Is it possible to insulate a bathhouse with foam plastic: floor, ceiling, foundation

Foam plastic began to be used as insulation in the mid-20th century. The foam consists of expanded polystyrene. When foaming, air bubbles form. Due to the large number of air bubbles, polystyrene foam is considered an excellent thermal insulator. But is it possible to insulate a bathhouse with foam plastic? Let's figure it out together.

Is it possible to insulate polystyrene foam and a bathhouse?

Arrangement of vapor barrier

Before you start work, you need to know how to properly insulate a frame bath in order to do it efficiently.
Regardless of which material was chosen as insulation, when laying it in the cells of the frame, it is necessary to ensure reliable vapor barrier (for more details: “Vapor barrier of a bathhouse - selection of material and its installation”). If you do not cut off the insulation from the bathhouse atmosphere with its high humidity, it will absorb water as the steam cools, which will certainly lead to the most undesirable consequences:

• a wet thermal insulator will significantly increase its own thermal conductivity and heat will quickly move from the room to the environment;
• the porous structure will not allow the material to dry quickly, which means mold may appear and the frame of the building will begin to rot.

Thus, when a frame bath is made, the walls are insulated using high-quality vapor barrier.

To do this, experts recommend using one of the following materials:

• aluminum foil will not only protect the insulation from moisture, but will also reflect thermal energy;
• polyethylene film;
• glassine is environmentally friendly and inexpensive.

Insulation of frame building walls

They begin to equip the thermal protection of a frame bathhouse building simultaneously with the construction of its walls. The fact is that the use of this technology assumes that the heat insulator is also a structural material. When building a panel bathhouse from insulation with your own hands, its layers are laid out between the load-bearing elements of the frame. A vapor barrier is installed on top of it.

At the end of the insulation work, you get something like a pie, in the center of which there is a heat-insulating material, lined with a vapor barrier on the inside, and waterproofing on the outside.

The outer layer of the cake will be represented by decorative finishing inside the bathhouses, and on the outside - by facade cladding. Both of these layers will not only provide additional thermal protection, but will also serve as a structural element that will enhance the strength of the entire building.

Among professionals, the best option is considered to be laying two layers of heat-insulating material into the bath frame. In this case, it is advisable to make the first of them from tile insulation, and the second from roll insulation. As a result, such a thickness of the walls of a frame bath can reliably protect the premises from heat loss.

In the process of laying insulation, special attention should be paid to the fact that most materials have different sides - external and internal. To distinguish them, pay attention to the recommendations of product manufacturers.

Why is thermal insulation made?

Do you need to insulate floors? Insulation of the base is an important component of insulation work in a bathhouse. The stability of the temperature regime in the wash room, dressing room, steam room, etc. will depend on the quality of the floor insulation in the future. Water has high thermal conductivity and therefore tends to cool quickly. To prevent a sharp drop in temperature in a log or brick bathhouse, the base is insulated using non-hygroscopic materials.

Why are timber houses insulated? Reducing heat loss in wet rooms is equally important for both a wooden and a brick house. Why? The bathhouse is one of those types of buildings where a high temperature must be constantly maintained.

Since the humidity level in it is always quite high, when it comes into contact with a cold floor, the water will quickly cool, which will lead to a general decrease in the temperature in the room.

We insulate the bathhouse from the inside: what do we need?

Any construction, repair and finishing activities begin with the preparation of materials, without which the implementation of the planned work will simply be impossible. Pay due attention to studying the list below: it is better to spend a little time reading and immediately buy everything you need, than to later return to the store and buy more of what you forgot.

Insulation

The main component of the list under consideration. The modern market offers a wide range of thermal insulation materials, but not all of them are suitable for use in a steam room - humidity and temperature may be too much for you. To insulate a bathhouse, the following are most often used: expanded clay (floor insulation), materials based on stone wool, and expanded polystyrene.

Important! It is strongly not recommended to use polystyrene foam to insulate the steam room itself - at high temperatures, material of dubious quality can most likely emit substances harmful to human health.

Comparative characteristics of the mentioned materials are given in the following table.

Table. Comparison of popular bath insulation

As noted, expanded clay is suitable for insulating bath floors. Bulk material allows you to provide the required thermal insulation of both wooden and concrete structures. Mineral wool insulation is optimal for insulating both walls and ceilings. The best option, as noted, is a thermal insulation material based on stone wool, equipped with an additional foil coating - the key characteristics of such insulation at a higher level.

Prices for mineral wool

Foil tape

In accordance with the current provisions of the technology for carrying out the work in question, the joints of the insulation boards must be glued with foil tape. This will create a sealed surface with the highest possible thermal insulation properties.

Prices for foil tape

Wooden blocks

The elements of the thermal insulation coating are placed in the cells of a pre-assembled sheathing, for the assembly of which wooden blocks are used. Select the section of the beams in accordance with the thickness of the thermal insulation. For example, if you are installing a 10-centimeter thermal insulation layer, use bars with a similar thickness or width to assemble the frame.

Choose the distance between the bars 1-2 cm less than the width of the slabs or roll of insulation. For bulk materials, the optimal distance between the bars is 45-60 cm.

Fasteners

The sheathing elements (bars) are fixed using dowels/screws (if the surface is wooden) or anchors (if the base is stone). The length of the fasteners is also selected in accordance with the base material: for wood - 2-2.5 cm, for permanent structures - from 4 cm.

