Insulating the floor in a private house with your own hands is a completely affordable task, and it can be solved without involving professional builders. The main thing is to decide on the choice of thermal insulation material and the technology for carrying out insulation work. This will largely depend on the design of the floor.
It is necessary to insulate the floor in any case, treating this task with the utmost responsibility. Without this, you will never be able to create comfortable living conditions in your home, even if you spend huge amounts of money on operating the most advanced heating system and other climate control equipment. Bet thermal insulation is money down the drain!
The publication will discuss materials used for thermal insulation, various technologies insulation, depending on the design of the floors.
Materials for floor insulation in a private house
The first thing you need to do is decide on the choice of thermal insulation material that is suitable for the floor of a particular design. Therefore, when considering the characteristics of insulation, it will immediately be noted for which floor they are suitable and an overview of the technology of their use will be provided.
So, today mineral wool (glass and basalt) and expanded polystyrene are most often used for thermal insulation of floors. various types and expanded clay. It should be noted that there are other materials for insulation, for example, ecowool or polyurethane foam. However, their use will require special equipment and experience with it. That is, it is difficult to put them under the “do-it-yourself” category.
There are other, let’s say, more “exotic” insulation materials, for example, foam glass slabs or cork. But they have not yet gained much popularity, apparently due to their inaccessibility or excessively high price. Our article is intended for the average home owner who wants to do the insulation themselves.
Synthetic foam insulation
This group includes the most commonly used thermal insulation materials today - ordinary white polystyrene foam, extruded polystyrene foam and polyethylene foam (). These insulation materials gained popularity due to their low thermal conductivity and quite affordable cost. In addition, foam materials have a number of other advantages, but they also have very significant disadvantages.
Extruded polystyrene foam
This material is made from the same raw materials as the familiar white foam, but using a completely different technology. Therefore, it has improved characteristics.
It is better not to consider white foam plastic at all as insulation for floors, and it is also better not to produce it. Honestly, he has no place in the system at all internal insulation residential building - there are too many shortcomings, including those that are extremely dangerous for humans. For extruded material, these “disadvantages” are still significantly reduced. Therefore, it is better to do it - this is what extruded polystyrene foam is called.
The disadvantages of this material are the following features:
- The flammability of the insulation, it belongs to the flammability group G2÷G4.
- Low heat resistance – at elevated temperatures the material begins to “float”
- Low vapor permeability, that is, the material is not breathable. Again, this is sometimes a clear advantage.
- Low tensile and compressive strength of thin insulation.
As a substrate, ordinary foamed polyethylene with a thickness of up to 3 mm is used. And the foil version can be laid on top of other rigid insulation, or also as a reflective substrate. In addition, the foil material is usually laid under the “warm floor” system, and any of its possible varieties - electric cable or infrared film, water, or other floor covering.
Polyethylene foam sheets are laid end-to-end and sealed together with foil tape. The coating must be airtight, since very often it is the layer of foiled polyethylene foam that is considered as a necessary vapor barrier.
So, the material is very good, but is designed only for use together with other insulation materials. Relying on the fact that only its use can create full-fledged effective thermal insulation of the floor of the first floor of a private house is simply naive.
Mineral wool
You can find three types of mineral wool on sale - stone (basalt), glass and slag. Slag wool is practically not used in residential construction, as it does not have outstanding characteristics and often does not meet the requirements of sanitary standards. Therefore, the features of this type of insulation will not be considered.
Basalt and glass wool also differ in their characteristics, but both of these types are widely used in insulating structures. These are the ones that will be considered in more detail.
Glass wool
Glass wool is made from environmentally friendly raw materials - sand, broken glass, borax, soda and limestone. From the melt of materials, fibers are formed that are quite brittle and brittle, but when they are pressed into mats using binders, a fairly stable air-saturated structure with high insulation capabilities is obtained.
Glass wool can have different thicknesses, have different densities, produced in regular and foil form. When using the second option for floor insulation, mats or slabs are laid with foil facing up, that is, towards the room. Thanks to this, heat from the room falling on the insulation is reflected back.
Glass wool has many advantages. These include high thermal insulation capabilities, fairly high heat resistance, resistance to fire and chemicals, and an affordable cost of the material.
Disadvantages: fairly high fragility of the fibers. This creates difficulties in work - the material is caustic and can cause severe irritation to the skin, respiratory system and mucous membranes. In addition, such fragility is a prerequisite for gradual shrinkage of the material during operation, especially if there are vibration loads. And this leads to a decrease in thermal insulation characteristics.
In addition, not all is well with glass wool when exposed to water - it can get wet and waste its insulating qualities. Measures are required to prevent it from becoming saturated with moisture.
Stone (basalt) wool
Stone wool has the most optimal characteristics of all types of insulation of this class. This thermal insulation material is made from molten basalt rocks, from which thin fibers are drawn, which are much stronger and more elastic than glass.
Quality basalt insulation- the most resistant to moisture. Such stability is achieved by special treatment, and sometimes reaches almost hydrophobicity - water does not penetrate into the structure of the material at all.
Basalt wool from leading manufacturers is highly resistant to open fire and can withstand very high temperatures. Therefore, such material is classified as NG group - non-combustible insulation. A very important quality for any home!
Manufacturers are also trying to minimize the possible emission of formaldehyde. Thus, basalt insulation labeled “ECO” or “Eurostandard” is environmentally friendly - it uses safe acrylic resins rather than phenol-formaldehyde as a binder. It is clear that the price of such products is much higher, but they are really worth it.
A significant drawback of any mineral wool is that mice love to make their nests and passages in them. Moreover, for some reason rodents are not at all afraid of the thorniness of the fibers - they feel great in warmth and dryness. And if the characteristics indicate that the material does not attract rodents, this should be treated with a fair amount of skepticism.
