Sound insulation in cross laminated timber buildings can be challenging and is difficult to predict due to lack of reliable predicting models. Details in either the construction itself or in mounting may cause measurement results to vary significantly. Solutions vary notably between projects. Pre-accepted solutions are sparse and in high demand. Residential buildings are especially challenging and commonly need complementary floors, suspended ceilings and wall linings due to high sound insulation requirements. Clients and consumers in Norway often want the timber to be exposed, which make the flanking sound control essential.
Sound tests on a full scale CLT model have been conducted to identify efficient solutions. Flanking sound paths were tested using various resilient interlayers and fasteners in the junctions, and the vibration level difference across the junctions was measured between rooms. Elastically decoupled angle brackets performed better than ordinary angle brackets and screws that penetrate the vibration protection. Additionally, sound insulation measurements are reported on for various slab constructions, including both light and heavy weight complementary floors.