Technology for insulating the floor in a bath

It is essential to insulate the bathroom floor in order to preserve comfort and energy economy. A bathhouse’s floor will always be warmer and your bathing experience will be enhanced by proper insulation, which also helps prevent heat loss in an area where humidity and heat fluctuate greatly.

The selection of insulation material is one of the most important factors to take into account when insulating a bathhouse floor. Materials such as mineral wool, foam boards made of extruded polystyrene (XPS) or expanded polystyrene (EPS) are typically used. These materials were selected because of their ability to withstand heat and moisture, two qualities that are critical in a moist setting such as a bathhouse.

The insulation is laid directly onto the subfloor during the installation process. To avoid any moisture problems later, it’s crucial to make sure the floor surface is clean and dry before installing the insulation. After installation, the insulation creates a barrier that lessens heat transfer through the floor, maintaining a warmer interior during use.

The effectiveness of the insulation can be further increased by adding a vapor barrier on top of it for best results, particularly in colder climates. By keeping moisture out of the insulation, this barrier helps to preserve its thermal qualities over time and lowers the possibility of mold or mildew growing there.

Material	Foam board insulation, mineral wool, or expanded clay pellets
Steps	1. Clear the floor surface and ensure it"s dry. 2. Lay a vapor barrier to prevent moisture buildup. 3. Cut and fit insulation boards or fill with mineral wool. 4. Cover with a plywood or OSB subfloor for stability. 5. Seal joints and edges to enhance insulation efficiency. 6. Finish with desired flooring material.

Is it necessary to insulate the floor in a bath

Advocates of bath floor insulation provide just two justifications for doing thermal insulation work:

• it is unpleasant to walk on a cold floor on the way to the shelf and back, which cannot be disagreed with;
• the cold from under the floor negatively affects the microclimate of the steam room. Firstly, it quickly cools it down, and secondly, after several cups of boiling water on the stones, the steam becomes damp (fog hangs near the ceiling), heavy, in which steaming is not the best pleasure.

Now let’s get right to it.

1. There are two approaches to address the issue of cold floors for feet:

• pour boiling water on the path to the shelf – this is what they did and still do in private bathhouses in rural areas. Doesn"t require much water. After all, we are not talking about the entire area of ​​the steam room, but only about the route. Even in the most severe frosts, 2-3 half-full basins of boiling water are enough to warm up the pouring floor in a village bathhouse (they have long forgotten about bathhouse gangs);
• using slates or sliders is the simplest solution used in city baths.

2. Without taking into account the physical processes occurring in the bathhouse, it is impossible to explain the sudden appearance of raw steam and the steam room’s loss of heat.

Physics in the steam room

From the moment boiling water is poured from a mug onto the hot stones in the steam room, let’s begin our examination of physics. Liquid is instantly turned into steam by stones heated to 300 o C (any higher or lower may not work). A vertical release of heated, moist air occurs. When the steam reaches the ceiling, it spreads beneath it to the sides, filling the ceiling space completely while also settling down and pushing out the bathhouse’s lowest, coldest air layer (assuming the ceiling is hermetically sealed with a vapor barrier).

The result is a layered cake made from air at different temperatures. At the top, 70-80 cm thick, there is heated steam, in which bath procedures are taken. Below, up to about 1 m, there is cold air. Between them there is a small (20-30 cm), slightly heated layer. The bottom and top do not mix with each other due to physical laws – warm air tends upward, cold air – downward. Therefore, it is impossible to say that a cold floor affects the quality of steam, especially since due to the increasing pressure in the steam room, which happens every time after steam is supplied, some of the air is displaced.

Anywhere there are cracks, such as in the ceiling, walls, or floor, they can be removed. The lowest layer exits through ventilation holes in the foundation or in the wall next to the stove if the walls and ceiling space are well insulated. What takes place in this instance? That’s correct, each time the heated layer descends farther, slightly warmer air replaces it. With vigorous vaping for about thirty minutes, nearly the whole cold layer will be removed from the room. Furthermore, what relevance does floor insulation have? In any case, the cold will go because of physical laws.

For information, the steam room door is a sign of a well-heated bath. If there is no latch, it always opens slightly after steam is supplied because of a dynamic shock brought on by an abrupt rise in pressure inside the steam room.

