Various housing codes require the installation of an air barrier system in the construction of structures, such as for example a house. Generally, an air barrier system is configured to “seal” the entire structure, thereby controlling the passage of air into and out of the structure.
In some instances, the air barrier system includes a continuous vapor barrier in the form of a polymeric sheet configured for application to interior walls. In other instances, the air barrier system includes a vapor barrier applied to external walls of the structure.
It would be advantageous to provide an improved air barrier system.
The above objects as well as other objects not specifically enumerated are achieved by an air barrier system. The air barrier system includes a plurality of framing members configured to form insulation cavities. A plurality of panels is attached to an exterior surface of the framing members and gasket material is positioned therebetween. Adjacent panels form joints. Insulative batts are positioned within the insulation cavities. Sealing material is positioned over the joints.
According to this invention there is also provided an air barrier system. The air barrier system includes a plurality of framing members configured to form insulation cavities. A plurality of panels is attached to an exterior surface of the framing members. Adjacent panels form joints. Insulative batts are positioned within the insulation cavities and sealing material is positioned over the joints.
According to this invention there is also provided a method of installing an air barrier system. The method includes the steps of forming insulation cavities within framing members, attaching a plurality of panels to an exterior surface of the framing members and positioning gasket material therebetween, wherein adjacent panels form joint, positioning insulative batts within the insulation cavities and sealing the joints.
Various objects and advantages of the air barrier system will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.
The present invention will now be described with occasional reference to the specific embodiments of the invention. This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for describing particular embodiments only and is not intended to be limiting of the invention. As used in the description of the invention and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.
Unless otherwise indicated, all numbers expressing quantities of dimensions such as length, width, height, and so forth as used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless otherwise indicated, the numerical properties set forth in the specification and claims are approximations that may vary depending on the desired properties sought to be obtained in embodiments of the present invention. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical values, however, inherently contain certain errors necessarily resulting from error found in their respective measurements.
The description and figures disclose an improved air barrier system for application to the exterior of a residence or building. Generally, the improved air barrier system is configured to replace conventional insulation and water vapor systems with an improved system.
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The exterior surface 18 of the exterior sheathing 16 is covered by a layer of house wrap material 20. The house wrap material 20 is configured to provide a water barrier between an outer cladding (not shown) of the sidewall 10 and the various framing members such as to allow water vapor to pass through, yet restrict air infiltration. One example of a commercially available house wrap material is Tyvek® manufactured and marked by Dupont, headquartered in Wilmington, Del.
The interior of the sidewall 10 can be covered by construction material 22. The construction material 22 can be any desired material or combination of materials, including the non-limiting examples of drywall and paneling. The construction material 22 has an interior surface 23.
Insulation cavities 24 can be formed in the spaces between the various structural framing members, the interior surface 19 of the exterior sheathing 16 and the interior surface 23 of the construction material 22. The term “insulation cavity” as used herein, is defined to mean any space within the building within which insulation is desired, including the non-limiting examples of a building attic or sidewalls. In certain embodiments, the insulation cavities 24 can extend from the bottom plate 12 to the top plate 14b. In other embodiments, the insulation cavities 24 can extend from the bottom plate 12 or the top plate 14b to a building fixture, such as for example a window (not shown). While the insulation cavity 24 illustrated in
The insulation cavities 24 have a width W. The width W of the insulation cavities 24 corresponds to the width of the bottom plate 12 and the top plates 14a and 14b. In certain instances, the width of the bottom plate 12 and the top plates 14a and 14b is nominally 6.0 inches, which generally corresponds to an actual width of 5.5 inches. In other embodiments, the width W of the insulation cavities 24 can be in a range of from about 3.5 inches to about 5.5 inches. In still other embodiments, the width W of the insulation cavities 24 can be more about 5.5 inches.
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The insulative batts 26 are configured to provide a desired insulative value (R) to the sidewall 10. Factors contributing to the insulative value (R) include the thickness of the insulative batt 26 and the density of the material forming the insulative batts 26. In the illustrated embodiment, the insulative batt 26 has a thickness of about 5.50 inches which, when combined with the density of fibrous material forming the insulative batt 26, yields a minimum insulative value of about R20. While the illustrated embodiment of the insulative batt 26 has been described above as having a thickness of about 5.5 inches, it should be appreciated that in other embodiments, the thickness of the insulative batt 26 can be more or less than 5.5 inches, corresponding to the width W of the insulative cavities 24. Other combinations of the thickness of the insulative batt 26 and density can provide other desired insulative values (R).
