Acoustic Performance Guide

Timberlink commissioned CSIRO to test a number of systems using NeXTimber CLT, which were then assessed by PKA Acoustic Consulting. Because CLT is a lighter construction material than concrete, it provides less airborne and impact sound insulation than denser materials. The systems in this guide reach the required performance by three approaches: adding mass with board materials such as plasterboard, fibre cement and chipboard; providing resilient separation between layers; and isolating or minimising rigid connections between layers.

Predictions fall within Rw plus or minus 2 and Ln,w plus or minus 2 points of the stated ranges when validated against laboratory test results. They are indicative, not a guarantee of field performance: sound flanking in field installation must be considered by the acoustic engineer.

NCC Volume One, Section F7 (previously BCA Section F5) requires walls and floors separating places of occupancy in Class 2 and 3 buildings to safeguard occupants from undue sound transmission. The deemed-to-satisfy provisions below are a general summary for indicative purposes and do not replace the need to review the NCC requirement for the project.

Representative Option 1 build-ups are shown below. Each system has additional lining options (for example a second plasterboard layer or fire-grade board) that trade thickness for performance. Refer to the guide for the full set of options and layer specifications.