Wood is one of the most popular natural materials. Nowadays, it is in great demand both for residents of country cottages and city apartments. Wooden floors look simply stunning and give the entire room an elegant and sophisticated look.
Despite the fact that constructing a wooden floor using joists is a rather labor-intensive process, anyone with some knowledge of technology and a certain list of tools can cope with it. In this article we will talk about the main nuances of installing it yourself. We'll give you some practical tips and recommendations that will help you create incredible comfort in your home or bathhouse.
Wooden floors have gained their wild popularity for a reason, because among the advantages:
But, like any other material, wood has its drawbacks:
A wooden floor will last you as long as possible if you take the choice of quality material seriously. If we take into account residential premises, then coniferous species such as cedar, spruce, fir are best suited here, because they not only have an aesthetic appearance, but also, due to the presence of tree resin in the fibers, are more resistant to moisture and more durable.
For a bathhouse, for example, everything is just the opposite. In a steam room where there is high humidity and high temperature, it is generally dangerous to use coniferous wood. Since the resin, in addition to the fact that it can leave a burn upon contact with the skin, it can also spontaneously ignite. Therefore, for the steam room it is better to select deciduous trees, such as linden, alder, aspen and others.
In the case where it is assumed that the floor covering will be varnished, it is better to choose light species with beautiful natural patterns, for example, walnut or mahogany, from cheaper ones - oak.
When purchasing, it is important to ask the seller about the moisture content of the wood. It should not exceed 20%, since raw lumber will be impossible to process, and very quickly such a coating will begin to crack and deform, forming cracks and “cold bridges.”
Immediately before installation, all raw materials must be treated with an antiseptic, and experts also recommend using an anti-corrosion compound that will prevent the destruction of wood fibers due to contact with metal fasteners (nails, screws, etc.).
The installation step of the logs depends mainly on the dimensions of the floor covering, that is, if you plan to use thin boards (thickness up to 3 cm), then the logs can be placed 30-40 cm from each other, but if massive boards (4-5 cm thick) - the distance should be increased to 80-100 cm.
Likewise, the cross-section of the logs themselves depends on the distance between them. For a bathhouse, beams with a cross section of 15x10 or 10x5 cm are often used and placed at a distance of 0.6-0.7, depending on the size of the insulation blocks.
We will divide the technology of laying on logs into several main stages:
When choosing the main building material, do not forget about the tools. You will need:
Advice! It is best to start installing a wooden floor in an apartment after the heating season, since during this period the wood has less chance of absorbing excess moisture, which can spoil the appearance of the raw material.
Let's consider the most commonly used option for installing a wooden floor, namely installation on a concrete screed, since this option can be used both for an apartment or house, and for a bathhouse or sauna.
It is necessary to begin all manipulations after all other work has already been completed: installing door and window frames, installing the ceiling and making the lower concrete screed, all surfaces are thoroughly dried and plastered.
Since the boards will have to withstand considerable loads, their optimal thickness will be 3-4 cm, and given the thickness of the logs themselves and, possibly, the counter-lattice, 7-10 cm, the ceiling height in the room will be slightly lower, so it is best to construct a wooden floor using logs in rooms with high ceilings.
Just before waterproofing, which is the next step, it is important to check the integrity of the concrete base. To do this, the floor is tapped in several places and carefully inspected. A high-quality screed should not contain any cracks or other defects. If such areas are found, they must be replaced, after which it is important to wait about 30 days for the base to completely dry, turning into a monolith.
The main task of waterproofing is to protect wooden floor elements from the harmful effects of moisture, which can lead to rotting of the wood, and this is fraught with negative consequences both for the wallet and for human health, especially children.
The most reliable option is to cover the concrete screed, which can also serve as a subfloor (more on that later), with roll polymer materials.
A layer of rolled waterproofing (usually roofing felt) is applied to the concrete base, either overlapped or joined, then the seams between the strips are glued with either construction adhesive or special bitumen mastic; ordinary resin is also suitable. It is important that the ends of the waterproofing tapes extend 5-10 cm onto the wall. In the future, the protruding parts can be trimmed.
If you want to increase the soundproofing properties of a wooden floor, you can lay a layer of rubber or compressed cork on top of the waterproofing.