This constitutes the theory’s initial section. The screed will be the focus of the second.

Is it necessary to insulate the floor screed?

The trend of porcelain stoneware flooring has increased recently. Absolutely, it’s both lovely and clean. In this scenario, the floor will remain intact until the walls collapse, so you can stop worrying about replacing and fixing it. Only a concrete screed can be used to lay tiles. The question of why to insulate the floor’s base twice—from below and in the middle—appears right away. In daily operation, residential buildings, apartments, and public baths require this technology.

Rarely is a private bathhouse heated. Consequently, it is unclear from what cold to safeguard its property. After all, the bathhouse’s water freezes during the winter, when temperatures as low as -5 o C are sufficient for several days. The walls are where most of the cold enters. Ultimately, heat is transmitted by wood, too, with a volume of 0.11-0.15 W/m*C. It turns out that the bathhouse owner made a battery by making a screed, which will store cold from the inside during the winter and release it intensely when washing.

When screeding floors beneath wooden panels or for water collection, the same scenario arises. It may need to be filled in certain situations. However, why insulate? That is the query.

Noteworthy: the physical processes in the sauna are a little different. However, floor insulation is not necessary.

Underfloor heating is a useful tool for warming a concrete floor base. However, even in this case, the so-called experts on bathhouses fail to grasp the crux of the problem. But that’s covered in more detail below. We will now expand on the theory and discuss why the microclimate is poor and the steam is damp, as well as how this relates to floors that are not insulated.

Why does the bathhouse get cold quickly?

The bathhouse was always constructed with solid red brick heaters. Compared to other materials, it has three properties.

1. When the stove is operating, heat is accumulated intensely. It suffices for a variety of uses:

• maintain a high temperature in the room;
• quickly dry the floor, walls, ceiling – as a rule, by morning all the moisture is gone, even without ventilation;
• initially compensate the stones for the loss of temperature due to water evaporation, which, by the way, is the main advantage of bricks.

Agree, a metal oven is not capable of doing all this.
2. The design of the furnace is such that the stones lie at a height of at least 1.5 m. It would seem like a trifle not worthy of attention. But what we wrote about a little higher? The layer of cold air is approximately 1 m high, plus a layer. In a metal stove, the stones are precisely located in this zone, as a result of which they cool not only due to the evaporation of water, but also in contact with the cold coming from below. A draft arises, like in a fire – when heated, the air rises. It is replaced by cold. Therefore, you won’t be able to take a steam bath for a long time with the stove turned off. Insulating the floor will not help for the reasons already given.

3. All sides of the stones are closed. The door lets in a torrent of boiling water and shuts as soon as the steam escapes. Consequently, we obtain two audacious benefits:

• the source of steam is located inside a fur coat made of brick, which retains the heat of the stones, and if the temperature drops significantly, it compensates for losses;
• the tornado effect is eliminated, when steam, rising upward, captures cold air on its tail.

Numerous stove producers have started to provide customers with comparable designs after realizing the value of entirely closed stones. Everything about this is positive. However, metal can never be as heat-accumulating as ceramics. Aims to line the metal around the stones and firebox are helpful. It cannot, however, totally take the place of brickwork.

In conclusion, damp steam and poor microclimate are entirely different issues. The floor cannot be insulated to solve them.

We offer thorough recommendations for those who, in spite of everything, feel compelled to perform thermal insulation work when arranging the floor.

Features of floor insulation in a bathhouse

The benefits of using thermal insulation materials in a bathhouse are widely discussed online. Mostly, they go by the following names:

• high humidity;
• sudden temperature fluctuations;
• frost resistance;
• Fire safety.

Two of the problems mentioned are dangerous positions: frost and moisture. When it comes to temperature, the walls and ceiling present the greatest threat. It’s not her on the ground. Display a minimum of one bathhouse where the air is heated to a minimum of 20 degrees Celsius, unless a "warm floor" is fitted.

It would appear that you need to search for insulation that is fire resistant. Ultimately, a bathhouse, particularly one made of wood, is in a high-risk area since fires can occur for a variety of reasons. But first, let’s examine. Since the insulation is inside the screed, it cannot catch fire. Not in a way. The finishing flooring boards will also be the first to light up beneath the wooden floor. The fire is fully engaged regardless of whether the insulation burns or not. It’s not a ceiling or wall, which is where fires almost always originate. Here, the flame is fueled by the combustible insulation material.

