You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND OF THE INVENTION 
     The subject invention relates to a wall and/or ceiling polymer-based composite structural sheathing board that has a polymer material or predominantly polymer material core layer and to a wall and/or ceiling system of a building structure that includes a plurality of the polymer-based composite structural sheathing boards overlaying and secured to a structural wall and/or ceiling frame and forming a wall and/or ceiling sheathing layer over the structural frame. 
     In current building wall and ceiling systems, the sheathing layers of the wall and ceiling systems are typically formed of plywood boards, hardboards, particleboards, and/or gypsum boards. While these structural sheathing boards perform satisfactorily, the physical properties of these structural sheathing boards, such as but not limited to their weight, handleablity, cutablity, durability, flame spread rating, water absorption and/or fungus growth characteristics, etc. can present problems during the installation of the sheathing layer and over the anticipated service life of a wall and/or ceiling system. Accordingly, there has remained a need for improved wall and ceiling systems which utilize sheathing layers that are formed by structural sheathing boards that can be relatively light in weight, that are easy to handle, and that are easily cut at the job site to form the sheathing layer. There has also remained a need for improved wall and ceiling systems that include sheathing layers made of structural sheathing boards that are strong and durable, that absorb and retain very little moisture, that are fungus growth resistant, that are flame spread resistant, that have relatively good thermal and acoustical properties, and that have good bonding surfaces for bonding a nonstructural finish layer to an sheathing layer formed by the structural sheathing boards. 
     SUMMARY OF THE INVENTION 
     The wall and/or ceiling polymer-based composite structural sheathing boards of the subject invention provide a solution to the above discussed installation and service related problems of the wall and ceiling sheathing boards of the prior art and the above discussed wall and ceiling system installation and service problems associated with wall and ceiling systems made with the wall and ceiling sheathing boards of the prior art. 
     In first and second embodiments of the wall and/or ceiling polymer-based composite structural sheathing boards of the subject invention, the sheathing boards have a polymer material or predominantly polymer material core layer. A facer overlays at least one of the major surfaces and preferably, facers overlay both of the major surfaces of the core layer of the polymer-based composite structural sheathing boards of the subject invention to reinforce and strengthen the boards and provide the boards with enhanced dimensional stability. To best enhance the integrity, dimensional stability, and fastener pull through strength of the polymer-based composite structural sheathing boards of the subject invention as well as other desired physical and performance characteristics of the polymer based composite structural sheathing boards of the subject invention, a facer of a polymer-based composite structural sheathing board of the subject invention is coextensive with or substantially coextensive with and bonded to the overlaid major surface of the polymer-based composite structural sheathing board. 
     In a third embodiment of the polymer-based composite structural sheathing boards of the subject invention, the sheathing board includes a low density polymer material or predominantly polymer material insulation layer and a polymer material or predominantly polymer material reinforcement layer having a higher density than the insulation layer. The sheathing boards of this embodiment may also include a woven or nonwoven reinforcement mat or reinforcement scrim between the insulation layer and the reinforcement layer, a first facer coextensive with or substantially coextensive with and bonded to a major surface of the reinforcement layer, and/or a second facer coextensive with or substantially coextensive with and bonded to a major surface of the insulation layer. 
     In a fourth embodiment of the polymer-based composite structural sheathing boards of the subject invention, the sheathing board includes a low density polymer material or predominantly polymer material insulation layer that is located intermediate first and second polymer material or predominantly polymer material reinforcement layers having a higher density than the insulation layer. The sheathing board may also include a woven or nonwoven reinforcement mat or reinforcement scrim between the insulation layer and the first reinforcement layer, a first facer coextensive with or substantially coextensive with and bonded to a major surface of the first reinforcement layer, a woven or nonwoven reinforcement mat or reinforcement scrim between the insulation layer and the second reinforcement layer, and/or a second facer coextensive with or substantially coextensive with and bonded to a major surface of the reinforcement layer. 
     In particular, the polyisocyanurate material or predominantly polyisocyanurate material polymer-based composite structural sheathing boards of the subject invention have good dimensional stability, can be relatively light in weight, are easy to handle, and can be easily cut at the job site to form a wall or ceiling sheathing layer. In addition, these polyisocyanurate material or predominantly polyisocyanurate material wall and/or ceiling polymer-based composite structural sheathing boards exhibit good thermal and acoustical properties, are strong and durable, absorb and retain very little moisture, are fungus growth resistant, are flame spread resistant, and have good bonding surfaces for bonding a nonstructural finish layer (e.g. paint or wall paper) to a wall or ceiling sheathing layer formed by the polymer-based composite structural sheathing boards. With their excellent physical properties and characteristics, the polymer-based polyisocyanurate material or predominantly polyisocyanurate material composite structural sheathing boards of the subject invention are not only well suited for forming sheathing layers for interior walls and ceilings, but are especially well suited for forming both interior and exterior sheathing layers over the structural framework of exterior building walls. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial schematic elevation of a wall, with portions broken away, illustrating the use of the polymer-based composite structural sheathing boards of the subject invention in the wall system. 
