Yes, you can use cork underlayment under carpets. The most important thing to keep in mind is to install these floors and underlayment in a room that’s not going to be exposed to water, moisture, and humidity on a regular basis. Cork can absorb liquids, which can cause damage and lead to mold and mildew.   Before deciding to use cork underlayment, you should check the room’s humidity levels and consult a professional as to whether this is the right approach.