This report summarizes the acoustics research component regarding sound insulation of elements and systems for the research project on mid-rise and larger wood buildings. The summary outlines the background, main research considerations, research conducted and major outcomes. Further details of the design and the results can found in the appendix of Client Report A1-100035-02.1 .
The goal of the acoustics research components was to develop design solutions for mid-rise wood and wood-hybrid buildings that comply both with the current National Building Code of Canada (NBCC) 2010  requirements for direct sound insulation and with the anticipated requirements for flanking sound transmission in the proposed, 2015 version of the NBCC. In addition, the design solutions were to provide better impact sound insulation while still achieving code compliance for all other disciplines (interdependencies) as identified in the final report of the scoping study conducted in FY 2010/2011 
This Report presents the results from experimental studies of airborne sound transmission, together with an explanation of calculation procedures to predict the apparent airborne sound transmission between adjacent spaces in a building whose construction is based on cross-laminated timber (CLT) panels.
There are several types of CLT constructions which are commercially available in Canada, but this study only focused on CLT panels that have adhesive between the faces of the timber elements in adjacent layers, but no adhesive bonding the adjacent timber elements within a given layer. There were noticeable gaps (up to 3 mm wide) between some of the timber elements comprising each layer of the CLT assembly. These CLT panels could be called "Face-Laminated CLT PAnels" but are simply referred to as CLT panels in this Report.
Another form of CLT panels has adhesive between the faces of the timber elements in adjacent layers as well as adhesive to bond the adjacent timber elements within a given layer. These are referred to as "Fully-Bonded CLT Panels" in this Report.
In recent years Cross Laminated Timber (CLT) was introduced as an emerging building system in the North American market. CLT elements consist of multiple layers of wooden beams that are laid-out cross-wise and laminated together to form solid wood panels for floors and walls. As part of a multi-disciplinary research project a comprehensive study was conducted on the impact and airborne sound insulation of this type of elements in order to create a data base that allows building designers to predict the acoustic performance of CLT systems. Parametric studies were carried out on the direct impact airborne sound insulation of CLT floor assemblies (with/ without various floor topping and gypsum board ceiling variants), on the direct airborne sound insulation of CLT walls (with/without gypsum board linings), as well as on the structure-borne sound transmission on a series of CLT building junctions. The results were then used as input data for predictions of the apparent impact and airborne sound insulation in real CLT buildings using the ISO 15712 (EN12354) framework that was originally developed for concrete and masonry buildings. The paper presents the prediction approach as well as results of prediction and measurement series for apparent impact and airborne sound insulation.