Insulated building structures containing compressible CPI foam and a method for their fabrication

Abstract

Fabricate an insulated building structure by applying a compressible polymeric insulating (CPI) foam over sheathing material such that a portion of the CPI becomes compressed between a window frame and/or door frame or jamb.

Description

CROSS-REFERENCE TO PRIOR APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 60/439,323 filed Jan. 9, 2003.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to an insulated building structure and a method for its fabrication.

[0004] 2. Description of Related Art

[0005] One common type of building construction utilizes a support framework covered on its outside surface with a sheathing material. Inside sheathing such as drywall often goes on an inside surface of a support framework. A typical support framework comprises a plurality of framework members such as “two-by” lumber (e.g., 2×4, 2×6, and 2×8 boards). Sheathing material, such as oriented strand board (OSB), is generally applied to the outside of a support framework to enhance structural stability. Exterior coverage, such as aluminum or vinyl siding, can go directly over the sheathing material.

[0006] Buildings usually include windows and doors. Installation of windows and doors typically occurs by cutting a hole through sheathing material and inserting a window or door at specifically designed locations in a support framework.

[0007] Manufacturers design standard window and doorframes to allow for a standard wall thickness for use in insulated building construction. For example, a standard wall thickness when using a 2×4 lumber support framework is between 4.44 inches (113 millimeter (mm)) and 4.56 inches (116 mm) thick. The wall thickness accounts for 0.5 inch (12.7 mm) drywall, a 3.5 inch (88.9 mm) stud, and {fraction (7/16)} inches (11.1 mm) to {fraction (9/16)} inches (14.3 mm) of sheathing material. If a wall is made using 2×6 lumber, the standard wall thickness is an additional 2 inches (50.6 mm) thick. If a wall has a thickness other than a standard thickness, jamb extensions are necessary for windows and doors. Jamb extensions undesirably increases, for example, a window's cost by $50-$60 dollars.

[0008] Recently, building construction containing a support framework and sheathing materials also include a housewrap or insulative foam between the sheathing material and exterior coverage in an effort to further isolate a building's interior environment from its exterior environment.

[0009] Housewraps serve as air barriers around building walls, covering joints between sections of sheathing materials. Housewraps tend to be permeable to water vapor, allowing moisture that may be near sheathing material to escape.

[0010] Cellular plastic or plastic foam generally consists of at least two phases; a solid polymer matrix and a gaseous phase derived from a blowing agent. The gaseous phase is dispersed within the solid polymer matrix either as discrete, non-interconnecting cells (usually referred to as “closed cell foam”) or with some degree of interconnectivity between adjacent cells (usually referred to as “open cell foam”).

[0011] Insulative foam is an attractive alternative to a housewrap. Insulative foam can both serve as an air barrier and provide additional thermal insulation in a building wall. Typical insulative foams for use against sheathing material in building construction today include rigid foams such as extruded polystyrene (XPS) foam, polyisocyanurate (PIR) foam, and molded polystyrene bead (EPS) foam. These insulative foam materials, however, also have their handicaps.

[0012] Sheathing material, such as OSB, is typically {fraction (7/16)} inches (11.1 mm) thick, allowing for only 0.125 inch (3.2 mm) in additional insulative foam thickness in order to maintain a standard wall thickness in typical wall construction. Rigid insulating foam, such as XPS, PIR and EPS tend to be fragile and offer minimal insulative value at such a small thickness. Often, a rigid insulative foam includes a facer sheet (e.g., polymeric film, glass fiber mat, or paper) on one or both opposing primary face(s) in order to enhance the foam's structural integrity. Such facer sheets tend to hinder water vapor permeability through a foam, which can result in increased moisture near a sheathing material. Thicker rigid insulating foams are more durable and offer better thermal insulation, but increase a wall's thickness beyond a standard thickness, resulting in a need for windows and doors that have jamb extensions.

[0013] EPS insulative foam has an added handicap in that it tends to absorb water more readily than other foams. Retaining moisture in an insulative foam undesirably increases the thermal conductivity through the foam and can accelerate degradation of adjacent sheathing material.

[0014] An insulated building structure comprising a polymeric insulating foam that is sufficiently flexible to allow it to be transported as roll stock, yet sufficiently strong to minimize, preferably eliminate, foam breakage during transport and installation is desirable for use as an insulative foam between sheathing material and exterior coverage in an insulated building structure. Such foam needs no facer, and preferably does not have a facer.