A layer of 1-2 mm of special mastic is applied to the lumber itself for better bonding of the wood and the rolled material.
The service life of the entire floor structure depends on the quality of this stage, so take this task as seriously as possible. The optimal cross-section for beams is 5x10 cm.
How to lay timber correctly? There are no specific rules. This often depends on the intended design decisions. It is only important to adhere to one rule - the boards must be positioned strictly at right angles to the joists. Professionals advise installing the joists in the direction where the light falls in the room.
The logs themselves are mounted edgewise. Installation begins with the two outermost logs, which are placed close to the wall or at a distance of several centimeters. After laying these bars, a thread is pulled between them, which is a guide and will help position all subsequent beams on the same plane. Holes are drilled in the concrete base and the logs themselves for metal dowels, which will actually attach the logs to the base. Screw in the screws and dowels in increments of half a meter to a meter. Sometimes small pieces of boards 4-6 cm thick are placed under the beams.
If you do not want to waste time on calculations, installation, and checking for flatness, you can purchase special bars that come complete with special adjustable supports. This will make the installation process much easier and take several times less time. After this, you can move on to insulating the floor.
If you have a concrete screed, you can use it as a subfloor, or you can do the following:
Be sure to leave a small gap between the insulation and the finished floor for ventilation.
For finishing flooring, use a high-quality edged board with a tongue-and-groove joint, as well as a longitudinal ventilation gap. I don’t think it’s worth saying that the boards for the finished floor should also be treated with an antiseptic.
When laying the floor, it is important to ensure that the growth rings alternate in direction. The boards are attached to each joist using nails so that the head is buried 1-2 mm into the thickness of the board. Don't worry about leaving holes. In the future, they can be easily covered with a corrective compound or a wax pencil. You can also use long screws, although installing them will be a little more difficult, since you will have to pre-drill holes for each one, and only then screw them in.
When connecting the boards together, it is worth punching them with a hammer for better adhesion.
If you do not plan to paint the floor, you can use two types of fastenings:
Between the walls and the floor, in order to hide the cracks, wooden baseboards are installed, under which, by the way, you can hide a telephone or Internet cable.
To achieve a perfectly flat surface, the floor must be additionally sanded. To do this, use a special grinder with several attachments. The nozzle with large grains is used for hard types of wood, with smaller grains - for soft wood. Sand the wooden floor in several stages, each time changing the nozzle to a finer one. For grinding in corners and other hard-to-reach places, use a special angle machine.
After you have finished sanding the floor, you need to use a vacuum cleaner to collect dust, small chips and other debris that subsequently formed.
After final finishing, a special moisture-resistant polyurethane-based varnish is used. It is important to apply it in several stages. After one layer has completely dried, apply the next one, and so on two or three times. Various compounds are often applied under the varnish to change the color of the floor covering.
Now that you know the basic rules and nuances of installing a wooden floor using joists, you can independently build a comfortable floor covering that will serve you for many years.
It is difficult to imagine constructing a residential building or carrying out renovation work without laying floors. Properly laid floors will serve “faithfully” for a large number of years, and mistakes during this work can blur the entire impression of the result. No matter how smooth the walls and ideal the ceiling, a collapsing floor with potholes and humps will nullify the entire repair. That is why this work should be approached very responsibly.
There are a large number of methods for laying flooring, as well as materials for it. One of the most popular types is wooden flooring. Wood, as a natural material, has a very beautiful appearance, retains heat, and with proper care lasts a very long time. We'll tell you how to lay a wooden floor with your own hands below.
Like any flooring, wood has its advantages and disadvantages. Among the first it is worth noting:
Among the disadvantages it should be noted:
Various technologies are used to lay wooden floors:
The structure of a wooden floor consists of two main parts:
For this work you will need:
Before installing the logs, they must be prepared. In order for them to better resist moisture, they are impregnated with drying oil. This should be done in a well-ventilated area. After finishing the work, the tree is allowed to rest for 2-3 days. The base of the floor must be cleared of construction debris and, if possible, leveled.
