Joint cement-free drywall joint construction and method

Abstract

A drywall joint construction and method consisting essentially of abutting drywall boards having a lengthwise crack therebetween and a joint finishing system formed within the crack to complete the drywall joint construction such that a flexible layer defines the joint's center-line surface. Where the drywall boards are non-tapered, the resulting crack therebetween may be filled with a flexible compound that also forms the flexible layer and flushes the joint finishing system with the drywall boards.

1 . An interior drywall joint construction consisting essentially of:
 a non-recessed first drywall board having a first lengthwise edge and an outwardly-facing first planar surface, the first lengthwise edge being substantially perpendicular to the first planar surface;   a non-recessed second drywall board having a second lengthwise edge and an outwardly-facing second planar surface, the second lengthwise edge being substantially perpendicular to the second planar surface, the second drywall board being positioned substantially adjacent the first drywall board such that the first and second lengthwise edges are brought into substantially abutting contact so as to form a lengthwise crack between the first and second planar surfaces, a center-line surface of the joint construction being defined as the outwardly-facing surface directly over the crack and exposed for surface treatment; and   a flexible compound filling the crack so as to form the center-line surface and flush the joint construction with the first and second planar surfaces.   
   
   
       2 . The construction of  claim 1  wherein the flexible compound comprises:
 20 to 25 percent by weight filler;   6 to 8 percent by weight lightweight filler;   10 to 15 percent by weight glass bubbles;   1 to 5 percent by weight methylcellulose;   30 to 50 percent by weight resin; and   10 to 20 percent by weight water.   
   
   
       3 . The construction of  claim 2  wherein the filler is selected from the group consisting of calcium carbonate and gypsum. 
   
   
       4 . The construction of  claim 2  wherein the lightweight filler is mica. 
   
   
       5 . The construction of  claim 2  wherein the glass bubbles have a T g  of greater than about −25° C. 
   
   
       6 . An interior drywall joint construction consisting essentially of:
 a support structure having an interior side;   a non-recessed first drywall board having a first lengthwise edge and an outwardly-facing first planar surface, the first lengthwise edge being substantially perpendicular to the first planar surface, the first drywall board being installed on the interior side of the support structure;   a non-recessed second drywall board having a second lengthwise edge and an outwardly-facing second planar surface, the second lengthwise edge being substantially perpendicular to the second planar surface, the second drywall board being installed on the interior side of the support structure substantially adjacent the first drywall board such that the first and second lengthwise edges are brought into substantially abutting contact so as to form a lengthwise crack between the first and second planar surfaces, a center-line surface of the joint construction being defined as the outwardly-facing surface directly over the crack and exposed for surface treatment; and   a flexible compound filling the crack in a single coat so as to form the center-line surface and flush the joint construction with the first and second planar surfaces, the flexible compound comprising:
 20 to 25 percent by weight filler; 
 6 to 8 percent by weight lightweight filler; 
 10 to 15 percent by weight glass bubbles, the glass bubbles having a T g  of greater than about −25° C.; 
 1 to 5 percent by weight methylcellulose; 
 30 to 50 percent by weight resin; and 
 10 to 20 percent by weight water. 
   
   
   
       7 . A method of forming a drywall joint consisting essentially of the steps of:
 installing a non-recessed first drywall board having a first lengthwise edge and an outwardly-facing first planar surface on an interior side of a support structure, the first lengthwise edge being substantially perpendicular to the first planar surface;   installing a non-recessed second drywall board having a second lengthwise edge and an outwardly-facing second planar surface on the interior side of the support structure such that the second drywall board is substantially adjacent the first drywall board, the second lengthwise edge being substantially perpendicular to the second planar surface, such that the first and second lengthwise edges are brought into substantially abutting contact so as to form a lengthwise crack between the first and second planar surfaces, a center-line surface of the drywall joint being defined as the outwardly-facing surface directly over the crack and exposed for surface treatment; and   filling the crack with a flexible compound so as to form the center-line surface and flush the drywall joint with the first and second planar surfaces.   
   
   
       8 . The method of  claim 7  wherein the step of filling the crack with a flexible compound comprises a single coat.