Insulating the floor in a bathhouse with polystyrene foam

Most lovers and owners of steam rooms come to the conclusion that it is best to insulate the floor in the bathhouse with foam plastic. Although they tell a lot of stories and speculations about polystyrene foam, how harmful and fire hazardous it is, they still use it. In terms of resistance to moisture and heat-insulating qualities, it is very difficult to find a material better than foam for an insulated floor in a bathhouse.

Thermal insulation is laid in “paths”

The sequence of insulating a concrete floor from the inside of the room

Carrying out insulation inside has its own characteristics:

the dew point is located inside the mounted structure;
the room does not have frost protection;
with this method it is necessary to create waterproofing on the cold side;
reinforced cement screed is poured on top of the insulation;
the insulating layer significantly reduces the height of the bathhouse room.

There are materials that have high strength and make it possible not to reinforce the screed.

Carrying out installation

To install polystyrene foam insulation you will need:

knife for cutting insulation;
container with polyurethane foam;
glue;
foil-coated polyethylene is required for insulation pairs;
metal construction tape (for gluing polyethylene sheets).

How to properly insulate a concrete bathhouse floor?

Necessary tools for working with mineral wool:

tool for cutting material;
tape for gluing joints of film or membrane material;
polyethylene film for waterproofing;
thermal insulating membrane for vapor barrier.

The process of insulating the floor in a bathhouse is very responsible; it requires a competent approach in choosing the material, as well as in following the technological process. It is faster, easier, and more effective to insulate with polystyrene foam than with a mineral slab. The cost of the material will pay off in the process of comfortable and durable operation.

Each bathhouse room performs its own function. For example, waterproofing is most important where people wash directly. In other rooms, for example in a room, for rest or in a dressing room, it is not so important.

When carrying out work in an already built bathhouse, the ideal solution would be to create a layer of insulating material on top of the existing base. The insulation is inserted between the built-in joists.

https://youtube.com/watch?v=nH8EUT14t0Q

In the steam room, the floor should be higher for the fastest heating of the air; the smaller the steam room, the faster it heats up. Before carrying out work, the required materials are calculated. Insulation of the bath should be carried out under favorable weather conditions. Under such circumstances, work will be challenging and satisfying.

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.

Floor insulation technology using joists

To properly insulate wooden floors in a bathhouse, some experts recommend using logs set in increments of 55 to 95 cm. This is the simplest and most affordable way to install flooded floors with a layer of insulation.

The work is performed in the following order:

Dismantling the old flooring, cleaning the surface from debris and dirt, eliminating unevenness and deformations.
Installation of logs from the underside of the base along its entire length.
Fixing the logs at the optimal distance from each other. To protect against rotting and destruction, they are treated with wood antiseptics.
Between the logs, boards or sheets of plywood are installed, on which thermal insulation material is laid. For insulation, mineral or basalt wool, as well as foam sheets, are used. The joints are carefully treated with sealant. When using cotton wool, a waterproofing layer of polyethylene film is additionally laid.
Finally, the finishing floor covering is installed.

Features of the material

Penoplex is a foamed polymer made by extrusion from general purpose polystyrene. Modern equipment makes it possible to produce material with an ordered structure in which small gas bubbles are evenly distributed. Such isolated and completely closed microscopic cavities have a size of about 0.1-0.2 mm. The reagent for foaming is light types of freon with the introduction of carbon dioxide.

Penoplex is a foamed polymer made by extrusion from general purpose polystyrene

By its nature, penoplex is chemically inert, which eliminates its oxidation or rotting. The main goal of developing this material is to provide high thermal insulation capabilities with low water absorption and very high compressive strength. An important characteristic is good manufacturability, i.e. It cuts and bends easily, allowing it to be used in hard-to-reach places.

As is known, the thermal insulation characteristics of any foamed or porous material are sharply reduced under the influence of moisture, which is absolutely not typical for penoplex. A slight water absorption by the material is observed only in the first 7-8 days, when moisture fills the cells located near the surface. Subsequently, the penetration of water stops, and the initial saturation has little effect on the thermal insulation capabilities of the product. Moreover, it should be noted that it is impenetrable to steam, which is very important for bath conditions.