Proper waterproofing can help avoid the hygroscopicity issue. When there is frost, it gets harder. However, it only terrifies expanded clay, and even then, only when it’s wet.

In conclusion, you can use nearly any heat insulator, such as vermiculite or polystyrene foam, to insulate a bathroom’s concrete floor if the urge is too great. A somewhat more condensed list of insulation options for wooden floors—in certain situations, the subfloor might not hold up.

How to insulate a bathhouse floor

It is impractical to take into account every kind of thermal insulation material for floors; instead, a select group of insulation materials that are popular among experts and the general public has been established. Let’s think about it. We offer links on the site for interested visitors to view the advantages and disadvantages, as well as the functional and technical features, of insulators that aren’t on the list but can still be used for insulation.

The screed can be insulated using any kind of insulation, even expanded clay. Proper application of waterproofing will shield it from moisture. However, the list of waterproofing materials is much shorter for wooden floors. The peculiarities of wood—that is, the fact that it rots under insulation that prevents air from passing through because it needs to breathe—are the real cause, not variations in humidity and temperature. If you’re still unsure, try a little experiment where you only lay linoleum on a wooden floor. As a result, vapor-impermeable materials are not suitable for solid floor insulation.

• liquid polyurethane foam;
• polyurethane foam boards;
• foam plastic;
• "Izolon" and other materials made of foamed polyethylene;
• extruded polystyrene foam.

Mineral wool

Three categories of raw materials are used to make mineral wool:

• fiberglass (glass wool);
• blast furnace waste (slag wool);
• basalt and gabbro melt (stone or basalt wool).

Glass and slag wool have been abandoned in private construction due to serious flaws. On the other hand, mineral wool insulation derived from rocks has gained popularity. The strengths and weaknesses are the cause.

• durability – will last at least 50 years;
• does not absorb water;
• retains heat well;
• you can insulate screed and wooden floors;
• mold and mildew do not grow on it;
• mice and rats do not make passages and nests;
• lightweight – easy to transport and carry;
• simple insulation technique;
• does not contain harmful substances.

• higher price compared to plastic insulation, which is justified with great durability.

Here is a detailed discussion of the various types of mineral wool.

Expanded clay

Expanded clay is categorized by experts as a universal insulation material that can be used to insulate floors, walls, and ceilings from heat. It is totally superfluous on the ceiling if you can still agree with the floor.

There are certain advantages and disadvantages to the content.

• acceptable price. Plus relative, t.To. as a result, the cost will be high;
• durability;
• fire resistance;
• frost resistance, but only in a dry state – wet expanded clay will tear;
• small specific gravity. As with price, value is relative. In order for the material to really work as insulation, a layer of at least 20 cm is needed. And this is already serious loads on the structural elements of buildings and structures;
• Possibility of use in cement mortars when pouring screeds. There are two advantages here: the weight of the floor base is reduced, its thermal insulation properties are improved;
• strength;
• ecological cleanliness.

• actively absorbs moisture;
• dries slowly – for weeks;
• you need a large layer of insulation, at least 20 cm, to get the insulation effect;
• the pellets are dusty.

Here is more comprehensive information about expanded clay.

Polyethylene foam

Excellent technical and operational qualities characterize foamed polyethylene. They perfectly align with the material’s benefits and drawbacks:

• thin;
• easy;
• lasting;
• durable;
• simple installation technology;
• affordable price.

• does not recover its shape well after compression – walking is undesirable;
• no adhesion to adhesives.

You can find more information about polyethylene foam by clicking the link.

Ecowool

A recent product on the building materials market is ecowool insulation.

• retains heat perfectly;
• lightweight – you can insulate subfloors and suspended ceilings;
• contains no harmful or dangerous substances;
• affordable price.

• part of the rodent food chain;
• sits down over time.

More about ecowool at this link.

Styrofoam

The class of insulating materials based on polystyrene foam includes thermal insulator foam. Just like any other building material, it has benefits and drawbacks.

• holds heat well;
• has high strength;
• easy;
• moisture resistant;
• budget price.

• releases stinol when heated to 30 o C and above;
• vapor-tight;
• small operational resource;
• rodents love to live.