The specific length of fasteners is determined in accordance with the characteristics of their use. For example, during the installation of sheathing, the fasteners must be of such length that they ensure high-quality fixation of the beam/profile of the selected section. The cross-section of the beam itself, as well as the profile parameters, are determined in accordance with the thickness of the thermal insulation layer being installed.

Additional materials

If you insulate a bath using a material other than foiled mineral wool, you will additionally have to purchase a water vapor barrier film.

If you plan to pour a concrete screed, the set for work will increase to include the following items:

• reinforcing mesh;
• mixture for pouring the screed or materials for preparing it yourself (cement, sand, water);
• lighthouses;
• damper tape;
• polyethylene.

Prices for water vapor barrier film

Insulating the foundation with foam plastic

Since polystyrene foam has excellent thermal insulation properties and is not afraid of moisture, it is successfully used for thermal insulation of foundations. True, to protect it from mechanical loads, a protective partition is needed. It is made either from boards, a cheaper but also much less durable option, or from brick (a half-brick wall).

Insulating the foundation with foam plastic

For loams and clayey soils, insulating the foundation with polystyrene foam is an almost ideal option. Due to the fact that polystyrene foam almost does not absorb water, it protects the foundation from winter and spring heaving: it simply does not allow water to seep through and be absorbed into the foundation material. It is not recommended to use polystyrene foam only if flooding often occurs with a high groundwater level: water can seep under the insulation layer, because perfect tightness is almost impossible to achieve.

Scheme of foam insulation of a strip foundation

With simple foundation geometry, foam slabs are most often chosen. For central Russia, their thickness should be at least 5 cm. But for better thermal insulation in the corners of the foundation, it is better to lay slabs 10 cm thick - in these places the heat loss is the most significant.

Preparatory work for insulating the foundation with foam plastic

The soil around the foundation is removed to the freezing depth (preferably a little lower), the walls are cleaned and primed. You can buy a primer on the market, or make it yourself: you will need molten bitumen, to which you need to add the same amount of diesel fuel or gasoline. Apply the resulting mixture to the foundation and wait until it dries (about 1 hour). A layer of waterproofing must be applied to the primed foundation. This can be liquid rubber (applied with a brush) or rolled bitumen materials (fused using a torch). Then they begin installing the foam.

Installation of foam plastic slabs on the foundation

It is better to lay the bottom row of slabs on a rigid base. If you are just planning a foundation, you can make a special ledge on which the foam plates will rest. If the foundation is already in place, but there is no protrusion, the gravel pad on which the foundation itself stands can serve as a stop.

Foam boards must be secured either with bitumen-polymer mastic or with polyurethane glue. But the glue should not contain acetone, gasoline and toluene, as they destroy polystyrene. The adhesive is applied pointwise or to the entire surface of the slab, but the joints must be glued. Some manufacturers make slabs with an L-shaped lock (this also needs to be lubricated with adhesive), which makes the connection of the slabs more airtight and reliable. With this connection, cold bridges practically do not form and the tightness of the entire insulation becomes almost ideal.

Grooved foam (with selected quarter) - avoids the appearance of cold bridges

Sometimes it is recommended to lay the slabs in two layers, shifting the seams relative to each other - in this way, losses through the joints of polystyrene slabs are also reduced. But this method has its opponents: they say that water will leak between the two layers of foam. Then the thermal insulation properties will deteriorate significantly. This possibility, of course, exists, especially with vertical soil displacements (shrinkage), but how great it is is difficult to judge.

After the foam has been laid around the entire perimeter to the required thickness, you need to apply another layer of waterproofing material on top (the same bitumen roll materials or liquid rubber). You can already build a protective brick wall on top. Sometimes boards are used. A good option is geotextiles. It also copes very well with loads from soil (it is laid under asphalt when constructing highways). Other options are possible. The main thing is to protect the foam from soil loads.

The last stage of thermal and waterproofing of the foundation (this is exactly how the result turns out if you use polystyrene foam) is the installation of a blind area. In general, thermal insulation of the foundation with foam plastic is quite a troublesome task, but as a result, your foundation is protected from moisture, and you don’t have to worry about soil heaving, and you spend much less on heating.

Types of ceilings and their insulation

Construction and protection of the ceiling structure should be done after the walls and roof have been erected. This way you will protect the building from the effects of unfavorable atmospheric conditions, the appearance of fungus and mold.

Before you begin, pay attention to the structure of the ceiling itself. He can be:

• flat (in small buildings);
• hemmed (for baths of large areas and volumes);
• panel (has superiority over the previous two).

In any case, the ceiling must have high-quality heat and vapor insulation - without cracks and with well-taped joints.

Bath roof installation

Flat ceiling

A flat ceiling is the best option when you need to insulate the ceiling in a small bathhouse without an attic. It can be easily and quickly installed, but in the long term it has a significant drawback - when you go to the ceiling, you can easily damage such thermal insulation.

The maximum span width that can be covered with this ceiling is 2.5 meters. Flooring boards (their thickness should be at least 5 cm) are placed with emphasis on the walls. Vapor barrier material is spread over them, and then loose or mineral insulation.