The main form of the slab: width 60 cm and thickness from 2 to 15 cm

The material is divided into 3 groups:

Its types differ in specific density, mechanical strength and heat resistance. Insulation of the floor in a bathhouse with penoplex is carried out by the first 2 types of material.

On a note! Penoplex 45 has increased mechanical strength and is intended for floors where significant load and vibration are possible.

The main form of production of the slab: width 60 cm and thickness from 2 to 15 cm. Sheets with a thickness of 10-12 cm are very popular. The standard length of the slabs is 120 and 240 cm; in special cases, material 4 or 4.5 m long can be used.

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.

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

Insulation using perlite

Perlite solution is convenient to use for insulating concrete floors. In this case, a layer of heat-insulating material is placed in the space between the rough floor screed and the final leveling fill.

Table. Floor insulation with perlite

Work stage Description

Preparation of the solution

Note! The unit of measurement in this example is a bucket. Based on the given proportions, you can prepare the required amount of solution, measuring the original ingredients in fractions, kilograms, bags, etc. Pour 2 buckets of perlite into any deep container of a suitable size, add a bucket of water to it and give the mixture time to completely shrink. Add half a bucket of cement no lower than M300 to the resulting solution, and then half a bucket of water

Important! Stir the mixture thoroughly after adding each component. Finally, you need to add a little more water (about half a liter) to the solution

The result will be a dry, crumbly mixture. Knead the semi-finished product until it becomes plastic.

Laying thermal insulation mortar

The resulting plastic solution is evenly distributed over the rough screed. The recommended thickness of the insulating layer is up to 100 mm. You can level it in any suitable way, for example, using a long rule. If you are insulating a large area, for convenience, using self-tapping screws/anchors, you can attach several guides to the floor, for example, from a profile for drywall or a wooden beam with a step corresponding to the length of the rule you are using.

Pouring the finishing leveling layer

5-7 days after applying the perlite solution (this is exactly how long it needs to harden), a finishing leveling screed is poured over the insulation. The most convenient and easy-to-use option is a modern ready-made self-leveling floor mixture. Reinforced mortars are available for sale, allowing you to create coatings with a layer of up to 8 cm or more. The developer can only prepare the mixture and apply it to the base in accordance with the manufacturer’s instructions. Helpful advice! Before pouring the final leveling layer, the surface can be covered with waterproofing material and a reinforcing mesh can be laid, but, as practice shows, the structure feels great even without such inclusions. After the leveling layer has dried, you can finish the insulated floor, for example, tiling it with suitable tiles.

Floor insulation with expanded clay

The procedure for filling the thermal insulation layer will vary depending on the design of the floor of the bathhouse being equipped. There are few options:

the floor is laid over logs installed on compacted soil;
the flooring is made on top of logs placed on brick supports;
the structure is represented by a concrete screed or reinforced concrete floor slab.

Choose your option, read the instructions specifically for it and get to work. The information is given in the table.

