Cork is one of the best types of underlayment for an engineered hardwood floor. The cork flooring typically is about ¼ of an inch thick. Cork flooring must be used in conjunction with a moisture barrier when used with engineered hardwood floors to prevent sweating and other flooring problems. Cork is ideal for use on engineered hardwood floors that require a muffled sound, such as those on pier and beam foundations or second-story wood floors.
Foam underlayment is one of the most common forms of underlayment for any hard flooring, engineered hardwood included. Foam underlayments are about 1/8th of an inch thick. When used in conjunction with hardwood floors, a moisture barrier is recommended, such as a plastic sheet installed between the subfloor and the underlayment. Typically, foam underlayments are used for engineered floors placed over a plywood subfloor, such as when used with a pier and beam foundation. This underlayment is not recommended for concrete foundations or for second-floor rooms.
A rubber underlayment is ideal for engineered hardwood floors where sound reduction is necessary, such as in an apartment or second-story floor. Rubber absorbs much of the sound that carries between floors. Rubber underlayments are preferred and sometimes even required for high-level floors, such as with a condo or other shared building. Rubber does not typically require the use of an additional moisture barrier. Rubber works well with concrete or wood subfloors.
Closed-cell foam underlayments are a thicker form of underlayment, which is ideal for sound-reduction. Closed-cell foam does not require the use of a moisture barrier. With engineered hardwood, the closed-cell foam is best with concrete subfloors. The thicker underlayment will reduce foot sounds and increase the comfort of the engineered hardwood minimally. This kind of underlayment will work on first and second or higher stories in a home or business.