         FIG. 2  is a partial schematic vertical cross section through a ceiling illustrating the use of the polymer-based composite structural sheathing boards of the subject invention in the ceiling system. 
         FIG. 3  is a fragmentary schematic perspective view of a first embodiment of the polymer-based composite structural sheathing boards of the subject invention with portions broken away to better show the layers of composite. 
         FIG. 4  is a fragmentary schematic perspective view of a second embodiment of the polymer-based composite structural sheathing boards of the subject invention with portions broken away to better show the layers of composite. 
         FIG. 5  is a fragmentary schematic perspective view of a third embodiment of the polymer-based composite structural sheathing boards of the subject invention with portions broken away to better show the layers of composite. 
         FIG. 6  is a fragmentary schematic perspective view of a fourth embodiment of the polymer-based composite structural sheathing boards of the subject invention with portions broken away to better show the layers of composite. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As schematically shown in  FIG. 1 , a wall system  20  of the subject invention includes wall sheathing formed by the polymer-based composite structural sheathing boards  40 ,  42 ,  44 , and/or  46  of  FIGS. 3 to 6  and a structural wall frame of studs  22 , a floor plate  24 , and a ceiling plate  26 . As shown, the wall system  20  also includes insulation  28  and may include other structural or nonstructural layers (not shown). Typically, the structural frame members of the structural wall frame are conventional wooden or metal wall studs, floor plates, and ceiling plates. The wall system  20  may be an exterior wall system and the polymer-based composite structural sheathing boards  40 ,  42 ,  44 , and/or  46  may be used as interior wall sheathing and/or exterior wall sheathing. The wall system  20  may also be an interior wall system and the polymer-based composite structural sheathing boards  40 ,  42 ,  44 , and/or  46  may be used as wall sheathing on one or both sides of the interior wall system. 
     As schematically shown in  FIG. 2 , a ceiling system  30  of the subject invention includes ceiling sheathing formed by the polymer-based composite structural sheathing boards  40 ,  42 ,  44 , and/or  46  of  FIGS. 3 to 6  and a structural ceiling frame of ceiling joists  32 . As shown, the wall system  20  also includes insulation  34  and may include other structural or nonstructural layers (not shown). Typically, the structural frame members of the structural ceiling frame are conventional wooden or metal ceiling joists. 
     The polymer-based composite structural sheathing board  40  of  FIG. 3  includes a polymer material or predominantly polymer material core layer  52  and a facer  54  coextensive with or substantially coextensive with and bonded to a first major surface of the core layer  52 . The polymer-based composite structural sheathing board  42  of  FIG. 4  includes a polymer material or predominantly polymer material core layer  52 ; a first facer  54  coextensive with or substantially coextensive with and bonded to a first major surface of the core layer  52 ; and a second facer  56  coextensive with or substantially coextensive with and bonded to a second major surface of the core layer  52 . 
     The first major surface and the second major surface of the polymer or predominantly polymer material core layer  52  of the polymer-based composite structural sheathing boards  40  and  42  are each defined by the length and the width of the polymer or predominantly polymer material core layer. The polymer or predominantly polymer material core layer  52  and consequently the sheathing boards  40  and  42  typically have a width of about four feet or greater and a length of about four feet or greater and, preferably, a length of about eight feet. 
     The polymer or predominantly polymer material core layer  52  of the polymer-based composite structural sheathing boards  40  and  42  may be made of various polymer or predominantly polymer materials [e.g. a polyisocyanurate, polyurethane, polystyrene, or phenolic material or a material made of a blend of these materials; a polyisocyanurate, polyurethane, polystyrene, or phenolic foam material or a foam material made of a blend of these materials; a predominantly polyisocyanurate, polyurethane, polystyrene, or phenolic material with up to 40% by weight, but typically between about 1% and about 25% by weight organic and/or inorganic filler(s) or a material made of a blend of these materials with up to 40% by weight, but typically between about 1% and about 25% by weight organic and/or inorganic filler(s); a predominantly polyisocyanurate, polyurethane, polystyrene, or phenolic foam material with up to 40% by weight, but typically between about 1% and about 25% by weight organic and/or inorganic filler(s) or a foam material made of a blend of these materials with up to 40% by weight, but typically between about 1% and about 25% by weight organic and/or inorganic filler(s), a material made of other thermoset matrix polymers; etc.]. However, a preferred material for the core layer  52  is a polyisocyanurate material or foam material or a predominantly polyisocyanurate material or foam material with up to 40% by weight, but typically between about 1% and about 25% by weight organic and/or inorganic filler(s). Examples of various fillers that may be used in the predominantly polymer materials of the core layer  52  include but are not limited to powdered, liquid, and fiber fillers. The polymer or predominantly polymer materials of the core layer  52  may also include fiber reinforcements, fungi growth-inhibiting agents, fire-retardants, and other agents to reduce the cost of and/or modify the properties of the core layer  52 , such as but not limited to the compressive strength, the toughness, the flexibility, the friability, and the fire resistance of the core layer. Examples of fillers, which may be used in the predominantly polymer material core layer  52 , are fillers such as but not limited to limestone (CaCO 3 ), fiberglass, recycled polyisocyanurate dust, extenders/plasticizers, ground up foam insulation, ground up rubber, wood dust, etc. 