Table. Floor insulation with expanded clay

Floor construction type	Insulation procedure
Floor on joists on the ground	It is assumed that the joists have already been installed and all that remains is to lay layers of insulation to create the final flooring. If you are insulating an already used wooden floor, you must first remove the flooring (damaged boards are replaced with new ones), replace rotten joists and thoroughly compact the soil. The subsequent steps are similar for both cases: - waterproofing is laid on top of the compacted soil. You can put either plastic film, roofing felt or glassine. Waterproofing is placed both in the space between the joists and on top of them. Lay the sheets with an overlap of 10-15 cm. Tape the joints with construction tape. You can attach the insulation to the joists using a construction stapler with staples or small nails; — a uniform layer of expanded clay is poured over the waterproofing. Further actions depend on whether expanded clay will be used as the only insulation, or whether a second thermal insulation layer, for example, mineral wool, is planned to be laid on top of it. If thermal insulation is performed exclusively with expanded clay, the order is as follows: - the selected vapor barrier material (preferably foil) is laid on top of a leveled layer of expanded clay with a thickness of 30 cm or more. The overlaps and fasteners are the same as when laying the material for waterproofing; — finishing of the floor is carried out at the discretion of the developer. If expanded clay is used together with other insulating material, the procedure is as follows: - a vapor barrier material is placed on top of a layer of expanded clay 10-15 cm thick (the specific value is selected taking into account the planned thickness of the upper thermal insulation layer). The recommendations are similar to the previous case; — expanded polystyrene or mineral wool is laid on the vapor barrier. The functions of the frame for placing the slabs will be performed by the logs - select the width of the thermal insulation elements according to the size of the spaces between the logs (or simply fill the frame with the required parameters from timber). If the height of the logs is not enough, nail a beam on top of them at the height of the top insulation; — the thermal insulation is covered with a layer of hydro-vapor barrier. The further procedure of work remains at the discretion of the owner. So, for example, if a concrete screed is to be poured, a reinforcing mesh is first laid on the insulation. If the floor is wooden, bars are nailed to the joists for laying the boards.
Floor on joists on brick supports	In this case, the procedure will differ little from the option discussed above. Minor differences are present only at the initial stages of insulation: - expanded clay is poured to the level of the logs laid on top of the brick supports; - cranial bars are nailed to the joists (the most commonly used option is 4x5 cm in size); - a rough flooring made of boards or wood boards is installed on top of the bars. Further actions are carried out similarly to the previous instructions.
Floor on concrete slab	The sequence of activities will differ little from the instructions you have already reviewed: - the base is covered with a water vapor barrier; — expanded clay is poured; — the backfill is covered with another layer of water vapor barrier. The further procedure is determined by the developer and depends on whether a concrete floor will be poured or a wooden structure will be installed.

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.

Is it possible to insulate a bathhouse with foam plastic floors?

Since polystyrene foam does not absorb moisture, it is often used to insulate floors in saunas. If you close the material in a screed, there will be no mechanical effects on it, and the floor will be warm.

Insulation under concrete screed

Part of the soil is removed and a sand cushion of 10–15 cm is filled in. It is leveled and compacted. Then gravel is poured, which must be hammered into the sand. Next, cover with PVC film or roofing felt, they will serve as a waterproofing material.

It is not difficult to insulate floors in a bathhouse under a screed with polystyrene foam, but the result is a structure with high heat-insulating properties.

Next, foam boards are laid, which are coated with bitumen mastic. A PVC film is again laid on top of the foam and a reinforced mesh is laid. The base for the concrete screed has been assembled.

How to insulate sauna floors using joists

We do not recommend insulating floors along joists, on top of the subfloor, in a steam room, but in other rooms (dressing room or rest room) a similar option is appropriate. For insulation, you can even use the material in crumbs, because it will be laid between the finishing and rough boards and there will be no load on it.

Even a beginner can lay foam boards along the joists.

The rough joists are covered with waterproofing, possibly with PVC film, and polystyrene foam is laid on top. Place it between the joists. A finishing floor is installed on top.

Ceiling insulation with foam plastic

Often the ceiling of a bathhouse is insulated with foam plastic. But to use insulation, you must follow a number of rules:

Place polystyrene foam on the second layer between the ceiling joists. The first layer can be expanded clay or a mixture of clay and sawdust. The vapor barrier must be of very high quality, otherwise wet steam will get under the foam and remain there. But if you do everything correctly and efficiently, heating the bathhouse will be easier, since the warming up time will be reduced by 2 times. You can see more details on how to perform the work in the video:

Polystyrene foam is a good insulation material. But like any material, it has pros and cons. Knowing the disadvantages, you can prevent them with some design features of the thermal cake. We answered the question: Is it possible to insulate a bathhouse with foam plastic? Then the reader decides for himself. And the video and photos in this article will help you make the right choice.

Source

Features of floor insulation in a bathhouse with penoplex

We carry out the work in the following order:

We cover the foundation pad with bitumen mastic in two layers.
We lay roll waterproofing with an overlap of 10 cm. Glassine or hydroglass insulation are excellent for this purpose.
We lay foam sheets. We check the evenness of the installation using a hydraulic level.
We make a reinforced concrete screed with a thickness of 6 cm.
We install the facing covering.
The best option for finishing the floor in a bathhouse is wood or ceramic tiles.