The procedure for laying support beams:
If you plan to install the logs on brick supports, you must first mount them. To guide the height of the pillars, cords are also pulled. However, the level for them will be the level of the finished floor minus the thickness of the board and the height of the joists. The cords are pulled between all opposite walls to form a grid. At their intersection a pillar is erected. Its dimensions do not exceed 2 bricks. They are laid with dressing on a regular cement-sand mortar. It is necessary to put a layer of waterproofing under the brick. After the solution has hardened, you can lay the logs. They are attached to brick pillars using anchor bolts.
The sequence of work on laying the coating is carried out in the following order:
The construction of any house is a complex process that includes several stages. Among these stages, the process of constructing floors stands out separately. In wooden buildings, many people prefer wood floors. This decision is completely justified, because a country house requires closeness to the surrounding nature, so natural material will look most impressive compared to concrete screed and synthetic finishing coatings. The installation of a floor in a wooden house is characterized by its own characteristics, so the installation of a floor structure should be taken seriously. What kind of floor can be built in a private house?
According to experts, floors in a wooden house can be either concrete or wood, since these two materials are suitable for use in the construction of private houses. The floor in a log house can be made using heated floor technology - modern technologies make it possible to implement this option.
A concrete floor is a screed pour, which you can do yourself. Choosing this option for a floor in a wooden house in some cases allows you to save some time. It takes almost a month for the screed to completely dry, and installing a high-quality lumber floor from scratch may require even more time.
The advantages of a concrete floor in log houses include a reduction in the cost of finishing the coating. A properly made screed has a flat surface on which any finishing coating can be mounted. The ability to lay the coating on the screed without additional work to level the working base reduces work time and material costs. The screeding process itself is not technically complicated; you don’t need any special skills.
When installing floors in a wooden house made of concrete, it is necessary to take into account the possibility of cracking of the screed under the influence of vibrations of the walls of the structure. Cracks that form during the operation of a concrete floor will not lead to serious consequences, but they can increase heat loss. To ensure that heat loss remains at a minimum level, when installing a cement screed, it is recommended to carefully consider the installation of high-quality insulation.
The cement floor in a wooden house has another drawback: it itself presses with its weight on the foundation. Before carrying out construction work, experts recommend making the necessary calculations so that during the operation of the house the foundation can withstand a heavy concrete screed. If you can’t handle this yourself, contact an experienced builder.
Another type of flooring in a wooden house is a covering made of the same wood. The advantages of such a floor design include the environmental friendliness of the material and aesthetic appearance. Wood is a natural material that does not contain synthetic additives and does not emit substances harmful to the human body during operation. The appearance of the plank floor harmonizes perfectly with the building itself and its surroundings. For a country house, a cement floor, unlike wood, will seem superfluous, even foreign.
Modern means of protecting wooden floors, which include various oils, varnishes and impregnations, allow not only to provide the floors in a wooden house with a long service life, but also a beautiful appearance in accordance with the overall interior of the rooms. During the work process, a wooden floor can be given the desired shade or its original texture and color can be emphasized. Natural wood provides a feeling of warmth and comfort in the room, helping to create a comfortable atmosphere throughout the house.
The advantage of a plank floor is that it is easy to repair. If necessary, you can replace the damaged part yourself using a standard set of tools.
The disadvantages of wooden floors usually include high financial and labor costs. Installing a floor in a wooden house is quite difficult: a large amount of work is sometimes impossible to do alone. Achieving a perfectly flat surface at such a cost can be problematic.
A wood floor can be made in a country house in three ways. The first method is used in cases where laying the floor in a wooden house does not involve installing load-bearing beams in the frame itself. The final wood covering will be a floating structure, not connected to the walls. This coating is assembled on support pillars.
The second and third methods of organizing wooden floors are used when the log house is assembled with the installation of load-bearing beams. Either a single or double plank floor is laid on a base of these beams. Installing a single-layer floor in a wooden house is not difficult even for a beginner. This method of installing the coating is easy to implement in practice, but is only suitable for houses that are used during the warm season. A single covering can be assembled at a dacha or in a summer house; for buildings in which year-round living is planned, such a design is unacceptable.
For a private house built for living throughout the year, only a double wood floor is suitable. This design of floors in a wooden house consists of the installation of rough and finishing flooring, between which hydro- and heat-insulating materials are laid. The top finishing floor is usually assembled from tongue and groove boards.
