What is a carpet underlay for? Its functions, characteristics and types, advantages of use. Rules for choosing a quality layer. The carpet underlay is an insulating material used to exclude possible contact of the cloth with the rough base. It provides heat, sound and moisture insulating function. Many characteristics of the floor covering, as well as the period of its operation, depend on the correct choice of the layer.
The need to use a backing under the carpet
Most of us like to save money, especially when it comes to some additional costs when laying flooring. Carpet is considered to be the most budgetary, soft and beautiful finishing of the floor from the “set and forget” series. But it's not that simple.
A carpet underlay is required, because it:
- Extends the life of the floor covering;
- Makes the floor softer and warmer;
- Creates the feeling of a thick carpet, even when laid with a short pile fabric;
- Improves sound insulation;
- Creates an additional waterproofing layer.
Thus, the answer to the question of whether you need a carpet underlay is unambiguous - you cannot do without it!
The main types of carpet backing
There are several types of insulation for floor coverings. Each has its own positive and negative characteristics. Choosing the right material is the task of a real professional.
Consider the main types of carpet substrates:
- Polyethylene foam substrates … The cheapest material on the market. It has a thickness of up to 6 mm, it is produced in rolls 1 m wide and 25 or 50 m long. Polyethylene foam is easy to install: the rolls are unwound, the joints are fixed with construction tape. The disadvantages of such a substrate are significant. It is fragile, quickly crushed and torn when carelessly laid.
- Polyurethane foam underlays … They are characterized by excellent thermal and waterproofing properties, suitable for both residential and office premises. The polyurethane foam backing under the carpet ideally protects against sounds. It can be laid on any surface. It is important that the base is dry and clean during installation. Polyurethane foam has high wear resistance. Substrates made of this material can withstand up to 200,000 load cycles.
- Polyurethane underlays … They differ from polyurethane foam in their thickness (it is slightly larger), they have a polyethylene layer that protects the material from the influence of moisture. This type of substrates is most often used when laying carpet using the "stretching" method. Felt-coated polyurethane underlays are also available. They perfectly isolate the room from extraneous sounds and smooth out the unevenness of the floor. Artificial jute or paper is used as the basis for polyurethane substrates.
- Rubber crumb pads … They can be used under various floor coverings. The structure of the material is quite dense, but after laying the carpet it becomes softer. The crumb rubber pad ideally protects against moisture, retains heat in the room, and also well "drowns out" various sounds. Installation is simple - with two-component adhesive, no additional waterproofing is required. The crumb rubber lining under the carpet is ideally combined with the carpet produced on a natural basis.
- Cork backing … This is the best kind of carpet interlayer. It is produced in the form of rolls or slabs of a certain thickness. Among the positive qualities are ecological cleanliness, complete safety for animals and humans. The cork does not rot, does not absorb moisture, does not deform, does not cause allergies and does not accumulate dust, therefore it is completely safe for allergy sufferers and asthmatics. Such substrates are distinguished by high thermal and sound insulation characteristics, they well hide small defects in the subfloor. They are suitable for both concrete (waterproofing required) and wooden substrates. Specifications: density - 200-250 kg / m3; thermal conductivity - 0, 042 W / m * K; sound absorption - 0.85; the dimensions of the roll are 1 x 10 m. The cork has one drawback - it costs much more than other options. Therefore, carefully consider your financial capabilities before buying.
A cork underlay for carpet is a good shock absorber. When used, the floor becomes much softer, so it is recommended for children. Having fallen on such a floor, the child will not receive bruises and bruises. And if you don't know which carpet backing is the best, feel free to choose cork.
Criteria for choosing a carpet underlay
Going to a hardware store, you must adhere to the following rules:
- Feel your chosen backing. It should be tight, but not stiff.
- Smell the stuff. The artificial layer should be odorless.
- Squeeze the material in a fist, then release. If it crumpled and very slowly returns to its previous state, it is better to refuse the purchase.
- Thick and loose material will not last long. The optimum thickness of the carpet underlay is 1 cm, it should be homogeneous in structure, flexible.
- If the base is made of concrete, buy a crumb rubber backing; if the subfloor is wooden, give preference to cork.
- For carpet on a synthetic basis, an artificial backing is suitable.
Important! Natural material requires an environmentally friendly interlayer, so get a cork.
Carpet underlay manufacturers
The market for carpet substrates is large and is represented not only by domestic manufacturers. Among the best quality natural interlayers, the Portuguese company PREMIUM CORK should be noted. Its material consists of natural cork, has the highest density and the lowest thermal conductivity, good noise insulation characteristics.
Another company from Portugal, Matrix, produces high quality cork and expanded polystyrene substrates. Both materials hold their shape under any pressure.