We carry out thermal insulation following the following algorithm of actions:

We cover the logs and the space between them with a vapor barrier membrane. You can use aluminum foil, kraft paper or plastic wrap for this.
We lay penoplex sheets with a thickness of 10 cm, pre-treated with fire retardants, between the logs.
We fix the second layer of vapor and waterproofing
We will equip the finishing flooring.

Features of penoplex

Do-it-yourself insulation of the floor in a bathhouse with penoplex depends on its design and material. There are several options for ensuring it: insulation of the foundation, log base and floor.

The process of insulating a strip bath foundation involves applying waterproofing using bitumen mastic. Penoplex sheets are attached using an acrylic-type adhesive.

The work is carried out in the following order:

Advice! When insulating the lower part of the floor in a bathhouse, it is recommended to take separate care of the thermal insulation of the basement part of the wall, which is in more difficult conditions.

The insulation of the base is carried out in the following order:

Specifics of thermal insulation of bathhouse walls with penoplex

The procedure for thermal insulation of walls in a bathhouse with penoplex looks like this:

Cover the surface with two layers of primer.
After complete drying, we fix the vapor barrier layer.
We apply an adhesive composition 7-8 cm thick to the foam sheet. It should cover about 40% of the surface.
We attach the part to the wall and additionally fix it with “fungi”.
Having completely covered the surface of the walls, we proceed to install the second layer, moving the elements to cover the seams.
After the adhesive has completely dried, we fill the gaps with foam.
We reinforce the surface with fiberglass mesh, attaching it with glue, and let it dry.
We plaster the walls and carry out further finishing of the walls.

Please note that glue for attaching the material can only be used based on cement, polyurethane or bitumen.

Technology

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

Frame installation

Required

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

Stages

Clean the ceiling from dirt and dust, eliminate unevenness, if any. Treat the surface with an antiseptic.
Remove electrical wiring. To do this, use a special protective corrugation.
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.
Install foam plastic using dowels or glue.
Treat joints and cracks with polyurethane foam.
Attach a vapor barrier layer to the insulation.
Finally, start installing drywall, wood or other material that matches the overall interior.

Adhesive mounting option

Required

sheets of foam plastic in an amount corresponding to the total area of the ceiling;
adhesive composition.

Stages

Clean the ceiling, treat it with an antiseptic and prime it for a better bond between the glue and the surface.
Prepare an adhesive composition or use a ready-made one.
Apply glue to the foam sheet (in continuous lines along the edge and in splashes in the center of the board). Press the foam sheet as firmly as possible against the ceiling and hold for a few seconds.
If you are insulating the ceiling using polystyrene foam, then all the sheets should be prepared in advance: scratch with an iron brush along the working side (the one on which you will apply the adhesive).
Start gluing the sheets from the middle of the ceiling in a checkerboard pattern.
For greater reliability, the foam sheets can be additionally attached with dowels after the glue has dried.
Glue the reinforced mesh on top of the foam and putty.

Tips and tricks

The insulation of a bathhouse follows the same principles as the thermal insulation of a house. But elevated temperatures and significant humidity make it possible to use not all coatings suitable for ordinary rooms. So, among mineral wool it is definitely not harmful to use only the latest modifications, which are connected using biologically neutral acrylic. Peat blocks filled with sawdust or straw do not allow bacteria to grow, but they do absorb water. It is advisable to consider the option of cork mats - they are mechanically strong and do not become saturated with liquid, and they stop heat quite well.

If the bathhouse is insulated with natural materials, then it would be correct to treat them with special compounds that block the effects of insects, rodents and microorganisms. It is advisable to caulk log houses and timber with jute (flax). When a bathhouse with brick walls is insulated, roll and slab products are most often placed in a steel frame with a zinc profile. The layer of mineral insulation on logs and beams can be limited to 80 mm (if there is no danger of severe frosts). In order for the insulator to retain its characteristics, it is taken 2-3 mm thinner than the cross-section of the bars.

To learn how and with what to insulate a bathhouse, see the following video.