The construction of a floor on supporting columns begins with preparing the base. To do this, it is necessary to remove the top layer of soil and then fill it with gravel, crushed stone or sand. The best option would be a base of crushed stone, and on top of it - tightly compacted sand. Next, brick support pillars are placed on the base, for which standard red bricks are most often used. Laying the floor in a wooden house must be done taking into account all the basic requirements, therefore, when assembling the support posts, it is necessary to correlate their height and cross-section. The higher you raise the level of the support pillars, the larger their cross-section should be. For supports with a height of more than 25 cm, a width of two bricks is recommended.
The installation of support posts for floors in a wooden house begins from the perimeter of the room, after which they proceed to the installation of the same structures in the middle of the working surface. Roofing felt is laid on the ends of the supports, which acts as a waterproofing material. On top of it, wooden pads are mounted on the pillars, on which logs made of timber or logs are installed.
When installing a floor in a wooden house, the logs are placed at a certain distance from each other; the pitch between the logs depends on the width of the boards that are supposed to be used in the future. To prevent the floor structure from moving in winter due to soil freezing, it is recommended to fill the space under the joists with slag. The embankment should not reach the log by about 5 cm - this air gap is left specifically for ventilation processes.
The floor itself is laid on mounted logs, and it is recommended to place the boards in the direction of light from the windows or in the direction of movement. Experts advise starting the flooring 1.5 cm from the wall; such gaps around the perimeter of the floor in a wooden house are made specifically to ensure the required level of ventilation.
Long nails are used as fastenings for plank floors, which should be driven into the board at an angle. After painting, the nail heads will no longer be visible. Once the floor is completely assembled, temporary baseboards are attached to opposite sides of the room. When laying floors in a wooden house, the slots of these skirting boards are used as buffer zones, necessary until the wood dries completely. When the lumber is completely dry, these skirting boards can be replaced with conventional structures. To understand the procedure for carrying out installation work to create a floor on supports, it is recommended that you familiarize yourself with the photos depicting each stage of the process.
A single floor can be implemented on a structure made of support pillars. In this case, beams are attached to the support posts, and a covering of tongue-and-groove boards is laid on top of the beams. Such a floor in a wooden house fully corresponds to the above-described structure, assembled on support posts.
There is another option for single flooring: when the covering is mounted on beams embedded in load-bearing walls. In such a situation, there is no need to build brick supports. The role of the working base will be performed by load-bearing beams. Since the distance between them is usually very large, before working on the plank flooring, a sheathing of joists should be constructed. 
The design of the floor involves the use of timber with a side of a square section of 5-6 cm as a lag. In a wooden house, the pitch between the lags is determined by the thickness of the final covering board. The thicker the tongue and groove board, the larger the pitch between the joists can be. When installing the sheathing, experts recommend constantly monitoring the evenness of its surface. Only a well-assembled sheathing will allow you to lay a smooth plank covering without any problems.
When the logs are assembled and secured with nails, you can proceed to the installation of the single flooring itself. The flooring can serve as both a rough and a finishing coating. If you are not going to additionally lay a decorative covering in the form of linoleum or other material on the floors in a wooden house, then the boardwalk will be considered finished. After completing all work, it is recommended to cover the finished surface with several layers of protective varnish.
If you cover the wood floor with any other material, it will actually act as a subfloor. To install the rough coating, it will be enough to use unedged material.
Installation of single floors on support columns or on a lathing made of logs is quite simple to do with your own hands. This coating is done quickly and easily, and does not require significant costs. The disadvantage of single-layer floors in a wooden house is their low degree of thermal insulation. In winter, the soil in the underground room will freeze. In the case of using support pillars, this can cause displacement of the brick pillars and the coating itself. A single floor can be used either for houses that involve living in the summer, or if there is heating in the cold season.
A double floor in a wooden house can be considered the optimal solution provided that you live in the countryside all year round. This coating is called double, as it consists of two mandatory layers - rough and finishing. How is installation carried out?
