Substrate under the laminate: which one to choose? Which substrate is better for laminate flooring: a comparative overview of different types What thickness should the substrate be

Sheet substrate for laminate flooring is an essential attribute of the flooring, which simultaneously performs several functions that ensure a long life of the floor. When choosing a damper, you need to take into account a number of features that affect many characteristics of the coating. One of the most important criteria is the optimal layer thickness.

Is a backing always needed?

Laminate is made from artificial materials that have significant drawbacks:

  • sensitivity to mechanical influence;
  • warping.

Only a substrate for a laminate can level these disadvantages. After all, the heat and sound insulation properties of the floor, moisture resistance and its service life depend on its presence. In this case, the damper layer must meet certain requirements:

  • The material must be neutral to interaction with chemical reagents, especially alkaline ones;
  • The bactericidal properties of the lining should exclude the possibility of mold development under the coating;
  • The material must be inedible for insects and mice;
  • The structure of the damper must ensure floor ventilation;
  • The lining under the laminate is designed to neutralize the serious load on the locking system of the lamellas.

In addition, the underlayment is able to eliminate minor irregularities on the rough base, and also act as a shock absorber that softens shocks while walking on the surface. Based on the foregoing, it becomes clear that the substrate in the case of installing a laminated coating is simply necessary.

Substrate thickness

The thickness of the substrate can vary in a significant range: from 0.8 to 10 mm. Each of the types should be used only in accordance with the condition of the subfloor, as well as the thickness of the laminated boards. The sizes of the underlayment considered below are most common:

  • Substrate under the laminate 2 mm. A thin damper layer that has excellent cushioning properties. Most often used for laying lamellas, the thickness of which does not exceed 5-6 mm;
  • Substrate under the laminate 3 mm. This type of lining reduces the noise level while walking on the surface, and is also suitable for the "warm floor" system. Often it already comes bundled with class 32 and 33 laminate;
  • Substrate under the laminate 5 mm. Thick damper, which is used in commercial premises. Improves the performance of the coating, extending its service life.

Tip: This material is used for laying lamellas whose thickness exceeds 10 mm. Because laminate flooring is "floating", thinner boards on a very thick underlay will sag.

Determination of the optimal damper thickness

Many experts argue that the thickness of the underlayment should be approximately 3 mm. This is enough to level minor defects on the rough base and provide cushioning. However, with significant height differences of 3 mm, the damper will be practically useless. But this does not mean at all that a thicker lining can solve this issue.

The fact is that the soft lining material on which the laminate is laid can provoke a breakdown of the locks located at the ends of the connected lamellas. This often happens during the operation of a floor laid on an uneven screed. As a result, large gaps appear on the surface, which further leads to tearing of individual planks from the floor.

In the case of dampers made of artificial materials, such as polyethylene or polystyrene, it is better to give preference to small thicknesses up to 3 mm. Such materials quickly deform and become thinner in places of the greatest mechanical load. This can lead to backlash between the laminate and the base. Therefore, the greater the thickness of the flooring, the more gaps are formed between the boards and the screed.

If the thickness of the coating, together with the synthetic underlay, is insufficient to bring the floor to the same level as another room, it is better to take a slightly thicker cork flooring. Firstly, it is little deformed and pressed, and secondly, it has a much longer service life. Such a need arises in the repair of private dwellings.

Often the floor level in the corridor and rooms turns out to be different, which leads to the appearance of small sills. This problem can be eliminated by dense substrates with a thickness of 3-4 mm.

Types of dampers and their sizes

The thickness of the substrate under the laminate depends not only on the size and thickness of the lamellas, but also on the type of materials used. Therefore, before you purchase flooring, you should study its varieties:

  1. Izolon. This type of material has excellent water resistance, so it can be laid in rooms with high humidity. At the same time, there are several types of isolon:
    • With a thickness of 1 to 1.5 mm. It is produced in rolls, the width of which is 80-90 cm;
    • With a thickness of 2 to 10 mm. Available in the form of tapes with a width of up to 50 cm;
    • With a thickness of 20 to 60 mm. Most often produced in the form of rectangular plates.
  2. foil material. It is produced on the basis of isolon, in addition, it contains a thin layer of foil, sometimes on a self-adhesive basis. The damper perfectly retains heat and resists moisture. Available in rolls with a width of up to 120 cm, and a thickness of up to 5 mm;
  3. Cork flooring. Very durable material with good sound and heat insulation. There are several types of it:
    • In the form of a sheet with a thickness of 2 to 4 mm. It is treated with a special antiseptic that prevents the development of mold under the floor;
    • Elastic cork flooring. Has good sound insulation. In this case, the layer thickness varies from 1 to 5 mm;
    • Bitumen-cork damper. Durable coating that can withstand heavy loads. As a rule, manufacturers produce substrates with a layer thickness of up to 5 mm.
  4. Composite lining. Consists of 3 main layers: film-polystyrene-film. Usually sold in rolls with a layer thickness of 3 mm;
  5. Styrofoam material. One of the cheapest dampers with a thickness of 0.5 to 6 mm. However, with prolonged use, it can become thinner, which will lead to damage to the floor.