It is possible to protect the thermal insulation layer, for example, by covering its areas accessible to rodents with a metal mesh with cells measuring 2÷3 mm - it will not succumb to the teeth of mice.
* * * * * * *
Mineral wool is used in different schemes floor insulation. Low and medium density materials are suitable for laying between beams or joists. High-density slabs can be used for insulation on the ground or floor slab with subsequent pouring of reinforced screed.
You might be interested in information on how to install
Expanded clay and its use for insulation
One of the most practical, reliable and durable, as well as environmentally friendly insulation materials is expanded clay. This material is produced from refractory purified clay using special firing technology.
This material has many advantages:
- Expanded clay does not contain toxic components, as it is a natural material.
- Good thermal insulation properties. Moreover, these qualities do not decrease throughout the entire operational period.
- Low moisture absorption. Expanded clay does not swell or deform.
- Excellent soundproofing abilities. Moreover, the smaller the fraction of the material, the higher the sound insulation.
- High vapor permeability.
- Fire safety. The expanded clay mass not only does not ignite, but also prevents the spread of fire.
- High frost resistance, resistance to temperature changes.
- Resistance to biological influences. Fungus or mold does not form on expanded clay, since it does not contain a nutrient medium for such microflora of organisms. Expanded clay is not tolerated by rodents - they only do not live in it, but they also cannot make passages in it.
- Simplicity and variety of use cases.
Expanded clay also has disadvantages, but they are much fewer than the advantages. And the main thing is that the thermal conductivity coefficient is still almost three times higher than that of expanded polystyrene or mineral wool. That is, a more significant layer of insulation will be required
Expanded clay is used in various floor insulation schemes.
- The first option is the simplest of all - pouring expanded clay onto the ground in the underground of a wooden floor. Before backfilling, a waterproofing material is laid on the soil base, which is removed and fixed on the walls to a height 50÷100 mm higher than the thickness of the backfill.
- Another option is to create bulk layers of the required thickness over the soil, followed by pouring a reinforced concrete screed
- Another way to insulate with expanded clay is to backfill it between joists or floor beams onto the subfloor:
If fine-grained expanded clay is used for backfilling, the subfloor must be prepared. Gaps between the boards, if any, can be sealed with clay-lime mass, which is also a natural material. It will securely hold the backfill between the joists on the subfloor;
An alternative option is to lay it on the subfloor and glassine logs. Its canvases are overlapped by approximately 100 mm. Glassine is also secured to wooden structural elements with staples driven in using a stapler.
The next step is to fill the expanded clay mixture between the joists and distribute it evenly throughout the space. A layer of vapor barrier film is sometimes laid on top of the expanded clay.
And finally, sheets of plywood or floorboards are laid and secured onto the joists.
- Another option for using expanded clay is mixing it with liquid cement-sand mortar. Concrete binds expanded clay granules together, which increases the strength of such a base.
This material becomes especially relevant when insulating floors on the ground - a leveling screed will be poured on top. True, they also use it for floors on joists, filling the entire space under the future flooring with the solution.
Since the insulating qualities of expanded clay still leave much to be desired, which requires very significant layers of backfill, it is often used in combination with other thermal insulation materials - expanded polystyrene or mineral wool. A calculation is made in advance which combination of material layers will provide the expected thermal insulation.
How to calculate the thickness of floor insulation based on the ground?
The main options for insulating the floor of the first floor of a private house
Now let’s learn more about how floor insulation is carried out in a private house.
Floor insulation on the ground
This approach is often practiced if the house is built on a strip foundation. The insulation can be expanded clay (on its own or in combination with another material), rigid insulating boards (extruded polystyrene foam) or blocks of premium mineral wool, specially designed for such purposes (this is specified in the passport characteristics of mineral wool). All insulation in this scheme has one thing in common - they are covered with a reinforced screed on top.
It might look something like this:
The soil (item 1) is thoroughly compacted, and its surface is leveled to the maximum.
Sand is poured on top (item 2), layer by layer, also with careful compaction. The thickness of the backfill is usually at least 100 mm (compacted).
Next, an optional but highly recommended layer of covered geotextile is shown (item 3). It will be a big plus for the stability of the entire created “pie” and will serve to separate the sand and gravel (crushed stone) layer, which will improve the drainage capabilities of this structure.
Above, a layer of crushed stone or coarse gravel (pos. 4) is poured, also with tamping, on which the so-called “concrete preparation” is performed (pos. 5). This is a filled layer skinny concrete(grade strength M50 is sufficient). On this basis, it is much easier to carry out further work, which will directly affect the insulation.
By concrete preparation a layer of waterproofing is laid (item 6) - the insulation must be protected from moisture from the ground. Rolled bitumen waterproofing can be used for these purposes - it will fit perfectly on a fairly strong concrete base.
Then it is laid thermal insulation material required thickness(pos. 7). The calculation of thickness is discussed separately - a link has already been given above. Possible combinations of insulation materials are also discussed there, so that thermal insulation becomes complete.
Next, the insulation is covered with another layer of vapor-permeable waterproofing material(item 8), which can be used as a polyethylene film, but very dense, at least 200 microns thick. The canvases must be laid with an overlap of 150÷200 mm and sealed along the seam lines with moisture-resistant tape. The waterproofing should extend onto the walls to a height above the surface of the future floor. The purpose of this layer is to prevent water from leaking out of concrete mortar when pouring the screed, that is, creating optimal conditions for hardening and maturing of concrete.
A reinforcing mesh is laid on top of the waterproofing, the cross-section of the rods and the cell sizes of which depend on the expected degree of load on the floors. But these are general construction issues that only indirectly relate to the insulation problems under consideration. The mesh must be lifted from the waterproofing layer so that it is approximately in the middle of the thickness of the screed.