The article "Foam insulation" contains comprehensive insulation characteristics.

Extruded polystyrene foam

Extruded polystyrene foam is commonly referred to by consumers as "Penoplex." made using a different process but the same raw materials as polystyrene foam.

Distinct manufacturing technologies influenced the benefits and drawbacks. These are distinct materials. The following are some benefits and drawbacks of EPP.

• retains heat well;
• withstands severe frosts (50 o C) and heating up to 70 o C;
• frost-resistant;
• does not serve as a base for fungus and mold;
• high level of strength;
• service life about 30 years.

• love rodents;
• price above average.

Perlite

When pouring screed, perlite can be added as a filler to cement-sand mortar. He:

• high thermal insulation properties;
• light weight;
• long service life.

Types of bath floors

Russian bath houses traditionally had pouring (leaking) floors. This is because the boards are fastened to logs at a certain distance from one another, which guarantees an almost instantaneous release of water through holes in the ground or into a drainage pit. You can now find a number of additional types:

• concrete – a screed is poured, and during washing, wooden panels are placed on it, knocked down with gaps: water flows through them;
• solid wood – the boards are connected as tightly as possible to each other, creating a solid floor covering. To drain water, a slight slope is created towards one of the walls;

• porcelain stoneware – porcelain stoneware slabs are laid on a concrete screed. To drain water, the floor may have a slope towards the wall or towards the funnel. In the latter case, it is difficult to lay tiles.

What to choose depending on the type of floor and bath design

As demonstrated previously, insulating a bathroom floor is similar to adding a fifth wheel to a cart. Therefore, it makes no difference how to insulate the floor in a bathhouse’s steam room and laundry room for a box constructed of various materials (logs, beams, bricks, blocks, frame structure), standing on any foundation. The type of floor is the only restriction-causing factor.

Solid timber. Basalt wool is the best choice. Perlite and ecowool are additional options. Vapor-proof materials should not be used as they will trample the subfloor. Lathing the bottom boards will help prevent this kind of problem by allowing air to enter and allowing the wood to breathe. It’s sufficient to fill the rail and cover it with insulation.

Hard as concrete. A concrete floor is suited for any kind of heat insulator. It’s important to use them correctly, which means to lay them down where needed and to waterproof them.

Tile made of porcelain. The use of any kind of thermal insulation material is unrestricted, just like with concrete floors. Furthermore, the "warm floor" system is available for use here.

In a bathhouse, extra care should be taken to insulate the floor on pillars or screw piles. Additionally, there is no pressing need to insulate the floor. The most important thing is to use decorative or heaping materials to close the gap between the soil and the grillage.

Floor insulation technologies depending on the base

Due to a lack of cumulative experience, all available insulation techniques are applied when it comes to bathhouse floors:

• on the ground;
• bottom of screed;
• the screed itself;
• between joists (wooden floor);
• "warm floor".

Insulation on the ground

Expanded clay is one method for insulating ground floors. Technologies vary. So let’s think about each one separately.

You will require the following supplies and equipment to complete thermal insulation work:

• sifted sand;
• expanded clay;
• cement-sand mortar;
• water;
• bayonet and shovel;
• watering can;
• vibrating plate.

The following is the step-by-step work algorithm:

1. a hole is dug under the entire bathhouse with a depth of about 50 cm;
2. the bottom is leveled and compacted manually or with a vibrator;
3. a water drainage system is installed;
4. about 10 cm of sand is poured, after which it is compacted, spilled with water and compacted again;
5. another layer of sand is poured (total thickness about 20 cm), after which all compaction operations are repeated;
6. several days are given for the sand to dry (2-4);
7. a layer of expanded clay about 30 cm thick is poured. If the hole turns out to be deeper, you can increase the thickness of any layer, but it is better to use expanded clay;
8. the screed is poured. How to properly carry out work, including marking, installing beacons, preparing a solution, etc.d., can be viewed on our website here.

Below is a diagram that illustrates how expanded clay insulation works on the ground.

Insulating ground plan using expanded clay. Soil, sand, expanded clay, screed, and finishing floor covering are the first five materials.