Flat ceilings are made in small baths

Hemmed construction

This type of ceiling assumes the presence of an attic space and is therefore considered more practical. The name says that this ceiling must be hemmed or attached to something. For this purpose, it is planned to create a load-bearing frame from ceiling beams.

Further work is carried out in the following order:

1. Using a stapler or additional slats, attach the vapor barrier material to the bottom of the beams (the main thing is to do it on the right side). The canvases should be overlapped and the seams should be taped with special mounting tape. Don't forget to make an allowance for the walls along the edges of the film (15-20 cm).
2. Along the vapor barrier layer, sew the beams from below with an edged board or clapboard.
3. On top of the vapor barrier (from the attic side), lay insulation between the beams on the bathhouse ceiling.
4. Cover the thermal insulation on top with waterproofing film.

1. Lay edged or unedged boards over the beams. This will give you the floor of the attic space.

False ceiling with sawdust insulation

Panel option

A panel ceiling is a structure consisting of identical panels. In the process of connecting them, a solid warm ceiling is formed. The complexity of installation means that several people must participate in it.

So, we insulate the bathhouse ceiling with our own hands in the following order:

1. First you need to make shields. To do this, choose a flat place and take three template measurements in advance (length 50 cm). To make one panel you will need 2 beams and boards 60 cm long.
2. Lay the beams parallel to each other at a distance of 50 cm.
3. Nail or screw the boards to them with self-tapping screws. Make sure that their ends protrude 5 cm above the outer edge of the beam on each side. When joining the shields, such “visors” form a pocket that will need to be filled with heat-insulating material.
4. Turn over the knocked down panel and lay a waterproofing film over its surface on the inside. Fastening is done using a stapler. You can nail two slanting slats on top of the shield, so it will be easier for you to transport it.
5. Assemble the panels on the walls of the bathhouse. Place the bathhouse ceiling insulation and vapor barrier layer into the boxes and the pockets formed between them. Secure the panels at the top using cross-section boards of the subfloor. They are nailed to the bars of the shield. The first board should cover all the laid panels with its length. The second and third boards can be composite, then a solid board is nailed again, then a composite one, etc.
6. Install the roof rafter system.
7. Cover the inner surface of the ceiling with decorative finishing material, such as clapboard.

Panel boards are prepared in advance

Are polystyrene foam and polystyrene foam the same thing?

The insulation of the ceiling of a bathhouse with foam plastic can be somewhat diversified, while remaining faithful to the choice of this particular material.

You couldn't help but hear about an improved type of polystyrene foam - polystyrene foam. Essentially, these are the same plates made of capsules filled with a gaseous substance, only stronger, stronger, better.

Let's analyze the qualities of polystyrene foam:

• it is not as fragile as polystyrene foam; even with not very careful transportation, the corners of the polystyrene foam plate remain intact;
• this material does not ignite as quickly as polystyrene foam filled with highly flammable gas;
• The service life of expanded polystyrene is from 15 to 35 years, polystyrene foam is from 10 to 20.

As for the price, expanded polystyrene is only 5-10% more expensive than its “big brother”.

No matter how good the material is, failure to adhere to the accuracy of the installation technology can, over time, negatively affect the quality of heat conservation.

Therefore, having prepared the necessary material, carefully study the step-by-step instructions.

Required:

• foam sheets;
• metal profile or wooden blocks 50x50;
• film for vapor barrier.

Stages:

1. Clean the ceiling from dirt and dust, eliminate unevenness, if any. Treat the surface with an antiseptic.
2. Remove electrical wiring. To do this, use a special protective corrugation.
3. Attach beams or a profile to the ceiling at a distance of 50 cm. Make sure that the shape of the attached beams takes on the appearance of a large cage, each cell of which should correspond in size to the foam sheet.
4. Install foam plastic using dowels or glue.
5. Treat joints and cracks with polyurethane foam.
6. Attach a vapor barrier layer to the insulation.
7. Finally, start installing drywall, wood or other material that matches the overall interior.

Principles of work

To insulate a bathhouse, you do not need to have any practical skills. It is enough to study the theory and perform the work as indicated in the instructions.

Thermal insulation of walls

Peculiarities:

1. Thermal insulation must be carried out at the construction stage, when the supports are erected.
2. Mineral wool slabs are located in the central part of the frame walls, covered on both sides with layers of vapor barrier.
3. At the last stage, the surfaces are sheathed with OSB boards and undergo decorative finishing.

The best option for thermal insulation of walls in a bathhouse is the use of two layers of insulation

It is important that one is in the form of slabs, the other - a roll.

Insulation of walls near the stove

Insulation features:

1. Surfaces around the oven must be protected from high temperatures.
2. You can lay a stainless steel sheet on the floor.
3. The oven should be located at a distance of 1 meter from the opposite surface.
4. The protective layer can be installed over decorative trim or over thermal insulation.

Asbestos boards can be used to protect surrounding surfaces, but many bath attendants believe that this material is harmful to the body. It is better to choose an analogue - basalt fabric. A reflective sheet of metal can be attached on top of it, which will screen thermal energy.

Thermal insulation of ceiling and floor

Floor insulation process:

1. Fill the soil with a screed.
2. Roll out a roll of roofing material on top, cut it across the entire area of ​​the screed.
3. Lay out thermal insulation plates.
4. Spread a layer of waterproofing on top.

All that remains is to pour the last layer of screed and wait for it to dry completely before performing the next work.