After hardening, maturing and gaining brand strength, the resulting screed will serve as a universal base for any finishing coating floor.
You might be interested in information about what it is
Insulated floor on the floor slab
This scheme is rarely used in a private home, but, nevertheless, it should be mentioned. Moreover, it is very similar to the previous one, but much simpler. If only because there is already a rigid, reliable foundation that does not require additional modifications.
What are the features here?
The base is already ready - this is the floor slab (item 1) above the cold underground, usually hollow. It must be primed with the composition deep penetration, and it would not be out of place to provide a layer of waterproofing on it (item 2). Coating insulation or even thick polyethylene film is quite sufficient here.
The next layer is again waterproofing (item 4), which will protect the insulation from moisture penetration from above and ensure an optimal water-cement ratio when the screed hardens.
Well, above there is a reinforced screed (item 5), in which pipes or a “warm floor” heating cable can also be located. And the entire structure is crowned with the selected finishing floor covering (item 6).
Insulation of floors using joists or floor beams
But this option occurs, perhaps, more often than all others. And first of all, because such a scheme turns out to be practically the only possible one if the house rests on a pile or columnar foundation. But even for strip foundation with a high base it is quite applicable. “Heavy” materials such as cement, sand, gravel are not used here - wood or materials based on it become the main one. Well, and a plus, of course, is the insulation itself.
The schematic diagram can be represented as follows:
Skull blocks (item 2) or support boards are placed on the floor beams or joists (item 1). The lights will serve as the basis for installing the subfloor (item 3). For this flooring, both low-grade boards and sheet materials such as plywood or OSB can be used. The flooring can be continuous, but more often the boards are mounted with a vacuum - both for reasons of economy and for better ventilation insulation.
Waterproofing - wind protection (item 4) is laid on the subfloor. It is important that this layer should not interfere with the free escape of water vapor, so that moisture does not linger in the insulation. Sometimes, when the boards are arranged frequently or when rigid polystyrene foam boards are used as thermal insulation, this layer is not laid at all - there is no need to fear direct water ingress from below, and the wind impact with a well-equipped base is unlikely to be so great that it can cause damage insulation.
Even a layer of thermal insulation of the required thickness is laid (item 5). The illustration shows installation in one layer, but usually this is not enough - at least two are required. But this is for the better - the slabs or mats of the upper layer cover the joints of the lower one, and there are practically no cold bridges left.
Further - required condition: a layer of reliable vapor barrier (item 6). The humidity level indoors during the cold season is always significantly higher than outside. And so that water vapor, looking for any loophole to escape outside, does not penetrate into the insulation, it is necessary to install a reliable hermetically sealed (without exaggeration) barrier.
And finally, a plank or plywood (OSB) floor covering is laid on top (item 7). In the diagram, again, a simplification has been made, but in reality it is recommended to leave a ventilation gap of about 20÷30 mm between the vapor barrier membrane and the flooring. This is easy to do by installing additional counter batten slats along the joists - they will additionally press the membrane and provide the required clearance.
It is clear that the thickness of the insulation with such a scheme must be calculated in advance, since in this case it also directly affects the choice of the cross-section of lumber for beams and joists. You will have to carry out a not particularly complex thermal calculation.
How to calculate the thickness of insulation of a wooden floor on joists?
A special article on the portal will introduce you to the algorithm for carrying out such calculations. It also contains a convenient calculation calculator.
One more nuance. To protect the insulation from mice getting into it, you can also use metal mesh. It is mounted directly on the subfloor boards under the waterproofing layer. The edges of the mesh are raised onto the wall 100÷150 mm above the thickness of the insulation. After laying the insulation, the mesh is folded onto its surface. After this, the insulation on top is completely covered with the same mesh - it is attached to the joists with brackets. Perhaps such measures may seem unnecessary to some, but it really helps if you don’t leave any loopholes for the mice.
Insulation of wooden floors on joists
This section of the article provides step-by-step illustrated instructions for insulating floors with mineral wool.
The most important thing in insulating a wooden floor raised above the ground by 300 - 500 mm is the choice optimal material and high-quality, according to all the rules, installation
The first thing you need to check when deciding to insulate such a floor is the presence of ventilation in the underground space. If there are no vents in the basement of the foundation, then they need to be equipped. Lack of ventilation with such floor insulation will lead to the appearance of dampness in the underground space, rotting of wooden structural elements, and their infection by fungus.
You might be interested in information on how to choose
The total area of all vents must be at least 1/400 of the floor area of the first floor, but not less than 0.85 m². The area of one vent is usually around 0.05 m². that is, it is easy to calculate the required number and then think about their uniform placement on the base. In this case, the outer vents should be located no further than 0.9 m from the corners of the foundation. one more thing important condition– symmetry of their placement, that is, the vent on one wall should correspond to a similar one on the opposite. Thus, their number is usually even.
However, we again delved into general construction issues - let’s return to floor insulation.
So, insulating an old wooden floor (if we're talking about not about installing a new one during construction) can be done in several ways:
- Using old plank flooring as a subfloor. This option is possible if the boards are in good condition, that is, they do not have signs of rotting and are not moistened with inside. In addition, it must be taken into account that the floors will rise by approximately 250 mm. If the ceilings in the room are high enough, then insulation using the old coating, without dismantling it, seems possible. But, to be honest, they rarely resort to this route.
- The second option involves dismantling the plank covering and laying insulation under it. In this case, the removed floorboards, if they are in satisfactory condition, can then be returned to their place. If the boards are intended to be reused, then when dismantling, it is recommended to number them.
Naturally, if a new floor is being built, then they start from scratch, that is, with the installation of the subfloor - and then in order.