Types of floors

Kinds:

Wooden. They can be continuous or leaky. In the first option, the floor is a solid flooring made of boards with a point for draining water. In the second, the supporting frame is knocked together from bars, boards are placed on their surface, with a gap of 1–2 cm between them. Water flows through them into the soil.
Concrete. Monolithic bases, similar to a multi-layer “pie”.

Types of concrete floors:

Polished. Suitable for large industrial enterprises, lobbies in shopping centers. Polished concrete surfaces look attractive and can withstand high operating loads. The technology for manufacturing such coatings is called “Superfloor”. When used, the result is a high-quality floor that retains its attractive appearance for a long time, regardless of the load. Machines with diamond abrasive discs are used for grinding.
Liquid. Such coatings are suitable for rooms with low operational load. The floors are seamless and smooth. The solution is poured into the center of the room and spread over the entire area. Then it levels itself, filling the voids.
Multilayer. They consist of several layers, each of which performs specific functions. The number of layers depends on the required technical characteristics.

Multilayer floors are suitable for residential buildings and industrial premises. To protect surfaces from cracks, scratches, and chips, special coatings are applied to them.

Leaking wooden floor (Photo: Instagram / arbenin.ea)

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.

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.

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.

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.

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.

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.

Polystyrene foam as insulation: pros and cons

Foam plastic is loved by users not only for its good thermal insulation properties. It has a number of advantages:

long service life (under good conditions up to 50 years, with temperature changes of 20);
high hydrophobicity (does not absorb more than 0.2% moisture per day, one might say, a good waterproofing agent);
does not emit toxic fumes and is not destroyed at temperatures of -60 – +95°C.
safe, as it is approved in the food industry for packaging some food products and for making toys for children;
price, but you should be wary if they offer to purchase a very cheap option;
does not create an environment within itself for the development of various microorganisms, does not rot;
easy to install, as it is light in weight and easy to cut.

But despite all the good looks, polystyrene foam has a number of disadvantages that manufacturers are constantly struggling with:

highly flammable;
when ignited, releases toxic fumes;
crumbles;
mice love to live in the material;
does not allow air or steam to pass through.

Indeed, when burned, the material emits fumes that are harmful to humans. But manufacturers claim that modern material is made with the addition of a special fire-resistant substance, which helps it become self-extinguishing. It can ignite spontaneously only at a temperature of +420 °C; for example, spontaneous combustion of wood begins at a temperature of +270 °C.

Insulating a bathhouse with foam plastic is not as scary as it seems at first glance.

Harmful substances are released by the material when it melts, and not when heated in a bath. It is difficult to answer whether the manufacturers are telling the truth, and how to distinguish modern material from old batches. But practice has shown that insulation can be used for some parts of the bathhouse.

Floor insulation technology using joists

The work is performed in the following order:

Dismantling the old flooring, cleaning the surface from debris and dirt, eliminating unevenness and deformations.
Installation of logs from the underside of the base along its entire length.
Fixing the logs at the optimal distance from each other. To protect against rotting and destruction, they are treated with wood antiseptics.
Between the logs, boards or sheets of plywood are installed, on which thermal insulation material is laid. For insulation, mineral or basalt wool, as well as foam sheets, are used. The joints are carefully treated with sealant. When using cotton wool, a waterproofing layer of polyethylene film is additionally laid.
Finally, the finishing floor covering is installed.

Insulation of a frame bath from the inside

To insulate a frame bath, rolled mineral insulation is most often used.

To insulate the walls of a frame bath from the inside:

Insulation is placed in the interbeam space of the structure;
The next layer is vapor barrier (foil);
Ventilation gap;
Sheathing.

Article on the topic: What does it mean to ban on VK

The photographs below show how KochevniK insulated his frame bathhouse. Insulation – basalt wool.

Insulating a bathhouse from the inside with your own hands: step-by-step instructions.

Foil acts as a vapor barrier, so it is important that there are no even the slightest holes or damage in it, and that all joints are well taped with high-quality tape. The tape is always sold together with foil, and its quality must be checked in the store (glue the tape to the foil and try to tear it off).

The nuances of using penoplex and similar materials

Penoplex and similar materials are used primarily for thermal insulation of concrete floors.

