Types of floor insulation for concrete and tips for choosing

Adequate floor insulation is crucial for constructing a cozy and energy-efficient home, particularly for homes with concrete flooring. Concrete floors can seem chilly and unwelcoming, but you can make them feel warm and inviting by adding the correct insulation.

There are various kinds of floor insulation available, and each has advantages and disadvantages of its own. Making an informed decision that fits your needs and budget will be made easier if you are aware of these options. There is a solution out there for you, regardless of whether you’re planning a large renovation or a straightforward do-it-yourself project.

The most popular forms of concrete floor insulation will be discussed in this article, including spray foam, insulated underlayments, and rigid foam boards. We’ll also offer helpful advice on how to select the ideal insulation for your particular needs, taking into account elements like installation ease, cost, and climate.

In addition to making your house more comfortable, the proper insulation can lower your energy costs and raise the overall value of your house. Let’s examine the various kinds of floor insulation to determine which is best for your concrete floors.

Type of Floor Insulation	Tips for Choosing
Fiberglass Insulation	Affordable and easy to install, good for soundproofing
Foam Board Insulation	High insulating value, moisture-resistant, great for basements
Spray Foam Insulation	Provides excellent coverage, seals gaps well, but more expensive
Mineral Wool Insulation	Fire-resistant, good for high-temperature areas
Radiant Floor Heating	Provides consistent warmth, ideal for new builds or major renovations

Material selection criteria

The price of insulation is often the buyer’s main concern. However, if the chosen material doesn’t fit the operating specifications, you won’t be able to save money. The best choice when a fair price is paired with the following crucial insulation features:

• Inability to absorb and retain water. Insulation swollen with moisture loses its properties and spoils the finish coating.
• Temperature resistance. It is important when a concrete screed is made over an unheated basement or under a “warm floor” system.
• If the insulation will be used in interfloor ceilings, you need to pay special attention to its weight.
• The material should not be subject to destruction from exposure to biological environments. If fungus or mold develops, you will have to completely open the floors.

In addition to the previously mentioned considerations, home craftsmen should research how simple it is to install the heat insulator yourself before making a purchase.

Since we are discussing the use of this material in a residential area, any heat insulator must come with the relevant environmental safety certificates.

Varieties

Thermal insulators are made from natural or synthetic raw materials, or they can come from a combination of sources. The cost usually increases with the number of natural ingredients in the composition.

Penofol

An aluminum layer is applied to one or both sides of foamed polyethylene, the basis for practical insulation. Penofol labeled as "self-adhesive" has foil on one side and an adhesive coating on the other. Foil functions as an efficient vapor barrier and heat flow reflector.

Due to its good reflectivity, some manufacturers choose to use lavsan instead of aluminum foil.

Advantages of applying penofol to a concrete floor:

• absorbs shock and high-frequency sounds;
• a light weight;
• unattractive to rodents;
• does not form mold;
• ease of installation.

Minuses:

• softness, creasing;
• foil reacts with concrete.

If Penofol is placed directly underneath the heating system on a concrete screed with the foil facing up, it can be used as reflective insulation. If pouring concrete over the top is not the plan, then this option makes sense. Experience has shown that when foil comes into contact with concrete, it disintegrates very quickly. Penofol works best when placed underneath laminate or linoleum.

The average cost of a 25 m roll of insulation with one foil side, 1.2 m width, 5 microns thick, and weighs 1,300 rubles. One linear meter of self-adhesive Penofol, measuring 60 cm in width and 10 mm in thickness, costs 210 rubles.

Expanded clay

Refractory clay varieties are used to create an eco-friendly natural material. Heat treatment causes the clay to swell, producing granules with a porous structure made up of various fractions.

Benefits of expanding clay for concrete pavement insulation:

• inertness to chemical reagents;
• is not destroyed by biological factors;
• a light weight;
• moisture resistance;
• vapor permeability;
• absolute environmental friendliness.

