What is the best underlay for laminate flooring?

7 min


Laminate flooring

1Laminate is an excellent flooring material due to the decorative and operational properties of this floor covering. First of all, it is beautiful, has a wide variety of different textures and colors for different types of wood or other natural materials such as stone or tiles. Also, the laminated coating has high strength, which allows it to be used in places with a high concentration of people. These are offices or shops.

Laminate is easy to install and quite practical to use without requiring much maintenance. Also, the laminate floor has good moisture resistance and thermal insulation, which gives a few more points ahead when choosing this floor covering. For laying the laminate floor, a special substrate is used, which has several types and has different properties. To choose the best laminate substrate, let’s look at its advantages, properties and main types. This will help you understand whether a laminate underlay is needed at all.

What are the advantages and properties of the laminate underlay?

Soundproofing

2The disadvantage of laminated flooring is its boomy, that is, when walking on such a floor, a characteristic sonorous sound will be heard. This can happen for the following reasons:

  1. The thickness of the laminate is too small, about 8 millimeters, which is the most popular thickness,
  2. A floating method of laminate flooring, which creates a kind of membrane between the main floor and the laminated panels. This contributes to the formation of a sonorous echo from walking on the floor.

To avoid this negative property, a laminate underlay is used, which is laid on the subfloor. Some manufacturers sell laminated flooring already with a special noise absorption system, usually a 32-34 class laminate, which has a rather high cost. Therefore, it is sometimes advisable to use simple laminated panels separately with a backing. This is beneficial as the underlayment for the laminate is inexpensive and can significantly reduce the repair budget.

Moisture insulation

3To avoid the swelling of laminated panels due to moisture build-up under the floor, a laminate underlay should be used to create an additional barrier between the subfloor and the floor covering to prevent water ingress.

In this case, you can use two types of laminate underlay:

  1. Foil-type laminate substrate, which is laid with the metallized side up. It is a good barrier for moisture coming from the sub-floor, protecting the base of the laminate from swelling and the outer surface from cracking.

  2. A combined type substrate with a special structure that allows you to ventilate the room. It consists of several layers and removes excess condensation. This is true in high humidity rooms or areas.

It can take a whole month for a fresh concrete screed to dry completely, which is often an unacceptable luxury, since the next stage of repair work should be carried out – laying the laminate floor, so the substrate will be useful in this case too. It will maintain the necessary microclimate between the floor and the laminated panels, thus avoiding damage to the laminate.

Thermal insulation

4This property of almost any substrate for laminated panels can significantly reduce the cost of operating a warm floor indoors, that is, an additional heating system. The underlay will retain heat more efficiently where it is placed.

By itself, laying a warm substrate under the laminate can exclude the installation of a warm floor altogether, since it is an excellent material that retains heat, preventing it from leaving the room into the floor slab. Why pay for energy costs and installation of an expensive underfloor heating when you can use a highly efficient and high-quality laminate underlay for thermal insulation.

Surface leveling

5The next property of the underlayment is very important, as it helps to level minor irregularities in the subfloor. Even a new concrete screed may have some defects and irregularities that can eventually damage the laminate flooring. On an ideal, even cement screed that has been recently poured, so-called “backlash”, that is, a slight subsidence, can form over time, which can lead to the separation of the joints of the laminated panels.

Therefore, additional leveling should be provided to ensure the laying of the leveling underlay. It should be noted that you should not use too thick material under the floor covering, as the joints may bend, which will negatively affect the operation of the laminate floor. The most optimal substrate is considered to be a 3 mm thick laminate.

How thick should the substrate be?

  • For an ideal subfloor that has been pre-leveled with a concrete screed, a 2mm underlay is suitable.
  • Also, for a flat surface with small flaws, a 3 mm substrate is suitable.
  • If there are significant irregularities, flaws or laying is carried out on an uneven sub floor without special preparation, for example, on linoleum or old parquet, a 4 mm thick substrate should be used.
  • In special cases it is necessary to use a leveling material with a thickness of more than four millimeters. If the irregularities are quite large and require a suitable thickness, then a substrate with a thickness of 6 mm or more should be requested, for example a substrate 10 mm thick.

Substrate selection criteria

6What kind of substrate to choose, because the modern construction market offers many options? You should not choose inexpensive material from little-known manufacturers, as this will ultimately result in additional costs for the restoration of the laminate floor, when a poor-quality substrate will provoke the floor to swell and deform.

