Vapor barrier with valve for a building

A vapor barrier for sealing an interior of a building from an insulation cavity defined by framing members of the building includes a flexible and substantially impermeable sheet having apertures to allow air to exit the insulation cavity during filling of the insulation cavity with loose fill insulation. The vapor barrier also includes one-way valves mounted across the apertures. The valves are configured to allow air flow out of the insulation cavity and into the building interior through the apertures and to prevent air flow and moisture diffusion from the building interior into the insulation cavity.

TECHNICAL FIELD

This invention relates generally to a method and apparatus for insulating buildings. More particularly, this invention pertains to a vapor barrier for insulating building walls, ceilings and floors.

BACKGROUND OF THE INVENTION

The exterior walls of a building can be insulated in order to reduce the heating and cooling demands resulting from variations between the exterior temperature from the desired interior temperature. A wide range of fibrous, solid and foam insulating materials can be used to achieve this insulation. Similarly, ceilings and floors can also be insulated.

An insulation cavity in a building wall can be defined between upper and lower plates and between adjacent wall studs. In a ceiling, an insulation cavity can be defined between two rafters, an eave strut, and a crest or peak strut. The structure of a floor can define an insulation cavity between floor joists. An insulation cavity can be filled with a variety of different kinds of insulation. In one method for insulating an insulation cavity, insulation particles or loose-fill insulation is mixed with adhesive and blown or sprayed into the insulation cavity.

It can be desirable to the fill insulation cavities with insulation prior to the enclosure of the insulation cavities so that walls or other coverings such as ceilings or flooring need not be punctured. A retaining material, such as for example netting can be placed over the insulation cavities prior to the blowing/spraying to retain the loose-fill insulation in the insulation cavity during filling. After the insulation cavities are filled, a vapor barrier can be placed over the netting and the remaining wall or other coverings can be installed over the netting and the vapor barrier.

It would be advantageous to provide a vapor barrier that is easier to use.

SUMMARY OF THE INVENTION

A vapor barrier is provided for sealing an interior of a building from an insulation cavity defined by structural members of the building. The vapor barrier includes a flexible and substantially impermeable sheet having apertures to allow air to exit the insulation cavity during filling of the insulation cavity with loose fill insulation. The vapor barrier also includes one-way valves mounted across the apertures. The valves are configured to allow air flow out of the insulation cavity and into the building interior through the apertures and to prevent air flow and moisture diffusion from the building interior into the insulation cavity.

According to the invention there is also provided a method for insulating a building. The method includes the step of applying a flexible and substantially impermeable sheet to an interior side of a building wall structure. The method also includes the step of directing loose fill insulation into an insulation cavity defined in part by the framing members and by the flexible and impermeable sheet after the applying step. The method also includes the step of allowing air to escape from the insulation cavity during the directing step though a one-way valve mounted to the flexible and impermeable sheet.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Referring now toFIG. 1, a wall frame10of a building can include an upper plate12, a lower plate14, and wall studs16,18,20. The perspective ofFIG. 1is from the inside of the building. A wall22closes an exterior side of the wall frame10. The wall22, the upper plate12, the lower plate14, and the wall studs16,18define five sides of a six-sided insulation cavity24. The wall22, the upper plate12, the lower plate14, and the wall studs18,20define five sides of a second six-sided insulation cavity26. The sixth sides of the respective insulation cavities24,26are defined by a sheet28. The exemplary sheet can be clear, allowing the interior of the insulation cavities24,26to be visible. The insulation cavity26is shown filled with loose-fill insulation and the insulation cavity24is shown with loose-fill insulation being introduced into the cavity24. The sheet28can be connected to the wall frame10through staples, adhesive, clips, or other suitable mechanisms.

The sheet28is part of an exemplary vapor barrier30according to one embodiment. The exemplary vapor barrier30also includes valves38and filters52, which will be described in greater detail below. The vapor barrier30is operable to seal an interior of a building from an insulation cavity defined by structural members of the building. In the illustrated embodiment, the sheet28of the vapor barrier30is substantially flexible and substantially impermeable to water vapor.

