## Experiences with sound insulation for cross-laminated timber floors

Dr.ing. Anders Homb

SINTEF Building & Infrastructure

Høgskoleringen 7B

NO – 7465 Trondheim, Norway.

E-mail: anders.homb@sintef.no

Siv.ing. Jan Arne Austnes MRIF

Sweco Norway

Postboks 400

NO - 1327 Lysaker, Norway

E-mail: jaa@sweco.no

During the last years, cross-laminated timber floor constructions have been introduced in Norway, due to an interest among architects and producers. A more extensive use of wood in buildings is of strategic interest in the wood industry. One possibility is to develop products and designs for extended use in multi storey buildings. In today’s solutions, the sound insu-lation proper¬ties of cross-laminated timber floors are undermined due to excessive flanking transmission of the supporting walls. Research has been conducted at SINTEF Byggforsk in collaboration with field measurements from Sweco with respect to the development of know¬ledge and support node solutions.

Several projects have been carried out to investigate the properties of such solutions concer-ning airborne and impact sound insulation. Research has been conducted earlier to develop design criteria and vibration controlled span width. But, due to preliminary calculations and field measure¬ment results, the main challenge is the airborne sound insulation in the vertical direction.

Sound insulation measurements have been carried out both in the SINTEF Byggforsk labora-tory and at different completed constructions in buildings. In Norway, the most interesting solution has been with an optimized top floor solution and visible cross-laminated timber in the room below. It was found that it is possible to fulfill impact sound insulation requirements for multifamily houses with such solutions, but in combination with load bearing massive wood solutions, the airborne sound insulation is limited. The paper presents some effects of different solutions at the junctions in combination with the floor solution itself. Planned activities to develop improved junctions with respect to airborne sound insulation will also be presented.