Ceiling insulation:

1. Use a construction stapler to secure the vapor barrier layer to the ceiling.
2. Lay insulation.
3. Secure the final layer of vapor barrier.

All that remains is to fill the decorative lining for the ceiling in the bathhouse.

Protecting insulation from moisture ingress

For protection you can use:

• foil;
• special film made of fabric.

The most important thing is that there is ventilation inside the wall. Without it, condensation will accumulate, which will lead to the destruction of thermal insulation and the formation of mold on the wood.

Other materials for bath insulation

In addition to foam plastic, other materials can be used to insulate a bath. For such work there are several insulation options:

• mineral wool;
• glass wool;
• expanded clay sheets;
• expanded clay concrete slabs.

They should not be seriously considered as an alternative, since each of them is much inferior to polystyrene foam. For example, although mineral wool provides good thermal insulation, it has a significant drawback - it can cause harm to health. This is explained by the presence of phenol-formaldehyde resins in the composition. The disadvantages also include good moisture absorption, as well as strong dusting when working with mineral wool. Due to the latter feature, when laying mineral wool, it is imperative to use personal protective equipment (respirator, goggles and gloves).

Glass wool has similar disadvantages; its only advantage is its affordable price. But even in cost it cannot compete with polystyrene foam, so it is not advisable to use it for insulating a bathhouse.

The use of expanded clay slabs for bath insulation is also associated with certain disadvantages, the main one being difficulty in installation. In particular, when installing them horizontally, it is necessary to use a special substrate. In addition, such material is characterized by high moisture absorption if there is no protective film on its surface. When wet, expanded clay slabs lose their effectiveness as insulation, and due to the long drying process, the material does not quickly restore its original properties.

The disadvantage of expanded clay concrete is that even the lightest varieties of this material have more weight compared to foam plastic. In addition, such sheets or blocks “eat up” space, since for high-quality insulation it is necessary to lay a thicker layer of this material.

Pros and cons of the material

Polystyrene foam is nothing more than foamed polymers that form gas capsules at high temperatures and retain their shape when cooled.

As a substance formed with the help of gas, polystyrene foam has a number of excellent insulation properties :

• ease;
• moisture resistance;
• durability;
• sound insulation;
• resistance to shrinkage.

In addition, in price lists, foam plastic consistently occupies a position among the cheapest building materials. Just what you need for economical and quick insulation.

However, don’t get too fascinated and think that polystyrene foam is perfect. Of course, it also has disadvantages, but whether or not to pay attention to the disadvantages of this insulation is your choice.

The disadvantages of polystyrene foam are::

• flammability (due to the nature of its formation - using gas);
• not too long service life, which may be further shortened due to violation of installation technology;
• unsuitability for insulation of wooden premises. In practice this is possible, but only if there is high-quality ventilation;
• fragility;
• release of toxic substances during combustion that can cause paralysis of the respiratory tract;
• poor quality of some brands of polystyrene foam produced in artisanal conditions.

Floor

When the thermal insulation of the top is ensured, you can take on the base of the room. After all, even if the walls and ceiling are quite warm, but the floors are cold, this devalues ​​all the work done. When using penoplex on joists you need:

• lay insulation between the elements on the subfloor;
• imitate a base (by laying cladding around the perimeter);
• create vents for ventilation (each minimum 0.05 sq. m);
• put a blind area on the perimeter to improve the discharge towards various drains and sediments.

Some believe that it is possible to impregnate wooden parts located on stilts with antiseptics. But the usual types of impregnations will evaporate already in the sixth or seventh year of use. Therefore, you should carefully choose the mixture and give preference to compounds that eat deeply into the wood. If the bathhouse is built on screw piles, even the most powerful floor insulation will not help ensure its normal operation. You will have to equip a fence and thereby prevent excessive ventilation of the underground.

Insulating a concrete floor with expanded clay is a real salvation for those who want to guarantee the environmental safety of the building. In addition, this material is relatively inexpensive and can be installed by anyone without expensive equipment. It is advisable to choose the lightest varieties: they are not only more convenient for transportation, but also more effectively block the escape of heat to the outside. There are three key working methods:

• wet;
• dry;
• mixed.

The insulation of bathhouse floors with penoplex has become quite widespread. The technology of work does not have any particular difficulties; moreover, it is quite accessible to any novice builder. At the bottom you will have to lay a substrate of sand and gravel or make a concrete floor. However, penoplex is ideal both on top of a rough wooden floor, and as one of the parts of the “pie” of a warm floor. But the material cannot be placed on damp soil; it must dry thoroughly.

The bath floor is always equipped with a water drain, and this circumstance cannot be ignored when working on thermal insulation. Square or rectangular point drains are small in size and can be placed anywhere

The slope for directing water into the drain is at least 1%; this is important not to miss when designing the floor pie. The optimal solution is compacted extruded polystyrene foam

Floor installation and selection of tools

The work of arranging the floor in a bathhouse requires the use of a variety of tools. Since in most cases they are made of wood (this is especially true for steam rooms), you need to use a regular carpentry kit. The floor can be made with water passing through cracks or into one separate drain. This drain is directed in one direction, otherwise the stability of the water flow cannot be guaranteed. If the floor is formed without ducts, there is a permanent flooring underneath it, which must be replaced only at the end of its working life.