First, a rough covering of unedged lumber up to 0.45 cm thick is assembled on the beams. Since this layer of the floor is located at the bottom, when arranging it, you can save on the purchase of materials. It is not necessary to use expensive boards for the subfloor in a wooden house; slab or low-grade materials are suitable here. This does not mean that the rough layer can be made of poor quality. For it, it is recommended to choose boards of coniferous trees, and also pre-impregnate them with antiseptic solutions.
The rough covering boards should lie close to each other. When this layer of construction is ready, it is necessary to lay thermal insulation material on top of it. Mineral wool, polystyrene foam, expanded clay, sawdust or other modern types of insulation are suitable for these purposes.
Installing a floor in a wooden house necessarily includes not only the placement of insulation material, but also a layer of waterproofing. All these structural components provide the future coating with a long service life. The finishing coating is installed after laying the thermal insulation; a gap of 1.5 cm should be left between these two layers. The boards are fastened in the same way as when constructing other types of floors.
On finished double floors in a wooden house, you can lay a finishing coating, and also use the finishing layer of the structure itself as decoration. To do this, the wood must be treated with protective varnishes or other special compounds with a tint effect.
A wooden floor on joists makes it possible to avoid without the use of reinforced concrete floors or other concrete foundations, the cost of construction of which is quite high.
Effective ventilation of wood on joists in a private house - a necessary and mandatory condition for the reliability and durability of the structure.
The figure shows a design option for a wooden floor on joists in a private house with an underground space.
The space under the floor is formed by the fact that the logs are laid on fairly high columns of brick or concrete blocks. This design allows you to raise the floor level of the first floor with a minimum volume of backfilling the basement space with soil.
Here the basement and basement space under the floor are outside, outside the thermal envelope of the house, and will be cold.
To ventilate the underground space, vents are made in opposite external walls, above ground level - through holes covered with a metal mesh to protect against rodents. The same openings should be in the internal load-bearing walls.
Air movement under the floor occurs mainly due to wind pressure.
In winter, there is a danger of soil freezing in the underground space, which can lead to heaving soils causing the floor to move relative to the walls.
To prevent freezing, it is recommended to close the vents for the winter and insulate the base.
However, deterioration of ventilation as a result of closing the vents leads to the accumulation of moisture in the insulation and wooden parts - reducing the thermal resistance and durability of these elements.
It must be said that such a device for underground space has been used in private construction for a long time. The design was not originally designed for the use of effective floor insulation.
In houses with weak floor insulation in winter, part of the heat from the room penetrated into the underground space and warmed it, preventing freezing, but increasing heat loss.
Modern floor insulation practically blocks the flow of heat into the subfloor from the premises.Freezing of the subfloor can only be prevented by saving ground heat.
Given modern requirements for energy saving, a cold underground ventilated through vents is not the best option. It is still used rather by inertia.
Scheme of effective underground ventilation in the basement of a private house through an exhaust duct To ventilate the subfloor of a private house or cottage, it is beneficial to use effective ventilation through an exhaust duct. This ventilation scheme is the only correct option for a house with an insulated base or basement.
In old books and construction regulations, you can find floor designs on posts using NOT effective heat-waterproofing materials.
The supporting columns are laid out from ceramic bricks or concrete blocks. The distance between adjacent columns along the log (span) is recommended to be no more than 2 m. The base of the column can be a layer of compacted crushed stone with a thickness of 50-100 mm, spilled with bitumen mastic. Or, instead of mastic, a waterproofing film is used.
The top of the columns is leveled to one level with a solution. If the solution thickness is more than 3 cm. The masonry mesh is embedded in the solution. The top of the posts is covered with a sheet of waterproofing material.
Wooden beams are laid on the waterproofing layer. The distance between adjacent joist beams (lag pitch) is determined by their cross-section, as well as the load-bearing capacity and rigidity of the overlying floor layers - sheathing, subfloor, finishing coating. Typically, a step convenient for laying standard mineral wool insulation slabs between joists is taken, about 600 mm.
For the above-mentioned lag pitch and span between the columns, taking into account the thickness of the insulation and sheathing, with normal floor loads, the lag cross-section is sufficiently 100-150x50 mm. A galvanized steel mesh is attached to the bottom of the logs lying on the posts. Instead of a mesh, you can nail boards or slats with a thickness of at least 20 mm.
A windproof, highly vapor-permeable film is laid on top of the mesh (boards) and logs.