Below we will consider an insulation option in which the old floor is dismantled. Moreover, if insulation is carried out in an old house, an inspection of the underground space, as well as the reliability of the floor beams, will never be superfluous.
For work you will need the following materials:
- Insulation material. In this case it is mineral wool. As practice shows, and calculations confirm, in private houses in most regions of Russia it is recommended to lay this insulation with a thickness of at least 150, or even 200 mm. this usually involves a minimum of two layers.
- Boards or plywood for installing the subfloor. A board 10 mm thick and 150 mm wide will be quite sufficient.
- Beam for counter-battens with a cross-section, for example, 30×50 mm. Larger size must match the thickness of the joist or floor beam.
- Waterproofing vapor-permeable membrane.
- Vapor barrier material.
- Self-tapping screws and staples for the stapler.
| Illustration | Brief description of the operations performed |
|---|---|
 | So, having dismantled the boardwalk, you can see the floor beams and evaluate the possibilities of further work. If the floor beams are in good condition, then the first thing to do is cover them with an antiseptic solution on all sides and let the coating dry well. |
 | Next, you can choose one of two options - use self-tapping screws to fix the cranial bars on which the subfloor boards will be laid on the load-bearing beams, or fix the boards to the bottom of the floor beams. Each option has its drawbacks. When fixing the cranial elements, the space for installing insulation will decrease. |
 | Securing boards from the bottom of floor beams, in principle, has no disadvantages, except for the labor-intensive nature of the work. If the height from the ground to the beams is small, then installation will have to be done while lying on your back. The subfloor is only needed for support insulation material, therefore, it is not necessary to make it continuous or lay the boards too often. The distance between them can be even 200÷250 mm. And the boards can be used even without edged ones. But they require antiseptic treatment no less. |
 | Another option for arranging a subfloor is to fasten transverse boards to the beams in increments of 700÷800 mm, and then lay a longitudinal plank covering on them. Moreover, gaps of 10÷15 mm can also be left between the longitudinal boards. Gaps are necessary for proper ventilation of the insulation. |
 | In some cases, OSB plywood sheets 10 mm thick are used for the subfloor. However, a gap must be left between the sheets every 500 mm for ventilation. Therefore, you will have to prepare pieces of plywood 500÷600 mm long and a width equal to the distance between the centers of adjacent floor beams (joists). As a rule, it is 600 mm - according to the traditional size of mineral wool insulation. |
 | The next step is to lay a vapor-permeable waterproofing and wind protection on the subfloor. It is laid to protect the mineral wool from water ingress (which is extremely unlikely in such conditions), as well as from wind, which will penetrate into the underground through ventilation ducts. The membrane sheets should go around the floor beams. They overlap each other by 100÷150 mm. It is not necessary to tape these overlaps with tape; there is no need for tightness. |
 | It is necessary to focus on securing the membrane to the walls. The material should be on them 50÷70 mm higher than the thickness of the insulation. On wooden walls the membrane is secured with staples, and on surfaces made of other materials - with double-sided construction tape. It is still recommended to isolate the insulation from possible contact with the walls. |
 | Next, the insulation material is laid. It is important to observe several nuances here. The slabs are most often laid in two layers, and the top one must overlap the joints of the lower insulation. The standard width of insulation slabs is 600 mm, and it must be laid opposite the floor beams, so optimal width between the beams in the clear is approximately 550÷570 mm (just along the axes - 600 mm, and due to the thickness of the beam the clearance is slightly reduced). However, it is not always possible to follow this step, so the slabs often have to be “replenished” with additional fragments. Their joints must also be covered with entire slabs of the top layer. |
 | A vapor barrier material is laid on top of the insulation and secured with staples to the floor beams. This layer is necessary to protect the insulation from the penetration of various fumes from the premises. The canvases are also laid with an overlap of 100÷150 mm (on the membranes the minimum width of such an overlap is often even marked in dotted lines). But here the requirements for sealing are strict: the canvases must be glued together along the overlap line with moisture-resistant tape. |
 | Then, if you plan to create a ventilation gap between the board covering and the vapor barrier (and this is highly recommended), then slats 25÷30 mm thick are attached to the ends of the beams on top of the vapor barrier sheet. Some craftsmen refuse this design element and consider it optional. But it is better not to neglect such ventilation - condensation will not accumulate on the vapor barrier membrane. |
The insulation is complete - and you can install a board covering or a plywood or OSB flooring on top. But these are questions beyond the scope of our consideration.
* * * * * * * *
Now, having at hand several options for floor insulation schemes various materials, it will be possible to choose the most suitable way for a specific case. By adhering to the recommendations received and strictly following the technology, it is quite possible to independently thermally insulate the floors in your own home. At the same time, not only saving a decent amount for the family budget, but also gaining confidence that the work was done conscientiously.
In conclusion, we invite you to watch an interesting video. In it, a completely amateur master produces self-insulation floors of your house under construction. Honestly, there is a lot to learn.
High-quality insulation of the floor in wooden house, you will simultaneously make the room more comfortable to live in and reduce heating costs. Familiarize yourself with the available range of thermal insulation materials, study the three main schemes for performing the work, choose the option that suits you and get started.
What material to choose for insulation?
Before you begin to study the properties of existing insulation materials, remember: it is recommended to carry out thermal insulation work only after the wood shrinks, i.e. no earlier than six months after the construction of the structure. Otherwise, shrinkage may damage the insulation.
When choosing a material for floor insulation, you need to pay attention to the following insulation characteristics:
- thermal conductivity;
- resistance to moisture;
- installation method;
- thickness;
- fire resistance;
- life time;
- environmental friendliness;
- price.
In the case of wooden structures, highest value have such characteristics as fire resistance and service life.
Excellent material for floor insulation.