Thermal insulation of the screed bottom

On dry soils, the screed’s bottom is insulated using technology. The guidelines are easy to follow:

• soil is selected under the floor to a depth of approximately 20-30 cm;
• the bottom is leveled and compacted;
• a pillow of river sand about 20 cm thick is poured. Everything is done using the same technology as for expanded clay;
• a "concrete preparation" is poured onto the cushion – a thin (20-30 mm) layer of lean concrete;

• EPP slabs are laid tightly against each other on lean concrete (this can be any insulation of the roll type or in the form of slabs);
• the joints are glued with construction tape;
• a cement-sand screed is poured.

The most common application of this technology is to insulate a bathroom floor using foam plastic and "Penoplex."

Important: Waterproofing is required and is not shown in the provided diagrams.

Be aware that in actual use, a mix of the aforementioned technologies can occasionally be found. The insulation pie looks like this in this instance, going from bottom to top:

1. soil;
2. sand;
3. expanded clay;
4. lean concrete;
5. roll or tile insulation;
6. screed.

Screed insulation

A screed can be used to partially insulate the floor. It must be given thermal insulation qualities in order to accomplish this. You can use perlite or expanded clay for this. Using expanded clay pellets as an example, let’s examine the technology.

Materials and tools

In order to work, you’ll need:

• expanded clay brand M600 or M700 with granules with a diameter of 5-20 mm and a specific gravity of no more than 700 kg/m 3 ;
• quarry sand;
• Portland cement M400 or M500;
• concrete mixer;
• buckets;
• rule;
• laser level or hydraulic level;
• roulette;
• metal profiles for lighthouses;
• mason"s trowel.

Instructions

The pouring screed instructions are divided into several sections:

• preparatory work;
• installation of beacons;
• preparing the solution;
• pouring the screed.

Our website has a thorough breakdown of every procedure. We will quickly review the order of work in order to avoid overloading the article, and in the event that problems occur, we will offer links to pertinent resources.

The following is the work order:

1. a sand cushion about 20 cm thick is poured under the screed. It must be well compacted. To do this, it is advisable to pour it in two stages with pouring water – details here;
2. Calculations are carried out to determine the screed line, after which the horizon line is first drawn on the foundation using a hydraulic level or laser level, and then the screeds. The technology is described in detail here;
3. beacons are installed (instructions can be found at the link);
4. a solution is being prepared. The proportions can be seen in the material “Technology of wet floor screed with expanded clay”;
5. the screed is poured (a manual explaining the details is here).

Insulation of a wooden floor

Remind yourself that, in theory, the pouring floor is not insulated. Solid wood flooring can be insulated in a number of ways if desired:

• on the ground. Pour a layer of expanded clay and install a solid floor above it;
• insulate the screed, organize water collection on it, and raise the floor.
• carry out insulation along the joists.

The previous section covered the first two options. Let’s just observe that there is no need to jam the subfloor onto the cranial bar in this instance. We’ll talk more in-depth about the insulation on the logs.

The following order is followed when performing all operations:

1. logs, cranial bars and subfloor boards are treated with liquid waterproofing compounds, preferably deep penetration. We especially note that the so-called experts protect the bottom of the floor from moisture in a different way: they attach a type A vapor barrier membrane (this technology is offered on almost all sites that have posted material on floor insulation in a bathhouse). You can write anything you want. Paper will tolerate. But they don"t say how to put the recommendation into practice. And they won"t say. It is impossible to perform such an operation. In the word, it is absolutely impossible – you won"t be able to crawl under the floor, which is raised above the ground or screed by 10-15 cm, and carry out the work;
2. logs are laid;
3. cranial bars are nailed;
4. the subfloor is laid;
5. a vapor barrier membrane is laid on the floor – the floor must breathe, but not allow water to pass from below to the insulation;
6. basalt wool is placed on top of the membrane. We especially note that other insulation materials are not suitable – they do not allow steam to pass through. Therefore, their use for insulating wooden structures is not recommended: the wood will begin to rot. As an option, a ventilation gap is left between the wood and the insulating layer. Otherwise, the owner of the bathhouse may be faced with a situation where the subfloor has failed and he doesn’t know about it. And he won’t find out until the flooring is replaced;
7. Type A vapor barrier material is laid on top of the insulation and joists. At the same time, so that steam molecules penetrate unhindered from bottom to top, and water from above is retained. Many experts recommend using two layers of plastic film for these purposes. But she"s not losing steam. Therefore cannot be used. As a last resort, the membrane can be replaced with roofing felt. At least he"s breathing a little;
8. finishing floor covering is laid.

