Study On Improvement Of Sound Insulation Of Old Timber/Brick Buildings Renovation

In the process of urban renewal, the number of old building renovation project is increasing, and the adaptive reuse of historical buildings has become a method of conservation. Many reconstructed buildings were timber frame or timber-and-brick buildings, of which the sound insulation cannot meet the high requirements of new functions. The improvement of sound insulation of old buildings is necessary, but the theory and practice experience are inadequate.In this paper, the old timber buildings were investigated to find out acoustic problems and reasons.Low mass and poor sealing performance are two major reasons that cause the acoustic defects of old timber frame or timber-and-brick buildings. Light weight (mass per unit area) of timber construction leads to poor air-borne and impact sound insulation. Timber walls and floors have gaps, and the wall integrity is destroyed by the special building construction, especially the complex roof frame, thereby increasing the difficulty of sealing.Many old buildings are historical buildings, so the building conservation is another concern when reconstructing. Two modes of reconstruction were put forward: 1. For buildings of little historical and cultural values, active measures can be taken, replacing or rebuilding building components using new materials with fine acoustic properties. For example, concrete floor and stairs, brick walls can be built to improve the sound insulation. 2. For protective historical buildings, original building components should be retained as many as possible and destruction should be minimized.Measures to improve the sound insulation must be discreet. For example, additional light-weight frame wall is more applicable to protective historical buildings with timber structure. A triple layer system floor, composed of a floating floor on top and a suspended ceiling as an independent third layer can efficiently reduce the airborne and impact sound transmission of timber frame floor.New finished sound insulation windows and doors are necessary for all buildings. The appearance and structure of newly built components should be coordinating with the old ones, which makes the acoustic improvement project more difficult. 4. Special consideration is needed for vibrations excited by installation equipment and pipes, and vibration isolation is important.At last, two cases of transforming buildings to hotels were put practice. Case 1 is a timber-and-brick protective historical building. Following the conversation rule, the main building structure and components are retained. A measurement is carried out after this project finished, showing that the acoustic goal is reached. Case 2 is a project of an ordinary buildings, with timber frame and loam walls,transforming to a homestay,with active measures. Different requests and methods of acoustic improvement are shown with these two cases, which should be helpful to the acoustic renovation of timber and timber-and-brick buildings.