To make the surface warmer, the gutter and the drain leading into it are placed in the lowest place. The design of removable floors implies the possibility of periodic disassembly when the bathhouse is not in use. When forming the screed, you will need a cement trowel and special rakes, trowels and spatulas of various sizes. The evenness of structures is ensured using a level (hydraulic or laser).

What materials to use

Water will become a problem when insulating the floor. Many materials are not designed for installation in conditions of high humidity. This applies to insulation with high absorption capacity.

For example, it is not allowed to use mineral wool to perform the work. This effective insulation is able to absorb water. When wet, cotton wool stops performing its intended tasks, wrinkles, settles and loses its shape.

For wet rooms, it is recommended to choose materials that are resistant to moisture. These include:

• Styrofoam;
• extruded polystyrene foam (or penoplex);
• penoizol, etc.

Optimal insulation for the floor in a bathhouse: which is better and for what reasons

Extreme conditions inside the bathhouse, constant temperature changes, and significant high humidity determine the selection of all materials for insulation with special care and accuracy. It is worth understanding that the raw materials usually used for this may not be suitable, since they simply will not withstand such operating conditions. The best insulation for the floor in a bathhouse should be resistant to both one factor and another, and in addition, experts recommend choosing a material with a pronounced cellular structure, which will help it last a long time, performing all the functions that it actually provides , and are expected.

Photo from the site: eleosstroy.ru

The most popular is insulating the floor in a bathhouse with expanded clay with your own hands, of course, provided that the floor is made of concrete or cement screed. This environmentally friendly, natural material is extremely lightweight and also has very enviable thermal insulation qualities and properties. Among other things, expanded clay has enviable fire-fighting properties, and it is also reliable and durable.

Photo from the site: ktovdome.ru

If you are seriously considering the best way to insulate the floor in a bathhouse, you should also pay attention to the various mineral insulation materials that are available on the market today in a wide range. Today, these are the most popular and relevant materials. Mineral wool is environmentally friendly, lightweight and it is possible to purchase foil rolls; it also does not burn at all, but it also has its drawbacks. When installing floor insulation using mineral insulation, great attention will be required to waterproofing, otherwise the entire effect will be reduced to zero.

Photo from the site: oaoplastic.ru

You can also insulate the bathhouse floor with polystyrene foam, that is, foam material that is sold in the form of slabs, weighs little, and does its job perfectly. Moreover, laying it is as easy as shelling pears, and you can even cut it with a penknife. However, it is worth knowing that when heated, this synthetic material can release aldehydes into the air, which can seriously affect human health. If you are not sure whether you can properly insulate it, then you should not use it. And the fire safety of insulating floors in a bathhouse with foam plastic and concrete can be safely questioned.

Photo from the site: donnaflora.ru

You can also qualitatively insulate a concrete floor in a bathhouse using perlite, a bulk material that also has a synthetic base, like polystyrene foam. You need to know that it is simply added to the cement-sand mortar during rough pouring. On top of such an insulating layer, a finishing coating will already be poured, which must be leveled over the surface, and only then the final finishing coating, such as boards, tiles, artificial or natural stone, etc.

Photo from the site: l-spb.ru

Among other things, it is possible to insulate the floor in a bathhouse with penoplex, which also belongs to the family of foam materials, such as styrofoam or polystyrene foam, which is essentially the same thing. This is a very high-quality material that is quite strong, durable, has high thermal insulation qualities, is resistant to moisture, and its installation is simple and accessible even to those who have never dealt with anything like this before.

As for the thickness of the thermal insulating layer, everything will depend on numerous particular conditions. For example, the climate zone plays a huge role, as well as the quality of the selected material. For example, expanded clay needs to be poured in a layer of 25-30 centimeters to ensure high-quality functionality, but mineral wool and 5-10 centimeters will be quite enough. To make calculations easier, you can use the following table.

Photo from the site: banya-expert.com

How to insulate a bathhouse ceiling from the outside

Inside the bathhouse, the ceiling is insulated in the same way as the walls, and a ventilated space is provided. From the outside of the attic, another technology is used. When the rough board ceiling is lined, it is covered with two layers of fiberglass. It is not advisable to use roofing material, since heating will cause an unpleasant smell of bitumen to appear inside the steam room.

Even rolled mineral wool can serve as thermal insulation, but in order to save money, natural materials are used for insulation. The space between the beams is filled with expanded clay. Kneading clay with the addition of fine straw, shavings, and sawdust is suitable.

When the clay pouring hardens and dries, slabs of polystyrene foam or expanded polystyrene are laid on top. The thermal insulation is covered with waterproofing, and a thin concrete screed is poured. You can even walk on this surface. If the attic of the bathhouse is allocated for a rest room, after insulation the final layer is laid on the finished floor.

We will equip a bathhouse from timber

Feature: a sauna made of timber necessarily shrinks - this happens due to the drying of the wood. The process can last about 3 years.

Therefore, when thermally insulating a building from the outside, it is necessary to pay attention to caulking the cracks.

We equip the floors. Insulation occurs according to the “pie” principle, as in the case of a brick bathhouse.

The only difference is in the overall thickness of such a “pie” and its individual layers:

• The layer of sand on which the insulating material is laid is about 25-35 cm;
• The solution layer is about 4-6 cm;
• Waterproofing material plus reinforcing mesh;
• Concrete screed – up to 7 cm.