Advantages:
- low thermal conductivity;
- good fire resistance. Mineral wool successfully prevents the spread of flame;
- vapor permeability. Mineral wool “breathes,” which is very important when it is used to insulate wooden surfaces;
- ease of arrangement;
- good environmental friendliness.
It is produced in the form of mats and rolls, which gives you the opportunity to choose.
Main flaw mineral wool – low resistance to water. When in contact with moisture, the insulation becomes deformed and loses its quality characteristics Therefore, special attention should be paid to the arrangement of the waterproofing layer.
| Those. characteristics of mineral wool | Indicators |
|---|---|
| Density | 115 kg/m3 |
| Water absorption at full immersion, no more | 1% |
| Average fiber diameter, no more | 0.2 µm |
| Content of non-fibrous inclusions in the mass, no more | 4,5% |
| Thermal conductivity at 283+1 K, no more | 0.044 W/m*K |
| Shear strength, not less | 50 kPa |
| Compressive strength, not less | 100 kPa |
| Tensile strength, not less | 150 kPa |
Great option floor insulation in a wooden house. It can only be used after the wood has gone through the shrinkage process. made on the basis of gypsum fiber.
Key benefits:
Main flaw– relatively high cost. A twenty-kilogram bag of mixture is enough to insulate no more than 1 m2 of surface.
The material also does not tolerate moisture well. Because of it, it is deformed. Such deformation does not affect the thermal insulation properties of the material in any way, but the finishing floor covering may deteriorate.
Popular material for floor insulation. Advantages the following:
Main flaw– significant shrinkage. In just a year of service, a meter strip of glass wool can decrease by 10-15 cm. As a result, the integrity of the thermal insulation layer is compromised. Also among the disadvantages are poor resistance to water and not the best thermal insulation properties.
Styrofoam
One of the most popular insulation materials. It features an optimal ratio of cost and quality.
The material does not deform under the influence of temperature changes and high humidity. Even with a relatively small thickness (up to 10 cm), polystyrene foam provides high-quality thermal insulation.
Main flaw– fragility. In order for the material to last as long as possible, the arrangement of the insulating “pie” must be done perfectly.
Important! Foam does not allow air to pass through. This may not have the best effect on the condition of the wood. Be sure to take this nuance into account.
This has many advantages, including:
- resistance to fire, moisture and temperature changes;
- incredibly low thermal conductivity;
- high noise insulation properties;
- excellent strength.
Main flaw– relatively high cost.
Find out how to do it by studying step by step instructions, in an article on our portal.
Prices for popular types of insulation
Instructions for carrying out thermal insulation work in different situations
Floor design wooden house can have a wide variety of appearances. Consequently, the procedure for carrying out thermal insulation work will also differ. We present to your attention instructions for insulation in the most common cases.
Due to the limited height of the subfloor, the insulation cannot be fixed from below to the joists. This leads to the need to dismantle the existing flooring, which makes this method the most labor-intensive.
In general, the work is performed in the following sequence.
First step. Remove baseboards and flooring elements. If replacing the decking is not in your plans, work as carefully as possible. For greater convenience, sign the boards to avoid problems during their reassembly.
Second step. Examine the condition of the lag. Dismantle rotten and deformed areas.
In place of the removed elements, install pieces of timber of similar sizes. To fasten parts of the structure, use wooden boards and galvanized screws.
Third step. Attach a support block to the bottom of each joist.
Fourth step. Prepare lumber for arranging the rough flooring. An unedged board works well. Saw it into pieces 10-20 mm long less step installation of logs - the flooring elements must be laid quite freely.
Fifth step. Assemble the subfloor. There is no need to attach the boards to the support beams.
Sixth step. Cover the flooring and joists vapor barrier material. If the building is located in an area with high groundwater, instead of vapor barrier, lay glassine or roofing felt. Lay the insulation with a 10-15 cm overlap on the walls. Tape the joints of individual strips of material with tape.
Seventh step. Install finished floor joists. Lay the selected thermal insulation material.
Eighth step.
Ninth step. Stuff counter battens to create a ventilation gap between the insulation “pie” and the finishing flooring. The recommended gap thickness is 20 mm.
Tenth step. Reinstall the previously removed floorboards or install new flooring.
| Floor board thickness, mm | Distance between lags, cm |
|---|---|
| 20 | 30 |
| 24 | 40 |
| 30 | 50 |
| 35 | 60 |
| 40 | 70 |
| 45 | 80 |
| 50 | 100 |
Insulating the floor above a high cellar
In this case, you can use a trick and insulate it from the cellar side.
First step. Go down to the cellar. Attach a moisture-proofing film to its ceiling.
Second step. Nail thin slats or support beams to the sides of the beams. If the cellar is damp, use a galvanized profile instead of timber.
Third step. Cut the insulation (it is best to use mineral wool) into pieces 20-30 mm wide larger than the pitch for installing the logs. Thanks to the increased width, the insulation slabs will be placed side by side and will be additionally fixed.
Fourth step. Place transverse bars onto the previously fixed beam (profile, slats) to maintain the insulating layer.
Fifth step. Attach a waterproofing film to the slats.
Sixth step. Install the finishing coating at your discretion.
If you want from the living area, work in in a similar manner– the “pie” will consist of the same layers.
Arrangement of a double floor
Suitable for rooms with high ceilings. The insulating structure will take up 12-20 cm of usable space.
Work in the following order.
First step. Remove the baseboards, replace damaged wooden supporting elements, and fill existing gaps with foam.
Second step. Lock wooden joists in increments of up to 90 cm. The optimal installation step is about 60-70 cm.
Third step. Make sure the top edges of the joists are horizontal. If there are deviations from the horizontal, get rid of excess wood using a plane. In places with insufficient height, place pieces of wood, roofing felt or other suitable material under the beam.
