Heat and moisture resistant subfloor and optional ceiling structures made using lightweight composite panels

Abstract

Thermally insulating and moisture and mold resistant subfloors include: a subfloor support structure that includes a subfloor framework comprising joists, beams, furring strips, and/or foam sheets, and optionally an intermediate underlayment comprising sheathing fastened to or applied over the subfloor framework, and lightweight composite underlayment panels fastened to the subfloor support structure. Lightweight composite panels include a foam core and fiber reinforced cementitious (or other protective) layers formed on the foam core surfaces. The subfloor support structure may include sheathing, wherein the lightweight composite panels are fastened to the sheathing to form the subfloor underlayment. In other cases, the subfloor support structure may omit sheathing, wherein the lightweight composite panels are fastened directly to the subfloor framework to form the subfloor underlayment. An optional ceiling structure of a lower floor can be formed by fastening lightweight composite ceiling panels under the subfloor framework of the subfloor.

1 . A method of constructing a subfloor of a building, comprising:
 forming or providing a subfloor support structure that includes a subfloor framework comprising joists, beams, furring strips, and/or foam sheets and optionally intermediate sheathing fastened to or applied over the subfloor framework; and   fastening a plurality of lightweight composite subfloor panels over the subfloor support structure to form a subfloor over which a floor finish can be applied, the lightweight composite subfloor panels each comprising:
 a foam core having a first surface and a second surface opposite the first surface; 
 a first protective layer selected from a first fiber reinforced cementitious layer, thermoset polymer layer, or magnesium oxide layer formed over and covering at least a portion of the first surface of the foam core; and 
 a second protective layer selected from a second fiber reinforced cementitious layer, thermoset polymer layer, or magnesium oxide layer formed over and covering at least a portion of the second surface of the foam core, 
 wherein the lightweight composite subfloor panels are positioned so that one protective layer faces toward, and another protective layer faces away from, the subfloor support structure. 
   
     
     
         2 . The method of  claim 1 , wherein the subfloor framework comprises at least one of wooden floor joists, beams, or furring strips. 
     
     
         3 . The method of  claim 1 , wherein the subfloor support structure includes the intermediate sheathing, and wherein the lightweight composite subfloor panels are fastened over the intermediate sheathing. 
     
     
         4 . The method of claim  4 , wherein the intermediate sheathing is selected from the group consisting of plywood, oriented strand board (OSB), gypsum board, lightweight composite sheathing panels, and combinations thereof. 
     
     
         5 . The method of  claim 3 , wherein the lightweight composite subfloor panels forming the subfloor have a cross-sectional thickness of about 3/16 inch to about ½ inch, or about 7/32 inch to about ⅜ inch, or about ¼ inch. 
     
     
         6 . The method of  claim 1 , wherein the subfloor support structure omits the intermediate sheathing, and wherein the lightweight composite subfloor panels are fastened over the subfloor framework. 
     
     
         7 . The method of  claim 6 , wherein the lightweight composite subfloor panels forming the subfloor have a cross-sectional thickness of about ½ inch to about 1¼ inch, or about ⅝ inch to about 1 inch, or about ¾ inch. 
     
     
         8 . The method of  claim 1 , wherein the subfloor forms part of a bottom floor of a building or is below grade and forms part of a basement floor of a building. 
     
     
         9 . The method of  claim 1 , wherein the subfloor separates an upper floor and a lower floor of a building, and wherein the subfloor framework comprises joists or beams and the subfloor support structure supports the subfloor of the upper floor. 
     
     
         10 . The method of  claim 9 , further comprising a plurality of lightweight composite ceiling panels positioned beneath an underside of the subfloor framework and forming a ceiling structure of the lower floor, wherein the lightweight composite ceiling panels comprise modified lightweight composite panels having a plaster finish, UV or chemical cured polymer finish, or paper layer on an exterior protective layer, optionally wherein the lightweight composite ceiling panels have a cross-sectional thickness of about ⅜ inch to about ¾ inch, or about 7/16 inch to about ⅝ inch, or about ½ inch. 
     
     
         11 . The method of  claim 1 , further comprising insulation positioned within the subfloor framework, such as between joists, beams, or furring strips. 
     
     
         12 . The method of  claim 1 , wherein the foam core comprises a polymer selected from the group consisting of extruded polystyrene (XPS), expanded polystyrene (EPS), polyisocyanurate, polyurethane (PUR), phenolic polymers (e.g., phenol-formaldehyde), melamine polymers (e.g., melamine-formaldehyde), and other thermoplastic and thermoset polymers that can be formed into a rigid or semi-rigid polymer foam structure. 
     
     
         13 . The method of  claim 1 , wherein the foam core comprises an inorganic foam material selected from the group consisting of silica gel, aerogel, silicate foams, urea-silicate foams, SiOC/SiC, ceramic foams, and refractory foams. 
     
