Purpose: The building industry has a big environmental impact. The timber construction can reduce the impact of the industry because timber is an environmentally friendly material. One of the biggest problems with lightweight construction is sound insulation. The aim of this report is to study two floor construction with different sound insulation materials from an environmental perspective. The materials that will be studied in this report are sand and macadam. The aim of the report is to create a clear comparison between these floor layers and to suggest an improvement proposal.

Method: The methods that have been used in the report are literature studies, life-cycle assessment, document analysis and interview. The LCA, document analysis and literature studies are the starting point, based on these methods, the first two questions in this paper will be answered. Using the interview was able to conduct information for the last question.

Findings: This study has shown that sand has a less environmental impact than what macadam has. The improvement proposal that has been suggested in this study is using sawdust with sand as sound insulations layer. Decreasing the amount of sand in floors can have a positive effect on the environment.

Implications: As a conclusion of this paper, it is proven that sand as a sound insulation material is more favorable for the environment than the macadam. The reason is caused by the process of extracting macadam. The process is more complicated and more energy demanding. Another conclusion is that reducing the amount of sand and replacing the missing amount with sawdust can reduce the environmental impact and increase the sound insulation ability. A recommendation for similar papers more abilities could be included in the analysis to provide a more including and fair result.

Limitations: This paper is limited to investigate sound insulation materials combined with CLT-slabs exclusively. The methods which have been used provided relevant data to help this paper create conclusions. The goal was to create an all-around answer so that the result could be applicable in other analysis.

Keywords: LCA, sand, macadam, lightweight construction, impact sound insulation, environment.