Does COREtec flooring need underlayment?

Does COREtec flooring need underlayment? No, COREtec flooring does not need additional underlayment as it has attached cork underlayment built-in, providing cushion, sound insulation, and comfort, with COREtec designed as floating floor with attached cork backing, so additional underlayment not required and may void warranty if used. COREtec Plus and COREtec Pro have attached cork underlayment 1mm thick providing sound absorption, warmth, and comfort, so no additional underlayment needed, with installation over concrete, plywood, or existing flooring with flat subfloor, with COREtec recommending no extra underlayment as cork already provides, and adding extra underlayment can cause too much cushion causing locking system to fail and void warranty. However, for concrete subfloor with moisture, you may need 6 mil vapor barrier if not included, but not underlayment. So COREtec does not need underlayment, as built-in cork serves as underlayment, making installation easier and cheaper, with subfloor prep requiring flat within 3/16 inch per 10 feet, with COREtec floating over subfloor with click lock, no glue, with attached cork providing IIC sound rating and comfort, so no additional underlayment needed, saving cost and time, with professional installation confirming no extra underlayment required.