Underlayment is the layer between your subfloor and your new floor. Underlayment is usually made out of rubber, cork, rubber cork, felt or foam. Underlayment has many advantages such as anti-mute, moisture-proof and etc. It is very important to choose the suitable underlayment for your flooring. 2mm or 3mm underlayment is good for Laminate flooring , 1mm or 2mm IXPE is good for SPC flooring, 2mm or 3mm EVA is good for hardwood flooring ( bamboo flooring , solid wood flooring and engineering flooring ).