     The first facer  54  of the polymer-based composite structural sheathing board  40  and the first and second facers  54  and  56  of the polymer-based composite structural sheathing board  42  typically overlie the entire or substantially the entire major surface of the core layer  52  of the polymer-based composite structural sheathing board  40  or  42  to which the facer is or facers are bonded. The facers  54  and  56  of the polymer-based composite structural sheathing boards  40  and  42  may be any sheet material that provides suitable first and/or second major surfaces for the polymer-based composite structural sheathing boards  40  and  42 , such as but not limited to coated or uncoated paper, foil, coated or uncoated woven or nonwoven mats made of fiberglass and/or other fibers or filaments, coated or uncoated scrims made of fiberglass and/or other fibers or filaments, etc. However, a preferred facer material for the facers  54  and  56  is a coated or uncoated, nonwoven, fiberglass mat or fiberglass scrim. Where a fiberglass scrim material is used, preferably, the scrim material has a tensile strength of at least 105 lbs per linear inch, a weight of about 10 grams/ft 2 , 8×8 strands per inch, and utilizes stands having a mean diameter of about 0.019 inches. 
     The polymer-based composite structural sheathing board  44  of  FIG. 5  includes a low density polymer material or predominantly polymer material foam insulation core layer  60 , a polymer material or predominantly polymer material foam or solid reinforcement layer  62  having a higher density than the insulation core layer  60 , a reinforcement sheet layer  64  (preferably, a woven or nonwoven reinforcement mat or reinforcement scrim) between the insulation core layer  60  and the reinforcement layer  62 , a first facer  66  coextensive with or substantially coextensive with and bonded to a major surface of the reinforcement layer  62 , and a second facer  68  coextensive with or substantially coextensive with and bonded to a major surface of the insulation core layer  60 . The insulation core layer  60  typically has a density of 4 pcf or less and preferably 2.5 pcf or less. The reinforcement layer  62  typically has a density that is greater than 4 pcf and a thickness less than that of the insulation core layer  60 . 
     The major surfaces of the polymer or predominantly polymer material insulation core layer  60  and reinforcement layer  62  of the polymer-based composite structural sheathing board  44  are each defined by the length and the width of the polymer or predominantly polymer material insulation and reinforcement layers. The polymer or predominantly polymer material insulation and reinforcement layers  60  and  62 , and consequently the sheathing board  44 , typically have a width of about four feet or greater and a length of about four feet or greater and, preferably, a length of about eight feet. 
     The polymer-based composite structural sheathing board  46  of  FIG. 6  includes a low density polymer material or predominantly polymer material foam insulation core layer  70 , a first polymer material or predominantly polymer material foam or solid reinforcement layer  72  having a higher density than the insulation core layer  70 , a sheet reinforcement layer  74  (preferably, a woven or nonwoven reinforcement mat or reinforcement scrim) between the insulation core layer  70  and the reinforcement layer  72 , a first facer  76  coextensive with or substantially coextensive with and bonded to a major surface of the reinforcement layer  72 , a second polymer material or predominantly polymer material foam or solid reinforcement layer  78  having a higher density than the insulation core layer  70 , a reinforcement sheet layer  80  (preferably, a woven or nonwoven reinforcement mat or reinforcement scrim) between the insulation core layer  70  and the reinforcement layer  79 , and a second facer  82  coextensive with or substantially coextensive with and bonded to a major surface of the reinforcement layer  78 . The insulation core layer  70  typically has a density of 4 pcf or less and preferably 2.5 pcf or less. The reinforcement layers  72  and  78  typically have a density that is greater than 4 pcf and a thickness that is less than the thickness of the insulation core layer  70 . The densities of the reinforcement layers  72  and  78  may be the same or differ from each other depending on the requirements of a particular application. 
     The major surfaces of the polymer or predominantly polymer material insulation layer  70  and reinforcement layers  72  and  78  of the polymer-based composite structural sheathing board  46  are each defined by the length and the width of the polymer or predominantly polymer material insulation and reinforcement layers. The polymer or predominantly polymer material insulation and reinforcement layers  70 ,  72 , and  78 , and consequently the sheathing board  46 , typically have a width of about four feet or greater and a length of about four feet or greater and, preferably, a length of about eight feet. 