     
         14 . The method of  claim 1 , wherein at least one of the first or second fiber reinforced cementitious layers is included and comprises fiber reinforcement embedded within a hardened cementitious composition, wherein the fiber reinforcement is selected from fiber mesh, alkali-resistant fiberglass mesh, embedded fibers, fabric, woven, scrim, felt, and non-woven, wherein the fiber reinforcement comprise at least one of plant fibers, polymer fibers, and inorganic fibers, which are selected from fibers or filaments formed from glass, basalt, rock wool, or carbon, wherein the at least one of the first or second fiber reinforced cementitious layers has a cross-sectional thickness in a range of about 0.5 mm to about 3 mm, or about 0.75 mm to about 2.5 mm, or about 1 mm to about 2 mm, or about 1.25 mm to about 1.75 mm. 
     
     
         15 . The method of  claim 1 , wherein at least one of the first or second thermoset polymer layers is included and comprises polyurea or polyaspartic and is optionally fiber-reinforced, wherein the at least one of the first or second thermoset polymer layers has a cross-sectional thickness in a range of about 1 mm to about 5 mm, or about 2 mm to about 4 mm. 
     
     
         16 . The method of  claim 1 , wherein the lightweight composite subfloor panels are fastened to the subfloor support structure by at least one of screws, nails, rivets, other mechanical fasteners, or adhesive. 
     
     
         17 . The method of  claim 16 , wherein the screws or other mechanical fasteners include corresponding washers or enlarged heads, pan head screws, or screws with integrated washers that are at least about 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 m, 65 cm, 70 cm, 75 mm, or 80 mm, in diameter to prevent damage to the lightweight composite subfloor panels, wherein the washers include a plurality of penetrating prongs configured to penetrate at least partially through the lightweight composite subfloor panels, including through an exterior protective layer and at least partially through the foam core, such as where the penetrating prongs penetrate all the way through the lightweight composite subfloor panels and make abutment with the subfloor support structure. 
     
     
         18 . The method of  claim 1 , further comprising a seam coat applied over exposed fasteners and joints or seams between adjacent lightweight composite subfloor panels. 
     
     
         19 . A finished floor comprising a subfloor made according to the method of  claim 1  and a floor finish applied over the lightweight composite subfloor panels. 
     
     
         20 . A subfloor of a building, comprising:
 a subfloor support structure that includes a subfloor framework comprising joists, beams, furring strips, and/or foam sheets and optionally intermediate sheathing fastened to or applied over the subfloor framework; and   a plurality of lightweight composite subfloor panels fastened over the subfloor support structure to form a subfloor over which a floor finish can be applied, the lightweight composite subfloor panels each comprising:
 a foam core having a first surface and a second surface opposite the first surface; 
 a first protective layer selected from a first fiber reinforced cementitious layer, thermoset polymer layer, or magnesium oxide layer formed over and covering at least a portion of the first surface of the foam core; and 
 a second protective layer selected from a second fiber reinforced cementitious layer, thermoset polymer layer, or magnesium oxide layer formed over and covering at least a portion of the second surface of the foam core, 
 wherein the lightweight composite subfloor panels are positioned so that one protective layer faces toward, and another protective layer faces away from, the subfloor support structure. 
   
     
     
         21 . A method of constructing a subfloor and ceiling structure of a building, comprising:
 forming or providing a subfloor support structure that includes a subfloor framework comprising joists, beams, furring strips, and/or foam sheets and optionally intermediate sheathing fastened to or applied over the subfloor framework, wherein the subfloor support structure is positioned between and separates an upper floor and a lower floor;   fastening a plurality of lightweight composite subfloor panels over the subfloor support structure to form a subfloor of the upper floor over which a floor finish can be applied; and   fastening a plurality of lightweight composite ceiling panels under the subfloor framework to form a ceiling structure of the lower floor,   the lightweight composite subfloor and ceiling panels each comprising:
 a foam core having a first surface and a second surface opposite the first surface; 
 a first protective layer selected from a first fiber reinforced cementitious layer, thermoset polymer layer, or magnesium oxide layer formed over and covering at least a portion of the first surface of the foam core; and 
 a second protective layer selected from a second fiber reinforced cementitious layer, thermoset polymer layer, or magnesium oxide layer formed over and covering at least a portion of the second surface of the foam core, 
 wherein the lightweight composite subfloor panels are positioned so one protective layer faces toward, and another protective layer faces away from, the subfloor support structure, 
 wherein the lightweight composite ceiling panels are positioned so one protective layer faces toward, and another protective layer faces away from, the subfloor framework. 
   
     
     
         22 . A subfloor and ceiling structure of a building made according to the method of  claim 21 .