Insulation-retaining sheet having integral vapor-retarding membrane

1. An insulation-retaining sheet having a top edge and an opposed bottom edge, and a first side edge and an opposed second side edge, the insulation-retaining sheet comprising:

a sheet of mesh having an air permeability of at least 200 cfm per square foot, a top edge and an opposed bottom edge, and a first side edge and an opposed second side edge; and

one or more strips of vapor-retarding membrane, each of the one or more strips of vapor retarding membrane each having a top edge and an opposed bottom edge, and a first side edge and an opposed second side edge, the one or more strips of vapor-retarding membrane being laminated to the sheet of mesh, the first side edge each of the strips of vapor-retarding membrane extending to the first side edge of the sheet of mesh, the second side edge each of the strips of vapor-retarding membrane extending to the second side edge of the sheet of mesh,

wherein the insulation-retaining sheet has a plurality of open zones extending laterally from the first side edge of the sheet of mesh to the second side edge of the sheet of mesh in which no vapor-retarding membrane is laminated to the mesh.

2. The insulation-retaining sheet according to claim 1 , wherein the mesh is a fabric mesh.

3. The insulation-retaining sheet according to claim 1 , wherein the vapor-retarding membrane has a water vapor permeance of no more than about 1 Perm at 25% relative humidity, as tested by ASTM E96 at 23° C., and a water vapor permeance of at least 2 perms at 75% relative humidity as tested by ASTM E96 at 23° C.

4. The insulation-retaining sheet according to claim 1 , wherein the vapor retarding membrane has one or more of a) a water vapor permeance of no more than 5 perms at 45% relative humidity, and b) a water vapor permeance of at least about 5 Perms at 95% relative humidity, both as tested by ASTM E96 at 23° C.

5. The insulation-retaining sheet according to claim 1 , wherein the vapor-retarding membrane is a polymer sheet, a polymer laminate, or comprises a sheet having a vapor-retarding coating formed thereon.

6. The insulation-retaining sheet according to claim 1 , comprising in the range of 2-10 strips of vapor-retarding membrane.

7. The insulation-retaining sheet according to claim 1 , wherein the one or more open zones include a top open zone extending along the top edge of the insulation-retaining membrane and a bottom open zone extending along the bottom edge of the insulation-retaining membrane.

8. The insulation-retaining sheet according to claim 1 , wherein the one or more open zones include one or more interior open zones extending across the sheet of mesh between its top edge and its bottom edge.

9. The insulation-retaining sheet according to claim 1 , wherein each of the strips of vapor-retarding membrane is laminated to the sheet of mesh substantially throughout its height.

10. The insulation-retaining sheet according to claim 1 , wherein the one or more strips of vapor retarding membrane comprise one or more first strips of vapor retarding membrane, each having

a top zone in a top-most portion of the first strip, the top zone extending from the first side edge to the second side edge of the first strip, the top zone being laminated to the sheet of mesh, and

a bottom zone in a bottom-most portion of the first strip adjacent the top portion of the first strip, the bottom zone extending from the first side edge to the second side edge of the first strip, the bottom zone not being affixed to the sheet of mesh, the bottom zone forming a flap having a bottom edge, a first side edge and an opposed second side edge.

11. The insulation-retaining sheet according to claim 1 , wherein each of the strips of vapor retarding membrane has a height of at least 15 inches.

12. The insulation-retaining sheet according to claim 1 , wherein each of the open zones has a height in the range of 1-24 inches.

13. The insulation-retaining sheet according to claim 1 , wherein at least 5% of the area of the insulation-retaining sheet is open zones.

14. The insulation-retaining sheet according to claim 13 , wherein no more than 30% of the area of the insulation-retaining sheet is open zones.

15. The insulation-retaining sheet according to claim 1 , wherein the insulation-retaining sheet has one or more apertures formed therein.

16. A method of insulating one or more building cavities, the method comprising:

providing one or more building cavities, each having an open face defined at least in part by a plurality of building members;

substantially enclosing the one or more building cavities with an insulation-retaining sheet according to claim 1 by affixing the insulation-retaining sheet to the plurality of building members; and then

blowing insulation into the one or more building cavities such that the insulation is retained in the cavity by the insulation-retaining sheet.

17. The method of claim 16 , wherein the insulation is blown into each of the one or more cavities through an aperture in the insulation-retaining sheet.

18. The method of claim 16 , wherein the method further comprises, after blowing the insulation into the one or more cavities, covering one or more of the open zones.

19. An insulated building cavity, the insulated building cavity comprising

a building cavity closed off on one face by an insulation-retaining sheet according to claim 1 ; and

loose-fill insulation disposed in the building cavity and retained in the building cavity by the insulation-retaining sheet.

20. The insulated building cavity according to claim 19 , wherein each of one or more of the open zones of the insulation-retaining sheet is covered by a flap, by a separate strip of material, by a separate strip of insulating material, or by a strip of adhesive tape.