BRIEF SUMMARY OF THE INVENTION

[0015] The present invention addresses a need in the building industry by providing both an insulated building structure and a method for fabricating an insulated building structure with a strong, flexible and compressible polymeric insulating foam (“CPI foam”), preferably a CPI foam that has no facer material adhesively bonded, or otherwise operatively attached, to either of its opposing primary faces.

[0016] In a first aspect, the present invention is an insulated building structure comprising a support structure, a sheathing material, and a CPI foam, wherein the support structure and the sheathing material each have opposing inner and outer surfaces with the inner surface of the sheathing material attached to the outer surface of the support structure, and wherein the CPI foam has opposing major surfaces with one major surface contacting the outer surface of the sheathing material, said CPI foam having a solid polymer matrix phase comprising a polymer resin containing polymerized propylene monomers, said CPI foam also having: a) a thickness of greater than 0.125 inches (in) (3.2 mm) and 0.75 in (19.0 mm)or less; b) a compressive strength at 10% compression of 10 pounds per square inch (psi) (68.9 kilopascals (kPa)) or less, according to American Society for Testing and Materials (ASTM) method D3575-00-D; and c) a water pick-up of less than 5% by both submersion testing (ASTM D3575-00L) and freeze/thaw testing (ASTM C666-97, 25 cycles).

[0017] In a second aspect, the present invention is a method for fabricating the insulated building structure of the first aspect, said method comprising the steps: (a) providing a support framework that has opposing inner and outer surfaces; (b) placing a sheathing material that has opposing inner and outer surfaces in operative contact with the support structure such that the inner surface of the sheathing material contacts at least surface portions of the support structure outer surface and attaching the sheathing material to the outer surface of the support structure; (c) securing a CPI foam to the outer surface of the sheathing material so that a major surface of the CPI foam contacts the outer surface of the sheathing material, wherein the CPI foam has a solid polymer matrix phase comprising a polymer resin containing polymerized propylene monomers, the CPI foam also having: (i) a thickness of greater than 0.125 in (3.2 mm) and 0.75 in (19.0 mm) or less; (ii) a compressive strength at 10% compression of 10 psi (68.9 kPa) or less, according to ASTM method D3575-00-D; and (iii) a water pick-up of less than 5% by both submersion testing (ASTM D3575-00L) and freeze/thaw testing (ASTM C666-97, 25 cycles).

[0018] “Securing”, as used herein, means attaching by way of fasteners, such as screws or nails or construction fasteners, or adhesives, or both fasteners and adhesives.

BRIEF DESCRIPTION OF DRAWINGS

[0019] FIG. 1 shows a portion of an insulated structure.

[0020] FIGS. 2A-2C shows portions of CPI foam.

[0021] FIGS. 3A and 3B shows a typical window for new construction and replacement installation, respectively.

[0022] FIG. 3C shows a cross-sectional view of a typical window for new construction in an insulated building structure of the present invention.

[0023] FIGS. 4A and 4B show a replacement window having a U-shaped frame.

[0024] FIG. 4C shows a cross-sectional view of a replacement window with a U-shaped frame in an insulated building structure of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0025] FIG. 1 shows a portion of insulated building structure 10, an example of an insulated building of the present invention. Structure 10 comprises, in part, support framework 20, which, in turn, comprises a plurality of interconnected support framework members 23 and has an inside surface 25 and an outer surface 27. Structure 10 also comprises sheathing material 40 that has an inner surface 43 and an outer surface 45. Construction adhesive 30 (shown as discrete aliquots, but continuous beads of adhesive may also be used) attaches inner surface 43 of sheathing material 40 to outer surface 27 of support framework 20. Construction fasteners 50 hold major surface 65 (not shown) of CPI foam 60 against outer surface 45 of sheathing material 40.

[0026] “Interior”, “inside” and “inner” may be used interchangeably. Similarly, “exterior”, “outside” and “outer” may be used interchangeably.

[0027] The insulated building structures of the present invention are not limited to a particular support structure or sheathing material. Support structures are well known in the field of building construction and serve to define a foundation for, e.g., walls, floors and ceilings of a structure. Examples of typical support structures include frameworks comprising wooden boards, metal beams, girders, polymer composite “boards”, or any combination thereof. Other support structures can include cement block or brick. Support structures encompass an interior space, such as the interior of a house. An interior space is considered as being inside of a structure. Support structures have opposing interior and an exterior surfaces, with the interior surface most proximate to an interior space encompassed by the support structure.