Why insulate the floor

Thermal insulation layer is necessary to prevent heat loss from the room. The microclimate in the bathhouse is characterized by high humidity and temperature. In the absence of proper insulation, several problems arise in this case:

• The heat quickly escapes. It becomes difficult to light the sauna. At the same time, the consumption of firewood or other fuel increases significantly. Carrying out all the necessary measures during construction will save money.
• The material of supporting structures is exposed to simultaneous moisture from the inside and cold from the outside. This combination has an extremely negative effect on both concrete and wood. In this case, operating costs increase again, but due to repair costs.
• The bathhouse cools down quickly. Drafts may get inside. Cold air causes spoiled rest or illness.

Proper insulation of the floor in a bathhouse with your own hands allows you to prevent problems, ensure an optimal indoor microclimate and not spend money on the services of professionals.

Features of heat transfer of a frame bath

Frame buildings belong to inertia-free thermal systems, that is, to houses with low heat capacity.
What is the meaning of this parameter? It reflects the ability of building components to accumulate thermal energy. Accumulated by the walls and foundation, heat is released into the room, ensuring, on the one hand, slow cooling of the space when the heating is turned off, and on the other hand, slow heating to the required temperature. Frame sauna is economical and prefabricated

A house built on the principle of a frame filled with thermal insulation heats up quickly and cools down just as quickly. There are no strong (in the traditional sense) walls, and the insulation for a frame bathhouse does not transmit energy well, but it also accumulates it in itself poorly.

During operation of the heating system, the level of heat saving of such an object is very high and is usually close to the standard of a “passive house”. However, the need for constant heating brings serious inconvenience to permanent residence in buildings of this type. But no one lives in bathhouses! The heating rate of the steam room is much more important here. It is for such objects that low inertia is rather a positive factor than a negative one.

So is it worth it to insulate with polystyrene foam?

And yet, there is an opinion among experts that all the disadvantages of polystyrene foam are more far-fetched than real. The popularity of foam sheets among developers has no equal. And if we talk about insulation as a low-cost, simple and fast process, then it is hardly possible to find a better material.

Insulating the ceiling of a bathhouse with polystyrene foam can be done without any problems by a non-professional, a person who has taken up repair work for the first time.

However, when purchasing foam plastic boards, you need to be very careful not to bring a pile of small balls instead of whole sheets. Use products only from trusted manufacturers.

What materials to use

Water will become a problem when insulating the floor. Many materials are not designed for installation in conditions of high humidity. This applies to insulation with high absorption capacity.

For example, it is not allowed to use mineral wool to perform the work. This effective insulation is able to absorb water. When wet, cotton wool stops performing its intended tasks, wrinkles, settles and loses its shape.

For wet rooms, it is recommended to choose materials that are resistant to moisture. These include:

• Styrofoam;
• extruded polystyrene foam (or penoplex);
• penoizol, etc.

Penoplex

The material is a close relative of foam plastic, but without its disadvantages. It costs more, but is distinguished by high strength, quality and resistance to moisture. The thermal insulation properties of these materials are the same.

The choice between them is made depending on the installation method and the expected load. When installing heavy furniture and laying insulation under the screed, extruded polystyrene foam is preferred. It definitely won’t wear out under load (if you choose the right brand for strength).

Insulating the floor in a bathhouse with penoplex allows you to do without vapor barrier and waterproofing. They should be used whenever possible (especially in areas with the highest humidity), but this is not a necessary step.

Which parts of the bathhouse are advantageous to insulate with foam plastic?

Since polystyrene foam is not only a good heat insulator, but can additionally protect the surface from moisture, it is often used to insulate the foundation of a bathhouse.

How to insulate the foundation of a bathhouse?

Polystyrene foam is excellent for foundation insulation. But we must not forget that the insulation crumbles and is afraid of mechanical damage. To protect it from the outside, it is necessary to make a protective partition from boards or bricks. Foam plastic is optimal for insulating the foundation. It does not allow water to pass through and the foundation will be reliably protected.

Polystyrene foam has proven to work well as insulation for the foundation of a sauna on loamy and clay soil. Since moisture does not get inside the material, it will protect the base of the bathhouse from moisture and heaving in spring and winter. But you should not use insulation when the groundwater level is higher than usual and flooding cannot be avoided. Moisture getting under the foam cannot evaporate and the foundation will begin to collapse.

The thickness of the foam for insulating the foundation of a bathhouse is chosen according to your region, so for the middle part of Russia 50 mm is suitable. In the corners of the structure, thicker material of 100 mm is used, since heat loss in the corners is the highest.

Progress of foundation insulation work:

The foundation is first excavated and cleaned of dirt. Apply a primer made of bitumen mastic and a waterproofing agent, for example, liquid rubber, to the wall. The coating is left to dry for 1–2 hours.

The foam is attached directly to the foundation wall using bitumen mastic or a polymer-based adhesive. The slabs begin to be laid from below, and they must rest on a hard base. If the foundation is just being built, then a protrusion is specially left for the foam slabs. For the old foundation, gravel is added on which the slab will rest.

The joints and the part that is glued are completely lubricated with bitumen mastic. On sale you can find foam boards with an L-shaped lock. These are easier to glue together and the protection will be more airtight.

