regardless of the material from which the flooring will be made, it is necessary to install joists in the interbeam space. What is it and what are they for? They can be called cross beams. The logs are installed perpendicular to the main beam floors. They serve to increase the stiffness of the floor between floors and reduce the load. Ceiling and floor coverings are attached to them.
The advantages of using lag are obvious:
- simplicity and speed of installation;
- saving building materials;
- the finished structure is immediately used;
- have excellent thermal insulation and sound-reducing characteristics;
- allow you to adjust the height of the floor covering;
- suitable for the installation of communication lines;
- serve as a good ventilation element;
- distribute the load over the entire surface among the beams;
- relatively low cost;
- the ability to quickly and efficiently repair or replace individual parts.
DIY lags
The production of logs is carried out from wooden beams with a rectangular cross-section. The section of the lag is in the ratio of width and height, like 2 to 3 or 1 to 2. In other words, the height of the lag should exceed its width by 1.5-2 times. Cheap coniferous wood is often used for the production of logs. For example, a pine or a Christmas tree. The bar is cut to the required length and a log is obtained.
Important!
Wood for logs must be dried, free from defects, treated with a special refractory solution, liquid from pests and fungal diseases.
We lay the logs correctly
The installation of the lag must be carried out in a direction perpendicular to the direction in which the floor covering will be laid. It is important to correctly calculate the installation step of the lag. If the step is chosen correctly, then the strength of the flooring will be quite high. But, with a smaller step, the work and the cost of the material will be more expensive. If the laying step is large, then the floor will sag and creak. To choose the right option, you must first of all take into account how thick the flooring will be. The thinner the coating, the closer to each other the installation of the lag should be. If the thickness of the floor covering (boards) is about 2-2.5 cm, then the installation step of the lag should be within 30-40 cm.With an increase in the thickness of the coating to 5 cm, the step can be increased to 1 m.
Mount lag
Lags are attached directly to the beam, to its side. This makes it possible to adjust them without using additional pads. Their slope is checked by a special level. Having achieved the required position, the logs are attached with beams with nails or screws.
In addition, the fastening of the lags and beams to each other can be carried out using iron corners. One part of the corner is mounted on a beam with self-tapping screws, logs are attached to the second parts of the corners. In addition to the corners, brackets in the form of the letter P, which are commercially available, can be used for mounting the lag.
Conclusion
When building your house or cottage, wooden beams will be a good substitute for concrete floors. Installation work can be done independently, without the involvement of special equipment. The presence of a lag in the interfloor floor will increase the stiffness of the floor. Their presence will give reliability to the entire structure. If everything is calculated and executed correctly, then the interfloor overlap on wooden beams will serve for a long time.
Interfloor overlap in aerated concrete house
Wooden floors in a house from a bar: how not to do
It is possible to independently carry out the installation of a wooden floor between floors, subject to significant experience in carpentry and general construction work. Interfloor floors made of wood belong to responsible structures in residential buildings and require careful adherence to installation instructions.
Do-it-yourself wooden interfloor ceiling - advantages and disadvantages
Any overlap between floors, including wood, must meet the following characteristics:
- Static and dynamic strength. The structure must withstand the weight of the expected load with a large margin;
- Rigidity sufficient for a high-quality foundation when arranging floors (upper floor) and ceilings (lower floor);
- Durability comparable to that of the entire structure. Replacing interfloor floors in an old building is a complex and expensive repair procedure; at the stage of capital construction, it is much easier to overlap between floors from strong wooden beams;
- A good floor must have decent heat and sound insulation values.
Wooden floors satisfy all of the listed qualities and have additional advantages. They are easily assembled by two people and do not require the involvement of heavy construction equipment. A span of up to 100 m 2 can be laid in one day, if we talk about the supporting structures, and not their finishing. Wooden beams are many times cheaper than reinforced concrete slabs or steel floors - and their service life is tens (or even hundreds) of years.
The potential dangers of using wood as a load-bearing interfloor structure include the danger of rotting and igniting in a fire. These factors are minimized by proper treatment of the beams prior to installation. It is equally important to take into account the minimum allowable deflection. For interfloor beams, due to their durability and resistance, coniferous wood is used. But it is quite plastic - therefore the maximum the size of the beam span made of wood is limited to 5 meters... If it is necessary to block a large room, additional supports (columns, crossbars, etc.) will be required.