[0028] Sheathing materials attach to at least a portion of an exterior surface of a support structure. Sheathing materials have opposing inner and outer surfaces. The inner surface of a sheathing material attaches to the exterior surface of a support structure. Sheathing material can serve multiple purposes. To some extent, sheathing material acts as an air barrier between the inside and outside of a structure. Usually, sheathing material also enhances a support structure's strength and stability. Examples of sheathing materials include OSB, plywood and rigid polymeric foam insulation (e.g., XPS foam board), with OSB being perhaps the most common.

[0029] The insulated building structures of the present invention also comprise a CPI foam. The CPI foam has opposing major surfaces, one of which contacts the outer surface of the sheathing material. The CPI foam has a solid polymer matrix phase that comprises a polymer resin containing polymerized propylene monomer units. For example, the polymer resin can comprise a propylene homopolymer, a propylene copolymer, a blend of a propylene homopolymer and a propylene copolymer or a blend two or more propylene copolymers. The resin can comprise a blend of different polymers, provided the polymers are suitably compatible such that the blend can form a foam and provided at least one of the polymers has polymerized propylene monomer units. Desirably, at least 50 weight-percent (wt %) of the polymer resin, preferably greater than 50 wt %, more preferably 60 wt % or more by weight of the polymer resin is polymerized propylene units. Polymerized propylene units are desirable in a polymer resin, e.g., to increase the resin's thermal stability. Generally, though not necessarily, the CPI foam comprises multiple distinguishable coalesced foam strands.

[0030] CPI foam for use in the present invention desirably has a thickness of 0.125 in (3.2 mm) or more, preferably 0.25 in (6.4 mm) or more, and 0.75 in (19 mm) or less. A particularly desirable CPI foam has a thickness of 0.5 in (12.7 mm). CPI foam thickness is a distance or span measured between opposing major surfaces.

[0031] CPI foam for use in the present invention further desirably has a compressive strength at 10% compression of 10 psi (68.9 kPa) or less according to ASTM method D3575-00-D; and a water pick up of less than 5%, preferably less than 3%, more preferably less than 1.5%, most preferably less than 1% by both submersion (ASTM method D3575-00L) and freeze/thaw (ASTM method C666-97, with 25 cycles) test methods.

[0032] A CPI foam having these desirable properties is particularly useful in building construction as an insulating component between a sheathing material and exterior coverage such as aluminum or vinyl siding. Such a compressive strength may allow enough compression of a CPI foam by a window or door frame to minimize and preferably eliminate a need for jamb extensions, particularly with CPI foam compressive strength values well below 10 psi, such as 1 to 2 psi (6.9 to 13.8 kPa), in conjunction with proper selection of fastening means that hold the CPI foam in a compressed state. In addition, water pick up of less than 5% hinders retention of water near a sheathing material.

[0033] CPI foams suitable for use in the present invention have a thickness that is sufficient to provide a desirable decrease in thermal conductivity through a wall structure. The CPI foams are preferably not so thick as to require extensive use of jamb extensions for window and door installation. Foams thicker than 0.125 in (3.2 mm) offer higher thermal insulation values than similar foams that are not as thick (e.g. foams having a thickness of 0.05 in (1.3 mm)).

[0034] The CPI foam is compressible between a sheathing material of a wall and a portion of window frame or a portion of doorframe and/or trim. Herein, “frame” and “jamb” are interchangeable and refer to a combination of header (top), sill (bottom) and sides of a window or door framework. Compressing a portion of CPI foam around window frames and door frames creates a seal around the windows and doors, enhancing insulation of the building structure that contains such window frames and door frames. Furthermore, compressing a portion of CPI foam between a window or door frame and a sheathing material allows for the use of thicker foams (i.e., greater than ⅛ inch (3.18 mm)) without requiring jamb extensions. Thicker foam is desirable in order to increase a wall's thermal insulation character. CPI foam desirably conforms to dimensional irregularities in wall thickness around windows and doors allowing for a more uniform seal around windows and doors than one can attain with a substantially incompressible foam (e.g. a foam with a compressive strength well in excess of 10 psi (68.9 kPa), such as 100 psi (689 kPa)).

