Thickness and Density
Underlay is an integral ingredient that shapes the way your carpet will feel, wear, and look long-term. Low-density foam underlays whether cheap or expensive with a density of less than 110kg will quickly lose their resilience. This includes high-density foam products 120kg or more that are also too soft.
Building Code Standards
The NZ Building code minimum standard for Sound insulation for floor coverings is NRC Noise Reduction Coefficient 55 (32dB), carpet and underlay combined. A high-quality underlay is designed for sound insulation and impact noise reduction..
Thermal: A quality underlay can also help towards reducing your energy bills by a significant amount as it traps heat under your floor, insulating the room and keeping it warm.
A carpet’s performance is dependent on the support it gets from underneath. If your underlay flattens quickly, your carpet will also flatten.
Find an underlay that has excellent rebound properties. Look at the acoustic insulation properties of the product as this will indicate its retention characteristics. The higher, the better.
AS4288:2003 certifies a carpet underlay as compliant and manufactured in accordance with performance, quality, and safety requirements deemed acceptable for their intended use.
Retention of thickness
A quality underlay acts as a shock absorber, reducing the effects of pile crush in high traffic areas. Here are some tips on what to look for when purchasing your new carpet.