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Underfloor Insulation Techniques and Materials

Discover the importance of underfloor insulation in floor structures for energy savings, living comfort, and noise reduction

In the field of building design and construction, attention to energy efficiency and living comfort is becoming increasingly crucial. One fundamental aspect to consider in this context is underfloor insulation, a technique aimed at improving both energy performance and occupant well-being.
In this article, we will delve into the basic concepts of this type of insulation, the most common insulating materials, as well as the benefits, installation methods, and practical considerations to keep in mind.
At the end of this article you will also find a video that shows how you can optimize your project’s design phase and achieve more reliable results using an energy calculation software, .

Inserting insulation in the underfloor by a worker

Inserting insulation in the underfloor

Definition and role of underfloor insulation

Underfloor insulation is a fundamental technique in the construction industry aimed at improving the energy efficiency and living comfort of buildings. This practice involves applying an insulating layer to the underside of a floor, the side facing the interior of inhabited spaces. Its main goal is to limit heat transfer between different areas of a building, thus helping to create a healthier, more comfortable, and energy-efficient indoor environment.

This significantly contributes to maintaining a comfortable temperature inside living spaces, reducing heat loss through the floor during colder months, and minimizing heat gain during summer periods. This not only leads to cost savings for building owners but also helps reduce the environmental impact associated with energy production.

Common insulating materials and their properties

In the realm of underfloor insulation, there are several commonly used insulating materials, each with unique characteristics that make them suitable for specific situations and needs. The choice of the right insulating material depends on various factors, including thermal conductivity, moisture resistance, and sound-absorbing properties. Below, we will explore some of the most common materials and their properties:

  1. Glass wool – this insulating material is composed of thin and flexible glass fibers, making it lightweight and easy to install. Glass wool offers excellent fire resistance and high-temperature resistance, and is particularly effective in reducing heat and sound transmission;
  2. Rock wool – similar to glass wool, rock wool consists of mineral fibers derived from volcanic rocks. It is moisture and mold resistant, and is often used in environments subject to adverse weather conditions;
  3. Expanded polystyrene (EPS) – also known as polystyrene, EPS is lightweight, durable, and has high insulating capacity. It is available in rigid panels or granular form for blowing, and is widely used for insulation;
  4. Polyurethane foam (PUR) – expanded polyurethane is a versatile insulating material, known for its excellent thermal insulation properties. It is available in rigid foam or spray form, and is suitable for insulating floors and walls;
  5. Wood fiber – this natural material is obtained from wood processing and offers excellent thermal and acoustic insulation properties. It is eco-friendly, biodegradable, and helps regulate humidity indoors;
  6. Cellular concrete – produced through an autoclave process, cellular concrete is lightweight, durable, and offers excellent thermal resistance. It is particularly suitable for insulating floors and walls, especially in environments exposed to high temperature variations.

Choosing the most suitable insulating material depends on the specific needs of the building, surrounding environmental conditions, and owner preferences. Before making a choice, it is advisable to consult a professional in the field to evaluate available options and ensure maximum energy efficiency and living comfort.

Insulation inserted in the underfloor

Insulation inserted in the underfloor

Installation methods and practical considerations

Installing insulation on the underfloor requires attention to detail and the adoption of appropriate precautions to ensure a healthy, comfortable, and energy-efficient indoor environment. It also requires careful planning and the use of appropriate techniques. Let’s see what the installation method can be and what practical considerations to keep in mind:

Application of insulating panels directly under the floor

This method involves applying insulating panels to the underside of the floor. This can be done by directly applying them to the floor with the help of specific adhesives and/or anchors, or in a less direct manner, using frames, for example, in wood that allow to “fit” and support the insulating material (usually this method is used for fibrous materials). Once the insulating panel material is positioned, it is important to ensure proper adhesion and sealing to prevent thermal losses and air infiltrations.

Practical considerations

During the installation of underfloor insulation, it is essential to consider some precautions to ensure an optimal result and prevent future issues:

  • Moisture and condensation prevention – it is important to ensure that the underfloor insulation system is designed to prevent moisture and condensation formation. This can be achieved by using moisture-resistant insulating materials and ensuring proper ventilation of the indoor environment;
  • Proper sealing – it is essential to carefully seal all joints and openings around the insulating panels or injection points to prevent air infiltrations and thermal losses. Good sealing will help improve the overall energy efficiency of the building;
  • Structural integrity verification – before proceeding with the installation of the insulating material, it is advisable to verify the structural integrity of the floor and the subfloor to ensure they can support the additional weight of the insulating material. If necessary, it is important to reinforce the structure to avoid problems of excessive load;
  • Continuous monitoring – once the insulation installation is completed, it is advisable to constantly monitor the indoor conditions to detect any signs of moisture, condensation, or deterioration of the insulating material. In case of issues, timely intervention is important to prevent more severe damage to the building.

Advantages of underfloor insulation

Underfloor insulation offers a range of significant benefits that positively impact both the energy performance and living comfort of buildings.

Reduction of energy costs

Underfloor insulation plays a crucial role in reducing energy costs associated with heating and cooling indoor spaces. By maintaining a more constant temperature inside living spaces, insulation reduces the need for heating and cooling systems, leading to a significant decrease in energy bills.

Improved living comfort

Another advantage of this practice is the enhancement of living comfort. By reducing heat and noise transmission between different floors of a building, insulation creates a quieter and more pleasant environment for occupants. This means that residents can enjoy increased privacy and tranquility within their living spaces, without being disturbed by noises from other areas.

Temperature uniformity

Underfloor insulation also helps maintain a more uniform temperature inside the building. This means there will be no significant temperature variations between different rooms or floors of the building, creating a more comfortable environment for occupants.

Better moisture control

Another advantage of insulation is its role in regulating indoor humidity. Proper insulation can help prevent condensation formation on internal surfaces, thus reducing the risk of mold and structural damage caused by moisture. This means that building occupants can enjoy a healthier and safer environment.

Video of an energy calculation software

Below, you can watch a video showing how an energy calculation software works, so you can proceed, among other things, in the correct design of underfloor insulation.