Overlapping the second floor by wooden beams - structural analysis
The correct calculation and competent general construction preparation largely determines how high-quality the device of the wooden floor between the floors will turn out. Interfloor openings can be filled quickly and easily for convenient seats with the help of optimally prepared beams. First of all, the direction of installation of ceilings is always chosen according to the short size of the room. The installation step is interdependent on the cross-section of the floor base, but is usually equal to 1 meter, since a smaller step will lead to greater laboriousness in arranging the seats. It is wiser to buy wood of a larger section than to spend money on a palisade made of weak floors.
For an installation step of 1 meter, provided that the second floor is habitable, you should acquire such load-bearing bars that will withstand a load of at least 400 kg / m 2:
- With a span of up to 2.2 meters - 75x150 mm;
- With a span of up to 3.2 meters - 100x175 mm;
- With a span of up to 3.2 meters - 125x200 mm;
- With a span of up to 5 meters - 150x225 mm.
Overlapping uninhabited attics are performed with the same step, but with a material of a smaller section. For example, for half the load (that is, 400 kg / m 2), bars 50x160, 50x180, 70x180 and 70x200, respectively, will be enough. Just keep in mind that you will then have to crawl in the attic with such an overlap, and not walk ... As you can see from the calculations, load-bearing beams with a ratio of 1.5: 1 height to width are considered optimal. For attic spaces, on the other hand, a narrow tree with an elongated profile is used due to the low load in the future.
Overlapping between floors - preparing for installation during the construction phase
When erecting walls made of bricks, silicate blocks, aerated concrete, openings for floor elements are provided in them. The step of these openings is 1 meter, the depth is at least 30 (or better than 40) centimeters, the width is the same. The beam should enter the wall by at least 20 cm, plus free space for its ends will be required. The end part of the ceilings is not poured with any building mixtures for the purpose of natural ventilation and preventing decay.
The more accurately the seats in the walls of the house are displayed in height, the easier it will be to floor the beam structure. In houses made of wood, you can embed beam structures directly into the walls, here the implementation of the future overlap does not require preparation at the stage of wall construction. It is important to take into account the inadmissibility of installing load-bearing bars close to a parallel wall, not closer than 10 cm, and it is imperative to maintain a strict constancy of the installation step - the permissible "run-up" from the nominal 1 meter should not exceed ± 5 cm.
Overlapping the second floor on wooden beams - installation stages
The walls with planting nests are ready, wood and auxiliary materials are purchased, the tools are ready - we are starting the installation of floors:
- One day before installation, the tree is coated with antiseptic mixtures and fire-resistant compounds - with the exception of the ends, no "chemistry" can be applied to them. The choice of such formulations is now very large, one can name brands Finesta, Seine well, Neomid, Pinotex and others with a wide selection of antiseptics and fire retardants. The entire primer should dry well;
- We measure the beams and saw off with a sharp saw on wood with a margin of 35-45 centimeters from the size of the room for reliable support on the walls. Cut at an angle of 60˚ so that when viewed from the side, the floor element looks like a trapezoid with a wide bottom. The ends, recessed into the walls, are coated with resin and wrapped in tar paper after it dries;
- We install the extreme beams. We work from a high, wide and reliable "goat", it will not be possible to do with step-ladders alone. We carefully set them in level and horizontally. Wide cuts from the same floors are used as linings, and in advance with antiseptic and fire-fighting compounds. Make sure that the ends of the beams do not rest against the walls, there should be a ventilation gap of at least 3-5 cm in depth;
- When there are no doubts about the accuracy of the installation of the side beams, they are fixed with dry crushed stone in the landing nests. The fishing lines are tightly pulled between the extreme beams. On these auxiliary lines, other elements of the floor beam frame are installed;
- The installed beams are carefully measured and adjusted again, after which the landing nests are concreted with a solution of cement and crushed stone.
When building a house, you often have to face the problem of choosing a type.
There are three main options for implementing this work:
- Installation of reinforced concrete slabs.
- The use of a wooden structure separating the two floors.
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Use of reinforced concrete slabs
Reinforced concrete slabs, with the help of which the floors in the house are overlapped, are structures made of iron and concrete. Inside the slabs there is a reinforcement crate and round voids that stretch along the entire length of the product. The main purpose of voids is to reduce its mass and increase the resistance to deformation to fracture.
Reinforced concrete slabs come in various sizes, both in length and width. You can find out their dimensions by the abbreviation. For example, PK 72.15-8 products mean that the length of the slabs is 72 decimeters, and the width is 15 dm. The figure "8" shows the design load that the structure will withstand (800 kgf / m).