Styling features

After you decide on the optimal size of the flooring and its type, you will have to install the flooring. The process is quite simple, so even a beginner who has never repaired a floor can handle it. It is only important to follow the instructions that will allow you to properly lay the flooring.

Sheet is laid in two stages:

  1. First stage
    • Before starting work, the rough base must be cleaned of dust and dirt, and then dried;
    • Then it is necessary to provide additional waterproofing of the floor;
    • For this, a durable plastic film is most often used, which is placed on top of the base;
    • To cut off the excess part of the film, use ordinary scissors;
    • It is important that the film overlaps the walls;
    • In the process of laying the material, the waterproofing layer may move out. Therefore, it is desirable to fix it with adhesive tape.
  2. Second phase
    • Now you need to place the substrate perpendicular to the lamellas. This is necessary so that during the installation or operation of the floor covering, its individual elements do not move;
    • As in the case of a waterproofing film, the substrate should overlap the walls, this will form a bowl;
    • If the interlayer has a corrugated surface, it is desirable that it be laid facing the subfloor. Then this will help to level the base;
    • In the case of a foil damper, it is desirable that the foil be turned up;
    • When laying a roll layer, connect adjacent sheets with molar adhesive tape;
    • To fix individual plates of cork or needles, you need to use either a stapler or glue.

Important! It is strongly not recommended to lay the damper in several layers to level the base. This can lead to very disastrous consequences. Firstly, under the influence of the load on the coating, the floor will sag and the locking system will be damaged, and secondly, the layers of the litter may shift relative to each other, which will lead to the formation of voids under the floor.

Subject to all the rules for choosing the substrate, as well as the way it is laid, the floor covering will serve you for at least 10 years. At the same time, the damper layer will provide a good level of noise and heat insulation. Moreover, a high-quality layer significantly reduces the load on the interlocks between the laminated boards, which allows the floor to remain “new” for a long time.

The performance of laminate flooring depends on many factors, including the thickness of the substrate and the grade of the laminate. The manufacturer of the floor material in the instructions for the coating determines with his recommendations what thickness of the substrate for the laminate will be the most optimal, indicates the method and criteria for selecting the base. Most amateur and professional installers of parquet and laminate flooring try to adhere to the recommendations, since excessive thickness of the laminate with the substrate can cause inconsistencies in the coatings of different rooms and interfere with the normal opening of doors.

How does laminate flooring work?

Durability, attractive appearance of the coating and high quality of the overall web of single lamellas can only be ensured using a material with a complex multilayer structure:

  1. The outer surface is a laminated layer based on a thick and durable acrylic or melamine acid polymer film;
  2. The core of the laminate panel is made from pressed cellulose fibers with the addition of viscose and a binder, waterproof grades are made on the basis of impregnations and PVC materials;
  3. The underside of the lamella is usually covered with an acrylic-latex compound to improve adhesion to the substrate.

Laminate coating is conditionally divided into two strength groups, conventional and reinforced. The first include home coatings, classes 21 - 23 with a lamella thickness of 9 mm. The second group includes commercial laminate 31, 32, 33 class, designed for high abrasion and contact load, with a standard substrate thickness of 4 mm.

Class 31 material is used for public institutions and offices with a small load, class 32 laminate flooring is the golden mean, used for bank offices, shopping centers and commercial institutions with an average load. The thickness of class 33 laminate is the maximum among laminated coatings and reaches 12 mm. And for each class there is its own optimal combination of lining thickness and material from which it is made.

Why is it so important to guess with the thickness of the substrate

With all its advantages, the laminate coating is very sensitive to the quality of the prepared substrate. According to the requirements of SNiP, for laying a home laminate flooring, it is necessary to provide:

  • The difference in height over a two-meter length of the coating is not more than 2 mm;
  • Local defects of a point type or a small “hillock - depression” with a height difference do not exceed 3 mm;
  • The slope on the base of the floor is no more than 4 mm on a two-meter section of the coating.