[0035] CPI foams for use in the present invention preferably have a density of 0.5 pounds per cubic foot (pcf) or more (eight kilograms per cubic meter (kg/m3) or more) and two pcf (32 kg/m3) or less, more preferably 1.5 pcf (24 kg/m3) or less. Determine foam density according to ASTM method D3575-93W. CPI foams having a density below 0.5 pcf (eight kg/m3) tend to have insufficient stiffness, flopping undesirably during handling. CPI foams having a density above two pcf (32 kg/m3) tend to have an undesirably high thermal conductivity.

[0036] Desirably, CPI foams of the present invention have a thermal conductivity of 0.28 British Thermal Units-inch per degree Fahrenheit-square foot-hour (BTU-in/° F.-ft2-hr) or less (40 milliwatts per meter-Kelvin (mW/m-K) or less) according to ASTM method D3575. A CPI foam for use in the present invention typically has a cell size of 1.5 mm or less and preferably one mm or less, as determined by ASTM method D3576.

[0037] CPI foam for use in the present invention advantageously is flexible enough to bend around a one-inch (25.4 mm) diameter mandrel without breaking. At the same time, the CPI foam is advantageously sufficiently rigid so that it has a deflection angle of less than 75 degrees (°), preferably 60° or less, more preferably 45° or less, still more preferably 30° or less, even more preferably 15° or less in a Horizontal Bend Test. Conceivably, CPI foam for use in the present invention can have a deflection angle of 0° in a Horizontal Bend Test.

[0038] To conduct a Horizontal Bend Test, place a major surface of a CPI foam having a length of at least four feet (1.2 meter (m)), preferably eight feet (2.4 m) and a width of two feet (0.6 m) on a horizontal support surface (e.g., a table top). The length and width define the CPI foam's major surface. Position the CPI foam such that three feet (0.914 m) of the CPI foam's length extends unsupported off from an edge of the horizontal support surface while holding the remaining length of CPI foam against the horizontal support surface, particularly at the edge of the horizontal support surface. Measure the deflection angle of the unsupported length of CPI foam. The deflection angle is an angle between a straight line from the unsupported end of the CPI foam to the edge of the horizontal support surface and a line corresponding to position the unsupported portion of CPI foam would make if it did not bend. Flexibility is desirable because it renders a CPI foam less likely to break or fracture during handling while the specified level of rigidity allows for easy handling and installation of the CPI foam, even by an individual installer.

[0039] Too much flexibility can be undesirable. For example, commercially available polyethylene foams that are less than 0.75 inches (19 mm) thick tend to be sufficiently flexible (floppy) so as to have a deflection angle of more than 45° in the Horizontal Bend Test. As a result, these polyethylene foams are difficult to handle and install, particularly by an individual installer.

[0040] CPI foams for use in the present invention desirably have an open cell content of 20% or more, preferably 30% or more, still more preferably 40% or more and up to and including 100% open cell content. Measure open cell content according to ASTM method 2856-94.

[0041] Insulated building structures in colder climates generally benefit from CPI foams having a higher water vapor permeability than insulated building structures in warmer climates. CPI foams for use in the present invention desirably have a water vapor permeability of one or more perms, preferably five or more perms, more preferably 70 g/m2-24 hr (10 or more perms) and preferably 140 grams per square meter per 24 hours (g/m2-24 hr) (20 or less U.S. perm units or perms) according to ASTM method E96-00. A CPI foam having 105 g/m2-24 hr (15 perms) is particularly desirable. A CPI foam that has a water vapor permeability of less than 7 g/m2-24 hr (one perm) tends to prevent moisture from escaping through it and may allow water build-up adjacent to sheathing material, unless air flow is present by means of, e.g., grooves in the CPI foam. A CPI foam may contain multiple perforations that enhance water vapor permeability. Interestingly, the perforations can either extend through the CPI foam (penetrating through opposing surfaces) or penetrate into a CPI foam without extending through the CPI foam (i.e., penetrating through only one surface) and still enhance water vapor permeability. A water vapor permeability below 140 g/m2-24 hr (20 perms) is desirable so the CPI foam will have a desirable air flow resistivity.

[0042] Desirably, the CPI foam has an air flow resistivity of less than 25 kilopascal-seconds per square meter. Having a low air flow resistivity is desirably to enhance isolation of a building's interior environment from its exterior environment.