     The polymer or predominantly polymer material insulation layers  60  and  70  and reinforcement layers  62 ,  72 , and  78  of the polymer-based composite structural sheathing boards  44  and  46  may be made of various polymer or predominantly polymer materials [e.g. a polyisocyanurate, polyurethane, polystyrene, or phenolic material or a material made of a blend of these materials; a polyisocyanurate, polyurethane, polystyrene, or phenolic foam material or a foam material made of a blend of these materials; a predominantly polyisocyanurate, polyurethane, polystyrene, or phenolic material with up to 40% by weight, but typically between about 1% and about 25% by weight organic and/or inorganic filler(s) or a material made of a blend of these materials with up to 40% by weight, but typically between about 1% and about 25% by weight organic and/or inorganic filler(s); a predominantly polyisocyanurate, polyurethane, polystyrene, or phenolic foam material with up to 40% by weight, but typically between about 1% and about 25% by weight organic and/or inorganic filler(s) or a foam material made of a blend of these materials with up to 40% by weight, but typically between about 1% and about 25% by weight organic and/or inorganic filler(s), a material made of other thermoset matrix polymers; etc.]. However, a preferred material for the insulation core layers  60  and  70  and the reinforcement layers  62 ,  72 , and  78  is a polyisocyanurate material or foam material or a predominantly polyisocyanurate material or foam material with up to 40% by weight, but typically between about 1% and about 25% by weight organic and/or inorganic filler(s). Examples of various fillers that may be used in the predominantly polymer materials of the insulation core layers  60  and  70  and the reinforcement layers  62 ,  72 , and  78  include but are not limited to powdered, liquid, and fiber fillers. The polymer or predominantly polymer materials of the insulation core layers  60  and  70  and the reinforcement layers  62 ,  72 , and  78  may also include fiber reinforcements, fungi growth-inhibiting agents, fire-retardants, and other agents to reduce the cost of and/or modify the properties of the insulation core layers  60  and  70  and the reinforcement layers  62 ,  72 , and  78 , such as but not limited to the compressive strength, the toughness, the flexibility, the friability, and the fire resistance of the layers. Examples of fillers, which may be used in the predominantly polymer material insulation core layers  60  and  70  and the reinforcement layers  62 ,  72 , and  78 , are fillers such as but not limited to limestone (CaCO 3 ), fiberglass, recycled polyisocyanurate dust, extenders/plasticizers, ground up foam insulation, ground up rubber, wood dust, etc. 
     The reinforcement sheet layer  64  of the polymer-based composite structural sheathing board  44  and the reinforcement sheet layers  74  and  80  of the polymer-based composite structural sheathing board  46  typically overlie the entire or substantially the entire major surfaces of the polymer or predominantly polymer material insulation layer  70  and reinforcement layer  72  and  78  of the polymer-based composite structural sheathing board  44  or  46  to which the reinforcement sheet layers are bonded. The reinforcement sheet layers  64 ,  74 , and  80  of the polymer-based composite structural sheathing boards  44  and  46  may be any sheet material that materially reinforces the polymer-based composite structural sheathing boards  44  and  46 , such as but not limited to coated or uncoated woven or nonwoven mats made of fiberglass and/or other fibers or filaments, coated or uncoated scrims made of fiberglass and/or other fibers or filaments, etc. However, a preferred reinforcement material for the reinforcement layers  64 ,  74 , and  80  of the polymer-based composite structural sheathing boards  44  and  46  is a coated or uncoated, nonwoven, fiberglass mat or fiberglass scrim. Where a fiberglass scrim material is used, preferably, the scrim material has a tensile strength of at least 105 lbs per linear inch, a weight of about 10 grams/ft 2 , 8×8 strands per inch, and utilizes stands having a mean diameter of about 0.019 inches. It is contemplated that for certain applications, the sheathing board  44  may not include a reinforcement sheet layer  64  and that the sheathing board  46  may not include either or both of the reinforcement sheet layers  74  and  80 . 
     The facers  66  and  68  of the polymer-based composite structural sheathing board  44  and the facers  76  and  82  of the polymer-based composite structural sheathing board  46  typically overlie the entire or substantially the entire major surface of the insulation core layer  60  or reinforcement layer  62 ,  72 , and  78  of the polymer-based composite structural sheathing board  44  or  46  to which the facer is or facers are bonded. The facers of the polymer-based composite structural sheathing boards  44  and  46  may be any sheet material that provides suitable first and/or second major surfaces for the polymer-based composite structural sheathing boards  44  and  46 , such as but not limited to coated or uncoated paper, foil, coated or uncoated woven or nonwoven mats made of fiberglass and/or other fibers or filaments, coated or uncoated scrims made of fiberglass and/or other fibers or filaments, etc. However, a preferred facer material for the facers of the polymer-based composite structural sheathing boards  44  and  46  is a coated or uncoated, nonwoven, fiberglass mat or fiberglass scrim. Where a fiberglass scrim material is used, preferably, the scrim material has a tensile strength of at least 105 lbs per linear inch, a weight of about 10 grams/ft 2 , 8×8 strands per inch, and utilizes stands having a mean diameter of about 0.019 inches. It is contemplated that for certain applications, the sheathing board  44  may not include one or both of the facers  66  and  68  and that the sheathing board  46  may not include one or both of the facers  76  and  82 , especially where the reinforcement layer  64  or one or both of the reinforcement layers  74  and  80  are utilized in the sheathing boards  44  and  46 . 
     The polymer-based composite structural sheathing boards of the subject invention preferably have the following physical properties: 
     