Referring now toFIGS. 2-4, the sheet28includes apertures32to allow a flow of air to exit the insulation cavities24,26(shown only inFIG. 1) while the insulation cavities24,26are filled with loose fill insulation. As best shown inFIG. 3, the air flow represented by arrows34,36will be directed toward the sheet28during filling of the insulation cavity24. The air flow represented by arrow34is blocked by the sheet28. The air flow represented by arrow36can pass through the aperture32to evacuate the insulation cavity24.

The vapor barrier30also includes one-way valves38mounted in the apertures32. The valves38are configured to allow air flow out of the insulation cavity and into the interior through the apertures32and to prevent air flow from the interior into the insulation cavities. As best shown inFIG. 3, air flow represented by arrow40is blocked by the valve38from entering the insulation cavity24.

As shown by theFIGS. 3-4, valves38can be flapper valves38. Each flapper valve38includes a valve sheet43. As clearly shown inFIGS. 3 and 4, the valve sheet43is flexible and valve sheet43is self-supporting, that is, the valve sheet43is not attached to or supported by any form of frame or framework. Each valve sheet43can extend between a base end42fixed to the sheet28and a distal end44. The distal end44of the valve sheet43is moveable between a first position in contact with the sheet28(a closed position) and a second position spaced from the sheet28(an open position).FIG. 4shows a first corner46of the distal end44in the first position and a second corner48of the distal end44in the second position.FIG. 3shows the distal end44in the second position.

As shown inFIG. 4, the base end42can be fixed to the sheet28through a seam weld50. The base end42can also be fixed to the sheet28through adhesive, clips, clamps, or other suitable mechanisms. The exemplary connection between the base end42and the sheet28is a discontinuous straight line, but the broader invention is not so limited. The base end28can be fixed to the sheet28along a continuous connection. Alternatively, the base end28can be fixed to the sheet28along an arcuate connection, such as a line of adhesive extending less than fully around the aperture32. Alternatively, the base end28can be fixed to the sheet28through other suitable connections.

Optionally, the distal end44can be statically charged such that the distal end44and the sheet28are normally drawn together to seal the aperture32. In operation, as the flow of air is evacuating the insulation cavity24, the distal end44can be positioned as shown inFIG. 3. After the insulation cavity24is filled, the distal end44can be drawn back into contact with the sheet28substantially immediately after air pressure in the insulation cavity24has lowered to ambient pressure or less. The valve38can be configured so that gravity will close the valve38if charging the sheet28or the valve38is not used.

It is noted that flapper valves38can be desirable based on their simple design. The flapper valves38can also be desirable because they can be made flat and won't interfere with subsequently applied drywall. However, the broader invention is not limited to being practiced with flapper valves. Other concerns may exist in other operating environments in which other embodiments can be practiced having valves of different form and/or operation. Embodiments can be practiced with diaphragm check valves in which a diaphragm plastically deforms in response to a predetermined level of pressure to allow an air flow in one direction. The diaphragm check valve could then revert to a static shape and thus close when the pressure has subsided. Poppet or ball check valves can also be used if desirable. It is also noted that embodiments can be practiced in which different types of valves are applied in different apertures on a single sheet.

In another alternative embodiment the valve38and the sheet28can be formed from different materials. For example, the valve38can be formed from nylon and the sheet28can be formed from other desired vapor barrier materials, such as but not limited to aluminum foil, paper-backed aluminum, polyethylene, asphalt-coated kraft paper. The valves38can have a water vapor diffusion resistance that varies in relation to ambient humidity. For example, the valves38can be formed from the material disclosed in U.S. Pat. No. 6,808,772, which is hereby incorporated by reference. This material can allow an acceptable level of humidity transfer between the interior of the building and the insulation cavities while, at the same time, prevent undesirable air flow.

Generally, water vapor can move in and out of a building by diffusion and by air transport. The movement of water vapor by diffusion is dependent on the permeability of the structures defining the vapor barrier for the building. Permeability is rated in perms and is a measure of the rate of transfer of water vapor through the material. The equation for the permeability of a material of predetermined thickness is:
P=G/(A*T*P)

The component G represents the amount of water vapor in grains that pass through the material. One pound is equal to seven thousand grains. The component A represents the area in square feet over which the water vapor diffuses. The component T represents the time in hours over which diffusion occurs. The component G represents the pressure during diffusion in inches of mercury. The perm rating is identified in conjunction with the thickness of the material.

