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Innovative solutions to improved sound insulation of CLT floors

https://research.thinkwood.com/en/permalink/catalogue3339
Year of Publication
2023
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Ljunggren, Fredrik
Organization
Luleå University of Technology
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Sound Insulation
Low Frequencies
Impact Sound
Compressed Wood
Research Status
Complete
Series
Developments in the Built Environment
Summary
Building with cross laminated timber (CLT) has gain increased interest over the last years, but in common to other wood-based building systems, inadequate low-frequency sound insulation is seen as a problem. This paper deals with two methods to improve the sound insulation of CLT panels, normally made from spruce: 1) heavy CLT, introducing compressed, i.e. densified, spruce as well as alternative wood species, and 2) elastic layer based upon shear motion. In addition to a series of laboratory measurements, a full-scale CLT floor made of two 60 mm birch panels with a 12 mm elastic layer in between was tested in a two-room test mock-up. The results from the acoustical measurements showed that the floor has about 7 dB greater airborne and impact sound insulation for one-third octave bands, 50–3150 Hz, compared to a standard CLT floor of the same total height.
Online Access
Free
Resource Link
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Correlation Between Sound Insulation and Occupants' Perception - Proposal of Alternative Single Number Rating of Impact Sound, Part II

https://research.thinkwood.com/en/permalink/catalogue2134
Year of Publication
2017
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Ljunggren, Fredrik
Simmons, Christian
Öqvist, Rikard
Publisher
Elsevier
Year of Publication
2017
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Impact Sound Insulation
Low Frequency
Lightweight
Footstep Annoyance
Subjective Perception
Single Number Quantity
Research Status
Complete
Series
Applied Acoustics
Summary
A previous Swedish research project indicated the potential need for evaluating impact sound insulation from 20 Hz in buildings with lightweight constructions. This is a discrepancy compared to the commonly used frequency intervals starting from 50 or 100 Hz. The statistical significance of this groundbreaking suggestion was however not satisfactorily strong since the result was based upon a limited number of building objects. The scope of the present paper is to secure the previous study by adding additional objects to the underlying database, thereby increasing the confidence of the results. The methodology is to perform impact sound insulation measurements in apartment buildings of various construction types and to perform questionnaire surveys among the residents. The measured sound insulation is compared to the subjective rating by the occupants in order to find the parameter giving the highest correlation with respect to frequency range and weighting. The highest correlation was found when the impact sound insulation was evaluated from 25 Hz using a flat frequency-weighting factor. Frequencies below 50 Hz are of great importance when evaluating impact sound insulation in lightweight constructions.
Online Access
Free
Resource Link
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Improving Impact Sound Insulation Performance of Mass Timber Floors with Dry Floating Floor Solution

https://research.thinkwood.com/en/permalink/catalogue2817
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
DLT (Dowel Laminated Timber)
Other Materials
Application
Floors
Organization
University of Northern British Columbia
Material
CLT (Cross-Laminated Timber)
DLT (Dowel Laminated Timber)
Other Materials
Application
Floors
Topic
Acoustics and Vibration
Keywords
Dry Floating
Floor Assemblies
Low Frequency
Mass Timber
Research Status
In Progress
Notes
Project contact is Jianhui Zhou
Summary
Sound insulation performance is critical to the broader market acceptance of mass timber buildings in both residential and non-residential building markets. The project aims to develop dry floating floor solutions for mass timber floors with improved sound insulation performance. The specific objectives are: 1. To design floating floor assemblies using wood-based panels such as medium density fiberboard (MDF), gypsum board, and structural concrete panels for mass timber floors with considerations for fire requirements; 2. To evaluate the impact sound insulation performance of developed floor assemblies with a focus in the low-frequency range.
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