[0043] CPI foams for use in the present invention can contain indentations in the form of, e.g., grooves and channels along one or more surface. Indentations penetrate into a surface, preferably a major surface, of the CPI foam to a depth less than the thickness of the CPI foam and desirably traverse a surface of the CPI foam. Traversing a surface means extending from one edge of a CPI foam to an opposing edge of that CPI foam. Accordingly, the indentations can extend, e.g., entirely along the CPI foam's length, across the CPI foam's width, or diagonally across a CPI foam's surface. The indentations may be straight lines or take on any other regular or irregular path so long as one end of the path intersects with one edge of a CPI foam and the other end of the path intersects with a different edge, preferably an opposing, but spaced apart, edge, of the CPI foam. As an example, a CPI foam can contain a series of regular parallel grooves that traverse one of its surfaces. Alternatively, a CPI foam can have raised portions, e.g., inverted dimples or small bumps along one or more surface. Upon placing such a CPI foam against a sheathing material such that a side with indentations or raised portions is adjacent to the sheathing material, one creates channels or pathways that facilitate fluid communication, or air flow, from one CPI foam edge to another edge of the same CPI foam. In such an orientation air can circulate along at least portions of the interface between the CPI foam and the sheathing material. Such air circulation can be desirable to enhance removal of any moisture that may otherwise accumulate at the interface or in the sheathing or CPI foam.

[0044] U.S. Pat. No. 6,583,193 (incorporated herein by reference) discloses a foam suitable for use as a CPI foam in insulated building structures of the present invention and its preparation. The CPI foam is an extruded, coalesced foam strand material made from a polymer composition that comprises a linear polyolefin resin or blend of a linear polyolefin resin, particularly propylene polymers. CPI foams made according to the teachings of U.S. Pat. No. 6,583,199 are especially desirable and such foams that meet one or more of the preferred embodiments described herein are preferred. Coalesced foam strand materials can advantageously have grooves along their major surfaces at points where strands meet, as described below.

[0045] While coalesced foam strand materials serve as preferable CPI foam materials, a skilled artisan recognizes that the CPI foam can also be free of coalesced foam strands, e.g., a coalesced foam bead structure, an extruded sheet material, a laminated sheet material, or a combination of any of these foams with coalesced foam strands. A skilled artisan can prepare such foam materials by standard, well known foam manufacturing methods.

[0046] While CPI foams that are suitable for use in the insulated building structures of the present invention preferably do not have a facer material for various reasons, such as cost, ease of fabrication and enhanced water vapor permeability, one can include facer materials (e.g., polymeric films, glass fibers, and paper) on one or both major surface(s) of the CPI foam without departing from the scope of the present invention.

[0047] FIGS. 2A, 2B, and 2C show portions of CPI foams suitable for use in the present invention. FIG. 2A shows CPI foam 100 comprising multiple distinguishable polymeric foam strands 110 and containing multiple regularly spaced perforations 120 through major surface 130. FIG. 2B shows CPI foam 200 comprising multiple polymeric foam strands 210. Major surface 230 contains regularly spaced grooves 220 where foam strands 210 meet. FIG. 2C shows CPI foam 300 comprising multiple polymeric foam strands 310 and containing multiple grooves 320 that extend through major surface 330 but to a depth less than the thickness D of CPI foam 300.

[0048] Insulated building structures of the present invention comprise a support framework with an inner surface of a sheathing material attached to the outer surface of the support framework and a CPI foam contacting an outer surface of the sheathing material. The insulated building structure can further comprise one or more window, one or more door, or a combination of one or more window and one or more door. The present insulated building structure contains at least one wall that contains the polymeric insulating foam, sheathing material and a support framework.

[0049] FIGS. 3A, 3B, 3C and 4A, 4B and 4C generally illustrate two types of windows suitable for use in the present invention.

[0050] FIGS. 3A and 3B illustrate a face and side view, respectively, of window 200 that is typical for use in original construction. Window 200 includes frame (jamb) 210 with nail flange 220. FIG. 3C illustrates a cross-sectional view of window 200 installed in wall 230. Wall 230 contains CPI foam 240, sheathing material 250, support framework 260, and drywall 270. Desirably, when using a window such as 200 that has a nail flange such as 220 in the present invention, position window 200 such that CPI foam 240 is between nail flange 220 and sheathing material 250. Nail flange 220 desirably compresses the CPI foam sufficiently to as to eliminate a need for a window with extension jambs.

[0051] The compressibility of the CPI foam allows for CPI foam thicknesses of 0.5 inches (12.7 mm) or thicker without requiring windows with extension jambs, even if the wall has irregularities in its thickness. Furthermore, compressing the CPI foam between the nail flange 220 and a sheathing material has a gasketing effect that works as a seal around window 200.