The insulative batts 26 include an interior surface 27, positioned to be adjacent the interior side 23 of the construction material 22, and an exterior surface 28, positioned to be adjacent the interior surface 19 of the exterior sheathing 16.
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The panel materials 42 are configured for several purposes. First, the panel materials 42 are configured to provide rigidity to the sidewall 10. Second, the panel materials 42 are configured to provide a surface for attaching exterior wall coverings (not shown). Third, the panel materials 42 are configured to provide an insulative value to the sidewall 10. The insulative value of the panel materials 42 will be discussed in more detail below. Fourth, the panel materials 42 are configured to provide a substantially water resistant barrier that limits the penetration of liquid water through the sidewall 10. Lastly, the panel materials 42 are configured to provide a water vapor barrier between the exterior wall coverings of the sidewall 10 and the interior spaces of the building, such as to allow water vapor to pass through, yet restrict air infiltration.
In the illustrated embodiment, the panel materials 42 are formed from closed cell, moisture resistant rigid foam materials such as the non-limiting example of extruded polystyrene. One non-limiting example of a closed cell, moisture resistant rigid foam material is Foamular® 250 marketed by Owens Corning Corporation, headquartered in Toledo, Ohio. Alternatively, the panel materials 42 can be formed from other materials sufficient to provide rigidity to the sidewall 10, provide a surface for exterior wall coverings, provide an insulative value to the sidewall 10 and provide a water barrier between an outer cladding (not shown) of the sidewall 10 and the various framing members such as to allow water vapor to pass through, yet restrict air infiltration.
The foam material forming the panel materials 42 can be defined to have certain properties including thermal resistance, thermal conductivity, compressive strength, flexural strength, water absorption, water vapor permeance, dimensional stability, flame spread, smoke development, oxygen index and service temperature.
To provide effective insulative value (R), the foam material has a thermal resistance value of 5.0° F.×Ft2×h/btu @ 75° F. and a thermal resistance of 5.4° F.×Ft2×h/btu @ 40° F. as determined by thermal transmission tests, such as ASTM C518. Generally, the standard practice for Test Method ASTM C518 involves the measurement of steady state thermal transmission through flat slab specimens using a heat flow meter apparatus. The heat flow meter apparatus establishes steady state one-dimensional heat flux through a test specimen between two parallel plates at constant but different temperatures. By appropriate calibration of the heat flux transducer(s) with calibration standards and by measurement of the plate temperatures and plate separation, Fourier's law of heat conduction is used to calculate thermal conductivity, and thermal resistivity or thermal resistance and thermal conductance.
To provide effective thermal conductivity (k), the foam material has a value of 0.2 Btu×in/hr×ft2×° F. @ 75° F. and a thermal conductivity 0.18 Btu×in/hr×ft2×° F. @ 40° F. as determined by thermal transmission tests, such as ASTM C518, described above.
To provide effective compressive strength, the foam material has a minimum compressive strength value of 25.0 lb/in2 as determined by compressive strength tests, such as ASTM D1621. Generally, the standard practice for Test Method ASTM D1621 involves the measurement of the compressive strength of a cellular material by applying a load to a test specimen with a square or circular cross section. The test specimens are centered between two compression platens and load is applied at a constant crosshead or actuator rate. Crosshead travel (displacement, in.) and load (lb) are recorded throughout the test. Compressive strength then can be determined by several methods depending on the characteristics of the stress-displacement curve.
To provide effective flexural strength, the foam material has a minimum flexural strength value of 75.0 lb/in2 as determined by compressive strength tests, such as ASTM C203. Generally, the standard practice for Test Method ASTM C203 involves the measurement of the flexural strength of a cellular material by applying a load to a preformed block-type thermal insulation specimen having a rectangular cross section. The test specimens are positioned as a simply supported beam supported at both ends and a center load is applied to the specimen.
To provide effective water absorption, the foam material has a maximum water absorption value of 0.10% by volume as determined by water absorption tests, such as ASTM C272. Generally, the standard practice for Test Method ASTM C272 involves the measurement of the water absorption of a core foam material when immersed or in a high relatively humidity environment. In this procedure, at least five test specimen measuring 3.0 inches×3.0 inches are dried, removed from the drying oven, and allowed to cool in a desiccator. The specimens are then weighed on an analytical balance to the nearest 0.1 mg. The specimens are then immersed in deionized water or placed in the appropriate conditioning environment. The specimens are removed from the conditioning environment after 24 hours, 48 hours, or after thirty days, depending on the conditioning required.
