Underlay for vinyl is beneficial when laying vinyl over concrete or wooden subfloors. It’s also helpful when fitting vinyl over existing floors such as lino or tile. If your subfloor is concrete, underlay offers thermal qualities and makes the floor more comfortable. Underlay reduces sound transfer and provides extra cushioning if your subfloor is wooden. If you’re laying vinyl over an existing floor such as lino or tile, underlay will improve comfort underfoot and reduce noise.