When the slabs are laid, they are once again covered with bitumen mastic and a protective partition is made. It's easier to install boards, but they will rot quickly, so use brick. A half-brick wall is made from it along the entire foundation. Among modern materials, geotextiles have performed well. It is simply rolled out along the foam and the protection is ready. But the price of geotextiles is high.

The entire structure is buried on the side with soil and a concrete blind area is made on top. Making such insulation is labor-intensive, but the bathhouse will be protected reliably.

We begin to understand from the very beginning: why and how to insulate the floor in a bathhouse with your own hands

Many people, even having built a Russian bathhouse on their own plot, do not even imagine what all this fuss with insulation is for, we look for the best option for materials, believing that this is not at all necessary. In fact, you can, of course, completely abandon the insulation of the concrete floor in the bathhouse, as well as the wooden one, and the insulation of the walls and ceiling, but the results of such construction will definitely not please you. Moreover, there are many objective reasons for this, of which we will name only the most “loud” ones, which can be considered compelling arguments in favor of floor insulation, and not only them.

It is for these reasons that it is worth immediately, even when creating the primary project, to take into account the thermal insulation of the entire building, and first of all, the floors, although insulation always begins from the top. Moreover, you need to understand that it is through the floor that most of the heat from the steam room flows away, spoiling the entire effect and significantly reducing the therapeutic value for health. But before you figure out how to insulate the floor in a bathhouse in a washroom, you need to understand what materials exist for this, and how to use them correctly, and only after that you can start working.

So is it worth it to insulate with polystyrene foam?

And yet, there is an opinion among experts that all the disadvantages of polystyrene foam are more far-fetched than real.

The popularity of foam sheets among developers has no equal. And if we talk about insulation as a low-cost, simple and fast process, then it is hardly possible to find a better material.

Insulating the ceiling of a bathhouse with polystyrene foam can be done without any problems by a non-professional, a person who has taken up repair work for the first time.

However, when purchasing foam plastic boards, you need to be very careful not to bring a pile of small balls instead of whole sheets. Use products only from trusted manufacturers.

Ceiling insulation in a house or apartment

Stages of ceiling insulation with foam plastic

Economical polystyrene foam will help you do the ceiling insulation of an apartment, wooden or brick house with your own hands at minimal cost. This will prevent heat loss and maintain a comfortable atmosphere in the room. The thickness of the foam sheets used for wooden bases is 40-50 mm, the thickness of panels for concrete and brick bases is up to 100 mm at 25 percent density.

Important! Before installing foam panels from inside the room, the base of the ceiling must be thoroughly cleaned of old paint, whitewash, dirt and dust. It should be leveled and primed

Insulation sheets are installed from the inside onto a special sheathing (wooden, aluminum, plastic), so the ceiling height will be slightly reduced. The profile, which is secured with dowels, gives the structure high rigidity and strength. The panels are adjusted to the dimensions of the sheathing cells and attached to the profile frame with screws or glue. The foam sheets must fit tightly together

It should be leveled and primed. Insulation sheets are installed from the inside onto a special sheathing (wooden, aluminum, plastic), so the ceiling height will be slightly reduced. The profile, which is secured with dowels, gives the structure high rigidity and strength. The panels are adjusted to the dimensions of the sheathing cells and attached to the profile frame with screws or glue. The foam sheets should fit snugly against each other.

The thermal insulation sheathing is covered with plaster and decorative paint. You can use decorative plaster. Drywall is widely used. Lamps are freely mounted on the ceiling. The master will install thermal insulating ceiling panels from the inside without damaging the interior.

Insulation of a strip foundation for a bathhouse with penoplex

It is necessary to start the process after thoroughly waterproofing the base using bitumen mastic. To securely fix the sheets we use acrylic glue.

We carry out the work in the following sequence:

1. We apply five to six dots of acrylic glue to the first slab and fix it from the bottom edge.

We secure the remaining elements around the perimeter, connecting them together with a tongue-and-groove system.

We blow out the joints using acrylic glue or polyurethane foam.

Install the second layer with the seams offset. In areas of future backfilling with soil, we use acrylic glue for fastening. It can be attached to the base with dowels 12 cm long and 1 cm in diameter.

We cover the depressions from the fasteners with acrylic glue and wait for complete drying.

We fix the reinforcing fiberglass mesh with an overlap of 10 cm.

We plaster with penoplex to protect against soil action.

Level the surface with cement-sand mortar.

If desired, you can use acrylic glue for leveling. After backfilling, it is also advisable to insulate the blind area.

Insulation under the screed

If the bathhouse is built of brick, most likely the ceilings are made of reinforced concrete. Also, sometimes there is a need to make a floor on the ground. In this case, insulation is performed under the screed. When using this technology, the load on the insulation increases, so you should follow the following recommendations:

• choose material grade PSB-S 35 (foam plastic) or EPPS 35 (penoplex);
• the thickness of the screed is prescribed 30-50 mm (when using the “warm floor” system - more);
• when using polystyrene foam, the screed is reinforced with wire mesh with a diameter of 3-4 mm and cells of 50 by 50 mm.

If it is necessary to insulate the floor on the ground, then the base is not only leveled, but also compacted. The floor pie in this case looks like this:

• compacted soil;
• sand-gravel mixture or medium-sized sand (20-30 cm);
• concrete preparation from lean concrete B7.5—B12.5;
• waterproofing;
• insulation;
• vapor barrier;
• screed with reinforcing mesh.

