Why is an underlayment needed under laminate flooring?

An appropriate underlayment can be installed between the laminate flooring and the subfloor, which is an important part of the entire flooring system. The underlayment can help address minor surface irregularities, improve sound absorption, and contribute to a more comfortable living experience.

However, when choosing an underlay, the goal is not to select the thickest or softest material possible. The right underlay must be compatible with the laminate flooring, the subfloor, and the specific room.

What factors should we consider?

Before choosing a washer, it’s a good idea to consider several factors:

• the manufacturers' specifications for laminate flooring,
• the condition and flatness of the substrate,
• any floor heating,
• sound insulation requirements,
• the use and occupancy of the premises,
• the moisture conditions of the substrate.

Based on this information, you can select the underlayment that is best suited to the specific flooring system.

1. The thickness of the washer

It is a common misconception that a thicker underlay is automatically better. However, an underlay that is too thick or too soft can actually be detrimental to certain types of laminate flooring.

For the click joints of laminate flooring to function properly, adequate stability is required. Therefore, you should always follow the manufacturer’s instructions for the flooring you have chosen.

2. What kind of underlayment is needed for floor heating?

When installing floor heating, choosing the right underlayment is particularly important. You should select a product that the manufacturer specifically recommends for use with floor heating.

A underlayment with excessive thermal resistance can impair the heat transfer of the floor heating system; therefore, when installing floor heating, it is not enough to simply check the specifications of the laminate flooring.

It is worth examining the thermal properties of the laminate flooring and the underlay together.

3. Sound Insulation and Footfall Noise

One important function of underlayment is to reduce footfall noise. This can be particularly important in upstairs apartments or condominiums, where sounds from foot traffic on the floor can travel into other rooms.

Different underlayments may have varying sound-dampening properties, so if sound insulation is an important consideration, it’s a good idea to take this into account when selecting the flooring.

4. Underlayment for concrete subfloor

When selecting an underlayment for a concrete or screed subfloor, the moisture content of the subfloor must also be taken into account.

For certain systems, a suitable vapor barrier layer may be required, while other underlays may already incorporate this feature. This should always be determined based on the technical specifications of the selected product.

It is important not to assume that a vapor barrier is necessary, but to decide whether it is needed based on the specific subfloor and flooring system.

5. Do I need an underlayment for existing flooring?

When installing laminate flooring over existing flooring, the need for an underlayment and its type still depend on the chosen laminate flooring, the subfloor, and the manufacturer’s specifications.

It must be stable and level, consistent with the existing floor tiles or other flooring. The underlayment does not replace the repair of a defective subfloor.

6. A washer that is too soft can cause problems

A very soft underlay may seem more comfortable at first, but it isn't necessarily a better solution under laminate flooring.

If the floor moves excessively on the underlayment, it can have a negative effect on the click joints over the long term. For this reason, it is not advisable to base your choice solely on softness or thickness.

7. What is the best washer?

There is no single type of underlayment that is best for all laminate floors and all rooms.

The right choice depends on the type of laminate flooring being installed, the condition of the subfloor, whether there is underfloor heating, the level of sound insulation required, and the manufacturer’s specifications.

Therefore, it is advisable to treat the underlay as part of the entire flooring system, rather than as a separate product.

Common Mistakes When Choosing Washers

When choosing underlayment for laminate flooring, there are several common mistakes you should avoid:

• choosing a washer that is too thick just because it seems to be of “better quality,”
• using a pad that is too soft,
• choosing an underlay that is not suitable for floor heating,
• attempting to compensate for subfloor defects with a shim that is too thick,
• failure to follow the manufacturer's instructions,
• ignoring the issue of vapor barrier.

What Kind of Underlayment Should Be Used Under Laminate Flooring? – Summary

Choosing the right underlayment for laminate flooring is an important part of planning the flooring system. The best underlayment is not necessarily the thickest or most expensive one, but rather the one that meets the requirements of the flooring, the subfloor, and the room.

With underfloor heating, thermal resistance is a key consideration; in apartment buildings or upstairs rooms, sound insulation is particularly important; and with concrete subfloors, moisture and vapor barriers can also be particularly important.