Instructions for insulating a concrete floor

The procedure for independently carrying out measures related to ensuring high-quality thermal insulation of concrete bath floors is given in the following table.

Table. Floor insulation with penoplex

Work stage Description

Preparing the base

Clean the base from all kinds of dirt and dust - the presence of such can impair the adhesion of the insulation to the floor. Coat the clean base with an adhesive primer designed for treating such surfaces. Thanks to such a coating, the quality of adhesion of the glue to the base will be improved and minor floor defects will be additionally repaired. For recommendations regarding the thickness of the primer layer, please refer to the instructions for the specific product. To apply such mixtures, it is convenient to use a roller with a long handle.

Preparation of the binder composition

To attach the insulation to the base, it is recommended to use glue specially designed for such work. For recommendations regarding the preparation of glue and the required thickness of its layer, please check the instructions for your particular product - these provisions may vary depending on the type of mixture. Sometimes polyurethane foam is used to fix the “foamed” insulation in question. This option is also successful, but in practice it is often more expensive.

Applying glue

The finished adhesive is applied in a uniform layer of the recommended thickness onto the foam board. A comb spatula is usually used for application. The glue is also applied to the floor. The slab is laid on the floor and pressed firmly.

Ensuring a tight fit of the slab using fungi

Using Anchor Bolts

To ensure the highest quality adhesion of the insulation to the floor, in addition to glue, fastening mushrooms are used in combination with anchor bolts for concrete.

Use of bricks

Fixing thermal insulation boards using mushrooms and self-tapping screws is a simple and proven method

But it is important to remember that each hole in the slab is a new cold bridge, reducing the quality of thermal insulation. If possible, avoid using fungi and press down the insulation boards using another method, for example, with bricks.

After laying the penoplex over the entire planned surface, all you have to do is wait until the glue dries - also check this point in the instructions for your product.

The nuances of floor insulation on the ground using penoplex

If penoplex is chosen as insulation for the floor on the ground, the procedure will differ from that discussed earlier. To eliminate the risk of uneven shrinkage of the structure in the future, the ground level should be located half a meter below the future floor (the difference can be increased to 60 cm).

Insulation scheme

The description of the circuit is as follows:

the bottom layer is compacted, carefully leveled and dry soil;
a layer of dry crushed stone or gravel about 300-400 mm thick. After backfilling, the material is carefully compacted;
a layer of sand about 10 cm thick. It is also carefully compacted. The backfill is leveled;
foam boards of selected thickness. In the case of this type of insulation specifically, it is better to use slabs equipped with joining grooves along the edges. Additionally, the joints of the heat-insulating boards are glued with construction tape or blown with foam;
3 – waterproofing film.

Positions 1 and 2 in this example are assigned to the concrete screed and reinforcing mesh, respectively. Assemble a mesh with cells 15x15 cm from steel rods with a diameter of 1 cm. Fasten the rods with knitting wire or special clamps for reinforcement.

In the photo - reinforcing mesh on top of penoplex and beacons for screed

Using appropriate clamps, ensure a 5mm gap between the base and the reinforcing mesh. Without it, the rods will quickly rust. A concrete screed is poured on top of the reinforcement (standard – a share of cement, 3 shares of clean sand, about 5 shares of crushed stone and water in the amount of half the mass of cement) of the designed thickness (most often this figure is 30-40 mm). For greater convenience, you can pre-install beacons on the base, for example, from a profile for drywall.

Pouring screed over penoplex, additionally laying a heated floor system

The photo shows the laying of penoplex on a sand and crushed stone cushion, as well as the pouring of cement mortar

Good luck!

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 installed with the seams bandaged (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.

The need to insulate the floor of a bathhouse

Insulation of the floor in the dressing room using extruded polystyrene foam

When heated, warm air rises, partially mixing with cold air masses penetrating through cracks and voids in the floor structure. Insulating the floor avoids heat loss and reduces the penetration of cold air.

In addition, floor insulation allows you to solve problems such as:

high fuel consumption;
slow heating of the room;
high humidity in the steam room;
formation of mold and rot.

A sharp difference in temperature on the floor surface in different rooms of the bath can have a detrimental effect on human health. Especially if a person leaves the steam room many times during bathing procedures and goes to the rest room or washroom.