Fourth step. Cover the surface of the base with a vapor or moisture insulating material with a 10-15 cm overlap on the walls.
Fifth step. Place the selected insulation in the space between the joists.
Sixth step. Cover the thermal insulation layer with waterproofing film.
Seventh step. Install the flooring elements.
Eighth step. Lay the selected covering and install the skirting boards.
Important! If a wooden house stands on a screw, bored or pile foundation, you need to additionally install windproof material. It installs with outside from the thermal insulation layer.
Now you have all the necessary knowledge to self-execution floor insulation in a wooden house.
Good luck!
Video - Floor insulation in a wooden house
When choosing how to insulate a wooden floor in a private home, they are based, first of all, on financial capabilities. Thus, expanded polystyrene is the most economical option, expanded clay is more expensive but is the most environmentally friendly, and mineral wool is easy to install and unattractive to rodents.
A warm base is the key to a warm floor
Before you start insulating the floor, you need to make sure that the base is thermally and waterproofed. At the same time, we must not forget about ventilation, which will prevent the development of fungi and mold in the underground. After all, this destroys the wooden base and the floor will last very little.
Insulation of the basement floor
If the house has a basement or ground floor, you need to take care of their insulation and waterproofing. This will prevent the basement from freezing in the winter and keep it cool in the summer. After all, the basement non-residential floor is often used specifically for storing food, and if it is located above the freezing level of the soil, such measures are mandatory. But there is no need to insulate an unheated basement underground.
The basement floor is insulated from the outside extruded polystyrene foam, since it is not hygroscopic, unlike ordinary polystyrene foam. The insulation must be laid on waterproofing, such as bitumen and roofing felt. The base is dug out a meter and the EPS is attached to a special glue.
After this, the soil is backfilled layer by layer.
On the ground part of the basement floor, the insulation is laid with glue, and fixed on top with dowels and reinforcing mesh. The final stage is facing the base. The material can be any - from decorative stone to PVC panels. But it is better to choose a damage-resistant and moisture-repellent material.
If the base is low, about 50 cm, it is better to fill the space under the subfloor. This option will turn out to be much warmer - there is no cold air under the floor of the house, there is no need to install vents that will have to be closed for the winter.
Backfilling is done with ordinary soil, and the last 10 cm to the floor is filled with sand. Both soil and sand must be compacted separately in a wet state.
More high plinth it is not economically profitable to fall asleep. In this case, it will have to be insulated according to the same principle as the ground floor, but organize vents for ventilation that remain open in summer time and close in winter. Special attention should be paid to insulating the basement for a house on a columnar or pile foundation.
Freely “walking” cold wind significantly increases heat loss from the floor.
General features of wooden floor insulation
When the base is in order, you can proceed directly to the floor. Regardless of the stage of work (during the construction process or in an already inhabited house), do-it-yourself insulation includes:
- Laying or checking and replacing joists.
- Laying waterproofing on the joists (or under them if the joists are lying on sand).
- Laying insulation between joists.
- A layer of vapor barrier on top of the insulation.
- Installation of a counter-lattice for the gap between the finished floor and the vapor barrier.
- Finished flooring.
For waterproofing you can use any roll material- from thick polyethylene to innovative, but expensive, materials.
For vapor barrier, it is best to use foamed polyethylene with aluminum coating On the one side.
This will provide both additional insulation floor, and will prevent condensation from entering the insulation. If the winters are not very cold, sometimes only a layer of polyethylene foam is enough without additional insulation. But it is better to insulate the floor as well as possible, because then you will have to remove the covering again if the insulation is not enough.
The vapor barrier is laid with the “shiny” side facing the finished floor. Both hydro- and vapor barriers are laid overlapping with an allowance of at least 10 cm, and the joints are sealed with metallized tape.
Insulation with roll and tile materials
Even at the stage of installing the log, you need to decide what material will be used for insulation. Depending on its width and length, the lag pitch will be selected, between which the insulation is laid very tightly and without gaps.
Ideally, the height of the logs should correspond to the thickness of the mineral wool layer, but given the need for an air gap between the vapor barrier and the finished wooden floor, you can simply not make a counter-lattice. In this case, the vapor barrier is attached with a construction stapler to the sides of the logs so that it lies on the mineral wool without an air gap between them.
It is important to remember that the sides of the slabs have different hardness. This type of insulation is installed with the hard side up. For convenience, the desired side is already marked with a blue stripe, so it’s difficult to make a mistake.
It is best to use slabs with corrugated edges - this will provide the best adhesion. Lay the slabs as tightly as possible, starting from the corner. The next row begins with an offset of half the slab. The last slabs must enter with force. Possible cracks are sealed with construction foam.
Insulation with bulk and sprayed materials
There are also more “exotic” ways to insulate floors in a house. For example, sawdust is increasingly used as a natural and environmentally friendly material.
The technology is not very different:
- on the slabs fixed under the joists, a vapor-permeable material is laid, not polyethylene;
- sawdust is poured out between the joists and watered with a weak lime mortar from a watering can;
- As soon as the material dries and settles, the finished floor is laid - no vapor barrier is needed.
But here you need to pay special attention to hydro- and vapor barrier, as well as the dryness of the expanded clay itself. Because of its pores, it is very hygroscopic, but practically does not release moisture. Therefore, when improper installation Expanded clay that has accumulated moisture will only worsen the situation.
Insulating the floor of a house with sprayed materials - polyurethane foam, ecowool or penoizol - is practically impossible to do on your own, and in some cases it is dangerous. This will require special equipment, and purchasing it to insulate a small house is extremely unprofitable.