[0052] FIGS. 4A and 4B illustrate a face and side view, respectively, of window 300 that is one type of replacement window. Window 300 differs from window 200 by having U-shaped frame 310 instead of a nail flange. U-shaped frame 310 has a width D that corresponds to a wall width. A polymeric insulating foam, sheathing material and support framework all fit between lips 320 and 330 of window 300 upon installing window 300 within the scope of the present invention. FIG. 4C shows a cross-sectional view of window 300 installed in wall 340, which contains support structure 350, sheathing material 360, CPI foam 370, and drywall 380. FIG. 4C shows how lip 320 can compress CPI foam 370 against sheathing material 360. Polymeric insulative foam 370 can have a thickness of greater than 0.5 inches (12.7 mm) to provide additional thermal insulation to wall 340 without requiring window 300 to have an extension jamb.

[0053] The present invention is also compatible with other types of windows, provided some portion of the window frame or even window trim, compresses a CPI foam between itself and a sheathing material. For example, replacement windows can also have an attachable nail flange that can be useful for compressing a CPI foam.

[0054] Door frames, once installed, have a similar cross-sectional view as window 300 in FIG. 4C except instead of lips 320 and 330 a door frame has trim around the door. Trim can compress a CPI foam of the present invention between itself and sheathing material in order to allow CPI foam thicknesses of greater than 0.5 inches (12.7 mm) without require door jamb extensions.

[0055] While the FIGS. 3C and 4C illustrate CPI foam compressing directly against sheathing material, a skilled artisan realizes that other materials such as a house wrap may reside between the CPI foam and sheathing material within the scope of the present invention. Similarly, a house wrap material may reside against the CPI foam on a foam surface remote from the sheathing material while within the scope of the present invention.

[0056] In general, fabrication of insulated building structures of the present invention begins with provision of a support framework and a sheathing material, each of which has opposing inner and outer surfaces, and a CPI foam of the type described herein with opposing major surfaces. Fabrication continues with a step of attaching the inner surface of the sheathing material to the outer surface of the support structure. In a subsequent step, fabrication proceeds with applying the CPI foam to the outer surface of the sheathing material so that a major surface of the foam contacts the outer surface of the sheathing material. Affixing or attaching the CPI foam to the sheathing material is acceptable and beneficial to hold the foam in place prior to and during installation of any exterior coverage. Construction adhesives such as glue and caulk as well as construction fasteners such as screws, nails, and staples are suitable for affixing or attaching the foam to sheathing material, as well as for attaching sheathing material to a support framework.

[0057] A typical installation involves first attaching multiple sheets of sheathing material to an outer surface of a support framework, butting adjacent sheets of sheathing material against one another. Installation continues with application of multiple sheets of CPI foam to the sheathing material. Position the CPI foam sheets adjacent to, and butting against, one another and, preferably, place tape over seams between sheets to seal the seams and minimize, preferably eliminate, air penetration via the seams. An especially preferred installation technique, staggers the position of CPI foam sheets relative to sheathing material sheets such that seams between sheets of sheathing material do not align with seams between sheets of CPI foam.

[0058] In general, installation of windows and doors occurs after application of CPI foam sheets to the sheathing material. In one embodiment, follow application of CPI foam sheets to the sheathing material by cutting one or more opening(s) through the CPI foam and sheathing material of appropriate size to receive a window or door, according to opening dimensions specified by the window or door manufacture. Alternatively, provide the necessary opening(s) in the CPI foam and sheathing material and then apply the CPI foam to the sheathing material while aligning the holes in the CPI foam with the holes in the sheathing material. Install window(s) and door(s) through the appropriate opening. Desirably, window frame or door trim compress a portion of the CPI foam between itself and the sheathing material, thereby forming a seal around the window and/or door.

[0059] In an alternative embodiment, install window and doors through sheathing material prior to applying CPI foam to the sheathing material. Within such an embodiment, tuck and compress a portion of the CPI foam between window frames and doorframes or trim and sheathing material.