Minuses:

• poor water resistance (moisture absorption level up to 25%);
• ability to crumble under mechanical stress;
• thermal insulation properties are worse than most modern insulation materials.

Fine-grained expanded clay or clay with a medium fraction is the most widely used. Concrete screed with expanded clay is another method for insulating concrete floors.

The average cost of an expanded clay bag 40 l, fraction 0–5 mm, bulk density 800 kg/m3 is 750 rubles. Expanded clay sold in bulk costs 2,650 rubles per cubic meter.

Different types of mineral wool

The following varieties of mineral wool are distinguished based on the raw material:

• Basalt is made from minerals of volcanic origin. Has excellent performance qualities. The downside is the use of toxic resins for gluing basalt fibers. The latest generation of stone wool contains safe polymers, but this material is very expensive.
• Glass is available in slabs or rolls. The raw material can be broken glass or quartz sand. The material is highly effective, but the fibers are very fragile. Debris can injure skin and remain in clothing. Therefore, handling insulation is very difficult; unprecedented safety measures must be taken.
• Slag is made from metallurgical waste. Used exclusively for industrial buildings. The insulation absorbs water, which leads to destruction of the metal component due to corrosion.

The high effectiveness of this insulation, along with its chemical and biological inertness and temperature tolerance, are its common advantages. Fibrous material is used to insulate a concrete floor screed in between joists, and a hard finishing coat is applied on top.

The average cost to pack 4 pieces of 1200x600x100 mm stone wool slabs is 1500 rubles. Glass wool in slabs measuring 1230 x 610 x 50 mm (16 pieces) can be purchased for 2300 rubles.

Penoizol

The insulator creates a seamless layer of thermal insulation using a modified formaldehyde-urea foam. Concrete can be foamed without first undergoing surface preparation.

Benefits of penoizol

• excellent thermal insulation properties;
• does not interact with biological and chemical reagents;
• combustion resistance;
• breathability;
• retains its heat-insulating qualities for a long time.

Minuses:

• if technology is violated, it cracks and crumbles;
• able to absorb moisture;
• tendency to shrink;
• penoizol, made on the basis of cheap urea resin, releases toxic substances during drying.

Penoizol insulation has unique qualities. Mechanical stress should not be applied to this material. utilized to insulate concrete floors before applying a hard finishing coat. The space between the joists in the room is completely covered with penoizol. The boards are jammed onto the joists once the mass solidifies.

Depending on the quality of the work, foam insulation insulation can cost as much as 250 rubles per cube meter on average.

Plywood and fiberboard

For concrete floor thermal insulation You can use the following materials made of recycled wood:

• plywood;
• fibreboards;
• particle boards.

The usage of these heat-insulating materials has increased in place of mineral wool. An interior microclimate can be comfortably created with fiberboard and plywood. Nevertheless, these materials’ thermal insulation qualities aren’t great enough to insulate the entire space.

Wood-based thermal insulators’ advantages

• high elasticity;
• safety for the respiratory tract and skin;
• no special fastenings required.

Its susceptibility to rot, mold, and rodent attraction are drawbacks. The material is given a variety of chemical treatments to prevent these drawbacks. Chipboard is the best material to use as a paint finish coat.

For RUB 1,200, one can purchase a tongue-and-groove moisture-resistant chipboard that measures 1830 x 600 mm and is 16 mm thick. A 12 mm thick sheet of plywood measuring 1525 mm by 1525 mm costs, on average, 680 rubles. A 3.2 mm thick, 1700 x 2745 mm piece of fiberboard costs roughly 550 rubles.

Sprayed materials

Polyurethane foam is the most widely used sprayed material for insulating concrete screeds. This is a counterpart to air-hardening polyurethane foam.

The following are some benefits of using polyurethane foam materials:

• forms a seamless surface;
• low thermal conductivity coefficient;
• ensures quick installation;
• service life more than 30 years;
• simultaneously acts as a waterproofing agent;
• dampens wave and impact noise.