The process of installing a wooden subfloor, its insulation, hydro- and vapor barrier is revealed in detail in the video:
Needless to say, how important it is to insulate a wooden floor in a private house to achieve proper comfort for the people living in it. When heat is lost through the floor covering, residents constantly feel cold feet, which affects their overall well-being. It is equally important to save energy resources, up to 20% of which can be spent on heating the ground under the building. Therefore, this article is devoted to the questions correct production works on insulation of wooden floors and selection suitable materials for this purpose.
Wood floor insulation technology
We decided to start with this question because this technology is performed the same way, regardless of what type of insulation you decide to choose. The simplicity is explained by the presence of logs, thanks to which an empty space is formed between the base and the floor covering. It remains to figure out how to properly fill it with thermal insulation material and thereby insulate the floors in a village or country house.
First, a little about the design wooden floor on the ground floor in order to better understand the physics of the insulation process. Logs are load-bearing wooden beams of large cross-section, resting on various types of foundations:
- strip foundation;
- frame of a pile-screw foundation;
- brick pillars;
- solid concrete slab.
In the first three cases, the beams are above the ground, so to create a rough filing, cranial bars are nailed to their sides on the sides. Boards impregnated with an antiseptic are placed and fastened on them, and they serve as the basis for laying the insulation. The floor insulation scheme on the first floor of a private house is shown in the figure:
- In order for do-it-yourself floor insulation in a wooden house to comply with generally accepted technology, it is correct to proceed in the following sequence:
- The bottom lining of the joists (subfloor) is covered with thick polyethylene film for waterproofing. The canvases are laid with an overlap of at least 10 cm.
- Insulation is placed tightly and without gaps between the joists.
- A vapor barrier film is again laid on top.
- A clean floor covering with a ventilation gap is installed. When the thickness of the insulation is equal to the height of the beam, it will not be possible to create a gap and you will need to additionally install special strips - counter-battens.
For reference. Sometimes in old houses you can see how the floors are insulated from below. This method can be used when there is sufficient clearance between the first floor and the ground. Then in an old house you can not remove the floor covering, but insulate it from below and immediately attach boards directly to the beams, which is very inconvenient.
The bottom layer of waterproofing is needed to prevent water from getting inside and wind from blowing in. The upper vapor barrier will not allow moisture released inside the premises to penetrate into the thickness of the insulation, and ventilation will allow the surface of the film to be ventilated and dried. In principle, the same technology is used to insulate floors on joists lying on concrete base. Only the waterproofing film is laid directly on top of the concrete surface, overlapping the joists.
Which insulation is better to choose for a wooden floor?
It must be said that the choice of thermal insulation materials is modern market so wide that it is sometimes very difficult for a simple homeowner to understand which insulation for a wooden floor is better. Let's give a general list of the most popular insulation materials and analyze the properties of each of them separately:
- sawdust;
- expanded clay;
- basalt wool;
- polystyrene foam and extruded polystyrene foam (penoplex);
- foamed polyethylene (isolon, penofol);
Before we begin to consider all the insulation materials used for floors on joists, it is worth touching on the topic of the thickness of the thermal insulation layer. In order not to go into complex calculations, the following method for determining it is proposed: for the middle zone with a temperate climate, the thickness of the foam layer (density 25 kg/m3) should be at least 100 mm. Accordingly, in the north this figure increases to 150-200 mm, and in the south it decreases to 80 mm.
Note. Polystyrene foam is one of the most common materials, so the calculations were made based on it. Other insulation materials will differ in thickness, but it still cannot be greater than the height of the beam and this must be taken into account.
Insulation with sawdust and expanded clay
These materials are still used to this day for insulating wooden floors on joists because they are the cheapest. Another thing is that their thermal insulation properties leave much to be desired compared to modern insulation materials very low. Therefore, they should be used when the requirements for insulation are low at home or at a dacha, where people visit periodically.
For reference. For example, the thermal conductivity of penoplex with a density of 33 kg/m3 is 0.031 W/m °C, while the best indicator of expanded clay with a density of 200 kg/m3 is 0.1 W/m °C. That is, 3 times worse.
Given the high thermal conductivity, when insulating with expanded clay or sawdust, there is no point in determining the thickness of the layer; each opening between the joists is filled to the top. In this case, the sawdust should be dry and, if possible, compacted. To prevent mice from eating them, an old one is offered folk way– Sprinkle milk of lime on top.
Although sawdust decays over time, they can easily be replaced with new ones, and this is a plus. It will take more time to dismantle and reassemble flooring. At the same time, expanded clay is a very durable insulation material and will happily serve for as many years as the house itself lasts. By the way, expanded clay insulation is used as a combination with other materials. In this case, it is poured into the cavity between the subfloor and the ground, as shown in the diagram:
Use of mineral wool
The main advantage of mineral wool in slabs or rolls over other insulation materials is resistance to high temperatures and non-flammability, which is very important for wooden structures. In addition, rodents do not like it very much. On the other hand, the material is able to absorb moisture and at the same time sharply increase thermal conductivity. Therefore, when insulating basalt wool it must be carefully protected from water vapor using different membranes (films).
Important. Cannot be used inside the house different kinds glass wool. This applies to ISOVER products intended for roof insulation.
Now let’s talk about how to correctly determine the thickness of the insulation layer for the floor. Since the thermal conductivity of mineral wool is only slightly higher than that of polystyrene foam, it can be taken with a thickness of 100-120 mm for the middle zone. If you take rolled material of a lower density, then it should be laid in 2 layers.
Polymer insulation
With polystyrene foam the situation is completely opposite: it is flammable, does not absorb moisture and is loved by rodents. The last drawback can create a lot of problems in the southern regions, since mice love to make nests out of foam plastic. Therefore, it would be better to insulate the floors of a wooden house with polystyrene foam or high-density penoplex. Rodents avoid these polymers, and their thermal conductivity is even better.