The requirements for the laminate are quite stringent, so many manufacturers, due to the optimal selection of the quality and thickness of the substrate, consider it possible to reduce the height of the defect on the base to 3 mm. The material and correctly selected thickness of the substrate under the laminate allows in some cases to solve the problem of uneven bases. In some types and brands of laminate, a very soft porous layer of foam is applied on the inside of the coating, which compensates for the formation of air cavities under the laminate when the material does not fit snugly against the lining.

In addition, the thickness and resistance to contact pressure of the substrate determines whether the laminate will pop and creak underfoot. The appearance of such a creak indicates friction between the individual parts of the lock, for example, the end surface of the spike can rub along the edge of the groove of the second lamella.

It is impossible to choose the thickness of the substrate so that two joined laminate panels are exactly in the same plane. This is affected by the curved floor, furniture and interior items that load the laminate flooring. Therefore, the situation with a creaking lock is quite well known to the manufacturer, who is trying to eliminate creaking with special types of substrate of various thicknesses and anti-creaking paraffin coatings for lock joints.

The main problem of the substrate-laminate pair is not the presence of pops or squeaks, although they also introduce some discomfort. The problem is that if the substrate is not thick enough, the laminate sheet is suspended in the air above the defective floor area. If you strongly press down with a pointed heavy object, for example, put a ladder on the lock and climb it, then the ladder support can simply break off the section of the lock connecting a pair of lamellas.

If the destruction process were local, concentrated on a small area, then the destruction of a joint two to three cm long would not affect the strength of the joint in any way. In practice, the lock is deformed, and a long break line is formed. Each time you have to step on a deformed area, the spike of the lock is destroyed more and more, and there comes a moment when the laminate no longer pops and creaks, because the joint is destroyed.

It remains to remove the lamella and replace it with a new one; the damaged area cannot be repaired.

Optimum substrate thickness for laminate flooring

To correctly choose the thickness of the substrate for the laminate, you will need to take into account three main indicators:

  • Rigidity of the laminate board. The stronger and thicker the lamella, the less its reaction to pressure from furniture, legs, stepladders. A rare but very popular class 34, 15 mm thick, can be laid on a self-leveling floor with a substrate of 1 mm or without it at all;
  • The quality of the concrete screed for laying the laminate flooring, the presence of defects and slope on the surface. The more bumps and sharp chips, the greater the chance that the thickness of the substrate is not enough to compensate for the defect;
  • The contact stiffness of the substrate material, the ability of the web to contact crushing, without the occurrence of an elastic reaction.

Note! The soft substrate is intended for that to be crushed without destruction and elastic deformation, to take the load from the laminate, redistribute it over the entire surface and compensate for sharp protrusions on a poured or concreted base.

In theory, the thinner the laminate, the thinner and stronger the substrate can be used. But in practice, the minimum thickness of the base is limited to the optimal 3 mm, the maximum thickness of the substrate does not exceed 4 mm. In some cases, for class 33, a 5 mm sublayer can be used. But that's not all, for a particularly durable class 34, you can use a maximum lining up to 7-8 mm thick.

The process of determining what suitable thickness of underlayment should be always comes down to the quality of the prepared subfloor.

What gives the use of cork

Cork canvas or sheets are ideal for use as a laminate underlay. Cork wood is very light and soft. At the same time, the softness of the cork substrate is combined with a small degree of elasticity, which is enough to resist crushing and at the same time absorb protruding pointed defects on the concrete floor well.

If you imitate a floor defect and strongly press a cork surface with a sharp object, the material is simply pressed through to a shallow depth, without an elastic reaction. This means that the cork base will simply "absorb" the defect in its structure, without transferring force to the laid laminate.

Cork lining material is produced in two types - in sheets and in the form of a rolled web. Cork sheet boards are used for heavier 23 and 33 laminate classes. Cork slab perfectly suppresses and dampens noise, has excellent thermal insulation and sound insulation. A rolled cork lining is laid on self-leveling floors, without treating the base with waterproofing mastics and primers. On concrete screeds, a sheet cork lining is used, but before laying, the concrete is treated with primers of the type of concrete contact and laid with film insulation.

The only significant drawback of the cork substrate is its low resistance to soaking and damage by pathogenic microflora. There are many branded underlays for laminate flooring made from different varieties of cork, but not all of them work equally well as a lining. The best options for underlays are cork materials from Spain.

