Roofing shingles and methods for installing and making them

1. A roofing shingle having a top surface and a bottom surface, the roofing shingle having an exposure zone at a lower end of the top surface thereof and a headlap zone at an upper end thereof, the roofing shingle comprising:

a first bituminous sheet providing the bottom surface of the shingle in the exposure zone thereof, the first bituminous sheet having a top surface and a bottom surface, the first bituminous sheet having a lower edge disposed at the lower end of the roofing shingle, the first bituminous sheet having one or more slits formed therein, each of the one or more slits extending from the lower edge of the first bituminous sheet toward the upper end of the roofing shingle; and

a second bituminous sheet having a top surface and a bottom surface, the bottom surface of the second bituminous sheet being at least partially laminated to the top surface of the first bituminous sheet by a meltable adhesive, the second bituminous sheet having a lower edge disposed at the lower end of the roofing shingle, the second bituminous sheet having one or more tabs formed in the exposure zone of the shingle, the one or more tabs being defined by one or more notches formed in the second bituminous sheet, each notch extending away from the lower edge of the second bituminous sheet,

wherein each of the at least one or more slits of the first bituminous sheet is covered by the second bituminous sheet.

2. The roofing shingle of claim 1 , wherein one or more of the at least one slits covered by the second bituminous sheet is covered by a respective tab of the one or more tabs of the second bituminous sheet.

3. The roofing shingle of claim 1 , wherein each of the one or more slits of the first bituminous sheet has a width of no more than 2 mm.

4. The roofing shingle of claim 1 , wherein each of the one or more slits of the first bituminous sheet extends at least 2 inches from the lower edge of the first bituminous sheet toward an upper edge of the first bituminous sheet.

5. The roofing shingle of claim 1 , wherein each of the one or more slits of the first bituminous sheet extends throughout the exposure zone toward the upper end of the roofing shingle.

6. The roofing shingle of claim 1 , wherein each of the one or more slits of the first bituminous sheet extends toward the upper end of the roofing shingle at least as far as a closest notch of the second bituminous sheet thereto extends toward the upper end of the roofing shingle.

7. The roofing shingle of claim 1 , wherein each of the one or more slits of the first bituminous sheet extends toward the upper end of the roofing shingle in the range of 0.4 to 0.8 times the distance from the lower end of the shingle to an upper edge of a closest notch of the second bituminous sheet thereto.

8. The roofing shingle of claim 7 , wherein the lower edge of the second bituminous sheet does not extend beyond the lower edge of the first bituminous sheet by more than 1 cm.

9. The roofing shingle of claim 1 , wherein the first bituminous sheet does not extend to the upper end of the roofing shingle.

10. The roofing shingle of claim 1 , wherein the first bituminous sheet comprises in the range of 2-6 slits.

11. The roofing shingle of claim 1 , wherein at least one of the one or more notches of the second bituminous sheet has a width of at least 5 centimeters.

12. The roofing shingle of claim 1 , wherein the one or more slits of the first bituminous sheet are substantially different from the notches of the second bituminous sheet.

13. The roofing shingle of claim 1 , wherein the lower edge of each of the first bituminous sheet and the second bituminous sheet is within 1 cm of the lower edge of the shingle.

14. A roof comprising a roof deck having an upper end and a lower end, and a plurality of roofing shingles of claim 1 , disposed thereon, the roofing shingles being disposed in a first course of a first plurality of the shingles and a second course of a second plurality of the shingles, the second course of shingles overlapping the headlap zones of the shingles of the first course of shingles, the headlap zones of the roofing shingles being disposed toward the upper end of the roof and the exposure zones of the roofing shingles being disposed toward the lower end of the roof.

15. A method for making a shingle according to claim 1 , the method comprising either

a)

providing

a first bituminous sheet having a lower edge disposed at the lower end of the roofing shingle, the first bituminous sheet having one or more slits formed therein, each of the one or more slits extending from the lower edge of the first bituminous sheet toward the upper end of the first bituminous sheet; and

a second bituminous sheet having a lower edge, the second bituminous sheet having one or more tabs formed in an exposure zone, the one or more tabs being defined by one or more notches formed in the second bituminous sheet, each notch extending away from the lower edge of the second bituminous sheet; and

at least partially laminating the second bituminous sheet to a top surface of the first bituminous sheet to form the roofing shingle; or

b)

providing a roofing shingle having a bottom surface, the roofing shingle having an exposure zone at a lower end thereof and a headlap zone at an upper end thereof, the roofing shingle comprising

a first bituminous sheet disposed at the bottom surface of the shingle in the exposure zone thereof, the first bituminous sheet having a lower edge disposed at the lower end of the roofing shingle; and

a second bituminous sheet at least partially laminated to a top surface of the first bituminous sheet, the second bituminous sheet having a lower edge disposed at the lower end of the roofing shingle, the second bituminous sheet having one or more tabs formed in the exposure zone of the shingle, the one or more tabs being defined by one or more notches formed in the second bituminous sheet, each notch extending away from the lower edge of the second bituminous sheet; and

forming one or more slits in the first bituminous sheet, each of the one or more slits extending from the lower edge of the first bituminous sheet toward the upper end of the roofing shingle.

16. A roofing shingle having a top surface and a bottom surface, the roofing shingle having an exposure zone at a lower end thereof and a headlap zone at an upper end thereof, the roofing shingle comprising:

a first bituminous sheet providing the bottom surface of the shingle in the exposure zone thereof, the first bituminous sheet having a top surface and a bottom surface, the first bituminous sheet having a lower edge disposed at the lower end of the roofing shingle, the first bituminous sheet having one or more slits formed therein, each of the one or more slits extending from the lower edge of the first bituminous sheet toward the upper end of the roofing shingle; and

a second bituminous sheet having a top surface and a bottom surface, the bottom surface of the second bituminous sheet being at least partially laminated to the top surface of the first bituminous sheet, the second bituminous sheet having a lower edge disposed at the lower end of the roofing shingle, the second bituminous sheet having one or more tabs formed in the exposure zone of the shingle, the one or more tabs being defined by one or more notches formed in the second bituminous sheet, each notch extending away from the lower edge of the second bituminous sheet,

wherein each of the at least one or more slits of the first bituminous sheet is aligned along a lateral edge of a notch of the second bituminous sheet, wherein each of the one or more slits of the first bituminous sheet has a width of no more than 2 mm.