In addition, foam insulation will last longer, since foam plastic simply crumbles after 15-20 years. Another thing is that these materials will cost significantly more. There is one point regarding the process of laying polymer sheets itself. They must be clearly cut to size between the beams so that the insulation is inserted there tightly, no gaps are allowed. This can result in a lot of useless waste material.
As for products made of foamed polyethylene such as isolon or penofol, they are too thin and will not provide the necessary degree of insulation for wooden floors. The same penofol can be used to lay the subfloor before laying mineral wool, that is, to use the materials together. Both isolon and penofol are vapor-tight products, which means they can be used as an additional barrier against moisture penetration.
Polyurethane foam has virtually no disadvantages. It is durable, does not absorb moisture, is not damaged by rodents, and can withstand fire for some time. The thermal conductivity of insulation is almost the lowest among polymers. One problem - to apply it you need compressor equipment, which will cost you a pretty penny, you won’t be able to insulate the floor with your own hands.
Conclusion
As you can see, mastering the technology of insulating a wooden floor on joists is much easier than choosing insulation for this purpose. Which of the following is better - you need to be guided by local conditions and the size of your budget. In practice, most often homeowners implement inexpensive options– cotton wool and polystyrene foam. If you have the financial means, then the best way is to apply polyurethane foam.
Wood is a traditional material that has been used by people since ancient times to build homes and outbuildings. However, due to its versatility, environmental friendliness, durability and excellent operational characteristics it has not lost its relevance today.
Modern wooden house
Wood is characterized by high thermal insulation properties (thermal conductivity coefficient, depending on the type of wood, varies from 0.1 to 0.23 W/(m*K)). But even in houses made of such material, the floor is a weak point that requires special attention.
Warmed air is lighter than cold air, so it always tends to rise - every schoolchild knows this. In this regard, the floor, especially on the ground floor, often needs to be additionally insulated.
Choice of insulation
Thermal insulation materials used to equip a wooden house must have a number of properties, which determine not only the microclimate in the room, but also the safety of its operation. These include:1. fire resistance;
2. non-flammable;
3. safety for human health.
The materials most often used for insulating a wooden house are:
sawdust;
expanded clay;
mineral wool;
ecowool;
Styrofoam;
penofol.
Each of them has its own advantages and disadvantages. The choice of insulation method in each case should be approached individually.
Preparatory work and sequence of insulation
Even at the stage of developing a new house project or during insulation already existing building you should think about creating a two-level floor:1. the first level (rough), on which layers of thermal insulation will be laid in the future. It consists of rough boards attached to beams;
2. The second level (finishing) will serve as the basis for laying the finishing coating or will itself be one.
Two-level floor
When starting to insulate the floor, you should take care of additional waterproofing. For this purpose you can use plastic film, which must be spread over the entire surface of the subfloor, including joists. Butt seams should be securely glued with tape.
Next, insulation is laid on top of the waterproofing layer, which is then covered with a vapor barrier (glassine is one of the options). However, for some types of thermal insulation materials, hygroscopicity is not typical.
The final stage is the installation of a finished floor.
Characteristics of the most common thermal insulation materials
Wood sawdust – available material, which is a by-product of the wood processing industry. They can be used as an independent thermal insulation material, or as a basis for preparing various mixtures, which may include, for example, cement or sand.
Floor insulation with sawdust
However, such insulation may soon become a refuge for small rodents and other pests.
Expanded clay- a common insulation material obtained by swelling of light grades of clay.
There are several types of it:
gravel;
crushed stone;
sand.
Such fractions differ in shape, size and thermal conductivity value. However, to achieve the most effective insulation a mixture of them is used. 
Floor insulation with expanded clay
Expanded clay has a number of valuable properties:
✓ can be used in a fairly wide temperature range;
✓ does not harm human health;
✓ unattractive to insects and rodents;
✓ characterized by excellent sound and heat insulation properties.
But it easily absorbs moisture, which is why the quality of such insulation can significantly decrease over time.
This problem can be solved by laying hydro- and vapor barriers.
The height of the expanded clay layer reaches 20 cm. In this regard, its use may be limited by the insufficient height of the walls in the room.
Expanded clay can be used as an independent thermal insulation material, or mixed with cement mortar.
Mineral wool Available in three types:
1. glass wool (glass wool);
2. stone (basalt) wool;
3. slag wool.
The advantages of such insulation include:
non-flammability;
vapor tightness;
resistance to significant temperature changes;
high sound insulation properties;
absence of mold, fungi, rodents and small insects. 
Layed mineral wool
When using mats, slabs, or mineral wool rolls, you should remember that such insulation is a hygroscopic material. Therefore, it is necessary to install vapor and thermal insulation.
Important: when installing the finishing level of the floor, it is necessary to avoid crushing or artificially compacting the mineral wool. Otherwise, the effectiveness of such insulation will be significantly reduced.
Important: when working with mineral wool, you will have to use products personal protection(glasses, gloves, respirator).
Ecowool, unlike mineral wool, is absolutely harmless, as it is made from sawdust. Using it as insulation, you need to take care of vapor and heat insulation. The high cost of such material may also be a surprise.
Ecowool distribution
Styrofoam– foamed polymer material, produced primarily in the form of slabs. It is characterized by a low thermal conductivity coefficient and does not absorb moisture at all. At normal conditions polystyrene foam does not harm human health. However, it is highly flammable and burns.
Polystyrene foam laid between the joists
Penofol– a foam material consisting of a polymer layer and foil, connected at the production stage. Such insulation does not require additional waterproofing.
Information: penofol must be laid with the foil side up. In this case, heat is reflected (returned) into the room.
Example of laying penofol
Floor insulation is a labor-intensive and rather expensive process. But by spending once, you can save on heating costs in the future and avoid unwanted health problems.