       
         
               
               
               
             
               
               
             
           
               
                   
               
               
                   
                   
                 Preferred Range 
               
               
                 Property 
                 Range or Minimum 
                 or Minimum 
               
               
                   
               
             
             
               
                 Thickness 
                 0.15 to 0.75 inches 
                 0.25 to 0.50 inches 
               
               
                 Density 
                 1.6 to 25 lbs/ft 3   
                 3 to 10 lbs/ft 3   
               
               
                 Compressive Strength 
                 at least 25 psi 
                 at least 50 psi 
               
               
                 Flexural Strength 
               
               
                 Modulus of Rigidity 
                 at least 400 psi 
                 at least 1500 psi 
               
               
                 (MOR) 
               
               
                 Load at Yield 
                 at least 20 lbf 
                 at least 30 lbf 
               
               
                 Fastener Pull Through 
                 at least 20 lbf 
                 at least 50 lbf 
               
               
                 (ASTM Test D1037—in 
               
               
                 effect—June 2006) 
               
               
                 Water Absorption by Volume 
                 4% or less 
                 2% or less 
               
               
                 (ASTM Test C209—in 
               
               
                 effect—June 2006) 
               
               
                 Thermal Conductivity 
                 R-value of at least 1 
               
               
                 Flame Spread Rating 
                 at least 20 
                 at least 25 
               
               
                 (ASTM Test E84—in 
               
               
                 effect—June 2006) 
               
             
          
           
               
                 Fungus Growth Resistance 
                 Does Not Support Fungus Growth 
               
               
                   
               
             
          
         
       
     
     In describing the invention, certain embodiments have been used to illustrate the invention and the practices thereof. However, the invention is not limited to these specific embodiments as other embodiments and modifications within the spirit of the invention will readily occur to those skilled in the art on reading this specification. Thus, the invention is not intended to be limited to the specific embodiments disclosed, but is to be limited only by the claims appended hereto.

Summary:
A wall and/or ceiling polymer-based composite structural sheathing board has a polymer material or predominantly polymer material core layer with a density between 1.6 lbs/ft 3  and 25 lbs/ft 3 . A facer overlays at least one of the major surfaces of the core layer. The facer is generally coextensive with and bonded to the overlaid major surface of the core layer and enhances the integrity and fastener pull through strength of the polymer-based composite structural sheathing board as well as other desired physical and performance characteristics of the polymer based composite structural sheathing board. A wall and/or ceiling system of a building structure includes a plurality of the polymer-based composite structural sheathing boards overlaying and secured to a structural wall and/or ceiling frame and forming a wall and/or ceiling sheathing layer over the structural frame.