Use of material for bath insulation

How to insulate the floor in a bathhouse with penoplex?

There is a limitation under which the material can be reliably used - these are temperature parameters - 50 ... + 75 ⁰С. It is this characteristic that complicates its use in bath conditions. Already at temperatures above 70⁰C in heated air, the release of harmful compounds dangerous to humans can begin.

At temperatures above 70⁰С in heated air, the release of harmful compounds dangerous to humans may begin

In the sauna, the temperature rises +90...+95 ⁰С, and with such heating, using penoplex for interior decoration is dangerous to health. In a Russian bath, the temperature of the steam room can be +60…+65⁰С, which also raises doubts about the possibility of using the material, especially for insulating the ceiling, where superheated steam rushes. Another thing is the floor in the steam room. Taking into account the laws of physics, there is no need to worry about maximum temperatures at the floor level, but in reality they do not exceed +45...+50⁰С below. Here, cooling the floor from the ground side plays a significant role. You should also take into account the fact that the floor in the bathhouse is not covered with penoplex on top. The material is used as thermal insulation, on which a finishing coating is then applied. All this indicates the possibility of using penoplex in the steam room of a Russian bath. In any other bath premises (washing room, dressing room, rest room) the use of the material does not raise any doubts.

The material is used as thermal insulation, on which a finishing coating is then applied.

Shower floors in the steam room

Let's start with the fact that the floor in the steam room is made only of wood. The tile, firstly, has a high heat capacity. By the time it warms up, it will be time to go home. Secondly, it can get so hot that even felt boots won’t save you. So, the floor in the steam room is wooden, but it can be torrential or not. Torrential is when the finished flooring of boards is deliberately made to be cracked. The board is laid with a gap of 5 mm or so. And under the flooring there is a rough floor, with a slope towards the drain, and the drain through the ladder leads into a drain hole or sewer.

In the washroom/shower room and in the steam room, you can make a leaky/spillable floor

With such a floor arrangement, you can pour water into the steam room. Even in bathhouses that are not heated in winter, until everything cools down it will dry out. True, if there is ventilation and it works well. To be more confident, you can not nail down the flooring, but make wooden ladders, which after the bath can be taken outside or into a more ventilated room to dry.

Insulation: how to lay materials

But what about insulating the floor in a bathhouse with such a device? And the floor under the bottom layer needs to be insulated. If as in the picture (the floor is along the joists), then nail the cranial bars. They can be a support for stacked polystyrene foam or foam glass blocks. The distance between the insulation and the timber is filled with foam.

For loose types of insulation, pieces of sheet moisture-resistant material (OSB or moisture-resistant plywood) are laid on the skull blocks. Expanded clay, granulated foam glass or its cuttings are poured into the resulting “troughs”.

The leaking floor in the bathhouse consists of two “layers”. The first one from the bottom is waterproof with a built-in drain/drain for water. The second is wooden slotted flooring

To lay mineral wool slabs between joists you can:

pull a cord or wire or strong synthetic twine “snake”;
line it with a net (albeit a plastic one);
stuff thin slats.

Mineral wool slabs are laid at random. Their width should be slightly larger than the width of the trough - by 2-3 cm. Then the material holds well, and cracks do not form during “shrinkage”.

Protection of insulation from soil moisture

When using mineral wool, expanded clay or foam glass granules, the insulation must be protected from moisture in the soil. It is always there and there is always evaporation. At the same time, no matter how hard you try, some of the moist air will get from the premises into the insulation. And this moisture must be removed. Where? Usually in the underground, in which ventilation holes (vents) are made. That is, if the floor was insulated with mineral wool, expanded clay, broken or granulated foam glass, we nail a membrane from below on the subfloor side.

To maintain the normal condition of the insulation, membranes are needed

The membrane must have one-sided vapor conductivity. It should release steam from the insulation, but not let it in. There are such membranes. They are nailed using clamping strips. The holes that are formed in this case are additionally sealed. Only in combination with protection from moisture, the insulation of the floor in the bathhouse will be durable. Otherwise, you will get problems in a year.

