Laminate flooring underlayment is necessary because laminate floors are free-floating and do not attach to the subfloor at all. Underlayment helps to deaden the sound when walking on laminate flooring and it covers imperfections in the subfloor. When installed in upper-level rooms, underlayment helps minimize the noise projection through ceilings below.
Manufacturers of laminate flooring should recommend the best type of underlayment for their particular product and your needs. There are 5 different kinds of underlayment:
Standard Foam Underlayment
Made of foam and generally 1/8-inch thick. This type of flooring does not provide much protection from sound and it is generally used on a ground-level laminate floor. There are varying sizes of rolls that you can buy depending on the size of the room that you are flooring.
Similar to standard foam underlayment except that it also has moisture protection on one side. Because it does not provide much sound protection, it is most often used on the ground floor, especially in areas where there is the possibility of moisture getting under the laminate floor.
Floor Muffler Underlayment
Used when there is the need for moisture protection and sound reduction on the floor. This type of flooring is more expensive than the other types of underlayment, though no flooring will completely eliminate the noise from laminate flooring.
Specifically designed to reduce noise. It is thicker than the standard foam underlayment. It is a good choice for second-level laminate floors and is most often chosen when there is a greater need for sound reduction.
The very best that you can choose as it reduces sound, resists moisture and it is environmentally sound. You can choose cork in varying thicknesses for the best sound reduction possible. Though more expensive, cork underlayment is ideal for upper-level rooms that require more sound reduction.
Installing Laminate Floor Underlayment
Measure the floor and purchase underlayment cut to fit the size of your room
Lay underlayment over a clean floor, keeping mindful of warping, nail holes, etc.
Tape all sections together at the seams.
Begin installation of your laminate flooring
One tip is to install the flooring in sections so that it does not shift. Shifting will cause the underlayment to become uneven, which will make the laminate floor bumpy.