The minimum weight of reinforced concrete floor slabs exceeds 500 kg. All these data indicate that it is impossible to do it yourself. To carry out the work, we cannot do without:
- reinforced concrete slabs;
- lifting crane;
- welding machine;
- spider devices;
- steel rods;
- crowbars;
- trowel;
- cement mortar.
Plates must necessarily have four mounting loops, which can be in the form of bent parts of reinforcement or free reinforcement placed in recesses near the corners of the product. When purchasing reinforced concrete structures, you should carefully inspect all loops. They must be whole.
The technological process involves the application of cement mortar to the wall at. This method leads to a more durable fit of the elements of the first and second floors, and also prevents the occurrence of cracks in the places of contact of reinforced concrete structures with the wall. But at the same time, making a mortar and laying it on walls, piles, beams or pillars should be at the time of preparing the slab for installation work. This will prevent it from hardening prematurely.
The next step in creating the floor between the floors is to attach the "spider" fixture to the reinforced concrete slab mounting loops. Only using this device (equipped with hooks and four ropes of the same length), it is possible to obtain the horizontal position of the plates without the occurrence of their rotation. It is better to overlap the floor with three people: one person will operate the crane, and two will be in the place of installation work and level the plates to be installed using crowbars.
The plane of the reinforced concrete product has the shape of a trapezoid. Its upper part is slightly narrower in size. When an overlap is created, and the slabs are laid next to each other, then at the junction a recess is obtained with a width of 5-7 cm.It is obtained by pouring concrete mortar into it. The hinges on adjacent slabs are also connected. It happens in the following way. Steel rods are taken, inserted into the hinges of adjacent slabs and bent. The reinforced concrete structures are now firmly connected to each other.
Mandatory requirements for overlapping the first and second floors with slabs are:
- compliance with safety rules;
- overlapping of supporting structures is carried out by the extreme points of reinforced concrete slabs;
- the installation of the structure should provide for a strip of more than 15 cm between the edge of the slab and the outer part of the wall (a place for laying bricks).
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Monolithic construction technology
The monolithic overlap of the first floor is a more solid structure. This technology is used in almost any house (brick, aerated concrete, aerated concrete, slag concrete, from reinforced concrete blocks) and it can be done independently. Sometimes a monolithic floor is the most suitable option due to the fact that reinforced concrete slabs cannot be installed for objective reasons (the presence of power lines, there are no entrances to the facility being built, etc.).
To make a monolithic structure between floors, we need the following materials and tools:
- cement (grade 400 and above);
- sand;
- crushed stone;
- roofing material;
- steel fittings (20-25 mm);
- reinforcement mesh;
- timber, wooden boards, channels or metal pipes for supports;
- unsuitable boards for formwork;
- concrete mixer;
- Master OK
- buckets;
- a hammer;
- rope;
- nails.
Monolithic overlap involves the construction of formwork when the walls of the first floor are erected to the required height. First, the vertical supports are installed at a meter distance from each other. Their dimensions must correspond to the dimensions of the formwork boards, which must be adjacent to the walls. The number of supports depends on the area of the house on which it is planned to overlap the first floor.
Particular attention should be paid to the soil, which should not sag under the mass of the monolithic floor. On the supports in the transverse position, boards are tightly laid, which will become the bottom when pouring concrete. Formwork is also created along the perimeter of the floor. It is necessary to do the work so that the monolithic overlap, which "lies" on the walls, does not push the formwork. An important point is a high-quality connection and fixing of corners.
There are several requirements for arranging formwork for a monolithic floor. The main ones are:
- To prevent the poured concrete from leaking, the boards are placed to each other at the shortest possible distance.
- To create vertical supports, only the strongest boards are used that will not bend under the weight of the monolith and cross beams.
- To fix the height of the monolithic slab, a gutter is created on the outer perimeter of the formwork.
- After the concrete mortar has set, the formwork is dismantled. For this reason, the formwork must be done in such a way that it does not lie on the walls.
After the construction of the formwork and a thorough check of the reliability of the structure, you can start pouring the monolithic floor. At its bottom, which is lined with boards, is covered with roofing material. Thanks to it, all remaining gaps between the boards are closed. Then, at a height of 6-8 cm from the roofing material, the reinforcement and the reinforcing mesh are fastened.
A concrete solution made of sand, cement, crushed stone and water is poured into the formwork. The overlap between the floors should be 10-15 cm thick. If it is smaller, then there is a danger that the overlap may not withstand the load. With a large thickness of the structure, the walls will undergo a solid load. A month later, the formwork is dismantled, and work on the construction of the second floor continues.