When using slabs made of foam glass or expanded polystyrene, additional protection from moisture is not needed. Both materials do not absorb moisture and practically do not conduct steam.

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

Photo from the site: samstroil.ru
Many people, even having built a Russian bathhouse on their own plot, do not even imagine why all this fuss with insulation, 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 will be much more difficult to warm up the steam room, and the entire room, if the floor is not insulated, since the concrete base takes a long time to heat up, but at the same time quickly loses heat.
In view of the first factor, the second also arises, that is, a huge rate of heat loss can lead to the fact that your bathhouse can only be used in the summer, when the heat outside the windows is thirty-five degrees.
The “viability” and durability of the entire structure will depend on how well thought out the design is, how to properly insulate the floor in the bathhouse, and the correct choice of materials.

An uninsulated floor in a bathhouse will make your costs to warm it up simply cosmic. This can seriously hit the owner's pocket. Among other things, incorrectly planned thermal, hydro and vapor barrier of the floor can lead to premature destruction of the entire structure.

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.

Required materials and tools

To insulate a concrete floor in a bathhouse you will need:

waterproofing material: polyethylene film, hydroglass insulation, armobitel and others;
insulation: polystyrene foam, penoplex;
reinforcing mesh with a wire thickness of 5 mm and a cell of 10 by 10 cm;
beacons for arranging cement screed;
dry construction mixture including additives that improve the quality of cement and screed;
building level, usually a trowel;
screwdriver;
drill with mixer and container for mixing the solution.

To insulate a wooden floor you need:

lumber (boards for rough and finished floors);
waterproofing film;
insulation: polystyrene foam, expanded clay and others;
tape measure, saw, plane, screwdriver and self-tapping screws.

A cold floor in a bath not only causes discomfort, but also causes large heat losses and temperature changes in the room, which can negatively affect human health. Properly performed insulation eliminates these shortcomings and also increases the service life of the structure as a whole.

How to insulate the floor in a bathhouse on stilts with your own hands, watch the video:

Is it possible to insulate a bathhouse with foam plastic and how?

You can use insulation to insulate some parts of the bathhouse. But you should refrain from insulating the steam room with it, since the temperature in it can rise to 95 ° C, and in the sauna even higher. And foam plastic can begin to collapse at temperatures above +95 °C, so even 90 °C will be critical for it.

It is not recommended to use polystyrene foam to insulate wooden baths from the inside; the fact is that the walls will be insulated from heat and the dew point will shift between the insulation and the wall. This will lead to premature rotting. Therefore, insulation is carried out only on the outside or along internal partitions.

According to user reviews, the bathhouse, insulated from the outside with polystyrene foam, has become more comfortable, the temperature in it quickly rises and in winter does not drop below +10. The only thing you should not forget about is the vapor permeability of the foam. To prevent the walls from getting wet, it is necessary to install a ventilation system in the bathhouse.

We recommend insulating baths made of stone, brick or blocks with foam plastic. Wood itself is a good heat insulator. Moreover, a wooden bathhouse is capable of accumulating heat, that is, accumulating and retaining it for a long time.

Insulation methods

Insulation methods:

Installation of the "Warm floor" system. An innovative way to heat surfaces. Pipes through which hot water circulates are installed in the screed, or mats with heating elements that produce infrared radiation are laid out. The main advantage is temperature control. Among the disadvantages is the need to connect a third-party energy source (water or electricity).
Laying an insulating layer under a concrete screed. It is carried out at the initial stages of building construction. If the building is already ready and has been in use for several years, you will need to first remove the old screed. For insulation under the screed, materials with increased strength, durability, and wear resistance are used.
Raised floor. Suitable for rooms on the second floor. If you want to insulate the floor on the first floor in this way, the house must have a basement or ground floor. Logs are fixed under the concrete floor, between which insulation blocks are installed or loose insulation is poured into a pre-prepared frame. The raised floor can be located on both sides of the ceiling. When located outside, the height of the room will decrease.
Complementing concrete with special fillers. This option is suitable for arranging a new screed or building a building. The usual crushed stone is replaced with perlite or expanded clay. The ready-made solution is suitable for creating a new screed or pouring over the soil.

Warm floor system