The exemplary vapor barrier30can be an air barrier that prevents the passage of water vapor by air transport. The exemplary vapor barrier30can also resist the diffusion of water vapor. The exemplary vapor barrier30can have a permeability rating of under 10 perms. The individual components of the exemplary vapor barrier30can define the same perm rating or can define different perm ratings. As set forth above, the valves38can be formed from a material having a water vapor diffusion resistance that varies in relation to ambient humidity. The sheet28can also be formed from a material having a water vapor diffusion resistance that varies in relation to ambient humidity.

The exemplary vapor barrier30optionally can also include filters52mounted on the sheet28and extending across the apertures32. As best shown inFIG. 3, the filter52can prevent particles54of loose-fill insulation from escaping the insulation cavity24when the flow of air evacuates during filling. The filters52can be made from any desired material or combination of materials. The filters52can be made from paper and can be pleated or unpleated. The filters52can made from woven or clumped plastic fibers. The filters52can be made from foam, cotton, or any other suitable material for filtering the flow of air evacuating the insulation cavity24.

In the exemplary embodiment, the filters52and the valves38can be mounted to the sheet28on opposite sides relative to one another. In other embodiments, the filters52and the one-way valves38can be mounted on the same side of the sheet28. The filters52can be mounted to the sheet28using any suitable approach, including but not limited to sonic welding and adhesive.

The filters52can be integral with one another. As best shown inFIG. 2, exemplary filters52can be defined by one of three strips56,58,60of filter material. Forming the filters52from strips of filter material can be desirable in that strips of material can enhance the strength of the vapor barrier30in holding the loose-fill insulation in the insulation cavity24.

It is noted that the apertures32can be formed in any shape and any number of apertures32can be formed in the sheet28. The apertures32can be arranged in any pattern or can be arranged in a random arrangement. The exemplary apertures32are arranged in top, middle and bottom rows76,78,80(referenced inFIG. 2). It is noted that the alternative embodiments can be practiced without the apertures32arranged in rows or with apertures32arranged in a different number of rows.

In operation, a nozzle or hose74(shown inFIG. 1) for injecting loose fill insulation can be inserted in an aperture32(shown inFIG. 2) of the middle row78(shown inFIG. 2) of apertures32and pierce the middle strip58(shown inFIG. 2) of filter material. As loose-fill insulation is received in the insulation cavity24, air can evacuate through the top row76(shown inFIG. 2) of apertures32, the bottom row80(shown inFIG. 2) of apertures32, and the apertures32of the middle row78(shown inFIG. 2) that communicate with the insulation cavity24(except the aperture32through which the nozzle extends). Thus, the insulation cavity24can be enclosed with a single flexible structure operable to both retain the loose fill insulation and define an impermeable vapor barrier.

FIG. 5is a simplified schematic of a building62. Insulation cavities64,66,68,70,72,74can be defined in the roof, the ceiling, the floor, and the walls, respectively. Embodiments of the invention, disclosed above or subsequently developed, can be applied to any of the insulation cavities64,66,68,70,72,74.

FIG. 6shows an alternative embodiment of the invention. The exemplary vapor barrier30inFIG. 6includes a sheet28, a valve38and a filter52. The valve38and the filter52can be coupled together prior to being mounted across an aperture32on the sheet28. During assembly, the valve38and the filter52can be connected together through a quantity of adhesive82. Methods other than the application of adhesive can be applied to connect the filter52and the valve38. The coupled valve38and filter52can then be mounted to the same side of the sheet. The valve38can be connected to the sheet28through a quantity of adhesive84. Methods other than the application of adhesive can be applied to connect the sheet28and the valve38. The filter52can be connected to the sheet28through first and second quantities of adhesive86,88. Methods other than the application of adhesive can be applied to connect the sheet28and the filter52. The filter52can be connected to the sheet28such that the connection is continuous about a perimeter of the aperture32so that all of the air passing out of the aperture is directed through the filter52. The perimeter of the valve38can surround the perimeter of the filter52so that the valve38fully covers the filter when in the valve38is in the closed position.

The principle and mode of operation of the invention have been described in its preferred embodiments. However, it should be noted that the invention may be practiced otherwise than as specifically illustrated and described without departing from its scope.