Installing a heat-insulating layer on a concrete screed requires the use of logs due to one of the drawbacks: the relatively low mechanical strength. Spraying occurs in the spaces between the joists, and a hard finishing coat is applied once the foam has solidified.

Sprayed materials cost roughly 500 rubles per square meter (depending on volumes and other production factors).

Cork

The bark of a particular cork oak tree is used to make premium cork insulation. manufactured as plates, sheets, and canvases.

Benefits of cork substance:

• ability to perfectly insulate surfaces;
• high sound insulation properties;
• optimal combination of light weight and strength;
• exposure to moisture does not change the properties of the material;
• high compressive strength;
• chemical and biological stability.

The low resistance to injury from sharp objects is one of the drawbacks. For this reason, the concrete screed needs to be tidy and smooth.

Cork is typically used as a substrate on top of a concrete screed beneath the primary floor covering. Such insulation is frequently kept as a separate finishing touch. A square meter of cork covering costs 2200 rubles on average.

What is the best way to insulate a concrete screed??

The location of the insulation influences the choice of insulation:

• You can use urethane foam spray between the screed and the concrete base. A more economical solution would be to use expanded clay concrete.
• On top of the concrete screed, under the finishing coating, you can use plywood or other insulation based on wood processing, cork, penofol.
• If the finishing coating is planned to be arranged along joists, expanded clay granules, mineral wool, or any of the sprayed materials will be suitable as insulation.
• It is advisable to use urethane foam insulation between the ground floor and the concrete screed; the quality and type of base are not important for it; it does not absorb moisture and is not subject to biological decay.
• Under the tiles, insulation is used that can withstand contact with wet concrete. The fact is that the tiles are laid only on a concrete screed. The composition of the insulation cake may include mineral wool, expanded clay, vermiculite, granulated polystyrene foam, and other materials that are not subject to rotting.
• Under the laminate you can put penofol, plywood, fiberboard, cork.
• Solid insulation based on wood products, as well as penofol and cork sheets, are suitable for linoleum.

Why is it important to make the right choice??

No matter how good a heat insulator is, it will need to be redone in at least a year if it doesn’t meet operating requirements. For instance, the finishing coating will easily crumble if mineral wool is placed beneath the laminate because of the high crushability of the insulation. Penofol will eventually collapse if it is used beneath a heated floor system and concrete is poured on top.

Only when a hard finishing coat is intended to be applied to the joists can sprayed materials and expanded clay be taken into consideration for concrete screed insulation. If not, the insulation will easily collapse when subjected to pressure.

To improve comfort and energy efficiency in your home, it is essential to select the appropriate type of floor insulation for concrete. This post will examine several insulation choices, each with their own advantages, such as spray foam, underfloor heating systems, and rigid foam boards. Knowing the advantages and disadvantages of each type will help you choose the best option for your needs and budget, resulting in a cozier and more functional living area.

Useful video

Watch the video for more details on the characteristics of concrete floor insulation:

Selecting the appropriate floor insulation for your concrete floor is essential to keeping your house cozy and energy-efficient. Knowing the advantages of each type of insulation will help you choose the one that best suits your needs. Using loose-fill, foam boards, or reflective insulation will all help you improve temperature control and reduce energy costs.

Because they are simple to install and have a high insulation value, foam boards are fantastic. If you’re searching for something strong and efficient, they’re a great option. Conversely, reflective insulation is the best choice in warmer climates when attempting to block solar heat. Fiberglass or cellulose are excellent loose-fill materials for easily filling in voids and adding insulation to already-installed flooring.

When choosing insulation, don’t forget to take your home’s unique requirements and climate into account. Consider the expenses, installation time, and long-term advantages. In addition to improving comfort, proper insulation raises the value of your house. Investing the time to select the appropriate kind will eventually pay off with a more comfortable and effective living area.

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