In our guide to bath floor insulation, we delve into the fundamental methods that will keep your bathhouse warm and dry. We go over common insulation materials, how-to installation techniques, and useful advice for maintaining long-term efficacy. Whether you’re building a new bathhouse or remodeling an old one, knowing these insulation techniques can help you design a sturdy and comfortable area that can handle humidity and temperature changes.

Insulation of the floor of a bathhouse on a pile foundation

Additionally, floor insulation is not needed when constructing a foundation on piles or pillars. The technology used to build a frame building is used to either insulate or close the space between the soil and the grillage. The following order is followed when performing the work:

1. along the perimeter of the pile foundation, the distance between the soil and the bottom of the building frame is sheathed on the inside with boards (plywood, OSB or flat slate). To prevent moisture from the ground from getting into the wooden sheathing and insulation, cut-off waterproofing is made directly along the ground. Rolled waterproofing materials are best suited for these purposes;
2. First, a vapor barrier membrane (type A) is attached to the boards, and then insulation;
3. the thermal insulation layer is covered with a windproof film;
4. the sheathing is stuffed again, but from the outside;
5. the bottom of the bath is sealed with decorative tiles or stone.

"Warm floor"

By using a "warm floor," the porcelain tile finish can be warmed. They started posting frequent articles about this on informational websites. However, just like with floor insulation, the writers are ignorant of the main points of the problem. They suggest using water systems for these purposes because they think that in high humidity, an infrared film or cable could easily short out.

Yes, if you have the money, a "warm floor" for a bathhouse is a blessing because it adds to the comfort level.

However, not the water one, dear "experts." It will simply burst all the pipes because it cannot tolerate the cold. You are gravely mistaken if you believe that you can empty the system of water after taking a bath. A few hours of labor and specialized equipment are needed for this process. Additionally, it is hard, if not impossible, to find given the hectic pace of modern life.

Output in an electric or infrared heat field. Neglect your fear of a short circuit. Nothing could endanger people taking baths if everything is done correctly, including installing high-quality waterproofing and grounding the heating components. As a last resort, when there’s no water, you can turn on the heating while you light the stove and turn it off when you start to wash.

The experience of using electric and infrared "warm floors" in bathrooms—where conditions are also not ideal—evidences that they operate safely.

You can find examples of how to physically connect underfloor heating systems here and here.

Traditional methods

Literature extensively discusses traditional techniques for insulating floors. The use of straws, sawdust, glass, and plastic bottles are demonstrated. However, confusion persists. The purpose of mixing sawdust and straw with clay and pouring earth into the space was to arrange water drainage rather than to insulate the floor.

Bottles are more difficult to explain. Let’s give it a shot. It’s likely that a lot of people who come to our website have heard about weird people who construct houses out of bottles. However, no one followed. In this case, too. Some originals are inert; they employ glass bottles for different uses. By the way, you can purchase insulation for multiple baths if you give them away as glass containers.

To sum up, insulating a bathroom floor is essential for preserving warmth and avoiding moisture damage. You can improve the overall insulation of your bathroom by installing a long-lasting and cozy floor using the appropriate supplies and installation techniques.

Using materials with superior thermal insulation and moisture resistance, such as mineral wool or extruded polystyrene foam, is important. In addition to keeping the floor warm, these materials aid in controlling humidity levels, which is essential for the structure’s longevity.

Furthermore, it’s crucial to use appropriate installation methods like vapor barriers and gap sealing. By taking these precautions, heat loss and moisture accumulation are avoided, guaranteeing the year-round effectiveness of your insulated floor.

By putting these tips into practice, you can have a well-insulated bathroom floor that increases comfort, boosts energy efficiency, and increases the lifespan of your bathhouse—creating a more sustainable and pleasurable place to unwind.

Video on the topic

How to make a WARM THROUGH FLOOR in a turnkey bathhouse? Detailed review of floor installation from SK Dominica

How to make a BATH FLOOR CORRECTLY! DIY bath floor

Error in insulating the floor in the house. Vapor barrier for floors.