How to insulate a concrete floor with polystyrene foam

Because of their strength and longevity, concrete floors are a popular choice for private residences. Without the right insulation, they can also be uncomfortable and chilly. This is particularly true in regions where temperatures drop dramatically, which is why it’s critical to address the problem of thermal efficiency in the flooring in your house. Polystyrene foam is one of the best materials to use for concrete floor insulation.

The excellent thermal properties, low cost, and simplicity of installation of polystyrene foam make it a popular choice for insulation. It helps to maintain a constant interior temperature by minimizing heat loss through the concrete slab. This lowers energy use and heating expenses while also improving comfort.

The advantages of insulating concrete floors in private homes with polystyrene foam will be discussed in this article. We’ll go over the various kinds of polystyrene foam that are available, how to install it, and important factors to take into account to guarantee efficient insulation. Whether you’re building a new house or remodeling an old one, knowing these things will make your living area cozier and more energy-efficient.

Step	Description
1	Prepare the concrete surface by cleaning and leveling it.
2	Lay a vapor barrier sheet over the concrete to prevent moisture from penetrating the insulation.
3	Place the polystyrene foam boards tightly together on top of the vapor barrier.
4	Seal any gaps between the boards with foam sealant to improve insulation efficiency.
5	Install a layer of waterproof membrane over the polystyrene foam to protect it from moisture.
6	Finish with a layer of screed or another flooring material of your choice.

Contents

Methods of insulating a floor with polystyrene
On a concrete base under a screed
On a concrete or wooden base with logs
On the ground with a screed
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Methods of insulating a floor with polystyrene

We immediately point out that, in certain situations, it is possible to keep the floor level, but doing so will cost a lot of money in terms of both time and materials, particularly if you handle everything yourself. Since it is advised to use polystyrene foam insulation to insulate concrete floors on the ground floor or in single-story private homes with slabs that are at least 10 cm thick.

Suggestions. If the house has a basement, you can insulate the ceiling and then just install floor slabs that are three to five centimeters thick.

Let’s examine the various technologies available for using this material to insulate floors.

On a concrete base under a screed

The best foundation for tiles, if you have decided to use them as a finishing floor covering, is a cement screed, which is then covered with insulation. In these situations, the guidelines mandate using polystyrene foam that can sustain the operational load by having a density of at least 35 kg/m3.

We dismantle the old floor covering to the concrete;
We clean the surface from dirt and dust and treat it with a primer;
After it dries, we lay a polyethylene film on the base as a waterproofing material, making overlaps at the joints 10-15 cm wide. The film should be wrapped around the walls to a height corresponding to the total height of the insulation and screed;
Then we begin insulating with polystyrene foam, laying it tightly against each other. It is best to take slabs with special mounting grooves so that there are no gaps between them;

The excess around the perimeter of the room is easily cut off with a regular knife along a ruler or a flat strip;
We cover the laid insulation with a vapor barrier film with an overlap and seal the joints with tape;
We lay the reinforcing mesh and fill the floor with a cement mortar 3-5 cm thick.

The screed is arranged for the final coating once it has dried completely.

Suggestions. By using polystyrene concrete to insulate the floor, you can expedite and somewhat reduce the cost of the work. To accomplish this, make a cement mortar with polystyrene granules rather than sand. In this instance, the screed is applied directly on the preexisting base, negating the need for insulation boards.

On a concrete or wooden base with logs

Sturdy slabs or boards can be placed on top of the insulated logs set on a concrete base.

After the preparatory work, a lattice of wooden bars is mounted on the concrete base, the height of which should not be less than the thickness of the insulation. And the size of the cells should correspond to the parameters of the polystyrene foam boards;
A film is laid between the logs, and the insulation boards are placed on it;

The gaps between the bars and the foam are filled with mounting foam;
A vapor barrier material is spread on top and attached to the logs;
The last stage is the installation of boards, plywood, OSB or other durable sheet materials on the logs, which will become the basis for the finishing coating.

Kindly take note. As the material won’t be subjected to loads, it is acceptable to use less dense extruded polystyrene foam in this situation to insulate a concrete floor over logs.

By the way, a wooden base can also be used with this technique. However, it is preferable to use extruded polystyrene foam in a private home with wooden floors. In contrast to traditional polystyrene foam, it does not attract rodents at all.

On the ground with a screed

The only option if maintaining the floor level is to disassemble the current base entirely and insulate the ground floor using polystyrene concrete or extruded polystyrene foam, then cover the floor with concrete screed.

A layer of crushed stone or gravel 30-40 cm thick is laid on the leveled and compacted soil, which is carefully tamped;
A 10-centimeter layer of sand is poured on top, it also needs to be leveled and compacted;
Then a subfloor made of reinforced concrete is arranged;
After drying, waterproofing, insulation and vapor barrier are laid on it;
All this is again filled with concrete mortar.

As you can see, this type of work will cost more in labor and take longer to complete. For this reason, it is worthwhile to estimate and compare the cost of replacing the doors first. If there are thresholds, we might be able to restrict ourselves to just taking them down or cutting the door panels.

Polystyrene foam insulation of concrete floors is a practical approach to lower heating expenses, increase energy efficiency, and improve comfort. In addition to offering superior thermal insulation, this sturdy and lightweight material also functions as a moisture barrier to keep out moisture and possible mold growth. Homeowners can contribute to overall energy conservation by installing polystyrene foam insulation, which will make their living spaces warmer in the winter and colder in the summer.

Polystyrene foam insulation of a concrete floor in a private residence has many advantages. It lowers energy expenses and improves overall comfort by assisting in the maintenance of a constant interior temperature. Because of its superior thermal insulation capabilities, lightweight design, and simplicity of installation, polystyrene foam is a sensible option.

To maximize the effectiveness of polystyrene foam floor insulation, proper installation must be ensured. To stop heat loss, this entails preparing the surface, choosing the appropriate insulation thickness, and caulking any gaps. The kind of flooring that will be installed on top should also be taken into account, as certain materials may need extra underlayment or preparation.

All things considered, installing polystyrene foam insulation under your concrete floor is a prudent investment that can raise your home’s energy efficiency and make it a more comfortable place to live. Reduced heating costs and a more stable indoor climate are just two long-term advantages that come with taking the time to install and maintain this insulation correctly. Due to its affordability and effectiveness, this insulation technique is something you should think about whether you’re building a new house or remodeling an old one.