[0060] Applying CPI foam to sheathing material prior to attaching sheathing material to a support structure is acceptable and can advantageously speed fabrication of an insulated building structure by allowing both sheathing and foam to be applied simultaneously to a support framework. As a particularly desirable example, apply a CPI foam sheet to a sheet of sheathing material that is of similar dimensions, but with the CPI foam offset so as to extend past an edge of the sheet of sheathing material. Within such an orientation, a portion of the sheathing material's outer surface along one or two of its edges remains uncovered by the CPI foam while a portion of CPI foam extends past an opposing edge of the sheathing material. When attaching these offset combinations of CPI foam and sheathing material to a support structure, orient them so that the portion of CPI foam that extends past or overhangs one combination overlaps the exposed portion of outer surface on an adjacent sheathing material. In this manner, CPI foam seals over joints between sheets of sheathing material. This type of joint overlap is also advantageous when applying CPI foam to sheathing material that is already attached to a support structure. Sheets of CPI foam and sheathing material can also be aligned with one another to form a single laminate sheet. Application of such laminate sheets results in less desirable, but still acceptable for purposes of the present invention, coinciding seams for foam and sheathing material.

[0061] The following examples provide further illustration of the present invention.

[0062] CPI Foam

[0063] Prepare or acquire a CPI foam that comprises a polymer resin containing 86 weight-percent (wt %) propylene monomer units and 14 wt % ethylene monomer units. The CPI foam has a density of 1 pcf (16 kg/m3), 0.6 mm average cell size, an open cell content of 40% (ASTM method 2856-94), a compressive strength at 10% compression of 4 psi (27.6 kPa), a water pick up of 0.2% by ASTM method D3575-00L and 0.9% by ASTM method C666-97. The CPI foam contains sufficient carbon black to achieve a thermal conductivity of 0.2377 BTU-inch/° F.-ft2-hr (34.3 mW/m-K) (ASTM method D-3575-00). The CPI foam is sufficiently flexible to bend around a one-inch (25.4 mm) diameter mandrel without breaking yet has a deflection angle in the Horizontal bend Test of less than 45°. Such a CPI foam is available from The Dow Chemical Company as extruded polypropylene foam XU52024.00.

[0064] Fabricating an Insulated Building Structure

EXAMPLE ONE

[0065] Provide a standard timber support framework of nominal 2×4 (1.75 in by 3.5 in (4.4 cm by 8.9 cm) lumber and attach 4 foot (1.22 m) by 8 foot (2.44 m) by {fraction (7/16)} inch (11.1 mm) sheets of OSB over the outer surface of the framework. Attach the OSB to the framework using standard construction nails or screws. Over the OSB apply 4 foot (1.22 m) by 8 foot (2.44 m) by 0.5 inch (12.7 mm) sheets of the above CPI foam, positioned so that seams between CPI foam sheets do not overlap with seams between adjacent OSB sheets. Affix the sheets of CPI foam to the OSB using plastic cap nails, preferably spaced 16 in (0.41 m) apart. Tape over all seams between adjacent CPI foam sheets using a contractor grade tape such as 3M Contractor Sheathing Tape No. 8086.

[0066] Install windows and doors according to manufacturer's recommendations. Desirably, compress the CPI foam slightly with window frames and door trim. Flash windows and doors according to building code requirements. When using 0.5 inch (12.7 mm) drywall to finish the inner surface of the support framework, jamb extensions are not necessary for the windows or doors.

[0067] Example One illustrates an insulated building structure of the present invention comprising a CPI foam over a sheathing material attached to a support framework.

EXAMPLE TWO

[0068] Prepare an insulated building structure as per Example One except use a polymeric insulating foam having a thickness of 0.6 inches (15.24 mm). Compress the foam with window and doorframes or trim sufficiently to preclude need for jamb extensions in the windows and doors.

[0069] Example two illustrates an insulated building structure and a method of fabricated an insulated building structure using a compressible polymeric insulating foam having a thickness of greater than 0.5 inches (12.7 mm) over a sheathing material wherein the building structure accommodates windows and doors without requires jamb extensions.

Claims

1. An insulated building structure comprising a support structure, a sheathing material, and a compressible polymeric insulative (CPI) foam; wherein the support structure and sheathing material have opposing inner and outer surfaces with the inner surface of the sheathing material attached to the outer surface of the support structure and wherein the CPI foam has opposing major surfaces with one major surface contacting the outer surface of the sheathing material; said CPI foam having a solid polymer matrix phase comprising a polymer resin containing polymerized propylene monomers, said CPI foam also having:

a) a thickness of greater than 0.125 inches (3.2 millimeters) and 0.75 inches (19.0 millimeters) or less;

b) a compressive strength at 10% compression of 10 pounds per square inch (68.9 kilopascals) or less, according to ASTM method D3575-00-D; and

c) a water pick-up of less than 5% by both submersion testing (ASTM D3575-00L) and freeze/thaw testing (ASTM C666-97, 25 cycles).

