How to insulate the ceiling in a bathhouse

The best sauna is hot! But it is not enough just to create the desired temperature - you must also maintain it. And if you don’t insulate the ceilings, then the heat, the pleasure, and the time and effort spent on kindling will disappear quite quickly.

What materials are used to insulate the ceiling in a bathhouse?

The most popular options are mineral wool, expanded clay, sprayed clay and sawdust. Each of them has its own advantages and disadvantages, and they also work with them differently. Due to the characteristics of these materials, the methods also differ.

How to insulate outside

This method is considered the most universal, because any of the listed materials can be used for this. If you don’t go into details, it’s enough to organize a reliable substrate and place or scatter insulation on top. It’s easy to guess that bulk can only be used for external insulation, so let’s take a closer look at it.

Expanded clay is small porous clay pebbles of different sizes. Its main advantages:

• low thermal conductivity;
• resistance to fire, mold and fungi;
• environmental friendliness and non-toxicity;
• long service life;
• low price;
• ease of use.
  

But, of course, one cannot do without shortcomings. For expanded clay it is:

1. The need to backfill a large amount of material, which makes the structure heavier.This is especially important if you plan to install a panel ceiling.
2. High water absorption, which imposes increased requirements when installing vapor and waterproofing.

The second type of bulk material is sawdust. It is loved by non-professional builders because it is inexpensive, and often even free if the shavings left over from other work are used.

Interesting! Many perceive the bathhouse as a tribute to the traditions of their ancestors, therefore, when creating it, they fundamentally use only natural materials. From time immemorial, baths have been insulated with sawdust, so this method can act as a kind of symbolic gesture.

Sprinkling unmixed sawdust is convenient, but risky from a fire safety point of view, since it easily ignites. Most often they are mixed with clay, less often with lime or cement. What are the disadvantages of this method? This:

• less durability compared to artificial materials;
• heavy weight - threatens with the same problems as expanded clay;
• intolerance to dampness.

How to insulate from the inside

By the method of elimination, we come to the conclusion that the ceiling side can be insulated with everything that is not listed in the previous paragraph - mineral wool and sprayed insulation. Let us remind you that nothing prevents them from being used for outdoor work.

Mineral wool is divided into the following types:

• slag, made from blast furnace slag;
• stone (aka basalt) from melted rocks;
• ecowool is a cellulose material.

All of them have excellent heat retention, are not covered with mold and fungi, and rodents do not grow in them. Slag wool is the cheapest and has high elasticity, making it convenient to use in insulating uneven ceilings.But, unlike stone, it has a tendency to shrink, absorbs moisture more and requires compliance with many safety measures (work with it only with gloves, a respirator and special clothing).

In this regard, stone is denser, more hygroscopic and more convenient. In addition, it can withstand higher temperatures than slag. But it is difficult to use in baths with non-standard geometry, since its elasticity is low.

Ecowool does not have all of the listed disadvantages, and its only disadvantage is difficulty in handling.

Sprayed insulation is more convenient than mineral wool for interior work, since it does not require additional reinforcement. But it will require a large consumption of material, which is not economical, especially for large-scale areas (therefore it is mainly used for small ones). In addition, not all of its types are suitable for baths. For example, it is contraindicated to use so-called liquid foam, since it releases toxic substances when exposed to high temperatures and humidity. By the way, it is highly not recommended to insulate baths with ordinary, “hard” polystyrene foam, for the same reasons.

How to properly insulate the ceiling in a bathhouse

Whatever method you choose, the main thing you need to remember is the sequence of layers (from top to bottom): waterproofing, thermal insulation, vapor barrier.

Interesting! In builder slang, this installation is called a “pie.”

Various types of films, membranes, modern varieties of roofing felt or glassine are usually used as waterproofing. We recommend not using polyethylene for these purposes, since condensation may accumulate on it.

The best material for vapor barrier is foil coating. Depending on the insulation method, they choose either a thin one, which is installed separately from the thermal insulation, or a “two-in-one” coating combined with mineral wool.

There are three common ways to insulate a ceiling.

The first is external, for the floor type. This is the simplest and cheapest method, designed for small rooms and low weight of insulation. It does not require nailing down beams; all layers are installed from the attic side, in a “bottom-up” sequence: ceiling boards, steam, heat, waterproofing and attic floor.

The second is internal, for the hemming type. Here, unlike the previous method, beams are used, so the structure is more durable and reliable. First, the beams are installed, and on top of them, from the attic side, the waterproofing is fixed, then the attic floor is laid. Further work is carried out from the inside. First, mineral wool is placed between the beams and secured. If other materials are used, then the rough ceiling is first installed and the thermal insulation is located on top (or below, if it is sprayed insulation). The last two steps are vapor barrier and finishing the ceiling.

The third is the panel type. This is a professional method because it is very labor intensive. First, panels are created on which all three layers are located. Then the ceiling is assembled from them.

Which one to choose is up to everyone to decide for themselves. The main thing is to take into account the pros and cons of this or that material and how to install it.