The thickness of the cork substrate is from 2 to 4 mm. Cork is one of the few completely sustainable materials used as a lining under laminate flooring. Cork fabric burns well, but in combination with laminate it smolders faster, without releasing toxic decomposition products of polystyrene and propylene.

Substrate alternatives

In addition to the rather expensive cork wood, foam materials are widely used as lining materials, such as expanded polystyrene or composite Tuplex. French development is the smallest closed balls of expanded polystyrene, sealed in a "sandwich" of polyethylene film. The thickness of the canvas is 2-3 mm.

According to its characteristics, Tuplex is closest to cork substrates. Most of the polymers used have mediocre vapor permeability, with the exception of bubble polyethylene. The additive in the form of polystyrene balls made it possible to obtain a very flexible and at the same time soft material, which has exceptionally high capabilities in redistributing the load on the laminate over the surface of the base.

Typical errors in the selection of the substrate of the required thickness

The most common variant of incorrect laying of the substrate is associated with an attempt to save on material. Instead of a full-fledged base under the laminate flooring, many mountain craftsmen try to lay out pieces of the substrate only in the places of depressions on the concrete base.

Often, a concrete screed is performed indoors in several stages of concreting, from different materials. In such cases, one edge of the concrete floor is “littered” or has a slope to the side or in the center of the room. In such cases, would-be craftsmen lay out the defective area with glue and a cheap polystyrene foam substrate 2 mm thick. As a result, after laying the laminate, the place with the reinforced substrate sticks out with a “hump”, and after a couple of months, due to the collapse of the lining, the laminate begins to clap and creak.

The second way to save is based on the fact that an expensive cork underlay or Tuplex is laid like a warm floor on a roll basis. The canvas is laid only in the central part of the room and pedestrian areas. The rest of the backing is replaced by cheaper polystyrene and fiberboard. As a result, it turns out that a part of the laminate, lying simultaneously on two types of lining material, quickly loses the strength of the joint and moves around.

Conclusion

Following the recommendations of the laminate manufacturer when selecting the substrate material and its thickness is the only right decision to ensure the durability and reliability of the flooring. For a home version of class 23 laminate, you can use a 3-4 mm thick substrate with guaranteed laying quality; for heavier lamellas, the thickness can be increased to 5 mm, but only if there are no height differences exceeding 4 mm per two meters length.

Laminate as a floor covering in modern interiors is used everywhere. The reason for this is the practicality of this material and the optimal price-quality ratio. In order for such a floor to serve for many years and not cause any trouble to the owners, it is important to choose the right material for the floor and the substrate under it.

Why do you need an underlay

The purpose of the substrate under the laminate is determined by the functions that it performs:

  • Laminate flooring is sensitive even to minimal unevenness of the rough coating. In the presence of a "backlash" even of 2 mm, the material begins to "walk", cracks form at the joints, and the fastening of the locks is weakened. For example, even a new concrete screed may have small differences in surface level. Therefore, the main function of the substrate under the laminate is to level the surface in order to prevent vibrations under the influence of the load.
  • When laying the laminate, a floating method is used, the material is not attached to the base. In combination with an elastic solid surface, a kind of sound membrane is formed. Under the influence of the load, such a floor makes a loud noise, unpleasant for both the owners and neighbors. A properly selected substrate dampens shock vibrations and eliminates unnecessary noise, performing an important function of sound insulation.

Reference: In the manufacture of class 32 and 33 laminate, a number of manufacturers use integrated substrate technology. The soundproofing underlay is glued to the back of the laminate sheets. Such material is easy to lay, but its cost is significantly higher than conventional material.

A well-chosen laminate underlay saves you from a number of problems.
  • The underlay acts as an insulator. Laminate itself is a heat insulating material, and in combination with the substrate, the ability to retain heat is increased. In this regard, the owner of the home does not need to think about other methods of thermal insulation. On the other hand, when using such a coating, it is not advisable to use the "warm floor" system, since the efficiency of the heating elements can be reduced to zero.
  • The waterproofing function performed by the substrate is associated with the need to neutralize the negative effects of moisture. Laminate is made from wood dust, has the ability to easily absorb even small amounts of moisture and deform under its influence. Properly selected substrate protects the lower surface of the coating from high humidity, creating an optimal microclimate.

Kinds

Depending on the material, manufacturing technology, technical parameters, several types of substrates for laminate can be distinguished. Knowing the advantages and disadvantages of each, the home master will select the material that is optimal in terms of the volume of functions performed, price and quality.

