We always recommend that underlay be laid or replaced when fitting a new carpet or wood and laminate flooring. Your underlay is the foundation of your floor covering, absorbing the daily pressure and stresses your carpet undergoes. Underlays have several advantages including: Excellent sound insulation properties - Some underlays have excellent acoustic properties and can literary eliminate most treading noises from the average household. Carpet with even the most basic of underlays can be 2 times quieter. Insulation properties - New underlay has excellent insulation properties which keep the heat in. Studies have shown underlay to reduce heat loss by as much as 15%. Wear and tear - Carpet underlay protects your carpet by assorbing the pressures thereby preventing your carpet from flattening. This is particularly important for high-traffic areas such as halls, stairs and landing. Underlay material can either be Foam, Rubber, Felt or a combination of Felt & Rubber. Learn more about underlays.