Floor structure having sound attenuation properties

Abstract

The floor structure has a base layer fastened to floor joists, a resilient layer laid over the base layer, and a top layer mounted over the resilient layer. The top layer has a stiffness that is greater than a stiffness of the base layer. The top layer is fastened to the base layer by wood screws that are placed substantially along a median between two adjacent floor joists. Each screw has a threaded portion extending simultaneously in both the top and the base layers. The installation of screws through the top and the base layers causes a backlash in the advance of the screws upon entering the base layer, thereby causing the occurrence of a larger gap between the layers as compared with an installation using nails. The larger gap relaxes a pressure on the foam layer and reduces the transmission of sound energy to the joists.

1 . A floor structure for attenuating impact and airborne sounds, said floor structure comprising spaced-apart floor joists, a base layer fastened to said joists, a resilient layer laid over said base layer, and a top layer mounted over said resilient layer; 
 said top layer having a stiffness greater than a stiffness of said base layer;    said top layer being fastened to said base layer by wood screws; said wood screws being placed substantially along a median between two adjacent ones of said floor joists, and each of said wood screws having a threaded portion extending simultaneously in both said top layer and said base layer.    
   
   
       2 . The floor structure as claimed in  claim 1 , wherein said top layer is made of balsam fir boards each having a thickness of about 2 inches, and said base layer is made of oriented fibre boards each having a thickness of ¾ inch.  
   
   
       3 . The floor structure as claimed in  claim 2 , wherein each of said balsam fir boards has a width of 24 inches, a length of 16 feet, and tongue-and-groove edges.  
   
   
       4 . The floor structure as claimed in  claim 3 , wherein said floor joists are spaced 24 inches apart.  
   
   
       5 . The floor structure as claimed in  claim 1 , wherein a stiffness of said top layer is 32 times greater than a stiffness of said base layer.  
   
   
       6 . The floor structure as claimed in  claim 1 , wherein each of said wood screws also has a segment traversing said resilient layer and said segment is in compression for preventing a collapsing of said resilient layer.  
   
   
       7 . A floor structure for attenuating impact and airborne sounds, said floor structure comprising spaced-apart floor joists, a base layer made of ¾ plywood and fastened to said joists, a resilient layer laid over said base layer, and a top layer mounted over said resilient layer; 
 said top layer having a thickness of 2 inches and being made of three plies with wood fibres in a middle ply oriented at right angle with wood fibres in outside plies;    said top layer being fastened to said base layer by wood screws; said wood screws being placed substantially along a median between two adjacent ones of said floor joists, and each of said wood screws having a threaded portion extending simultaneously in both said top layer and said base layer.    
   
   
       8 . The floor structure as claimed in  claim 7 , wherein each of said wood screws also has a segment traversing said resilient layer and said segment is in compression for preventing a collapsing of said resilient layer.  
   
   
       9 . A floor structure having an impact-sound attenuation properties better than 55 dB, said floor structure comprising floor joists spaced at 24 inches apart, a base layer having a thickness of about ¾ inch fastened to said floor joists, a resilient layer having a thickness of about ⅛ inch laid over said base layer, and a top layer made of balsam fir boards mounted over said resilient layer; 
 said top layer having a thickness of 2 inches, and being fastened to said base layer by wood screws; said wood screws being placed substantially along a median between two adjacent ones of said floor joists, and each of said wood screws having a threaded portion extending simultaneously in both said top layer and said base layer.    
   
   
       10 . The floor structure as claimed in  claim 9 , wherein each of said wood screws also has a segment traversing said resilient layer and said segment is in compression for preventing a collapsing of said resilient layer.  
   
   
       11 . The floor structure as claimed in  claim 10 , wherein each of said balsam fir boards has a width of 24 inches, a length of at least 8 feet and tongue-and-groove edges.  
   
   
       12 . The floor structure as claimed in  claim 11 , wherein said base layer is made of oriented fibre boards.