Floating Floor Underlayment

What kind of underlayment should you use when installing floating flooring? The question is easier asked than answered. The best kind of floating floor underlayment varies according to the kind of floor you’re putting down, and what kinds of features you’re looking for.

Underlayment is absolutely necessary for any installation of engineered real wood flooring or laminate, since they’re not attached to the sub-floor – which means that the underlayment is responsible for absorbing imperfections, sound dampening, and softening the floor.

Before choosing an underlayment, check with your flooring manufacturer to see what kinds of underlayment can be used with the flooring. Otherwise, there are several distinct types of underlayment to choose from.

Standard Foam

This is the most common kind of floating floor underlayment, and it consists of a thin foam padding that normally measures around 1/8”. The available roll size will vary according to brand, but you should be aware that it only reduces sound and comfort minimally – the least of all options for underlayment. Standard foam is considered ‘entry level’ underlayment, and should only be used if absolutely necessary.

Homeowners should also note that standard foam underlayment doesn’t normally have a moisture barrier attached, which means it should only be used where there is no chance of moisture seeping through the sub-floor. If there is a potential for moisture, you may want to look into using plastic sheeting laid down before the underlayment, or choosing a standard foam underlayment with an attached moisture barrier.

Combination Foam & Film

This is generally the same idea as the standard foam, but one side of the foam has a moisture barrier directly attached. This will prevent moisture from causing major damage to your flooring over time, and is normally used on ground levels where a sub-floor might be simply a concrete slab.

However, you should also note that the combination pieces offer the same noise dampening and softness that standard foam offers, which really only makes it worthwhile in areas where noise is absolutely not an issue.

Modified Underlayment

These underlayments are thicker than standard foam, and are made from materials such as closed-cell foam, rubber, fiber, or high-density foam. They provide much better sound reduction, though not quite in the range of cork. The modified pieces will vary in thickness and quality according to the manufacturer, and you should always check to see whether you are purchasing a modified product with or without moisture barrier attached.

Since the sound reduction quality is higher, these pieces are used on second floors and above. The comfort level of the flooring will remain the same, which is worth noting if you have a particularly hard flooring material. However, modified underlayment is much less costly than cork, making it a viable alternative for many home renovators.

Cork Underlayment

Cork underlayment is possibly the best choice for a floating floor, but it is also the most expensive. Cork is a porous material, moisture-resistant, it’s environmentally-friendly, and there is optimum sound reduction. The product can be purchased in various thicknesses, and gives a solid-hardwood feel to floors when they’re walked on, providing maximum comfort.

Cork can be used under nearly all floating floors, and it can also be used to increase sub-floor height to level off any various areas in the house which changed after re-doing the floors.