This Rothoblaas document explores the role of underfloor insulation in improving acoustic performance in long-span cross-laminated timber (CLT) floor systems. Intended for designers, engineers, and building professionals, the document addresses key soundproofing challenges associated with larger spans and exposed timber structures.

The document explains how underfloor insulation contributes to reducing airborne and impact sound transmission, with discussion of system behaviour, material selection, and integration with CLT floor assemblies. It also highlights design and construction considerations that influence acoustic performance, including detailing, installation quality, and coordination with other building systems.

Developed as a technical reference, this document supports informed design decisions for long-span CLT floors, helping project teams achieve acoustic comfort while maintaining structural and architectural objectives.