Parkolag from the Danish brand Icopal-group confidently holds the palm in combined linings. The composition of the material is paper impregnated with bitumen and densely sprinkled with cork chips. With a thickness of only 3 mm, this underlay has a long service life, wear resistance, and is impervious to moisture (works as a waterproofing layer). Parkolag is a breathable material, so moisture will not accumulate under the carpet and mold will not form.
Izolon PPE from Izolon-Trade LLC is a bright representative of foamed polyethylene. This material is a good alternative to expensive cork and cheap uncrosslinked polyethylene. Among its technical characteristics: high elasticity, low thermal conductivity, good sound insulation properties.
Polyurethane underlays are presented by two brands - American DTR 3 and English T 5. The basis of the material from DTR 3 is artificial jute and felt, carpet can only be laid by stretching. The material from T 5 has a paper base and a felt top cover. The carpet can be laid on top in any known manner.
The British company Interfloor produces a high-quality version of Durafit 500 crumb rubber substrates. The base is polyjute. The material has high strength and can be used in both residential and commercial premises with high vertical loads.
From polyurethane foam substrates, it is necessary to highlight such manufacturers as NC-Blue, Berber Max, Napa. NC-Blue has high strength, is reinforced on one side with mesh and viscose yarns, and has high wear resistance. Carpet on such a substrate is laid by the methods of "pulling on hooks" and "gluing". Berber Max can be installed on all types of substrates.
The material has reinforced strips and is resistant to fracture. Suitable for residential areas. Napa has the largest thickness of the carpet backing - 1, 2 cm, the material is suitable for all types of substrates. The carpet is laid using the "Stretching" or "Double-sided gluing" methods. For all of the above substrates, the maximum carpet thickness is 2 cm.
The technology of mounting the underlay under the carpet on the floor
There are no problems with laying the material. Each of the interlayers can be applied both dry and glue. But preparatory work with the subfloor is necessary in any case!
Preparatory work before laying the underlay under the carpet
For work, you will need a minimum set of tools: a knife for cutting, glue, if hard laying is to be done, the substrate itself and a waterproofing film, if it is necessary by technology. Also, do not forget the construction tape for securing the seams.
Whether or not to level the base before laying the underlay and carpet is a question asked by those who want to finish the repair as soon as possible. In this case, it all depends on what material will be placed between the topcoat and the sub-base.
It is imperative to level the base under very dense substrates! If you lay the cork on a "humped" floor, it will also begin to "hunch down", laying a carpet on such "waves", nothing good will come of it.
For more elastic materials, it is permissible not to carefully level the base, however, it is imperative to knock down the bumps and seal the pits with cement mortar. If the level difference is more than 2 cm per 1 meter, you will have to pour a concrete screed.
If a carpet is placed on concrete, the order of work is as follows:
- You clean the concrete slab from debris.
- Perform a rough alignment.
- Remove dust.
- Divide the floor into squares if the room is large, or into two equal halves if it is small.
- Cover the self-leveling concrete mixture with water.
- Pour it into the selected square, roll it with a needle roller to remove air bubbles.
- Do the same with the rest of the cavities. After a couple of days, remove the dividers, fill the holes with a cement mixture and carefully level them.
- Let the surfaces dry well.
If the underlay is laid under the carpet on a wooden floor, it is undesirable to pour a self-leveling concrete screed. Use plywood alignment. This will give extra rigidity to the rough subfloor. Remove debris and dust from the floor and check the level of deviation from the horizontal. Calculate the thickness of the plywood. In places where the surface level is slightly lower, thicker sheets will be needed.
The ideal option is to lay the plywood in two layers. The bottom layer is located with the obligatory spread of vertical seams (like brickwork), fixation is made on nails or self-tapping screws. The second layer is also laid with a bandage, but above each seam of the first layer there should be a whole sheet of the second. Fixation is similar. The preparatory work has been completed.
How to install a carpet backing
Consider how to mount the underlay under the carpet on the floor:
- Floating underlay … A simple option, however, it is fraught with the fact that the material will wrinkle somewhere if the carpet is unsuccessfully laid. Installation is done from the far corner along the long side of the room. The rolls of material are rolled out and allowed to rest so that it does not roll back into the tube. When the substrate is flattened, the joints are minimized and the panels are connected with construction tape. A polyethylene film with a thickness of 200 microns and more must be placed under the cork.
- Laying the substrate on glue … Before such work, you must carefully remove all dust from the base. It is best to fix material that is prone to wrinkling, i.e. not very tight. The installation technology is simple: unscrew half the length of the substrate, apply glue to the base, put the material back and carefully level it with your hands. To secure the result, roll something heavy on top. Do this with each of the rolls. Secure the joints with construction tape.
Important! Choose glue based on the backing material, otherwise there is a high probability of shrinkage and the appearance of gaps between the rolls. How to lay the backing under the carpet - watch the video:
The need for laying a special lining under the carpet is beyond doubt. This material will make the floor warmer, softer, and muffle sounds. When choosing a substrate, pay attention to the presence of a certificate and consult with the seller.