To effectively retard the flow of air, moisture, and gases, the foam material has a maximum permeability rating of 1.1 (ng/Pa·s·m2) as determined by water vapor transmission tests, such as ASTM E96. Typical water vapor transmission tests, such as the ASTM E96, evaluate the transfer of water vapor through semi-permeable and permeable materials over a period of time.
To provide effective dimensional stability, the foam material has a maximum linear change of 2.0% as determined by dimensional stability tests, such as ASTM D 2126. Generally, the standard practice for Test Method ASTM D 2126 measures how rigid foam material responds to humidity and temperature. Test Method ASTM 2126 exposes the rigid foam material to different humidity and temperature environments. The size and shape of the rigid foam material is measured over time. A percent change in size is reported as the end result.
To provide effective flame spread, the foam material has a rating of 5 as determined by flame spread tests, such as ASTM E 84. Generally, the standard practice for Test Method ASTM E 84 measures the relative burning behavior of the material by observing the flame spread along a test specimen.
To provide effective smoke development, the foam material has a rating in a range of from about 45 to about 175 as measured by smoke development tests, such as ASTM E 84, described above.
To provide effective oxygen index, the foam material has a minimum rating of 24% by volume as determined by oxygen index tests, such as ASTM D 2863. Test Method ASTM D 2863 is a method to determine the minimum concentration of oxygen in an oxygen/nitrogen mixture that will support a flaming burn in a plastic specimen. Generally, the standard practice for Test Method ASTM D 2863 involves positioning a test specimen vertically in a glass chimney. An oxygen/nitrogen environment is established with a flow from the bottom of the chimney. The top edge of the test sample is ignited, and the oxygen concentration in the flow is decreased until the flame is no longer supported.
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Panel material 42a includes longitudinal edges 42a-1 and 42a-2. Panel material 42b includes longitudinal edges 42b-1 and 42b-2 and panel material 42c includes longitudinal edges 42c-1 and 42c-2. Panel material 42a includes lateral edges 42a-3 and 42a-4. Panel material 42b includes lateral edges 42b-3 and 42b-4 and panel material 42c includes lateral edges 42c-3 and 42c-4.
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The sealing material 50 is configured to seal the butt joints formed between lateral edges of the panel materials. In the illustrated embodiment, the sealing material 50 is a tape formed from the combination of a pressure sensitive adhesive and a polymeric film material. One example of a sealing material 50 is BILD-R-TAPE™ manufactured by Owens Corning Corporation headquartered in Toledo, Ohio. In other embodiments, the sealing material 50 can be made from other desired materials, sufficient to seal the butt joint formed between lateral edges of the panel materials.
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One measure of the efficiency of the improved air barrier system 40 is the “airtightness” of the resulting building structure. The term “airtightness”, as used herein, is defined to mean the measure of how many times the air within a defined space (normally a room or house) is replaced for a given period of time. In certain instances, the airtightness of a building structure is measured in terms of air changes per hour (ach). A building structure having a more efficient airtightness has a lower value of air changes per hour and a building structure having a less efficient airtightness has a larger value of air changes per hour. The airtightness of a building structure can be measure by several test methods, including diagnostic tools such as for example a “blower door”. A blower door consists of a calibrated fan for measuring an airflow rate, and a pressure-sensing device to measure the air pressure created by the fan flow. The combination of pressure and fan-flow measurements is used to determine the building airtightness.
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While the improved air barrier system 40 has been described above as incorporating the panel materials 42, the gasket material 44, the insulative batts 126 and the sealing materials 50, it should be appreciated that in other embodiments, the air barrier system can have other configurations. A first alternate embodiment of an air barrier system is shown in
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The sealing material 150 is configured to seal the shiplap joints formed between the longitudinal edges of the panel materials and the butt joints formed between lateral edges of the panel materials, thereby providing an effective vapor barrier. In the illustrated embodiment, the sealing material 150 is a tape formed from the combination of a pressure sensitive adhesive and an acrylic-based film material. Alternatively, the sealing material 150 can be other desired materials.
While the embodiment illustrated in
A second alternate embodiment of an air barrier system is shown in
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The coating material 250 is configured to seal the butt joints formed between lateral edges of the panel materials thereby providing an effective vapor barrier. In the illustrated embodiment, the sealing material 250 is a spray-on coating formed from single-part or multi-part polymeric materials. In other embodiments, the sealing material 250 can be other desired materials, including materials that are applied by brush or roller. While the embodiment illustrated in
In accordance with the provisions of the patent statutes, the principle and mode of operation of the improved air barrier system have been explained and illustrated in its preferred embodiment. However, it must be understood that the improved air barrier system may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.