The concrete floor consists of the following layers:

• reinforced concrete slab;
• waterproofing;
• insulation;
• vapor barrier;
• screed (with or without reinforcement).

Insulation of a bathhouse begins with clearing and leveling the base. All cracks in the concrete floor must be covered with cement mortar. After this, special leveling mixtures can be used. A line is drawn on the wall to mark the finished floor. This is required in order to control evenness.

Waterproofing is placed on the prepared base. It is mounted with an overlap of 10 cm (including on walls), gluing the joints with a special film.

Polystyrene foam or polystyrene foam is laid on glue. The solution is applied only along the edges and to several points in the center

When purchasing glue, it is important to check that it does not contain solvents or other substances hazardous to the insulation. The slabs are mounted with bandaging of the seams (in a staggered manner)

A gap of 1-2 cm is provided between the polystyrene and the wall, taking into account the expansion of the material during operation; this space is filled with damper tape. Before pouring the screed, the slabs are secured to the base using disc dowels.

How to choose insulation

The bathhouse usually has: a dressing room, washing rooms, a steam room, a dressing room, and a relaxation room. These rooms have different levels of humidity and temperature during washing. Therefore, how you can insulate a bathhouse inside is determined for each room separately.

According to their mechanical characteristics, insulation materials are divided into bulk, block and tile, matte and fibrous materials.

Plastic-based heat insulators are best used for insulating rooms with low levels of moisture and temperatures. They are not used in the steam room due to their easy flammability and deformation when heated. Cheap and safe organic heat insulators can be used in a steam room only after fire prevention treatment.

Inorganic heat insulators are considered the most practical. These materials are fire resistant and non-hygroscopic. They do not rot and can serve for a long time without losing their basic technical properties.

Practical and organizational implications

The main room of the bathhouse is the steam room, and especially close attention must be paid to the insulation of this particular room due to the constantly high humidity and hot air. When moist air is heated in a steam room, most of the insulation materials produced by our industry emit toxic fumes to one degree or another. Therefore, the selection of not only high-quality, but also safe material is a paramount problem. We already know that mineral wool is the presence of formaldehyde, and polystyrene foam or expanded polystyrene is the evaporation of styrene, which in large quantities can be harmful to health. When buying insulation, you need to pay attention to this aspect, and any fastening technology can be used.

Article on the topic: How to build a mini sauna at your dacha with your own hands

Underfloor heating system

Another option for insulating the flooring in a bathhouse is installing a heated floor system. In this case, you can choose a design based on electric heating elements or water pipes.

The perfect solution

Such floors can not only make the floor warm, but also heat the entire room. Therefore, if they are used in a steam room, they can participate in creating the necessary environment. Their location in other rooms of the building will make it possible to move comfortably barefoot.

They are installed in the same way as other insulation materials under reinforced lattice and screed in a concrete floor and between joists under boards in a wooden floor. An important addition is the need to install heat-insulating material under the system to prevent heat loss into the ground.

Installation on joists

Insulation of the floor in a bathhouse on screw piles (or for a wooden structure on any foundation) is most often carried out between joists or beams. Unlike the previous method, here you can choose insulation with less strength, since the material does not take the load from furniture and people.

Expanded polystyrene is mounted between wooden floor joists or between floor beams. The floor pie for a wooden bath in this case looks like this:

• subfloor boards (or plywood, DSP, OSB);
• waterproofing;
• insulation between load-bearing wooden beams;
• vapor barrier;
• clean floor.

The insulation is simply laid between the beams. There is no need to use glue or dowels. But it is necessary to fill the gaps between polystyrene and wood with sealant or polyurethane foam.

Proper insulation of the bathhouse will ensure a comfortable microclimate and extend the service life of the building. An increase in construction costs in this case leads to savings in operation.

And a bathhouse is a room in which even one percent of the required temperature disappears noticeably, so insulating the ceiling here becomes a priority.

How to insulate a bathhouse from the outside

To insulate a bathhouse from the outside, two technologies are used: “wet facade” and “ventilated facade”. In the first case, the thermal insulation is slabs of polystyrene foam, expanded polystyrene or basalt wool. First, they are glued to the wall with foam, additionally secured with plastic dowels and umbrellas, and decorative plaster is applied on top. In the second case, a lathing is attached to the wall of the bathhouse. The cells are filled with mineral wool or basalt slabs, covered with windproof film, and a counter-lattish is filled onto which the facing material is attached. A gap remains between the film and the lining, forming a ventilated space.

Summarizing

A good bath is a warm bath. And in order for it to warm up well to the required temperature, it is necessary to choose the right thermal insulation and insulate all structural elements.

The bathhouse is also insulated from the inside:

• Windows, doors and all openings - with natural sealants;
• The outer door is made from good natural materials.

At FORUMHOUSE, the issues of insulating a steam room are discussed in detail, and the insulation of the ceiling of a steam room is discussed separately. Find out how to properly insulate a timber bathhouse from the outside. Read our article about insulating the floor in a bathhouse. Get acquainted with the guide to bathhouse constructions of our users and find the answer to any question about arranging a bathhouse. Watch our video on how to build a full-fledged bath complex.