Methods for manufacturing pre-fabricated insulated foam wall structures with high racking strength and related pre-fabricated wall structures

Abstract

Methods of manufacturing wall structures having high racking strength are described in this specification. The methods include spray applying a foam-forming composition into a cavity of a wall structure, wherein the wall structure is disposed in a climate-controlled spray application station and allowing the foam-forming material to expand within at least a portion of the cavity to form a foam layer deposited in the cavity. In the methods, the foam layer is formed in-situ during the manufacturing method, and the density of the foam layer is selected and the relative humidity and dew point of the air in the climate-controlled spray application station throughout the spray applying is selected so that the wall structure has a racking strength of at least 500 pounds per linear foot.

1 - 26 . (canceled) 
     
     
         27 . A wall structure comprising:
 a) a first member;   b) a second member spaced apart from the first member;   c) connecting members extending between the first member and the second member, wherein the first member, the second member, and the connecting members each comprise a front surface and a rear surface that form the front frame surface and a rear frame surface;   d) a foam panel attached to the front frame surface, such that foam panel, the first member, the second member, and the connecting members define a cavity within the frame; and   e) an in-situ formed polyurethane foam layer having a density of at least 2.8 lb/ft 3  when measured according to ASTM D1622-08 deposited in the cavity and adhered to the foam panel,   wherein the wall structure has a racking strength of at least 500 pounds per linear foot (2224 N) when the wall structure is tested without the presence as part of the wall structure of a wood panel, a plywood panel, an oriented strand board panel, a fibrous structural panel, a gypsum panel, and/or a composite panel that includes a wood panel or a fibrous panel.   
     
     
         28 . (canceled) 
     
     
         29 . The wall structure of  claim 27 , wherein the density of the foam layer is 3.0 to 4.0 lb/ft3 measured according to ASTM D1622-08. 
     
     
         30 . The wall structure of  claim 27 , wherein the racking strength of the wall structure is at least 600 pounds per linear foot (2669 N). 
     
     
         31 . The wall structure of  claim 27 , wherein the foam layer comprises a thickness extending from the rear surface of the first foam panel to a position intermediate the front frame surface and the rear frame surface such that a gap is formed within the frame between a rear surface of the foam layer and the rear frame surface. 
     
     
         32 . The wall structure of  claim 27 , wherein the foam panel comprises a polyiso panel, an expanded polystyrene panel, or an extruded polystyrene panel. 
     
     
         33 . The wall structure of  claim 32 , wherein the foam panel comprises a polyiso panel comprising a polyisocyanurate foam layer and a facer material attached to a front face and a rear face of the polyisocyanurate foam layer. 
     
     
         34 . The wall structure of  claim 33 , wherein the facer material attached to the rear face comprises a coated glass fiber comprises coated glass fibers. 
     
     
         35 . The wall structure of  claim 27 , wherein the wall structure does not include any panels aside from foam panel(s). 
     
     
         36 . The wall structure of  claim 27 , wherein the racking strength of the wall structure is at least 900 pounds per linear foot (4003 N).