The main requirements that must be met for the substrate:

  • Neutrality to alkaline substances and materials;

  • Have antibacterial properties to prevent the appearance of mold or fungus, as well as microbial foci;
  • Thermal insulation, as we have already found out one of the main properties of the substrate for the laminate;

  • Moisture resistance is also very important for this material, since it will keep the laminated coating from deterioration;

  • It is also important to prevent the spread of such biofactors as insects and rodents;
  • Micro ventilation, which will remove condensation that occurs under the floor;

  • Resilience and elasticity are responsible for relieving pressure from joints (seams) during the operation of the laminate.

Types of laminate substrates

Expanded polystyrene underlay for laminate

7Quite often, extruded polystyrene is used, which perfectly levels the floor and eliminates boominess, that is, it creates good sound insulation. The choice of this material will be optimal for premises with high traffic. The thickness of this substrate under the laminate is 3 mm, but it can be even more.

High resistance to vibrations and their suppression, as well as resistance to stresses that occur from pressure when people move on the floor or from furniture standing on the floor, guarantee a comfortable walk and the integrity of the seams and the entire laminate floor as a whole.

The polystyrene underlay for the laminate insulates the floor well and protects it from moisture, thanks to its closed cell structure. The material itself has a high density and will retain its original elasticity and integrity for a long time, which will extend the life of the laminate.

Polystyrene foam backing is affordable and easy to install.

Polyethylene foam underlay for laminate

8This type is probably the most popular, as it has high practicality and resistance to various factors, such as physical activity, biological component (bacteria, mold, fungus) and has a low cost.

Also, when working with the material, little waste occurs, which is also an important factor. The polyethylene backing has excellent moisture resistance and thermal insulation properties; it is also not interesting for rodents and insects, which is important for private houses.

This type often has a metallized aluminum base, that is, a foil laminate substrate. This option has improved thermal insulation and moisture resistance.

Of the many positive characteristics, the negative aspects of this substrate should also be noted. This is a low density, which over time can lead to sagging of the material, which will lose its original shape.

Cork underlay for laminate

9If you ask – which substrate is warmer under the laminate? It is safe to say that this is a cork substrate as this material has excellent thermal insulation characteristics. Also, this type has good resistance to rot and mold. Other positive characteristics are that the underlayment is perfect for floating floors.

This material is used for indoor underfloor heating. The cork material does not deform or lose its shape over time.

The cost of cork is quite high, so it is impractical to lay this underlay under an inexpensive laminate, it is better to use it when creating a high-quality expensive laminate floor with high resistance.

Combined underlay

10Quite often, combined substrates are used for laying under a laminate. These are materials in which both expanded polystyrene and polyethylene are used. The most common and well-known such material is Tuplex, which consists of several layers like a “sandwich”, where a layer of polystyrene balls is laid between two layers of polyethylene.

This type of underlay is sold in rolls and is up to 3 millimeters thick. Quite an interesting design of this combined film allows you to ventilate the space. The top layer of polyethylene has a denser structure and prevents the penetration of moisture that has got on the surface of the laminate. The lower polyethylene layer, on the contrary, allows moisture to pass through and removes it along the middle layer through hollow polyester granules.

Laying the substrate under the laminate with your own hands

Stages of work:

  1. Floor preparation. Proper installation of the laminate underlayment will contribute to the durability of the laminate flooring. Before laying the underlay, clean the floor surface from dirt and debris. If the material is laid on a cement or concrete floor, then additional waterproofing should be carried out by laying a polyethylene film intended for these needs, which has a thickness of 0.2 mm or more.

  2. Laying the backing material. It is recommended to lay the material across the direction of laying the laminated panels themselves. It is imperative to put the substrate on the walls to ensure the safety and durability of the floor covering. Fastening of joints can be carried out with mounting construction tape. The substrate itself is glued with glue or double-sided tape. If one surface of the substrate has a corrugated structure, then the corrugated side is laid on the subfloor. If one side is foil, then it is turned towards the laminate to prevent moisture from entering from the side of the flooring.

In principle, there is nothing super complicated in laying the substrate under the laminate, and even a beginner who has never taken up tools can cope with this repair construction work. This article will help you understand the nuances of laying a substrate under a laminate.

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Steve

Passionate about DIY for over 10 years and all the new tools, I give you through this blog all my advice, tips, tests in all areas: carpentry, electricity, masonry, gardening, home automation ...

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