  • One of the most popular substrate materials is polyethylene foam, or isolon. This material has good waterproofing and thermal insulation properties, is not susceptible to infection by bacteria and fungi. Rodents and insects do not like it. The positive aspects also include low cost and a small amount of waste remaining after installation. This material is also available with additional layers either in the form of an aluminum foil substrate or in the form of a metallized film. These varieties slightly increase the cost of the material, but enhance the positive qualities. The material also has a number of disadvantages: the material does not retain its shape well after deformation.

Foamed polyethylene is most often used as a substrate
  • The next most popular substrate material is extruded polystyrene foam. Usually it has two layers - a substrate in the form of a polystyrene plate, on which a layer of aluminum foil is fixed. This material is more resistant to stress due to its elastic structure, it performs sound-absorbing and moisture-proofing functions well. The low cost is also on the positive side. However, expanded polystyrene does not roll well when laying and is pressed under significant loads.

Expanded polystyrene substrate is more resistant to stress compared to isolon

Reference: A number of manufacturers produce combined substrates using polyethylene and expanded polystyrene. This material is a kind of sandwich, in the middle of which polystyrene balls are located between the layers of polyethylene. Such a composition has the advantages of both materials and is devoid of their disadvantages.

  • Technical cork underlay is a material made from pressed oak bark. This environmentally friendly material is an excellent heat insulator, is not subject to deformation throughout the entire service life and smoothes out all the unevenness of the base. At the height and soundproofing characteristics. However, cork flooring is sensitive to moisture and may cause condensation to form on the underside of the laminate during use. Due to the high cost, a cork underlay is not advisable to use when laying a floor from a cheap laminate.

Cork is an environmentally friendly material
  • Bitumen-cork substrates have much better moisture insulating properties compared to cork. They are made from kraft paper treated with bitumen, the surface of which is covered with cork chips. Along with reliable moisture insulation, such substrates provide good air exchange. The disadvantages of such substrates are the same as those of cork, and the main one is the high price.

Bitumen-cork substrate has high waterproofing properties
  • Relatively recently, another type of substrate appeared on the market - coniferous. It is made from natural needles by pressing, and coniferous resin acts as a connector. The result is a natural material. It is produced in the form of small tiles, has high strength, creates conditions for optimal air exchange. The material is heat-resistant, so it can be used with underfloor heating systems. The disadvantages include the ability to easily and permanently absorb foreign odors. In addition, rodents, harmful insects and bacteria can easily start in such an environmentally friendly material. The cost compared to synthetic substrates is also high. When using such a substrate, there is a risk of denial of the guarantee for the coating, since its thickness is from 4 to 7 mm.

Coniferous substrate is laid in diagonal rows

Which one to choose for an apartment and a house

When determining the type of substrate, one should take into account the type of room in which the floor is laid, operating conditions, the expected maximum load and economic feasibility.


Rules for laying on the floor under the laminate

Each type of substrate has its own styling features. The general rule is careful preparation of the base. The surface should be thoroughly cleaned of debris and vacuumed. If the base is a concrete screed, and the substrate is not equipped with a waterproofing film, it is worth providing insulation with a plastic film. Wooden floors usually do not need additional waterproofing, but often have bumps. You can get rid of them in different ways. For example, the missing elements of the parquet floor are restored and then scraped. If the floor level differences are large, they are eliminated by laying plywood sheets on top of the floor. When the base is ready, start laying the substrate. For cutting all types of substrate, a construction knife is used.

  • The insulating substrate is spread on the floor with an overlap on the walls. Overlapping layers on the floor is not allowed. For convenience, the canvases at the joints are attached to the floor and to each other using double-sided tape.
  • The polystyrene substrate is sold in sheets that are laid out on the base, in which case overlapping of the sheets is also not allowed. Overlapping on the walls is not carried out, the sheets should lie close to the walls, but not go over them. The sheets are connected to each other with construction tape. Some craftsmen recommend using metallic tape for better waterproofing.
  • Sheets of cork substrate are placed on the base without overlaps, while leaving a distance to the walls within 10 mm to ensure moisture removal. The ends are joined with construction tape. Prior to this, the substrate is allowed to age at room temperature to adapt to the coating.
  • Softwood underlay is produced in the form of tiles, which are laid on the floor at an angle of 45° to the walls. The first tiles are cut diagonally, and the laying starts from the far corner of the room. Tiles are butted together and do not require additional fastening. Laminate is laid on top.

Using the right underlay will give your laminate flooring many years of service. At the same time, the shortcomings of this coating are eliminated, which will significantly increase the comfort conditions in any room.

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