This film prevents makes it difficult to carry away insulation particles by air flow (dust formation), but does not prevent the evaporation of moisture from the insulation and wooden parts.
A sheet of windproof, vapor-permeable film is laid on top, across the joists, and lowered on both sides of each joist until it touches the steel mesh so that a tray is formed between the joists. The film is stapled to each side of all joists.
Mineral wool insulation is laid in the formed channel between the joists on the windproof film. You can do without a windproof film if you use special insulation boards with a compacted windproof layer for the bottom layer.
The thickness of the floor insulation is selected according to calculation, providing standard heat transfer resistance R = 4-5 m 2 o K/W. If the base is not insulated, then the thickness of the floor insulation is determined from the condition that the temperature of the space under the floor is equal to the temperature of the outside air. The recommended thickness of mineral wool insulation in this case is no less than 150-200 mm.
For a house with an insulated foundation and plinth, the thickness of the floor insulation can be reduced so that the sum of the heat transfer resistance of the plinth + floor is no less than the standard (see above).
How to calculate the thickness of floor (floor) thermal insulation
A sheathing of bars with a thickness of at least 50 mm is laid across the joists. Another layer of insulation is placed between the sheathing bars. This two-layer insulation design ensures that the insulation covers the cold bridges through the joists. The distance between the sheathing bars is chosen in the range of 300-600 mm., a multiple of the width of the subfloor covering slabs.
This two-layer construction of the floor base (joists + sheathing bars) allows you to conveniently place both insulation boards and floor covering slabs (CBF, plywood, etc.).
The insulation with the lathing on top is covered with a vapor barrier film. The joints of the film panels are sealed. The junctions of the film to the walls are connected to the waterproofing of the walls and the same is sealed.
It is recommended to choose the thickness of the sheathing bars at 25-30 mm. greater than the thickness of the top layer of insulation. This will allow, by lowering the film on both sides of each sheathing bar, to create a ventilated gap between the vapor barrier film and the floor covering.
Instead of the top layer of insulation and vapor barrier film, it is more profitable to lay penofol - a foamed polymer covered with aluminum foil, 10 mm thick. mm. (also available under other trade names).
Penofol must be laid with the aluminized side up, towards the ventilated gap, across the sheathing bars and lowered on both sides of each bar. After this, penofol is nailed to each side of all the bars with a stapler so that a gap of 3-4 is formed between the aluminized surface and the floor slabs cm.. The joints of the penofol panels are sealed with aluminized adhesive tape. A layer of penofol will provide heat transfer resistance equivalent to a layer of mineral wool with a thickness of 40 mm., and the necessary vapor impermeability.
Subfloor boards are attached to the sheathing bars on top of a vapor-proof film or penofol. Instead of boards, slabs are more often used: cement-bonded particleboard (thickness > 22 mm.), plywood (> 18 mm.), etc. Sheets and slabs are placed with the long side on the sheathing bars. Spacers are secured under the short side between the sheathing bars. All edges of the laid sheet must be supported - a block or spacer.
The use of polystyrene foam and polystyrene foam boards as insulation is not recommended. Such slabs serve as a barrier to moisture, which is always contained in the wood of the floor. By preventing moisture from escaping from the wood, foam insulation shortens the service life of the wooden floor parts. In addition, mineral wool insulation, due to its better elasticity, adheres more tightly to the joists than polystyrene foam.
To protect the underground space from ground moisture, it is advisable to cover the entire surface of the soil with a waterproofing film (and not just under the posts, as in the figure). The joints of the covering panels are sealed. The junction of the film to the walls must be connected to the waterproofing of the walls and also sealed. The floor posts lie directly on the film.
As a result, we obtain a ventilated underground space, limited by sealed shells - on top (vapor barrier) and below (waterproofing).
Such an underground space protects the house not only from moisture and cold, but also from penetration into living spaces.
In modern floor designs, joists are located at a short distance from each other, which makes it possible to use lumber of a smaller cross-section, and therefore cost, and also to conveniently place insulation boards.