2. The building structure of claim 1, further comprising a door with its associated frame, a window with its associated frame, or both a door with its associated frame and a window with its associated frame, wherein the door, or the window, whichever is appropriate, penetrates through both the CPI foam and the sheathing material, and at least a portion of the CPI foam is disposed beneath, and compressed by, the door frame, the window frame or both the door frame and the window frame, whichever is appropriate.

3. The building structure of claim 1, wherein the CPI foam has a density of 0.5 pounds per cubic foot (8 kilograms per cubic meter) or more and 1.5 pounds per cubic foot (25 kilograms per cubic meter) or less.

4. The building structure of claim 1, wherein the CPI foam is sufficiently flexible to bend around a one-inch (25.4 millimeter) diameter mandrel without breaking, yet sufficiently rigid so as to not bend more than 45° in the Horizontal Bend Test.

5. The building structure of claim 1, wherein the CPI foam has an average cell size of one millimeter or less.

6. The building structure of claim 1, wherein the CPI foam comprises multiple distinguishable polymeric foam strands.

7. The building structure of claim 1, wherein the CPI foam contains multiple perforations through at least one surface of the CPI foam.

8. The building structure of claim 1, wherein the CPI foam has a water-vapor permeability of one or more and 20 or less perms according to ASTM method E96-00.

9. The building structure of claim 1, wherein the CPI foam has at least one groove traversing the major surface contacting the sheathing material; and wherein said groove penetrates through the CPI foam surface contacting the sheathing material to a depth of less than the CPI foam's thickness.

10. A method for fabricating the insulated building structure of claim 1, the method comprising:

a) providing a support framework that has opposing inner and outer surfaces, and a CPI foam with opposing major surfaces;

b) placing a sheathing material that has opposing inner and outer surfaces in operative contact with the support structure such that the inner surface of the sheathing material contacts at least surface portions of the support structure outer surface and attaching the sheathing material to the outer surface of the support structure;

c) securing a CPI foam to the outer surface of the sheathing material so that a major surface of the CPI foam contacts the outer surface of the sheathing material, the CPI foam having a solid polymer matrix phase comprising a polymer resin containing polymerized propylene monomers to the outer surface of the sheathing material so that a major surface of the CPI foam contacts the outer surface of the sheathing material, the CPI foam having:

i) a thickness of greater than 0.125 inches (3.2 millimeters) and 0.75 inches (19.0 millimeters) or less;

ii) a compressive strength at 10% compression of 10 pounds per square inch (68.9 kilopascals) or less, according to ASTM method D3575-00-D; and

iii) a water pick-up of less than 5% by both submersion testing (ASTM D3575-00L) and freeze/thaw testing (ASTM C666-97, 25 cycles).

11. The method of claim 10, further comprising sequential steps:

d) providing at least one opening through both the CPI foam and sheathing material, each opening being of sufficient dimensions to accommodate only a window or a door, whichever is appropriate;

e) inserting a door or window of a door and associated frame combination or a window and associated frame combination, whichever is appropriate, and applying pressure against the associated frame sufficient to compress at least a portion of the CPI foam against the outer surface of the sheathing material; and

f) securing the associated frame to the sheathing.

12. The method of claim 10, wherein the CPI foam has a density of 0.5 pounds per cubic foot (8 kilograms per cubic meter) or more and 1.5 pounds per cubic foot (25 kilograms per cubic meter) or less according to ASTM method D3575-93W.

13. The method of claim 10, wherein the CPI foam is sufficiently flexible to bend around a one-inch (25.4 millimeter) diameter mandrel without breaking, yet sufficiently rigid so as to not bend more than 45° in the Horizontal Bend Test.

14. The method of claim 10, wherein the CPI foam has an average cell size of one millimeter or less according to ASTM method D3576.

15. The method of claim 10, wherein the CPI foam comprises multiple distinguishable polymeric foam strands.

16. The method of claim 10, wherein the CPI foam contains multiple perforations through at least one surface of the CPI foam.

17. The method of claim 10, wherein the CPI foam has a water-vapor permeability of one or more and 20 or less perms according to ASTM method E96-00.

18. The method of claim 10, wherein the CPI foam has at least one groove traversing the major surface contacting the sheathing material and penetrating through the CPI foam surface to a depth of less than the CPI foam's thickness.

19. The method of claim 10, wherein step (c) occurs prior to step (b).