How do I choose the right underlay?


When you have purchased a new floor, it is also best to check whether you need an underlay. You will undoubtedly want to keep your house nice and warm on those cold winter days. You’d probably rather not wake up your housemates with a lot of noise when you just want to enjoy a refreshing shower late at night. In both cases, a subfloor is the perfect solution. It insulates against moisture and cold, dampens noise, and is also ideal for levelling out the substrate. Of course, every floor or room needs a suitable underlay. Don’t know which one you need? We’d be happy to explain it to you in detail.

Underlay with a floating floor

When a floating floor is laid, this means that the floor is not glued or nailed to the substrate. In this case, it is recommended to lay an underlay. The right choice of underlay for you depends on the floor and the situation where it will be laid.

Underlay for parquet, laminate flooring, SPC, Vinyl, PVC, or LVT

The choice of underlay often depends on the type of floor being laid. Laminate parquet or laminate flooring are thicker floors (from 6 mm to 15 mm) with a wide choice of underlays: from 1.5 mm to 7 mm thick. Don’t forget to take your doors into consideration. If the floor becomes too high, the doors will have to be shortened.

PVC, vinyl or SPC vinyl floors are thinner floors (3-5 mm) where a thinner subfoor (1-1.5 mm) is also used. An important aspect with these floors is the compressive strength of the underlay. Because of the small thickness of the floor, there should not be too much movement in the click connection when walking on the floor. A stiffer underlay ensures that the joints hold up well and the floor therefore remains beautiful for a long time.

Underlay in an apartment or house

Apartments often require that an underlay have very good soundproofing, i.e. that as little noise as possible is transmitted to the downstairs neighbours. There are underlays for these applications that have a certificate for soundproofing of 10 dB Lin. This is less important for residential properties, so you can choose which characteristics you find most important.

Flat or slightly inclined substrate

Depending on the thickness of the underlay, this may smooth out small differences in height so that levelling of the substrate may not be necessary. A thicker underlay, 5-7 mm, can level out height differences of up to 4-5 mm (measured over 1 m). Thinner underlays, 1.5-2.2 mm, smooth out height differences of 1-2 mm (measured over 1 m).

Suitable for underfloor heating

Warm feet when you get out of bed in the morning… fabulous. This is why many houses nowadays have underfloor heating. This is why it is important that the subfloor has a low heat resistance and allows sufficient heat to pass through it. If you would like more information about heat resistance, please read our document on underfloor heating.

Underlay for soundproofing/reduction of walking noise

Clicking heels, an office chair rolling on the floor, or something falling on the floor. It’s all too easy to make a lot of noise. this can be very annoying, particularly when you live in a block of apartments. Good soundproofing is certainly a must in that case.

When talking about soundproofing, this can mean muffling the sound of walking or muffling the sound of what gets transmitted through the floor to the space beneath it (soundproofing). For maximum soundproofing, as is desired for apartments, a thick underlay is almost always required (from 5 mm) when laying floating laminate or wooden floors. The disadvantage of these underlays is that they cannot be used in combination with underfloor heating. For homes, there are underlays that offer slightly less soundproofing but are also suitable for underfloor heating. When it comes to reducing walking noise, the slightly thinner subfloors perform better than the thicker ones.

PVC, LVT, SPC, and vinyl flooring are naturally better at soundproofing. The walking noise on these floors, even without an underlay, is much less than on a laminate or wooden floor. With a subfloor, these floors absorb the sound as much as possible and can be installed in apartments, in combination with underfloor heating too.

underlayThe ease of laying underlays

Underlays are available in various designs, on a roll, in slabs, or harmonica plates. You often get the best price/quality ratio on the roll, but you have to cut the underlay to size and affix it yourself. Slabs and harmonica plates are slightly more  expensive, but easier to lay without the need for an adhesive.

Moisture insulation

When laying floating floor on concrete or on screed, it is necessary to lay a moisture insulating layer under the floor. This prevents moisture from accumulating under the floor. Many underlays have an integrated moisture-insulating layer so you do  not have to apply this layer separately. In the case of a wooden substrate, it is not necessary to lay a moisture-insulating layer.

Underlay guarantees insulation against cold

Don’t have underfloor heating but still want toasty warm feet? Then it is advisable to use a thicker underlay. underlays 5-7 mm thick provide good insulation against the cold.

How intensively is the space used?

The more intensively a floor is used, the more important it is for the floor to spring as little as possible when walking on it. A lot of movement in the click connection between the planks can mean that it does not close tightly over time due to wear and tear. If the floor is to be used intensively, choose a rigid underlay with a high compressive strength. These are often the thinner underlays. This is particularly important in commercial applications, such as in a shop.

Is something unclear or would you like extra advice on the right underlay for your floor planks? Then don’t hesitate to contact us; our staff will be happy to help you!