Home / Indoor / Gymnasium Flooring / Underlayment Options Underlayment Options Sport Court underlayments are designed to provide a sound deadening and resilient sub base to our performance flooring systems. The various thicknesses provide a perfect balance of resilience given the various applications. For most basketball, volleyball and multi-purpose sports floors, our 1.5 mm underlayment will provide the best combination of resilience and sound absorbtion and can be used with our standard floors. On group fitness or other aerobic and exercise facility floors requiring greater shock absorbtion, the 5mm, and 7mm underlayment would be the best choice. All Sport Court modular performance floor systems using underalyments greater than 1.5mm will want to specify our HRHD type floor which is manufactured to handle the added resilience while not sacrificing any structural integrity.