Instead of brick columns, it can be advantageous to rest the logs on intermediate walls laid across the logs at intervals of about 2 m. Bricks or blocks in the wall are laid using the honeycomb masonry method, half a brick thick, leaving increased gaps of 1/4 brick in the vertical joints for ventilation of the underground space. If the wall has a height of more than 0.4 m., then no less than every 2 m. length of the wall, lay out pilasters - brick-thick columns to increase the stability of the wall.
If the lag step is no more than 600 mm. and span less than 2 m., then the cross-section of the wooden log is enough to be 100x50 mm.
Another option for a wooden floor along joists in a private house is shown in the following figure:
Here, unlike the first option, the floor level is raised to the required height by filling the base with compacted soil.
Ventilation of the floor is carried out due to the movement of air under the influence of the draft of the ventilation duct.
Warm air is taken from the room and enters the space between the joists through the ventilation holes in the baseboards and the gap between the subfloor covering and the wall. Next, the air enters the ventilation duct.
To ensure ventilation of the underground space, baseboards with holes are used or baseboards are installed with a gap between them and the walls.
In order for the air to move more or less evenly under the entire surface of the floor, the gap for air passage is made of different widths - the farther from the ventilation duct, the wider the gap (2 cm.). Near the ventilation duct, no holes are made in the baseboards or gaps between the wall and the floor covering (or the gap is sealed with tape).
It is important to understand that in this ventilation option, unlike the first, the underground space is located inside the heat-protective shell of the house and must be warm. The outer shell of the subfloor must have a heat transfer resistance no less than the wall of the house. Otherwise, the flow of warm air from the room may lead to condensation on the subfloor parts.
Make the layer of bulk soil thicker than 600 mm. Not recommended. Pour the soil and carefully compact it in layers no more than 200 thick. mm. It is still not possible to compact the fill soil to the state of natural soil. Therefore, the soil will settle over time. A thick layer of fill soil can cause the floor to settle too much and unevenly.
The waterproofing film is laid on a leveling layer of sand with a thickness of at least 30 mm. The joints of the film panels are sealed. The junctions of the film to the walls must be connected to the waterproofing of the wall and also sealed.
Thermal insulation is laid on top of the waterproofing.
In this option, it is better to use polymer insulation boards - polystyrene foam (expanded polystyrene). The thickness of the insulation is 50-100 mm., since the ground temperature under the house is always positive.
If the walls and basement of the house are not insulated, then along the external walls a width of at least 800 mm. a thicker layer of insulation should be laid, 150 - 200 mm.
In a house with multi-layer external walls with insulation on the outside, to eliminate the cold bridge bypassing the insulation of the walls and floor, the outside must be insulated(see picture in the first part of the article).
The floor joists rest on low pads made of brick or concrete blocks.
If extruded polystyrene foam boards (XPS, penoplex, etc.) are used as thermal insulation, then the logs can be laid on pads cut from these boards.
A gap of 3-5 should be provided between the thermal insulation and the wooden floor joists. cm. for free air movement.
According to building regulations, there is one restriction on flooring. Since the space under the floor is ventilated through a natural ventilation exhaust duct, it is prohibited to make the final floor covering from combustible materials: boards, parquet boards and panels, etc. Or a non-combustible base should be provided under them, for example a prefabricated screed made of plasterboard, gypsum fiber sheets or a subfloor made of cement bonded particle boards.
In this option, the joists and other floor elements are in better humidity conditions than in the first case.
In this design, the ventilation duct serves to ventilate not only the subfloor, but also the rooms of the house. About what needs to be done to save heat emitted by the ventilation system,
Ground floors are not connected to the foundation and rest directly on the ground under the house. If it is heaving, then the floor can “go on a spree” under the influence of forces in winter and spring. To prevent this from happening, the heaving soil under the house must be made not to heave. The easiest way to do this is the underground part
The design of pile foundations on bored (including TISE) and screw piles involves the installation of a cold base. Insulating the soil under a house with such foundations is a rather problematic and expensive task. Floors on the ground in a house on a pile foundation can only be recommended for non-heaving or slightly heaving soils on the site.
When building a house on heaving soils, it is necessary to have an underground part of the foundation to a depth of 0.5 - 1 m.
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| In a house with external multilayer walls with insulation on the outside, a cold bridge is formed through the base and load-bearing part of the wall, bypassing the insulation of the wall and floor. |
