Patent Application
20100319275
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.
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.
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.
Various advantages of this invention 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.
Referring now to
The sheet 28 is part of an exemplary vapor barrier 30 according to one embodiment. The exemplary vapor barrier 30 also includes valves 38 and filters 52, which will be described in greater detail below. The vapor barrier 30 is operable to seal an interior of a building from an insulation cavity defined by structural members of the building. In the illustrated embodiment, the sheet 28 of the vapor barrier 30 is substantially flexible and substantially impermeable to water vapor.
Referring now to
The vapor barrier 30 also includes one-way valves 38 mounted in the apertures 32. The valves 38 are configured to allow air flow out of the insulation cavity and into the interior through the apertures 32 and to prevent air flow from the interior into the insulation cavities. As best shown in
As shown by the
As shown in
Optionally, the distal end 44 can be statically charged such that the distal end 44 and the sheet 28 are normally drawn together to seal the aperture 32. In operation, as the flow of air is evacuating the insulation cavity 24, the distal end 44 can be positioned as shown in
It is noted that flapper valves 38 can be desirable based on their simple design. The flapper valves 38 can 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 valve 38 and the sheet 28 can be formed from different materials. For example, the valve 38 can be formed from nylon and the sheet 28 can 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 valves 38 can have a water vapor diffusion resistance that varies in relation to ambient humidity. For example, the valves 38 can 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 barrier 30 can be an air barrier that prevents the passage of water vapor by air transport. The exemplary vapor barrier 30 can also resist the diffusion of water vapor. The exemplary vapor barrier 30 can have a permeability rating of under 10 perms. The individual components of the exemplary vapor barrier 30 can define the same perm rating or can define different perm ratings. As set forth above, the valves 38 can be formed from a material having a water vapor diffusion resistance that varies in relation to ambient humidity. The sheet 28 can also be formed from a material having a water vapor diffusion resistance that varies in relation to ambient humidity.
The exemplary vapor barrier 30 optionally can also include filters 52 mounted on the sheet 28 and extending across the apertures 32. As best shown in
In the exemplary embodiment, the filters 52 and the valves 38 can be mounted to the sheet 28 on opposite sides relative to one another. In other embodiments, the filters 52 and the one-way valves 38 can be mounted on the same side of the sheet 28. The filters 52 can be mounted to the sheet 28 using any suitable approach, including but not limited to sonic welding and adhesive.
The filters 52 can be integral with one another. As best shown in
It is noted that the apertures 32 can be formed in any shape and any number of apertures 32 can be formed in the sheet 28. The apertures 32 can be arranged in any pattern or can be arranged in a random arrangement. The exemplary apertures 32 are arranged in top, middle and bottom rows 76, 78, 80 (referenced in
In operation, a nozzle or hose 74 (shown in
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.
